# Top Car Audio Myths...



## J0ne (Aug 7, 2007)

Happy turkey day friends. 

Just pondering what are the top car audio related myths. not particularly looking for explanations that bust the myth, just the general idea. I will be doing write-ups in my own words debunking each of the myths on my website.

juts a few:
Max Power
Boxes/Enclosures
Speakers/subwoofers-size, quantity, ohm, driver placement
Dimming lights
Power Wire
Rattling-(the myth is that rattling sounds cool...which it certainly does not)

thanks for your input.


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## shadowfactory (Oct 20, 2008)

Alternator whine being all electrical noise in every system.
$150 RCA's being "a strong link in the signal chain."


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## unpredictableacts (Aug 16, 2006)

Bigger is Better.
DVC is going to be louder than SVC.


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## ItalynStylion (May 3, 2008)

Anything concerning clipping...


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## ///Audience (Jan 31, 2007)

12" subs will hit lows better but be slower than a 10".....?
Buying expensive equipment creates a good sound system.
more speakers are better
rear speakers make the sound "fuller"


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## michaelsil1 (May 24, 2007)

BassBaller5 said:


> Buying expensive equipment creates a good sound system.


x2


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## 14642 (May 19, 2008)

Damping factor
Sealed boxes increase damping and control
High end wire of any kind


and the best one of all:

cars sound better without EQ


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## Nelson de Leon (May 24, 2005)

unpredictableacts said:


> Bigger is Better.
> DVC is going to be louder than SVC.





BassBaller5 said:


> 12" subs will hit lows better but be slower than a 10".....?
> Buying expensive equipment creates a good sound system.
> more speakers are better





Andy Wehmeyer said:


> cars sound better without EQ


These actually depends on the enxlosure design and how you install your system.


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## 14642 (May 19, 2008)

Nelson de Leon said:


> These actually depends on the enxlosure design and how you install your system.


No, they don't.


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## Nelson de Leon (May 24, 2005)

Andy Wehmeyer said:


> No, they don't.


Yup, they gon't, given equal parameters.


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## robspeed325i (Nov 8, 2008)

that damping factor and slew rate dont matter.


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## bafukie (Nov 23, 2007)

opening a can of 'cable' worm


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## ChrisB (Jul 3, 2008)

More myths to bust:

Techflex adds mad Deebeez!

Tspence73 NEVER had Violent Bass Air!

JL Audio is the end all subwoofer

The JL Audio W3 series is a GREAT series

JL Audio amps are horribly underrated (This stems from a kid trying to tell me that his 500/1 puts out 950 watts RMS @ 2 ohms)

Capacitors actually help

All 12 volt amplifiers sound the same because a watt is a watt

Sealed boxes produce better SQ than ported with the same drivers

That is all I can think of right now!


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## AAAAAAA (Oct 5, 2007)

That old school is always better.
That old school is last year's product line.


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## [email protected] (Jun 12, 2008)

robspeed325i said:


> that damping factor and slew rate dont matter.


I am with this one here


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## Kpg2713 (Feb 10, 2008)

06BLMUSTANGGT said:


> More myths to bust:
> 
> Techflex adds mad Deebeez!
> 
> ...


Dude, you really want to make this one of "those" threads? Lets leave the amp sound or lack there of out of it, plz.


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## ItalynStylion (May 3, 2008)

Kpg2713 said:


> Dude, you really want to make this one of "those" threads? Lets leave the amp sound or lack there of out of it, plz.


Isn't that what this thread is about? All the myth/debates?


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## ChrisB (Jul 3, 2008)

Kpg2713 said:


> Dude, you really want to make this one of "those" threads? Lets leave the amp sound or lack there of out of it, plz.


That is one of the top car audio myths, isn't it?

Ever hear of the Richard Clark challenge?


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## quality_sound (Dec 25, 2005)

^^^Exactly. If all amps sounded the same he wouldn't have to EQ them to have the same response before the test. 

Mine is the "distortion or clipping kills speakers" crap.


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## ca90ss (Jul 2, 2005)

sq amps

claiming your 6.5" "midbass" has good output crossed at 50hz

low midbass/sub crossover point required for up front bass 

df and slew rate matter


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## ItalynStylion (May 3, 2008)

quality_sound said:


> ^^^Exactly. If all amps sounded the same he wouldn't have to EQ them to have the same response before the test.
> 
> Mine is the "distortion or clipping kills speakers" crap.


I was always under the impression that clipping to an extreme extent could damage a speaker. Basically, I was told that it's a principle of the same peak power but more power over time because the peak power is held for much much longer.

....or that was the way it was explained to me. :blush:


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## quality_sound (Dec 25, 2005)

ItalynStylion said:


> I was always under the impression that clipping to an extreme extent could damage a speaker. Basically, I was told that it's a principle of the same peak power but more power over time because the peak power is held for much much longer.
> 
> ....or that was the way it was explained to me. :blush:


Exactly. It's not the clipping that's doing the damage. It's the extra power over time that does it, just like if you overpowered it with an unclipped signal. Either way you've exceeded the driver's thermal limits.


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## J0ne (Aug 7, 2007)

Autiophile said:


> Tuning is easy.
> Fabrication is hard.
> Drivers must be designed for car use.
> You must adhere to manufacturer recommended uses, alignments.
> ...


great article thanks.


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## unpredictableacts (Aug 16, 2006)

People that live in arkansas do not wear shoes.
The more exotic your baffle material the better your mids will sound.
2 way active is easier to accomplish than 3 way active.
....and my most personal favorite......turning up the Gain on the amplifier =turnig up the amplifiers volume.


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## drtool (Nov 26, 2007)

If your amp is rated at 300 w and your speaker is rated at 200 peak you will blow your speaker.


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## It_Hertz (Mar 4, 2008)

you must run RCA's and power on oppsite sides of the vehicle.


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## unpredictableacts (Aug 16, 2006)

It_Hertz said:


> you must run RCA's and power on oppsite sides of the vehicle.


LOL I always do this even after being told there is no need to......Just incse I do have noice problems I will not have 52 people telling me that that is my problem. I also shake the milk before pouring a glass....My wife used to say that I was going to keep doing it and turn it into butter.....no butter yet.


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## WrenchGuy (Jun 10, 2007)

Under powering a subwoofer will ruin it.


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## ChrisB (Jul 3, 2008)

unpredictableacts said:


> People that live in arkansas do not wear shoes.
> The more exotic your baffle material the better your mids will sound.
> 2 way active is easier to accomplish than 3 way active.
> ....and my most personal favorite......turning up the Gain on the amplifier =turnig up the amplifiers volume.


Dang it, now you are making me think of that Robot Underground quote... I am going to look it up so I can QFT!

ETA - Here we go and QFT:

"Wrency says:

Remember kids that your amp, especially a class D mono block amp will run full power into a 2 ohm load even though its 1ohm stable or states that it produces full power into a 1ohm load.. I know, this goes against what everyone says, but it's true. Simply adjust the gain properly to the 2ohm load and PRESTO, full power. If you want more info on this please email, [email protected] Remember that an amp is simply a gain device. Signal in plus whatever +db gain the amp can do = output."


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## Nelson de Leon (May 24, 2005)

It_Hertz said:


> you must run RCA's and power on oppsite sides of the vehicle.


I think this is standard practice for installers and DIYers, otherwise, more often than not, you'll run into static problems.


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## Nelson de Leon (May 24, 2005)

Autiophile said:


> 10 Biggest Lies in Audio:
> http://www.theaudiocritic.com/downloads/article_1.pdf


We've had a lengthy discussion here about these myths. Allow me to post and share the link:

http://www.kotseaudioclub.com/forum/viewtopic.php?f=19&t=14041


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## ~thematt~ (Sep 14, 2007)

The biggest myth?
That you actually need to know what you are talking about before people online believe you. 


> http://www.theaudiocritic.com/downloads/article_1.pdf


Like this. This guy debunks 'myths' using scoff and cynasism. No an IOTA of scientific proof. I'm not saying he's right or wrong, just that he uses nothing to back him up.


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## quality_sound (Dec 25, 2005)

Nelson de Leon said:


> I think this is standard practice for installers and DIYers, otherwise, more often than not, you'll run into static problems.


It's standard practice because it's easier, not because of any noise issues.


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## FbodyAudio (Nov 26, 2008)

An amp is always delivering it's rated RMS power to the speakers, regardless of the music or volume setting.


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## Hillbilly SQ (Jan 26, 2007)

If you have a speaker that's used to big power it won't like lower power cuz it's used to the high power.


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## Hillbilly SQ (Jan 26, 2007)

ca90ss said:


> claiming your 6.5" "midbass" has good output crossed at 50hz


Gonna have to play devils advocate on this one. "Good output" is completely subjective. To me "good output" is being able to stay linear at a volume that makes it difficult to hear yourself talk. Others call "good output" BARELY loud enough to be heard over mild road noise. With a REAL set of tires (streetslicks that's get you stuck in wet grass don't count) you're gonna have road noise. How much of that noise you intend on drowning out is up to you


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## ca90ss (Jul 2, 2005)

Hillbilly SQ said:


> Gonna have to play devils advocate on this one. "Good output" is completely subjective. To me "good output" is being able to stay linear at a volume that makes it difficult to hear yourself talk. Others call "good output" BARELY loud enough to be heard over mild road noise. With a REAL set of tires (streetslicks that's get you stuck in wet grass don't count) you're gonna have road noise. How much of that noise you intend on drowning out is up to you


While I'll agree that "loud" is subjective lets take a look at the Dyn mw162 for example








Looks like it's capable of just under 88db at 50hz mounted IB and add 3db for the 2nd driver receiving an equal amount of power so that's 91db. Depending on cabin gain you might be able to add a couple db to that number but still, I have a hard time believing that ~90-95db at 50hz is enough to be considered loud by too many people and it's definitely not enough for me to consider it loud.


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## thehatedguy (May 4, 2007)

A couple? Most cars I've tuned need about 8-10 dB of cut in the 40-50 range.

But I do agree with you.


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## squeak9798 (Apr 20, 2005)

ca90ss said:


> Looks like it's capable of just under 88db at 50hz mounted IB and add 3db for the 2nd driver receiving an equal amount of power so that's 91db.


That would theoretically be a _6__db_ increase as you are doubling displacement.

Myths I see a lot;

 You need to break in your speakers or subwoofers for an arbitrary period of time at an arbitrary volume level ("I keep it below half volume for the first 10 hours then below 2/3 volume for another 48 hours")
 A higher preamp voltage has better sound quality
 Underpowering damages speakers
 Distortion [in and of itself] damages speakers
 Smaller subs inherently play higher or sound better than larger subs
 Smaller subs are "faster" or "tighter" than larger subs
 Running your RCA's (or any other wire, for that matter) opposite from the power wire
 A y-splitter splits the voltage


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## ca90ss (Jul 2, 2005)

squeak9798 said:


> That would theoretically be a _6__db_ increase as you are doubling displacement.





Eric Stevens said:


> This is a common misunderstanding. You do not gain +3dB of system efficiency every time you double the cone area.
> 
> If you have 1, 2, 4, or 8 speakers the nominal splo at 1 watt is still the *same *regardless of how many drivers you have reproducing the sound.
> 
> ...


....


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## killerb87 (Oct 24, 2008)

squeak9798 said:


> That would theoretically be a _6__db_ increase as you are doubling displacement.
> 
> Myths I see a lot;
> 
> ...


distortion does kill speakers, harmonic distortion. odd order harmonics at clipping increase power dramaticly. the first odd order harmonic will add over 33 watts to a 100 watt amp, the second odd order 20 watts and so on. just in the first 2 harmonics thats over 50 watts. thats alot of extra heat for a speaker to disipate. thats what kills drivers.


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## ca90ss (Jul 2, 2005)

killerb87 said:


> distortion does kill speakers, harmonic distortion. odd order harmonics at clipping increase power dramaticly. the first odd order harmonic will add over 33 watts to a 100 watt amp, the second odd order 20 watts and so on. just in the first 2 harmonics thats over 50 watts. thats alot of extra heat for a speaker to disipate. thats what kills drivers.


It's not the distortion, it's the extra power. You can take a 10 watt amp and hook it up to a 1000w sub and clip it as much you want and you still won't blow the sub.


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## ItalynStylion (May 3, 2008)

ca90ss said:


> It's not the distortion, it's the extra power. You can take a 10 watt amp and hook it up to a 1000w sub and clip it as much you want and you still won't blow the sub.


No one will argue against that. But the point is that if the extra power is caused by the distortion it was the distortion that was the extra variable that caused the failure to happen. If the distortion was not there everything would have been peachy.


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## Viperoni (Oct 14, 2006)

ItalynStylion said:


> No one will argue against that. But the point is that if the extra power is caused by the distortion it was the distortion that was the extra variable that caused the failure to happen. If the distortion was not there everything would have been peachy.


Is the power level really increasing, or is it simply the same amount of power applied for a longer period of time?

IE: a signal that is 15vac peak to peak gets clipped to look more like 15vdc peak to peak is still 15v peak to peak... but there's more current being applied for a longer period of time.


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## ca90ss (Jul 2, 2005)

ItalynStylion said:


> No one will argue against that. But the point is that if the extra power is caused by the distortion it was the distortion that was the extra variable that caused the failure to happen. If the distortion was not there everything would have been peachy.


So what if we added the extra power without any distortion? Would the driver all of a sudden not blow? It's just as easy to blow a speaker with too much "clean" power.


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## ErinH (Feb 14, 2007)

ca90ss said:


> So what if we added the extra power without any distortion? Would the driver all of a sudden not blow? It's just as easy to blow a speaker with too much "clean" power.


I was just about to ask about this.

So, how do we justify 'headroom'? I'm easily sending some of my speakers more than rated power and the signal is unclipped (at least, gains were set with oscope, then never went above that point). I'm not talking gobs of extra power, but there is extra power there. ... edit.... now that I think about it, I'm not able to say for sure they always see this extra power when playing music, but I'm pretty sure that the transients see it....

Also, one of our valued members suggests setting amp gains with a -10dB tone because it gives extra dynamics and we can't hear that low level of distortion. <--paraphrasing, so I could be a tad off on rationale here, but it's the general idea suggested.


I was always under the impression that what kills a driver is both electrical and mechanical distortion. Not just one or the other.


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## quality_sound (Dec 25, 2005)

Viperoni said:


> Is the power level really increasing, or is it simply the same amount of power applied for a longer period of time?
> 
> IE: a signal that is 15vac peak to peak gets clipped to look more like 15vdc peak to peak is still 15v peak to peak... but there's more current being applied for a longer period of time.


There is no DC in a clipped signal. Yes the signal gets cropped but the suspension and momentum of the driver keeps it from ever stopping.



bikinpunk said:


> I was always under the impression that what kills a driver is both electrical and mechanical distortion. Not just one or the other.


Erin, barring any outside influences, only two things can kill a speaker. 
1) Exceeding the driver's thermal limits (over powering it)
2) Exceeding the driver's mechanical limits (over driving it)
That's it.


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## ca90ss (Jul 2, 2005)

http://www.audiovisualdevices.com.au/downloads/rane/note128.pdf


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## bigabe (May 1, 2007)

Here's a myth that has been annoying me lately:

diymobileaudio = SQ


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## michaelsil1 (May 24, 2007)

bigabe said:


> Here's a myth that has been annoying me lately:
> 
> diymobileaudio = SQ


There are some of us that are into SQ.


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## bigabe (May 1, 2007)

michaelsil1 said:


> There are some of us that are into SQ.



Ok...

diymobileaudio = SQ and ONLY SQ



I can't tell you how many times I've seen people post things along the lines of, "diymobileaudio is an SQ forum"....

********.

Like SPL guys don't do things themselves???


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## quality_sound (Dec 25, 2005)

No one ever said you can't DIY SPL, but this forum was started as an SQ forum. It wasn't until it was sold and the new owners advertised anywhere with ad space that it shifted.


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## 60ndown (Feb 8, 2007)

all car audio forum members are humble and clever. 

_*myth bitches!*_


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## squeak9798 (Apr 20, 2005)

ca90ss said:


> ....


20*log(2/1) = 6db

Double displacement, gain 6db

Quoting Eric Stevens won't change that.


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## 14642 (May 19, 2008)

squeak9798 said:


> 20*log(2/1) = 6db
> 
> Double displacement, gain 6db


Hmmm...


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## PaulD (Nov 16, 2006)

headroom is for transient peaks, which add very little to the average power. Clipping can double the average power at full clip (100% squre wave)


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## trebor (Jun 30, 2008)

bikinpunk said:


> I was just about to ask about this.
> 
> So, how do we justify 'headroom'? I'm easily sending some of my speakers more than rated power and the signal is unclipped (at least, gains were set with oscope, then never went above that point). I'm not talking gobs of extra power, but there is extra power there. ... edit.... now that I think about it, I'm not able to say for sure they always see this extra power when playing music, but I'm pretty sure that the transients see it....


You want the extra power during transients for increased dynamics. Theyre brief enough the coil(s) will have time to cool in between.



bikinpunk said:


> Also, one of our valued members suggests setting amp gains with a -10dB tone because it gives extra dynamics and we can't hear that low level of distortion. <--paraphrasing, so I could be a tad off on rationale here, but it's the general idea suggested.


It can potentially decrease dynamics but does increase average power, think more average volume. Your right about being unable to notice the distortion during peaks, the idea is to get more from your amp.


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## ItalynStylion (May 3, 2008)

bigabe said:


> Ok...
> 
> diymobileaudio = SQ and ONLY SQ
> 
> ...


We all like bass; no one here will deny that. Bass is a part of SQ though. You own a DD sub so I know you understand. It's not about banging your sub(s) all the time but it's nice to have the potential on tap. 

I still think this is mostly a SQ forum. Not 100% but mostly.


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## vecc205 (Nov 18, 2007)

killerb87 said:


> distortion does kill speakers, harmonic distortion. odd order harmonics at clipping increase power dramaticly. the first odd order harmonic will add over 33 watts to a 100 watt amp, the second odd order 20 watts and so on. just in the first 2 harmonics thats over 50 watts. thats alot of extra heat for a speaker to disipate. thats what kills drivers.


Most music in itself is not perfect sine waves but some of it may be synthesized with added distortions intended to be in the recording. Even instrumental stuff all instruments have a different sound character and thats because of the harmonics they produce and we all know a perfect sine wave doesn't produce any other harmonics except the fundamental frequency. So this would seem to rule out distortion in this sense killing your speakers but I don't think you meant this anyway but thought I would mention it. As long as the signal doesn't overdrive the mechanical limits of the speaker or its thermal limits that is what really counts.


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## 2DEEP2 (Jul 9, 2007)

squeak9798 said:


> 20*log(2/1) = 6db


OK, (log2) * 20= 6.02, OK it's not 6 ??


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## ca90ss (Jul 2, 2005)

squeak9798 said:


> 20*log(2/1) = 6db
> 
> Double displacement, gain 6db
> 
> Quoting Eric Stevens won't change that.



Now I'm 

Eric's 2nd response in that thread
http://www.diymobileaudio.com/forum/showpost.php?p=601598&postcount=198
Chad's response to Eric's response
http://www.diymobileaudio.com/forum/showpost.php?p=601604&postcount=199

After playing around with bassbox a little it seems that adding the 2nd driver with no power increase does add ~3db and then doubling the total power adds another ~3db for ~6db total so it seems I was incorrect in my previous response.


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## killerb87 (Oct 24, 2008)

vecc205 said:


> Most music in itself is not perfect sine waves but some of it may be synthesized with added distortions intended to be in the recording. Even instrumental stuff all instruments have a different sound character and thats because of the harmonics they produce and we all know a perfect sine wave doesn't produce any other harmonics except the fundamental frequency. So this would seem to rule out distortion in this sense killing your speakers but I don't think you meant this anyway but thought I would mention it. As long as the signal doesn't overdrive the mechanical limits of the speaker or its thermal limits that is what really counts.


your right i didnt mean distortion kills them but the byproduct can. a speaker can play distortion all day as long as the thermal or mechanical limits are not exceded. distortion is like a punch. i can take them all day from my niece, but not from mike tyson. well, maybe now i can. same thing with the 1000 watt sub analogy that 100 watt amp wont kill it, but a bigger amp will. if you get knocked out what caused it the fist or the force? both i guess.


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## killerb87 (Oct 24, 2008)

Viperoni said:


> Is the power level really increasing, or is it simply the same amount of power applied for a longer period of time?
> 
> IE: a signal that is 15vac peak to peak gets clipped to look more like 15vdc peak to peak is still 15v peak to peak... but there's more current being applied for a longer period of time.


i do believe its the duration of the peaks.


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## squeak9798 (Apr 20, 2005)

ca90ss said:


> After playing around with bassbox a little it seems that adding the 2nd driver with no power increase does add ~3db and then doubling the total power adds another ~3db for ~6db total


Exactly 

The theoretical difference in output between two displacements (Vd1 & Vd2) is expressed by the equation 20*log(Vd1/Vd2).....which as 2DEEP2 correctly pointed out is 6.*02*db (  ) when the displacement is increased by a factor of 2 (i.e. doubled).


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## FoxPro5 (Feb 14, 2006)

Ensoheavy blockalot in a single layer all over your car on top of 19 layers of foil-tar stickem will make your SPSQLPSQL vehicle quieter than mausoleum.


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## Boyd1184 (Nov 12, 2008)

Everyone has always told me that 12s put out a lower sound than 10s.


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## ClintMJ23 (May 3, 2007)

06BLMUSTANGGT said:


> Capacitors actually help!



They do help, within an amplifier...


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## ClintMJ23 (May 3, 2007)

Boyd1184 said:


> Everyone has always told me that 12s put out a lower sound than 10s.


I think you mean, more low freq output. Assuming we are concering the same line of subs, just different sizes, each in optimal enclosures!


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## tspence73 (Oct 14, 2008)

trebor said:


> You want the extra power during transients for increased dynamics. Theyre brief enough the coil(s) will have time to cool in between.


I think this is a safe assumption.




> It can potentially decrease dynamics but does increase average power, think more average volume. Your right about being unable to notice the distortion during peaks, the idea is to get more from your amp.


I think the reason the "-10db" number was thrown out there is because most modern music is heavily compressed but almost always is at least an average of -10db below the 0db peak during mastering. This means that when any frequency hits 0db, it is usually a split second peak.

I tried this method recently while setting my older brother's system and must now disagree with the -10db advice.

Here is what I found:

My older brother's amp is a Hifonics 5-channel amp rated at 55x4 + 200x1 @ 4-ohms. I did not do this test with a load connected as my previous tests have proven to me that if the math is done properly, the amp DOES NOT NEED A LOAD to be set accurately. 

I first used the -10db test tone disc @ 75% of the HU volume (46 out of 62 on the dial) @ 300Hz and maxed out the speaker outputs' gain and could only reach 7.1 volts (or 13 watts for a 4-ohm speaker). 

Then I put in the 0db test tones and found that same setting (max gain) reached an astounding 30-volts! Outrageous. That would not only be distortion, but very audible as music playback showed.

After further testing I settled on using the 0db test tone disc and chucking the -10db disc, then applying a 19-volt (14.8-volts = rated RMS watts of amp) setting on the speakers and a 34 volt setting for the sub channel (28-volts = RMS rating on that channel). Even with these FAR more conservative settings, I could STILL detect distortion/clipping at a volume setting of 42 creeping in on the music playback. 

My recommendation based on my personal listening tests is that if you are setting the amp for midrange/hi speakers, and only if your amp is running it's RMS right at your speaker's RMS, then it seems good to use 25% more voltage than the RMS of the amp is rated for and your volume will be higher and the distortion will be negligible until you reach the volume point at which you set the amp on the dial. For subs that number is more like 50% more voltage since it's far more difficult to hear distortion/clipping on bass.

So, I can say, pretty safely that the -10db test tone recommendation is WRONG. Don't use it. I know it makes sense when you think about how studios master their music, but in practice, I could definitely hear clipping on music playback WAY before coming even close to the 75% headunit setting.


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## FoxPro5 (Feb 14, 2006)

tspence73 said:


> I could definitely hear clipping on music playback WAY before coming even close to the 75% headunit setting.


I bet you dollars to donuts I could play 5 random songs and you couldn't tell me which ones were clean at -10 dB RMS and which ones had all the tips of the mountains cut off (heavly clipped at 0dB). I'd let you use all audiophile equipment and the best headphones in the world, if you wanted.


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## tspence73 (Oct 14, 2008)

FoxPro5 said:


> I bet you dollars to donuts I could play 5 random songs and you couldn't tell me which ones were clean at -10 dB RMS and which ones had all the tips of the mountains cut off (heavly clipped at 0dB). I'd let you use all audiophile equipment and the best headphones in the world, if you wanted.


I'm not going to submit to that test. I will however submit to any blind test under the conditions where I set the amp using the -10db test tone. It was not only clear to hear, there is no way you could make it back to that 46 volume setting without fearing the speakers would be ruined. It wasn't even a fine line I'm talking about here. It was enormous. I invite you to set your amp voltage with a -10db tone and compare that output voltage to a 0db tone. Then try playing back music with the -10db set amp. If you don't hear the distortion by the time the volume control reaches even 50%, you're a liar. Just my 2 cents on this. It's pretty obvious and it's not an exaggeration. It's so obvious that I would take any average Joe with bad jackhammer hearing and he could tell you when it sounds like shredded beef at 50% volume. It's literally that obvious.


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## ErinH (Feb 14, 2007)

Andy needs to chime in on this...

But, FWIW, I believe the reason for using the -10dB tone vs. 0dB tone is due to the constant (can't think of the word here) of the test tone. Music isn't nearly as constant, therefore the suggestion to set it with a tone more along the lines of what we would expect out of music is suggested.

My $.02


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## tspence73 (Oct 14, 2008)

bikinpunk said:


> Andy needs to chime in on this...
> 
> But, FWIW, I believe the reason for using the -10dB tone vs. 0dB tone is due to the constant (can't think of the word here) of the test tone. Music isn't nearly as constant, therefore the suggestion to set it with a tone more along the lines of what we would expect out of music is suggested.
> 
> My $.02


That's what I said earlier regarding the studio mastering. You'll get a -10db average on quite a bit of modern recordings which is why I understand the suggestion. I'm just saying that when setting the amps in actual practice using this assumption, the results were not good. Not at all. I would invite someone else here to do a similar test where their amp RMS and speaker RMS are close to each other, then try the -10db tone to set the amp. I would be very surprised if you could even get the voltage to the RMS, let alone tolerate the distortion at whatever level you managed to get. Again, the -10db tone got me 7.1-volts (13-watts at 4-ohms) and that doesn't even get the 55-watts RMS I was shooting for, yet even with that 7.1-volt setting the playback was heavily distorted at 50% volume, let alone the 75% it was set with. 

I don't think my math was wrong. It would be cool if someone could confirm this just to be 100% sure.


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## killerb87 (Oct 24, 2008)

i never like setting gains with a -10db signal, i use -5db. with no standard in recording levels its all a crapshoot.


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## FoxPro5 (Feb 14, 2006)

tspence73 said:


> It wasn't even a fine line I'm talking about here. It was enormous. I invite you to set your amp voltage with a -10db tone and compare that output voltage to a 0db tone.


Repeat your test and pay very special attention to the increase in voltage as you increase HU volume click by click. For the HU's i've used, none have been linear, meaning that it isn't until the final 5-10 clicks where the voltage really kicks in. If you plot the volume change against voltage on a graph, I highly doubt you will see a nice straight line from lowest to max.

This is the reason for your observation. It has little to do with the RMS of the source. In fact, a 0 dB tone is not at 0 dB, it's -3.011 dB RMS. 

You and details DO NOT mix, my friend.


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## 14642 (May 19, 2008)

If you're using the preamp output of the deck and it's not a Dual or Kenford, then it probably doesn't clip and there's no reason to set the gains with the volume at 75%. If you use a scope, then the idea is to set the head unit volume to the maximum unclipped level. Then. set the amplifier's gain to it's maximum unclipped level. All of that can be done with the 0dB track. The reason for the -10dB track, is so you'll have additional sensitivity at the amplifier so you have volume conrtol left over when you play a recording that has a big crest factor (not much dynamic range compression). You won't hear the distortion on the peaks, but without the additional sensitivity, those tracks won't play very loudly. Of course, when you put in Green Day, the average level will be much higher, and you won't be able to turn the volume up as far.

The problem that Tim has may be because he used the -10dB track AND only used 75 percent of the volume control. If you don't have a scope, this is all a crapshoot. Go buy a scope. Go to a military surplus store and spend 50 bucks on an old scope. Or, download winscope for free, build a voltage divider with a pair of 5-cent resistors and use it. The procedure whereby one sets gains with a DMM is like running a marathon with only one shoe. It's almost no better than a guess.

Tim, I've set sensitivity controls like this for over 20 years and for hundreds (if not thousands) of customers and competitors. I can assure you, it works and works well. In some cases, customers (especially those who listen to lots of classical music) prefer 20dB of extra gain. There's no reason outside protecting yourself from your own indescretion with the volume control to be so anal about matching the output power of your amp to the RMS power handling of the speaker. 

Furthermore, I'm glad that you confirmed with your math that a load on the amplifier isn't necessary during this procedure. I seem to remember suggesting that to you several times and also suggesting that you disconnect the speakers to prevent them from being damaged. Hmmm...


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## ErinH (Feb 14, 2007)

Andy Wehmeyer said:


> If you're using the preamp output of the deck and it's not a Dual or Kenford, then it probably doesn't clip and there's no reason to set the gains with the volume at 75%. If you use a scope, then the idea is to set the head unit volume to the maximum unclipped level. Then. set the amplifier's gain to it's maximum unclipped level. All of that can be done with the 0dB track. The reason for the -10dB track, *is so you'll have additional sensitivity at the amplifier so you have volume conrtol left over *when you play a recording that has a big crest factor (not much dynamic range compression). You won't hear the distortion on the peaks, but without the additional sensitivity, those tracks won't play very loudly. Of course, when you put in Green Day, the average level will be much higher, and you won't be able to turn the volume up as far.


Andy, thanks for chiming in. You've helped me in the past, and I believe you've answered this, but to be sure...

Maybe I'm just reading this wrong, but this appears to me that you're saying:
Set h/u to max uclipped level (for most h/u's this can be max volume) 
Set amp in same fashion

Do this with -10dB track (or whatever attenuation you want). 

Now, what I don't get is bolded above. How do you have extra sensitivity if you've maxed the h/u out? Seems to me you've set the wall at that point and can't go any higher. Maybe I'm just reading you wrong?


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## Knobby Digital (Aug 17, 2008)

cajunner said:


> this thread is going off track...


Myth #1 is that someone can start a thread without attention whore tspence jacking it with previously answered questions and useless specs and misused/skewed information - followed by a barrage of warranted insults - followed by previously answered questions and useless specs and misused/skewed information - followed by a barrage of warranted insults...




How about these:

Adding a sub will improve the sound of your system.

You need a dmm to set gains.


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## 14642 (May 19, 2008)

bikinpunk said:


> Andy, thanks for chiming in. You've helped me in the past, and I believe you've answered this, but to be sure...
> 
> Maybe I'm just reading this wrong, but this appears to me that you're saying:
> Set h/u to max uclipped level (for most h/u's this can be max volume)
> ...


Sorry for the continued hijack. Maybe this will put an end to it.

Years ago, amps were only amps and all the signal processing was done externally. The scope thing was helpful because every one of those processors had a sensitivity control. Let's say you have a head unit that doesn't clip, an eq, a crossover and an amp. Each of those components has a signal to noise ratio--which means they each make some noise. If I turn the sensitivity of the EQ to max, now I've amplified the signal and the noise of the head unit and the EQ. Then, I max the sensitivity of the crossover. Now I've amplified the signal from the head and its noise, the signal from the EQ and its noise and the signal from the crossover and its noise. 

Now I have tons of signal and tons of noise. IF I turn the volume down on the head unit, I don't have any signal, but I have tons of noise from all of the preamp sections that have been amplified by each gain stage. No matter the setting on the amp, I still have a ton of noise. Additionally, the output of the EQ may clip the input of the crossover and the output of the crossover may clip the input of the amp. 

The idea behind level setting is that i should get all the signal possible from each preamp component without distrotion. So, we use the 0dB track to determine the maximum unclipped output of the head. Then, we turn the sensitivity of the EQ DOWN and check the output with the scope. IF it's a clean sine wave, we know we haven't clipped the input. Then, we turn the sensitivity control of the EQ up until we reach the max level without clipping. THen we do the same thing for the crossover. 

Now, we have a clean signal, with no clipping which gives us the highest clean signal and the least amount of noise with that signal. There's no benefit in allowing preamp compnents to clip.

Then, we go to the amp. If we don't want to allow any clipping, we use the 0dB track and set the sensitivity so the amp make its full power but doesn't clip. That means that no transient, no matter how short, will ever cause the amp to clip. 

Let's characterize a good recording as having a crest factor of 12dB. That means that if our amp can make 100 watts, it'll make 100 watts when there's a peak, but the average output will be 6.25 watts. All the dynamics included in the program material will be preserved and there won't be any distortion, but it won't play very loudly. Put in a modern recording with plenty of dynamic range compression that has a crest factor of something like 6dB and the average level will be 25 watts, while the peaks will be at 100 watts. 


Now, if after I've set all the processor gains using th 0dB track, I put in the -10dB track and set the amplifier gains, I can raise the average level of the music by 10dB for those good recordings. People have a really hard time hearing distortion on transients until it reaches about 20%, so there won't be any audible distortion. IF there is, I simply turn down the volume control. When I listen to Green Day, the peaks will still provide some distortion that won't be audible, but the average level will be much higher. I probably won't turn the voume control up as high. 

The point of all of this is that the signal to noise ratio through all of the components will remain high, and the only distortion present in the system will come from the amps where it provide s the opportunity for me to raise the average level of the music WHEN I WANT TO rather than me being at the mercy of the recording engineer to determine how loudy I want to listen. 

With the -10dB track, I sacrifice a little clean signal for higher average level when I need or want it. If you want to be precise when you set gains, use a scope. If not, or if you have only a radio with preamp outputs and amps, turn the volume of the head all the way up and set the amp's sensitivity controls so there is a little audible distortion on big peaks in the music. The DMM isn't very helpful and can cause problems unless you know the maximum unclipped voltage the amp is designed to provide. For evidence of this, see Tim's post that indicates he got 30V out of an amp that's rated to deliver 55 watts at 4 ohms. DMMs don't tell you when clipping occurs and if they're RMS meters, they'll keep indicating more voltage until you reach a square wave, where average voltage and peak voltage are the same.

Sensitivity controls allow you to adjust the average output level of your system by managing the compromise between noise and distortion. It's easier to use a test signal recorded at some predetermined level than it is to try to determine exactly how much distortion you'll allow by viewing the output on a scope. If you had an AP or some scope that would display the distortion as a percent or in dB, then usiing the 0dB track and setting the sensitivity to allow a specific amount of distortion would be more precise.


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## tspence73 (Oct 14, 2008)

Andy Wehmeyer said:


> The idea behind level setting is that i should get all the signal possible from each preamp component without distrotion. So, we use the 0dB track to determine the maximum unclipped output of the head. Then, we turn the sensitivity of the EQ DOWN and check the output with the scope. IF it's a clean sine wave, we know we haven't clipped the input. Then, we turn the sensitivity control of the EQ up until we reach the max level without clipping. THen we do the same thing for the crossover.
> 
> Now, we have a clean signal, with no clipping which gives us the highest clean signal and the least amount of noise with that signal. There's no benefit in allowing preamp compnents to clip.


I'm with ya here.



> Then, we go to the amp. If we don't want to allow any clipping, we use the 0dB track and set the sensitivity so the amp make its full power but doesn't clip. That means that no transient, no matter how short, will ever cause the amp to clip.


This is what would be ideal of course and why buying an amp with lots more RMS wattage than the speaker's RMS is a great idea and why I did just that on this round of equipment upgrades.



> Let's characterize a good recording as having a crest factor of 12dB. That means that if our amp can make 100 watts, it'll make 100 watts when there's a peak, but the average output will be 6.25 watts.


Not to slice things too finely but many classical recordings will have an average db of like -18 to -20db when analyzed through a mastering program like Soundforge. Most modern recordings get like -10db.

I made these just now with sound forge just now to show an example of what I'm talking about:

Classical/orchestra music example with a track from the Edward Scissorhands soundtrack showing a scanned average of -27db:









Modern pop music example of Gwen Stefanie's 4 in the morning showing an average scan of -10db (which is much louder):











> All the dynamics included in the program material will be preserved and there won't be any distortion, but it won't play very loudly. Put in a modern recording with plenty of dynamic range compression that has a crest factor of something like 6dB and the average level will be 25 watts, while the peaks will be at 100 watts.


Close enough, I get the example.




> Now, if after I've set all the processor gains using th 0dB track, I put in the -10dB track and set the amplifier gains, I can raise the average level of the music by 10dB for those good recordings. People have a really hard time hearing distortion on transients until it reaches about 20%, so there won't be any audible distortion. IF there is, I simply turn down the volume control. When I listen to Green Day, the peaks will still provide some distortion that won't be audible, but the average level will be much higher. I probably won't turn the voume control up as high.


The thing I found about setting it this way was that it leaves an enormous amount of room to overdrive the sound. This should only be necessary for someone who's RMS wattage on the amp runs close to the RMS wattage on the speaker. Some distortion will be necessary. I've found that when setting my brother's truck system, using a % of total wattage extra is a better way to judge it than using db on a CD track. 



> With the -10dB track, I sacrifice a little clean signal for higher average level when I need or want it. If you want to be precise when you set gains, use a scope. If not, or if you have only a radio with preamp outputs and amps, turn the volume of the head all the way up and set the amp's sensitivity controls so there is a little audible distortion on big peaks in the music. The DMM isn't very helpful and can cause problems unless you know the maximum unclipped voltage the amp is designed to provide. For evidence of this, see Tim's post that indicates he got 30V out of an amp that's rated to deliver 55 watts at 4 ohms. DMMs don't tell you when clipping occurs and if they're RMS meters, they'll keep indicating more voltage until you reach a square wave, where average voltage and peak voltage are the same.
> 
> Sensitivity controls allow you to adjust the average output level of your system by managing the compromise between noise and distortion. It's easier to use a test signal recorded at some predetermined level than it is to try to determine exactly how much distortion you'll allow by viewing the output on a scope. If you had an AP or some scope that would display the distortion as a percent or in dB, then usiing the 0dB track and setting the sensitivity to allow a specific amount of distortion would be more precise.


When using a DMM you must take the amp specs at their word. If the amp is rated at 55-watts RMS and your speakers are 4-ohms, and you can trust the rating, then using a 14.8-volt setting on the DMM with a 0db tone and a headunit set to it's highest clean output is a reliable way to reach an unclipped output on the amp. If the amp specs are wrong, then you run into trouble.

I found 25% more wattage than the max rating was a more effective method than using a blanket -10db theory. When I set the DMM to exceed the 55w RMS to 90w on a 0db tone, it seemed to work to give extra volume, but I could STILL detect distortion at the upper range of the volume control where I had the 75% set.


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## TXwrxWagon (Sep 26, 2008)

quality_sound said:


> ^^^Exactly. If all amps sounded the same he wouldn't have to EQ them to have the same response before the test.
> 
> Mine is the "distortion or clipping kills speakers" crap.


if not Distortion or clipping what DOES kill speakers?

Rob


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## TXwrxWagon (Sep 26, 2008)

Autiophile said:


> Has anyone with a reasonable understanding of amplifiers ever actually said that all amps sound the same? I thought the line was always "all amps that measure the same sound the same".
> 
> Kind of like the cable argument where the general argument is "if the difference doesn't show up in RLC then it doesn't exist".



RLC?

Rob


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## tspence73 (Oct 14, 2008)

I think the right way to characterize the amp comparison is this:

All amps that are designed *PROPERLY* (i.e. to produce a flat response from 20Hz-20KHz with certain minimum noise standards and a damping factor of 50 or higher) will sound the same when compared within their unclipped wattage limits. If any amp is designed improperly or has poor noise/equalization/etc then it will of course sound different. When amps are clipping they can sound different from each other, which likely accounts for why some people think they hear a difference or have an amp preference.


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## ChrisB (Jul 3, 2008)

Ooh, ooh, I have more myths to test:

Tspence73 is an expert in audio engineering and system tuning.

Tspence 73 knows all there is to know about 12 volt audio electronics.

Proven fact, plausible, or busted?


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## tspence73 (Oct 14, 2008)

06BLMUSTANGGT said:


> Ooh, ooh, I have more myths to test:
> 
> Tspence73 is an expert in audio engineering and system tuning.
> 
> ...


I would say busted because I have never presented myself as an 'expert'. In fact I have often gone out of my way to say I'm not an engineer. However, it's not against the rules for an 'average' Joe like myself to put actual facts and data into a thread which is subject to any criticism someone wants to interject.


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## tspence73 (Oct 14, 2008)

TXwrxWagon said:


> if not Distortion or clipping what DOES kill speakers?
> 
> Rob


It looks like exceeding the thermal or mechanical limits of the speaker puts it in direct danger of failing or being damaged. Clipping an amp just gives a much higher chance of exceeding a speaker's limits both thermal and mechanical.

Clipping and distortion in and of themselves do not ruin speakers. Most modern rock and guitar based music is heavily clipped and distorted yet doesn't ruin speakers.


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## ca90ss (Jul 2, 2005)

TXwrxWagon said:


> RLC?
> 
> Rob


resistance, inductance, capacitance


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## quality_sound (Dec 25, 2005)

FoxPro5 said:


> If you plot the volume change against voltage on a graph, I highly doubt you will see a nice straight line from lowest to max.


IME, it depends on the brand. Alpines have always been very non-linear where Sonys have been linear. I agree that one should plot their output voltage to see what they're working with though.


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## TXwrxWagon (Sep 26, 2008)

thanks... I was making sure my Feeble, old mind was keeping up with the modern youngsters.... LOL

I just hadn't seen the RLC used in that context/sentence structure... threw me off. I'm usd to R-L-C or other formats...

Its just funny to me that so many can have such "stanch" opinions like "clipping & distortion don't kill speakers"... then in the same statement its is agreed that exceeding the thermal/mechanical limits IS the culprit... DUH... why did the engine blow? Seized bearing (mechanical limit reached) but WHAT CAUSED the mechanical limit to be reached? lack of oil? spun to fast? 

I love threads like this.... I break out the popcorn & the beer & just chuckle...

Rob


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## quality_sound (Dec 25, 2005)

TXwrxWagon said:


> if not Distortion or clipping what DOES kill speakers?
> 
> Rob



We've already discussed it in this thread but to recap only two things kill speakers. Over powering them and over drving them.


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## quality_sound (Dec 25, 2005)

TXwrxWagon said:


> thanks... I was making sure my Feeble, old mind was keeping up with the modern youngsters.... LOL
> 
> I just hadn't seen the RLC used in that context/sentence structure... threw me off. I'm usd to R-L-C or other formats...
> 
> ...


Chuckle all you want but that doesn't make you correct. Clipping doesn't kill speakers. Only if the clipping results in over powering the speaker will there be a problem. You can just as easily overpower a speaker without clipping and it'll die just the same. We don't really care why the speaker got more power that it can handle only that it got more power. If you want to follow the silly logic you're using you could blame it on the power wire used for allowing the amp to draw enough current to make enough power to kill the speaker or the RCAs for not limiting the signal, or the bonehead that kept turning up the volume. Really, we can play this game all day long.


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## t3sn4f2 (Jan 3, 2007)

quality_sound said:


> IME, it depends on the brand. Alpines have always been very non-linear where Sonys have been linear. I agree that one should plot their output voltage to see what they're working with though.


Here's a little detailed page on how they come up with the attenuation curves.

http://www.tangentsoft.net/audio/atten.html


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## tspence73 (Oct 14, 2008)

Do you think it's feasible to have a thermal passive fuse or circuit breaker tuned specifically for a speaker's thermal limits that will blow if before your voice coils cook?


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## RedGTiVR6 (Jun 26, 2007)

J0ne said:


> Just pondering what are the top car audio related myths. not particularly looking for explanations that bust the myth, just the general idea. I will be doing write-ups in my own words debunking each of the myths on my website.


CarPCs don't sound very good.


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## 14642 (May 19, 2008)

Fuses and breakers don't know the thermal limits of your speaker. They are designed to open when enough current passes to get them hot enough to trip or blow. IN my experience, speaker fuses are more hassle than they're worth. Either they blow all the time or they don't blow before the speaker is destroyed. 

Why all this concern about blowing speakers? In my 25 years as an enthusiast/installer/whatever-the-hell-I-do-now I've never blown a speaker. I've had customers who have never not blown a speaker no matter what i've done to prevernt it.


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## TXwrxWagon (Sep 26, 2008)

quality_sound said:


> Chuckle all you want but that doesn't make you correct. Clipping doesn't kill speakers. Only if the clipping results in over powering the speaker will there be a problem. You can just as easily overpower a speaker without clipping and it'll die just the same. We don't really care why the speaker got more power that it can handle only that it got more power. If you want to follow the silly logic you're using you could blame it on the power wire used for allowing the amp to draw enough current to make enough power to kill the speaker or the RCAs for not limiting the signal, or the bonehead that kept turning up the volume. Really, we can play this game all day long.



Ah... err... how did I give YOU a wedgie? jeez... the chuckle is not specifically at any one post/myth or even concept... pull your panties out of your bum & take a deep breath.... I feel privileged I got your attention this strongly.

I'm quite comfortable in my "silly logic" & am proud that over 25+ years of home & car audio I have no speaker failures. I guess I am just not pushing my speakers hard enough...

Rob


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## 14642 (May 19, 2008)

tspence73 said:


> I'm with ya here.
> 
> 
> 
> I found 25% more wattage than the max rating was a more effective method than using a blanket -10db theory. *When I set the DMM to exceed the 55w RMS to 90w on a 0db tone,* it seemed to work to give extra volume, but I could STILL detect distortion at the upper range of the volume control where I had the 75% set.


If the amplifier is designed to provide 55W at 4 ohms (14.8 V AC), how do you get it to provide 90 watts--or how do you read 90 watts on your DMM?


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## TXwrxWagon (Sep 26, 2008)

quality_sound said:


> Chuckle all you want but that doesn't make you correct. Clipping doesn't kill speakers. Only if the clipping results in over powering the speaker will there be a problem. You can just as easily overpower a speaker without clipping and it'll die just the same. We don't really care why the speaker got more power that it can handle only that it got more power. If you want to follow the silly logic you're using you could blame it on the power wire used for allowing the amp to draw enough current to make enough power to kill the speaker or the RCAs for not limiting the signal, or the bonehead that kept turning up the volume. Really, we can play this game all day long.


ok I was going to take the higher ground... but not so much....

Why in the WORLD would you not care what caused the over power issue? Why would you not want to find the true point of failure?

In your "silly logic"... WTF... its blown... give me a new one... la-la-la... <fingers in ears don't want to hear reality>..... something caused the failure

I didn't say that clipping, distortion or any SPECIFIC thing ALWAYS caused the failure... I simply said that in order to REACH a thermal or mechanical failure SOMETHING causes it... its not just "oh gee... my speaker let the Genie out"..... 

EDIT * I am asking a serious question here..... what is the ROOT cause of the failure? saying it was "cooked" (thermal) or "maxed" (mechanical) is not the answer... WHY did the speaker fail? why did the speaker REACH that thermal/mechanical limit? I can take the speaker & plug it into a wall socket to get either answer. I can take a torch & heat up the magnet/Vc & get it to fail... what in the signal/power chain failed?

Rob


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## tspence73 (Oct 14, 2008)

Andy Wehmeyer said:


> If the amplifier is designed to provide 55W at 4 ohms (14.8 V AC), how do you get it to provide 90 watts--or how do you read 90 watts on your DMM?


I set it to 19-volts, which would be 90-watts RMS when on a 4-ohm load. Is that wrong?  It seemed correct since I wasn't anywhere near maxing out the gain. In fact, the gain was just a few pinches higher than the 14.8v setting.


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## TXwrxWagon (Sep 26, 2008)

Andy Wehmeyer said:


> Fuses and breakers don't know the thermal limits of your speaker. They are designed to open when enough current passes to get them hot enough to trip or blow. IN my experience, speaker fuses are more hassle than they're worth. Either they blow all the time or they don't blow before the speaker is destroyed.
> 
> Why all this concern about blowing speakers? In my 25 years as an enthusiast/installer/whatever-the-hell-I-do-now I've never blown a speaker. I've had customers who have never not blown a speaker no matter what i've done to prevernt it.


I know of a competitor who was 1 spot out of a finals spot due to a poor connection on the sub woofer fuse. (looking in the mirror).. lol

back in the IASCA days of flash, displays & excess, you had to fuse anything that had current... 

As I said above... i'm just a 40 year old moron, testing 25+ years of audio stupidity.. never a blown speaker... thanks Andy for reinforcing the concept

Rob


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## tspence73 (Oct 14, 2008)

TXwrxWagon said:


> EDIT * I am asking a serious question here..... what is the ROOT cause of the failure? saying it was "cooked" (thermal) or "maxed" (mechanical) is not the answer... WHY did the speaker fail? why did the speaker REACH that thermal/mechanical limit? I can take the speaker & plug it into a wall socket to get either answer. I can take a torch & heat up the magnet/Vc & get it to fail... what in the signal/power chain failed?
> 
> Rob


Speaker reached mechanical limit: Say a 4-inch driver is not made to produce a 20Hz tone at 50-watts but it's rated as a 100-watt driver for it's intended range. The speaker could be pushed beyond it's mechanical limit and cause the cone or material itself to warp or tear apart. Or, a woofer is rated at 40-1,000Hz response and is intended for a sealed enclosure only, and you put it in an infinite baffle instead then try to run it with a 30Hz bass boost at +12db. Likely you will exceed it's mechanical limits with a relatively low wattage and the speaker looks like a party hat afterwards. That would I think be a logical example of exceeding the mechanical limits.

Speaker thermal limit: More wattage is reaching the voice coil than it's designed for, for a longer period of time than it can safely dissapate the heat. The voice coil burns out thermally due to too much input wattage for too long of a time.

So, those are the two ways I figure you ruin a speaker. Either by exceeding it's designed specs and not using it for it the intended application or by exceeding it's thermal limits. Either way, distortion is not likely going to cause a failure as long as the input is limited to the driver's mechanical and thermal specs.


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## 14642 (May 19, 2008)

tspence73 said:


> I set it to 19-volts, which would be 90-watts RMS when on a 4-ohm load. Is that wrong?  It seemed correct since I wasn't anywhere near maxing out the gain. In fact, the gain was just a few pinches higher than the 14.8v setting.


That's my point. The amp doesn't produce 19V RMS withut some clipping. Now we have to determine whether you have an RMS meter or not. IF you got a square wave out of the amp designed to provide 14.8 V RMS you'd have 14.8 x 1.4 or 20.72 volts. This us why the DMM method sucks unless you know at precisely what voltage the amp clips.


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## quality_sound (Dec 25, 2005)

TXwrxWagon said:


> ok I was going to take the higher ground... but not so much....
> 
> Why in the WORLD would you not care what caused the over power issue? Why would you not want to find the true point of failure?
> 
> ...




Because the root cause is simple, it was the user turning it up too loud. All of this other crap you're throwing out there is a smokescreen. The final ultimate cause is the owner. 

Happy? Jesus ****ing christ...


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## TXwrxWagon (Sep 26, 2008)

tspence73 said:


> Speaker reached mechanical limit: Say a 4-inch driver is not made to produce a 20Hz tone at 50-watts .


no offense Ts... Blah... blah... blah... the those are all givens... too low, to much juice.. the usual... 

I am trying, like so many other posts, to give others who are having the issue something to grab on to.. some logic.. if you over extend a 12" woofer with Legacy/Pyramid power... shame on you... no warranty for you!... if you send a 4" coax to below 50hz... I revoke your Driver's license & smack you on the head... those are givens...

but naturally there are failures in well designed/planned systems... what is the REAL failure?

Rob


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## tspence73 (Oct 14, 2008)

TXwrxWagon said:


> no offense Ts... Blah... blah... blah... the those are all givens... too low, to much juice.. the usual...
> 
> I am trying, like so many other posts, to give others who are having the issue something to grab on to.. some logic.. if you over extend a 12" woofer with Legacy/Pyramid power... shame on you... no warranty for you!... if you send a 4" coax to below 50hz... I revoke your Driver's license & smack you on the head... those are givens...
> 
> ...


I've had a speaker failure because of my own screwup. That was recently when I decided to run a full 0db tone at my speaker's lowest impedance curve to see if I actually needed a load to set the amp gain. I learned I didn't need a load but that knowledge cost me my rear 6x9s because their coils got cooked. 

Now as for all the other installs, I would have to say one subwoofer failed because it was defective a year ago. I was pushing it's limits I admit, but I didn't exceed them and it failed. So, that might answer your question. defective equipment. Live and learn.


----------



## FoxPro5 (Feb 14, 2006)

God I hate the *DMM gain setting method* more than life itself. It's maddening to see people even try and do such a silly thing. Thanks, Andy, for explaining it with figures and relative examples.


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## TXwrxWagon (Sep 26, 2008)

quality_sound said:


> Because the root cause is simple, it was the user turning it up too loud. All of this other crap you're throwing out there is a smokescreen. The final ultimate cause is the owner.
> 
> Happy? Jesus ****ing christ...


Q-SQ... you're a riot... I am chuckling more than when we started...

you FINALLY said what no one wants to say... "no control over their right wrist" or "left wrist" overseas... combined with Deaf ears...

But... you opened the door..(thanks very much)... why would turning the volume up too much cause the speaker to fail?... the thermal & mechanical limits are the final failure... is that say a GAIN problem? a signal/noise problem? a distortion/clip problem?....

You do realize I am egging you on right?

the bottom line to speaker failure is a FAILURE to control the wrist on the volume control past the point where music becomes noise... nothing else.. you can argue "thermal/mechanical" all you want... there is a fundamental failure BEFORE the thermal or mechanical limit of the speaker. Its HUMAN error...

Like soooo many "engineer types" who sleep, jerk off & caress their O-Scopes & DMM... the thing we all seek is an EMOTIONAL attachment to the musical experience... It doesn't matter how much I or anyone else screams "perfection"... if it doesn't sound right... it doesn't sound right, & unless you are trying to please a "judge" in one of the many sanctioning bodies, a person's daily experience has NOTHING to do with thermal/mechanical limits... if he blows up ****... he is blowing up ****... & there is a REASON he is hitting those limits...

education over "theory".... TEACH don't preach...

Rob


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## 14642 (May 19, 2008)

It isn't clipping or distortion. It's simply too much power for too long that causes thermal failure. The cause? The person applying too much power. 

The cause of mechanical failure is more difficult to determine unless there's a hole iin the cone or surround. That's why companies will take broken speakers back without a fight but won't often provide warranty replacement for burned coils.


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## ca90ss (Jul 2, 2005)

Andy Wehmeyer said:


> That's my point. The amp doesn't produce 19V RMS withut some clipping.


It might if there is no load connected to the amp. Amps generally will put out a bit more voltage before clipping when there is no load on the amp which is generally how people using the dmm method do it to prevent blowing their speakers during gain setting.


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## Knobby Digital (Aug 17, 2008)

TXwrxWagon said:


> education over "theory".... TEACH don't preach...
> 
> Rob


You're thinking about it the wrong way.

Put a 20w amp on a 2000w sub and clip it all you want. The speakers not going anywhere.

On the other hand give a 20w speaker 2000 watts of clean power and see what happens.

The engine analogy is a bad one because speakers don't need lubrication to function.


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## squeak9798 (Apr 20, 2005)

TXwrxWagon said:


> Its just funny to me that so many can have such "stanch" opinions like "clipping & distortion don't kill speakers"... then in the same statement its is agreed that exceeding the thermal/mechanical limits IS the culprit... DUH...


When someone is shot with a gun, it's easy to blame the gun itself. After all, the gun killed the person!

But guns don't shoot themselves. They need someone to pull the trigger. So ultimately, while the gun happened to be the _method of delivery_....the real reason that person was killed via gunshot was because _someone pulled the trigger_. So is it more accurate to blame the gun for the death (the method of delivery), or the person who pulled the trigger?

In the same sense, clipping may result in _excessive power_ being delivered to a speaker, causing it to exceed it's mechanical or thermal limits and ultimately being damaged. Clipping in this instance happens to be the _method of delivery_, but it's not the true _cause_. It only damaged the speaker because the resultant _power_ _exceeded_ the mechanical or thermal driver limits. If it hadn't exceeded one or both of those limits, *no *damage would have been done. 

It's better to explain to someone _why_ the clipping is potentially damaging (due to _excessive power _exceeding the speaker's limits), rather than just blaming the clipping itself.

As you yourself said....*teach*, don't preach 

Don't preach the perils of clipping without teaching what is perilous about it.


----------



## 14642 (May 19, 2008)

ca90ss said:


> It might if there is no load connected to the amp. Amps generally will put out a bit more voltage before clipping when there is no load on the amp which is generally how people using the dmm method do it to prevent blowing their speakers during gain setting.


I think it's far more likely that he was measuring a seriously clipped signal with an RMS meter or measuring peak voltage with a non-RMS meter.


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## SublimeZ (Jan 28, 2008)




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## ca90ss (Jul 2, 2005)

Andy Wehmeyer said:


> I think it's far more likely that he was measuring a seriously clipped signal with an RMS meter or measuring peak voltage with a non-RMS meter.


Without using a scope to see exactly what's going on nobody knows for sure what's happening. All I'm saying is that it is possible for an amp without a load to produce more voltage than with a load. Take the Linear Power 1002 I tested, it put out [email protected] (48.37w) with a load connected before clipping and without a load connected it did 19.6v ([email protected]) before clipping.


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## ca90ss (Jul 2, 2005)

cajunner said:


> but did it clip hard, or soft?


Measurements were just before the onset of clipping. There was only a few watts difference between soft and hard clipping.



> at what frequency did you test?


I measured at several frequencies but got the best #'s at 1khz.


----------



## evan (Dec 2, 2006)

bigabe said:


> Ok...
> 
> diymobileaudio = SQ and ONLY SQ
> 
> ...


"Do it yourself" originally referred to combining different speakers from different applications (mostly home audio, some pro audio and car audio) not just installing pre-packaged component sets without the help of a professional installer.


----------



## TXwrxWagon (Sep 26, 2008)

squeak9798 said:


> When someone is shot with a gun, it's easy to blame the gun itself. After all, the gun killed the person!
> 
> But guns don't shoot themselves. They need someone to pull the trigger. So ultimately, while the gun happened to be the _method of delivery_....the real reason that person was killed via gunshot was because _someone pulled the trigger_. So is it more accurate to blame the gun for the death (the method of delivery), or the person who pulled the trigger?
> 
> ...


Squeak... thanks!... that's a perspective I hadn't given any thought too... 

Its saying the same thing, but with a different twist I hadn't considered.

thanks again.

Rob


----------



## TXwrxWagon (Sep 26, 2008)

SublimeZ said:


>



I need that link.. that's freaking AWESOME!

anyone got one with a sexy chick stirring a pot/cauldron?

Rob


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## tintbox (Oct 25, 2008)

unpredictableacts said:


> LOL I always do this even after being told there is no need to......Just incse I do have noice problems I will not have 52 people telling me that that is my problem. I also shake the milk before pouring a glass....My wife used to say that I was going to keep doing it and turn it into butter.....no butter yet.


x2 on that


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## NCMazda3 (Dec 13, 2008)

Hi everyone, this is my very first post here and I have a lot of questions but I'm keeping it simple. I understand the clipping/distortion/thermal and mechanical limits stuff. But according to you guys, I should have blown my system up a long time ago. I'm running JL Audio C5 6 1/2" components in my front doors and TR 570cxi coaxes in the rear. My amp is an Alpine PDX4.150. The components are rated at 75w RMS and the coaxes are 50w RMS. With my amp being rated at 150 watts RMS, how is it I have never had to change my speakers in the 2 years I've had them? I'm using an Alpine Head unit with AudioControl Line Driver. I'm not easy by any means on my speakers....I like it loud and I'm usually listening to Heavy Metal (Trivium, Avenged Sevenfold, StoneSour, that sort of stuff). My x-overs are set to offer great midbass at normal volume but I don't have to turn my head unit's x-overs on at high volume either. I also have a PDX1.1000 that I had on a Diamond D6 12 (rated at 600 watts RMS) in my last car that I rocked on but never had a problem with. (Sealed box) I've been buying and installing this stuff since I was 15 (14 years) and have only blown 1 tweeter in my entire life. So from what you all have stated, I am exeeding my speakers' thermal limits for sure, maybe not so much on the mechanical limits? So help me out here b/c if there's something I'm doing that would still prevent my speakers from blowing then that would clear things up a lot for me. Thanks a lot everyone.


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## t3sn4f2 (Jan 3, 2007)

NCMazda3 said:


> Hi everyone, this is my very first post here and I have a lot of questions but I'm keeping it simple. I understand the clipping/distortion/thermal and mechanical limits stuff. But according to you guys, I should have blown my system up a long time ago. I'm running JL Audio C5 6 1/2" components in my front doors and TR 570cxi coaxes in the rear. My amp is an Alpine PDX4.150. The components are rated at 75w RMS and the coaxes are 50w RMS. With my amp being rated at 150 watts RMS, how is it I have never had to change my speakers in the 2 years I've had them? I'm using an Alpine Head unit with AudioControl Line Driver. I'm not easy by any means on my speakers....I like it loud and I'm usually listening to Heavy Metal (Trivium, Avenged Sevenfold, StoneSour, that sort of stuff). My x-overs are set to offer great midbass at normal volume but I don't have to turn my head unit's x-overs on at high volume either. I also have a PDX1.1000 that I had on a Diamond D6 12 (rated at 600 watts RMS) in my last car that I rocked on but never had a problem with. (Sealed box) I've been buying and installing this stuff since I was 15 (14 years) and have only blown 1 tweeter in my entire life. So from what you all have stated, I am exeeding my speakers' thermal limits for sure, maybe not so much on the mechanical limits? So help me out here b/c if there's something I'm doing that would still prevent my speakers from blowing then that would clear things up a lot for me. Thanks a lot everyone.


Spend a few weeks reading up on music, watts, and speakers and it will be clear as day.


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## 14642 (May 19, 2008)

No need to read for weeks, but if you decided you had nothing better to do, I'd suggest a little reading here and more reading at the Library.

The answer to your question is simple--you haven't exceeded the thermal or mechanical limits of your speakers for long enough to have damaged them.


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## NCMazda3 (Dec 13, 2008)

Even on an hour drive to Raleigh or and hour and a half to the beach? What about a 3 hour drive to Myrtle Beach? How long is too long to exceed these limits? If I can't exceed them on that drive, I'm pretty sure the average user would have just as hard a time around town. I would think that this is where the distortion would be a problem.


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## trebor (Jun 30, 2008)

NCMazda3 said:


> Even on an hour drive to Raleigh or and hour and a half to the beach? What about a 3 hour drive to Myrtle Beach? How long is too long to exceed these limits? If I can't exceed them on that drive, I'm pretty sure the average user would have just as hard a time around town. I would think that this is where the distortion would be a problem.


The problem is you are listening to music. If your really determined to blow them up then make sure your gains are properly set and play some 0dB test tones through them within their range at full volume. 

If not, then I'm sure it sounds quite nice the way it is by having the extra power on reserve for musical peaks.


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## W8 a minute (Aug 16, 2007)

I don't know if it's been said yet but there's a myth that states: People with a higher post count have more knowledge.


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## NCMazda3 (Dec 13, 2008)

trebor said:


> The problem is you are listening to music. If your really determined to blow them up then make sure your gains are properly set and play some 0dB test tones through them within their range at full volume.
> 
> If not, then I'm sure it sounds quite nice the way it is by having the extra power on reserve for musical peaks.


I don't want to blow them up. I just am curious what I'm doing different than the average consumer that keeps blowing stuff up with no more than recommended RMS power if distortion doesn't destroy speakers. What I was getting from this thread was that distortion doesn't destroy the speaker, the added power and subsequent heat does. If that's true, shouldn't I be having a problem? I'm just curious. I know there are a lot of you up here who know a lot more than I do and that's why I'm here. I'm one of those that likes to have it explained to me...the whys and why-nots...so I can learn and one day pass the proper and correct knowledge along like you guys here will to me.


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## Foglght (Aug 2, 2007)

PaulD said:


> headroom is for transient peaks, which add very little to the average power. Clipping can double the average power at full clip (100% squre wave)


Show........graphs.......straining..........do not under.......stand......

I know what a square wave is. So what does a normal test tone wave look like from peak to peak? How does that differ in actual power output to a square wave?


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## chad (Jun 30, 2005)

Foglght said:


> Show........graphs.......straining..........do not under.......stand......
> 
> I know what a square wave is. So what does a normal test tone wave look like from peak to peak? How does that differ in actual power output to a square wave?


It's tough to explain but here we go. 

From the onset of clipping the Peak to peak AC voltage will not go up as you go more an more into clipping (from a sine wave just onset to a full square wave) BUT as you raise the input and approach a square wave the RMS AC voltage will continue to rise, which is one of the issues about people thinking that they can detect clipping with a true RMS meter, you can't.

Also think of it this way. Color in the area of the waveform of a sine wave, this is power (for the most part) now color in the area of a square wave. Note that you will use more crayon on the square wave than with the sine wave


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## falkenbd (Aug 16, 2008)

TXwrxWagon said:


> if not Distortion or clipping what DOES kill speakers?
> 
> Rob



tspence73


----------



## Foglght (Aug 2, 2007)

chad said:


> It's tough to explain but here we go.
> 
> From the onset of clipping the Peak to peak AC voltage will not go up as you go more an more into clipping (from a sine wave just onset to a full square wave) BUT as you raise the input and approach a square wave the RMS AC voltage will continue to rise, which is one of the issues about people thinking that they can detect clipping with a true RMS meter, you can't.
> 
> Also think of it this way. Color in the area of the waveform of a sine wave, this is power (for the most part) now color in the area of a square wave. Note that you will use more crayon on the square wave than with the sine wave


Yeah the crayon thing helped, but I still wanna see graphs, or direct me to the cheapest way to pick up a scope, hook it up, and see what you are talking about.


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## t3sn4f2 (Jan 3, 2007)

Foglght said:


> Yeah the crayon thing helped, but I still wanna see graphs, or direct me to the cheapest way to pick up a scope, hook it up, and see what you are talking about.


Why Do Tweeters Blow When Amplifiers Distort?


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## t3sn4f2 (Jan 3, 2007)

Andy Wehmeyer said:


> No need to read for weeks, but if you decided you had nothing better to do, I'd suggest a little reading here and more reading at the Library.
> 
> The answer to your question is simple--you haven't exceeded the thermal or mechanical limits of your speakers for long enough to have damaged them.


Excuse me, I meant learning not reading.


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## shagdrum (Dec 7, 2007)

There seems to be a lot of distortion and mischaracterization in the presentation of the claims that is are "myths", in this thread.


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## 14642 (May 19, 2008)

http://www.jblpro.com/catalog/support/getfile.aspx?docid=246&doctype=3


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## squeak9798 (Apr 20, 2005)

Foglght said:


> Yeah the crayon thing helped, but I still wanna see graphs, or direct me to the cheapest way to pick up a scope, hook it up, and see what you are talking about.













Too Little Power Blowing Speakers


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## t3sn4f2 (Jan 3, 2007)

NCMazda3 said:


> Hi everyone, this is my very first post here and I have a lot of questions but I'm keeping it simple. I understand the clipping/distortion/thermal and mechanical limits stuff. But according to you guys, I should have blown my system up a long time ago. I'm running JL Audio C5 6 1/2" components in my front doors and TR 570cxi coaxes in the rear. My amp is an Alpine PDX4.150. The components are rated at 75w RMS and the coaxes are 50w RMS. With my amp being rated at 150 watts RMS, how is it I have never had to change my speakers in the 2 years I've had them? I'm using an Alpine Head unit with AudioControl Line Driver. I'm not easy by any means on my speakers....I like it loud and I'm usually listening to Heavy Metal (Trivium, Avenged Sevenfold, StoneSour, that sort of stuff). My x-overs are set to offer great midbass at normal volume but I don't have to turn my head unit's x-overs on at high volume either. I also have a PDX1.1000 that I had on a Diamond D6 12 (rated at 600 watts RMS) in my last car that I rocked on but never had a problem with. (Sealed box) I've been buying and installing this stuff since I was 15 (14 years) and have only blown 1 tweeter in my entire life. So from what you all have stated, I am exeeding my speakers' thermal limits for sure, maybe not so much on the mechanical limits? So help me out here b/c if there's something I'm doing that would still prevent my speakers from blowing then that would clear things up a lot for me. Thanks a lot everyone.


A little clearer explanation to maybe why you haven't blown your speakers.

Speaker power handling < Pro-Audio References


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## FG79 (Jun 30, 2008)

Andy Wehmeyer said:


> Why all this concern about blowing speakers? In my 25 years as an enthusiast/installer/whatever-the-hell-I-do-now I've never blown a speaker. I've had customers who have never not blown a speaker no matter what i've done to prevernt it.


Haha, agreed 100%!

Blowing speakers is more of a function of the user than anything else. 

Myth: higher power amps (or amps with gains up high) are more dangerous to speakers than lower power amps (or low gains). 

My take: for the ghetto blaster, yes. For a mature listener, no. 

IMHO, that statement is a C.Y.A. disclaimer propagated by manufacturers to prevent themselves from making more warranty claims, which is understandable.


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## Matt Borgardt (Mar 26, 2006)

> Why all this concern about blowing speakers? In my 25 years as an enthusiast/installer/whatever-the-hell-I-do-now I've never blown a speaker.



I will back you up on this !!!!! as I like to say "it is the nut behind the wheel that %$#@s it up!"


here is my myth for everyone...


The internet will make you smarter on buy audio equipment.
Midbass only comes from midbass drivers.
Manufactures always post the real specs on there speakers and amps.
Ipods are good for audio
You can only get good staging with drivers on the dash or in the pillars.
More expensive the car the better it is built.

my favorite: is the the simpler the system the easier it is to build.


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## WRX/Z28 (Feb 21, 2008)

It_Hertz said:


> you must run RCA's and power on oppsite sides of the vehicle.


You are saying this is a myth? really? Tell me you're joking.


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## Matt Borgardt (Mar 26, 2006)

WRX/Z28 said:


> You are saying this is a myth? really? Tell me you're joking.




This is really not a myth... when you lay cable in the car you must be mindful of the cars electric system and work from there if the car is older you want to look at the wiring under the hood and see how good the ground system is, if this is OK and wired right you will most likely not have problems running the power and RCA's on the same side but if it is not them you may have problems with noise. Also you must remember to properly ground the amps you are working with and the head unit.


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## 14642 (May 19, 2008)

iDtech said:


> This is really not a myth... when you lay cable in the car you must be mindful of the cars electric system and work from there if the car is older you want to look at the wiring under the hood and see how good the ground system is, if this is OK and wired right you will most likely not have problems running the power and RCA's on the same side but if it is not them you may have problems with noise. Also you must remember to properly ground the amps you are working with and the head unit.


Long ago, when most car audio equipment included some connection from audio ground to chassis in the signal input circuit, this was not a myth. these days, most electronic equipment sold by reputable companies is no longer susceptable to radiated noise. Therefore, it's now a myth--mostly. The idea that grounds are super-important is also now nearly a myth. When RCA connections and single-ended outputs also go away, we'll never have to worry about that again. 

Ever hear a facatory system with a bunch of noise? Ever seen a factory system with RCA cables?


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## W8 a minute (Aug 16, 2007)

I haven't had a radiated noise issue since I stopped using tape decks.


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## MarkZ (Dec 5, 2005)

WRX/Z28 said:


> You are saying this is a myth? really? Tell me you're joking.


The signal is too high and the impedance is low enough for inductive noise to not be much of an issue. Unless maybe you zip tied them together for about 150 feet.


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## FG79 (Jun 30, 2008)

iDtech said:


> I will back you up on this !!!!! as I like to say "it is the nut behind the wheel that %$#@s it up!"
> 
> 
> here is my myth for everyone...
> ...


I agree with the heart of what you're saying but wanted to be more specific how:

1) In 99% of car systems, the midbass fundamental comes from a combination of sub and midrange drivers....if you define midbass being in the 60-300 hz range. 

When you talk about midbass harmonics going up to 1.5k or so, then whatever drivers you have playing that high play a role too. HLCDs help out tremendously here. 

So yes, midbass doesn't just come from a 6.5" or 8" in the door, but the foundation for outstanding midbass is typically dictated by the physical installation and tuning of such drivers. They provide a certain upper frequency punch that subs cannot do, no matter how many of them you have!

2) Manufacturers are starting to be more legit with their specs.....some like Alpine have been posting test sheets with their amps, and I figure others have followed suit. 

However, that stuff is pointless to me in many cases because I'm not a specs guy. 

3)Ipods are obviously not better than CDs, but its effect on the music chain (in a car at least) isn't anywhere as important as amplifier, speakers, head unit, recording, etc. etc. IMO. 

In fact, a well recorded song on an ipod will sound better than a compressed CD record....to clarify, a 128kbps version of a Jamiroquai album downloaded from itunes playing through an ipod will massacre a DVD-A, SACD, or MFSL copy of Lil Wayne's "Tha Carter III" if such formats existed for this record, lol! 

I take such comparison from personal experience...

Given the convenience if ipods and their good in car performance, it's a worthwhile addition to a system.


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## t3sn4f2 (Jan 3, 2007)

iDtech said:


> I will back you up on this !!!!! as I like to say "it is the nut behind the wheel that %$#@s it up!"
> 
> 
> here is my myth for everyone...
> ...


Sure.


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## t3sn4f2 (Jan 3, 2007)

Studio quality sound card (better then any good headunit)

RightMark Audio Analyzer test: LynxTWO-B


iPod 5G next to the theoretical limits of a 16bit/44KHz file.

RightMark Audio Analyzer test: comparison

Not bad at all.

If you use one with a good line driver to your amps, then its as good as any head unit out there.


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## WRX/Z28 (Feb 21, 2008)

MarkZ said:


> The signal is too high and the impedance is low enough for inductive noise to not be much of an issue. Unless maybe you zip tied them together for about 150 feet.


Yeah? I'd suggest you try running them next to each other in a Buick GN for an extreme example of how this is still not a good idea.


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## WRX/Z28 (Feb 21, 2008)

iDtech said:


> I will back you up on this !!!!! as I like to say "it is the nut behind the wheel that %$#@s it up!"
> 
> 
> here is my myth for everyone...
> ...



I'd take an Ipod that had all cd files ripped to lossless over a scratched cd any day.


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## envisionelec (Dec 14, 2005)

Andy Wehmeyer said:


> Sorry for the continued hijack. Maybe this will put an end to it.
> 
> Years ago, amps were only amps and all the signal processing was done externally...<snip>



Posts like this _should_ not only put an end to the debate, but they also _should_ eliminate the need for entire threads based on car audio myths.


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## starboy869 (Dec 16, 2006)

I would even take an ipod with 256k mp3 vs having more than three cds in my car. Dvd-a is another story.


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## t3sn4f2 (Jan 3, 2007)

starboy869 said:


> I would even take an ipod with 256k mp3 vs having more than three cds in my car. Dvd-a is another story.


What does DVD-A offer really, greater clean dynamic range? Not very useful unless you are playing classical on a speaker system with the dynamic range to resolve it.

I do like the 256K idea.


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## MarkZ (Dec 5, 2005)

WRX/Z28 said:


> Yeah? I'd suggest you try running them next to each other in a Buick GN for an extreme example of how this is still not a good idea.


Um...I don't have access to a Buick GN. I stand by my comment. Induction isn't even close to being any of the dominant sources of noise in an automobile. Especially in such a ****ty electrical environment.


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## envisionelec (Dec 14, 2005)

MarkZ said:


> The signal is too high and the impedance is low enough for inductive noise to not be much of an issue. Unless maybe you zip tied them together for about 150 feet.


Hmm, I have to disagree with you on this. While the output impedance of a deck may be low enough, the termination impedance may be 10k or higher. Given that the slope of noise riding along the B+ line could be 31v/microsecond* and is easily coupled into a nominally shielded RCA cable, albiet on the order of microvolts. With amplification of 28dB, a 100 microvolt noise signal could be heard as faint whine occuring at 2.5mV. That is audible through a tweeter in a quiet environment.


*49V Stator Peak, 1kHz noise


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## MarkZ (Dec 5, 2005)

envisionelec said:


> Hmm, I have to disagree with you on this. While the output impedance of a deck may be low enough, the termination impedance may be 10k or higher. Given that the slope of noise riding along the B+ line could be 31v/microsecond* and is easily coupled into a nominally shielded RCA cable, albiet on the order of microvolts. With amplification of 28dB, a 100 microvolt noise signal could be heard as faint whine occuring at 2.5mV. That is audible through a tweeter in a quiet environment.
> 
> 
> *49V Stator Peak, 1kHz noise


Not in comparison to ground loops and internal ground issues. We're talking about a really minor amount of induction, especially if you don't zip tie the two cables together. You can run on the same side of the car and still leave a fair amount of space which would virtually eliminate the effect altogether.


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## starboy869 (Dec 16, 2006)

Wouldn't going to optical cable be a much better idea if you have the option to do so?


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## envisionelec (Dec 14, 2005)

MarkZ said:


> Not in comparison to ground loops and internal ground issues. We're talking about a really minor amount of induction, especially if you don't zip tie the two cables together. You can run on the same side of the car and still leave a fair amount of space which would virtually eliminate the effect altogether.


I am responding to your post; not making comparisons to dominant sources of noise... 



MarkZ said:


> The signal is too high and the impedance is low enough for inductive noise to not be much of an issue.


:shifty:


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## MarkZ (Dec 5, 2005)

envisionelec said:


> I am responding to your post; not making comparisons to dominant sources of noise...
> :shifty:


How can you examine one without the other? In that quote, I said "...to be much of an issue." If it's overwhelmed by other sources of noise, how could it be an issue?


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## envisionelec (Dec 14, 2005)

MarkZ said:


> The signal is too high and the impedance is low enough for inductive noise to not be much of an issue. Unless maybe you zip tied them together for about 150 feet.





MarkZ said:


> How can you examine one without the other? In that quote, I said "...to be much of an issue." If it's overwhelmed by other sources of noise, how could it be an issue?


The signal is *not* too high, and the impedance is *not* too low to be affected. That is to which I am referring.


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## MarkZ (Dec 5, 2005)

envisionelec said:


> The signal is *not* too high, and the impedance is *not* too low to be affected. That is to which I am referring.


I didn't say "to be affected." I said "to be an issue." It's only an issue if it gives rise to an audible effect. I think that's the point here, is it not?


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## WRX/Z28 (Feb 21, 2008)

First hand installation experience for 10+ years, plus working as a service tech tells me that running signal cable near a power cable will only cause problems. Opposite sides may not be nescessary, for instance, my signal cables run up the center of my car, but running down the same side is a bad idea. Anyone who doubts this is welcome to run their cables all on the same side...


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## envisionelec (Dec 14, 2005)

MarkZ said:


> The signal is too high and the impedance is low enough for inductive noise to not be much of an issue. Unless maybe you zip tied them together for about 150 feet.





MarkZ said:


> I didn't say "to be affected." I said "to be an issue." It's only an issue if it gives rise to an audible effect. I think that's the point here, is it not?


An issue. Affected. 

Same thing. You are incorrect. Next.


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## MarkZ (Dec 5, 2005)

WRX/Z28 said:


> First hand installation experience for 10+ years, plus working as a service tech tells me that running signal cable near a power cable will only cause problems.


I don't understand how. You never do it, right? There are plenty of people on this board (including me) who have done it dozens and dozens of times with no adverse effects. You don't ever do it. So who has more experience with it?



> Opposite sides may not be nescessary, for instance, my signal cables run up the center of my car, but running down the same side is a bad idea. Anyone who doubts this is welcome to run their cables all on the same side...


And I do. And have for nearly 15 years.


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## MarkZ (Dec 5, 2005)

envisionelec said:


> An issue. Affected.
> 
> Same thing. You are incorrect. Next.


It isn't the same thing and I explained why. I'm sorry you don't understand.


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## 14642 (May 19, 2008)

WRX/Z28 said:


> First hand installation experience for 10+ years, plus working as a service tech tells me that running signal cable near a power cable will only cause problems. Opposite sides may not be nescessary, for instance, my signal cables run up the center of my car, but running down the same side is a bad idea. Anyone who doubts this is welcome to run their cables all on the same side...


 Oh Yeah? Well I've been doing this for 25 years and I can't tell you how many times I've zip-tied power, remote, ground, speaker and RCA together, run them all out through the firewall, wrapped them around the ignition coil a couple of times, then the distributor and then run them back through the firewall and to the amplifiers. No noise, ever--at least not after the begining of inputs that weren't tied to ground. 

The fact is that once inputs are all differential and outputs are balanced, we won't have to talk about this any more. Optical is an easy fix, but it's unnecessary,


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## starboy869 (Dec 16, 2006)

I would think optical give you a better signal transfer over rca.


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## t3sn4f2 (Jan 3, 2007)

starboy869 said:


> I would think optical give you a better signal transfer over rca.


It does, but better like cleaning a mirror in a class 100,000 clean room gives you a clearer reflection then some Windex and a paper towel.


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## WRX/Z28 (Feb 21, 2008)

MarkZ said:


> I don't understand how. You never do it, right? There are plenty of people on this board (including me) who have done it dozens and dozens of times with no adverse effects. You don't ever do it. So who has more experience with it?
> 
> 
> 
> And I do. And have for nearly 15 years.


Being that I work on demonstration boards, I'd say I have more firsthand experience with signal and power being too close. 

Top that off with installation experience where people bring me cars with noise where they ran it all down the same side, and again i'd say I have more first hand experience. You are of course more than welcome to continue to run everything down the same side. With the plethora of electrical noise running up your power cable, running it near a signal cable is never a good idea. Twisted pair may keep you from noticing a problem, but it's still not a great idea.


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## WRX/Z28 (Feb 21, 2008)

Andy Wehmeyer said:


> Oh Yeah? Well I've been doing this for 25 years and I can't tell you how many times I've zip-tied power, remote, ground, speaker and RCA together, run them all out through the firewall, wrapped them around the ignition coil a couple of times, then the distributor and then run them back through the firewall and to the amplifiers. No noise, ever--at least not after the begining of inputs that weren't tied to ground.
> 
> The fact is that once inputs are all differential and outputs are balanced, we won't have to talk about this any more. Optical is an easy fix, but it's unnecessary,


Yeah? out and around the ignition box huh? lol. Come on Andy, being that you work for JBL, i'd expect you'd have seen inductance noise problems at some time. If you haven't, kudo's to you, you must deal with some stellar products that reject that nosie.


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## MarkZ (Dec 5, 2005)

WRX/Z28 said:


> Being that I work on demonstration boards, I'd say I have more firsthand experience with signal and power being too close.


Oh. So, not in a car though? Where is this power coming from anyway? And why do you think the noise that's injected into the cable is similar to what an alternator produces?



> Top that off with installation experience where people bring me cars with noise where they ran it all down the same side, and again i'd say I have more first hand experience. You are of course more than welcome to continue to run everything down the same side. With the plethora of electrical noise running up your power cable, running it near a signal cable is never a good idea. Twisted pair may keep you from noticing a problem, but it's still not a great idea.


The type of people who have noise issues and bring it to somebody to fix tend to be the same types of people who...well...don't know how to prevent and fix noise issues. So how do you know that the noise culprit is proximity to the power wire? And, in the cases where you believe that's the culprit, what does it look like?



> If you haven't, kudo's to you, you must deal with some stellar products that reject that nosie.


Well, why should the product have much to do with the induction of noise into the signal cable, anyway? Aside from the (somewhat arbitrary) value of input impedance of the amplifier, which isn't really a product of quality. If anything, you should be LESS likely to notice that kind of noise if the product is crappy and introducing its own noise, thereby burying the inductive noise even further below the noise floor.


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## WRX/Z28 (Feb 21, 2008)

MarkZ said:


> Oh. So, not in a car though? Where is this power coming from anyway? And why do you think the noise that's injected into the cable is similar to what an alternator produces?
> 
> 
> 
> ...


Ok, you missed my tongue in cheek tone there... 

twisted pair cables can help with some of this noise. RF can affect the power cable and if you run your signal cables right next to a big rfi noise generator, i'll give you three guesses what happens. 

I've had experience first hand solving noise problems by simply relocating the rca cables away from the power line period starting as early as 1992. If you don't have issues, continue running them wherever you like, just don't tell me it never happens in other peoples vehicles.


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## MarkZ (Dec 5, 2005)

WRX/Z28 said:


> Ok, you missed my tongue in cheek tone there...
> 
> twisted pair cables can help with some of this noise. RF can affect the power cable and if you run your signal cables right next to a big rfi noise generator, i'll give you three guesses what happens.
> 
> I've had experience first hand solving noise problems by simply relocating the rca cables away from the power line period starting as early as 1992. If you don't have issues, continue running them wherever you like, just don't tell me it never happens in other peoples vehicles.


Well, I never said anything about nothing ever happening in people's vehicles. I think you have the logic backwards here. Basically, you're saying because you haven't been able to successfully run the wires down the same side, then it can't be done. What I'm telling you is that lots of people HAVE done it successfully, and routinely do it every time. 

Why doesn't it work when you used to do it? I don't know. Maybe it's worth comparing more detailed installation strategies to get to the bottom of the issue. Or maybe we should try to figure out the exact procedure you're using when you try to eliminate other variables as being the culprit. But the point is that it most certainly IS a valid way of doing things, as evidenced by the fact that lots of people DO it successfully. Again, since you presumably avoid trying to do it, I wouldn't expect you'd have as much experience doing it as other people would.

I'm trying to think of an analogy that would demonstrate what I'm talking about a little better. Ok, suppose we both play the Super Mario video game and I tell you about the secret world you can get into if you do X, Y, and Z. Then you do X, Y, and Z and your player always dies. Does that mean that X, Y, and Z doesn't work?

Sorry for the 1986 analogy.


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## WRX/Z28 (Feb 21, 2008)

Well, I never said anything about it happening in every car did I?

Someone just put it up as being a myth that you should run cables away from each other. I'm simply stating that it's not a myth, and it's a good practice to be in the habit of.


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## MarkZ (Dec 5, 2005)

WRX/Z28 said:


> Well, I never said anything about it happening in every car did I?
> 
> Someone just put it up as being a myth that you should run cables away from each other. I'm simply stating that it's not a myth, and it's a good practice to be in the habit of.


Unless you know how to do it.


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## WRX/Z28 (Feb 21, 2008)

Unless you know how to do what? Uncork the magic of running rca's and power cable zip tied to each other noise free? lol Come on...


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## MarkZ (Dec 5, 2005)

WRX/Z28 said:


> Unless you know how to do what? Uncork the magic of running rca's and power cable zip tied to each other noise free? lol Come on...


Well, there are apparently people (myself included) who manage to do it so that no noise is introduced. There must be something we're doing that you're not. Or vice versa.


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## WRX/Z28 (Feb 21, 2008)

MarkZ said:


> Well, there are apparently people (myself included) who manage to do it so that no noise is introduced. There must be something we're doing that you're not. Or vice versa.


Hmmm... there's people out there that use knives and cut towards themselves, yet they manage not to cut themselves. I still wouldn't say it's a good idea, nor would I say that that person will never cut themselves...


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## chad (Jun 30, 2005)

think logically here, what has to happen in that power cable to induce noise on the signal cables. hint: what's NOT happening in that power cable at system idle when noise would be heard


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## W8 a minute (Aug 16, 2007)

chad said:


> think logically here, what has to happen in that power cable to induce noise on the signal cables. hint: what's NOT happening in that power cable at system idle when noise would be heard


The answer is "What is current flow?"


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## qwertydude (Dec 22, 2008)

I've found some expensive wire isn't so good. I installed an amp for a friend using some expensive 4 gauge wire, forgot the brand, but it used a silicone insulator which though flexible and easy to strip, also meant it could get cut and short out easily. Don't go too cheap though because I've bought "4" gauge which had so much insulation the wire inside was about the same as standard 8 gauge cough-Walmart-cough. Touch of the flu seems to be going around :lol:


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## ChuckBerry (Jan 9, 2009)

unpredictableacts said:


> I also shake the milk before pouring a glass....My wife used to say that I was going to keep doing it and turn it into butter.....no butter yet.


LOL that's hilarious...if you did that with RAW cow milk straight from the teat, sure, after hours of shaking it would happen. But sans cream and most of the fat removed, and being homogenized, it is impossible to make butter with store bought milk.


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## whynotmoo (Feb 15, 2009)

Sheesh, I have alot to learn.....


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## rain27 (Jan 15, 2009)

As far as all amps sounding the same (all things being equal)...I know I would not want to take a listening test to pick out the 10k amp out of a lineup. Same goes for speaker wire and cable.


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## 89grand (Nov 23, 2006)

MarkZ said:


> Well, there are apparently people (myself included) who manage to do it so that no noise is introduced. There must be something we're doing that you're not. Or vice versa.



You're not alone by any means. I've ran my main power wire right next to my RCA's numerous times and have NEVER had electrical noise in the system.

I agree it's a myth.


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## J0ne (Aug 7, 2007)

just reading through some of these...might be good for n00bs


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## ChrisB (Jul 3, 2008)

Since this thread has been bumped back up to the top, I have an interesting spin on the not running your RCAs near the Power cable. What about unibody vehicles? If the power cable can induce noise, isn't every single piece of sheet metal in a Unibody vehicle one big conducting ground for the electrical system? If my logic is correct, then one would have to suspend their RCAs to reject noise from the power or ground, correct?

Then again, this was just an interesting thought I had.... I only got 3 hours of sleep last night and figured I would ask the experts.


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## MarkZ (Dec 5, 2005)

06BLMUSTANGGT said:


> Since this thread has been bumped back up to the top, I have an interesting spin on the not running your RCAs near the Power cable. What about unibody vehicles? If the power cable can induce noise, isn't every single piece of sheet metal in a Unibody vehicle one big conducting ground for the electrical system? If my logic is correct, then one would have to suspend their RCAs to reject noise from the power or ground, correct?
> 
> Then again, this was just an interesting thought I had.... I only got 3 hours of sleep last night and figured I would ask the experts.


What's wrong with that? Then your power cable can double as a clothesline.


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## 89grand (Nov 23, 2006)

Like I said earlier in this thread, separating the RCA's from the main power is a waste of time. I've never done it, and I've never had electrical noise.


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## mjgonegm (Jun 21, 2008)

qwertydude said:


> I've found some expensive wire isn't so good. I installed an amp for a friend using some expensive 4 gauge wire, forgot the brand, but it used a silicone insulator which though flexible and easy to strip, also meant it could get cut and short out easily. Don't go too cheap though because I've bought "4" gauge which had so much insulation the wire inside was about the same as standard 8 gauge cough-Walmart-cough. Touch of the flu seems to be going around :lol:


That pisses me off not only is it dangerous it could start a fire BIG LAWSUIT COMING, wally land


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## ChrisB (Jul 3, 2008)

MarkZ said:


> What's wrong with that? Then your power cable can double as a clothesline.





89grand said:


> Like I said earlier in this thread, separating the RCA's from the main power is a waste of time. I've never done it, and I've never had electrical noise.


I got into it with the guys on my ricer forum a while back when they said *"NEVER run your RCA cables near your power wire because it will induce noise"*. Well, they agreed that Civics are unibody vehicles yet they tried to tell me it is different regarding running your RCAs near the sheet metal than it is near the power cable 

Maybe I am wrong in my line of thinking but if one is going to suffer from induced noise, it can come from either direction meaning power or ground, correct?


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## 89grand (Nov 23, 2006)

Well they're ricers...of course they are wrong!


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## quality_sound (Dec 25, 2005)

A new one: The Mag v4 is a 12" midbass driver not a real sub and can't play anything under 40Hz.


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## farshad (Mar 4, 2007)

89grand said:


> Like I said earlier in this thread, separating the RCA's from the main power is a waste of time. I've never done it, and I've never had electrical noise.


But I had this problem one time! once I separted the rca cable's from the power cable, the noise completely went away!


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## ChrisB (Jul 3, 2008)

quality_sound said:


> A new one: The Mag v4 is a 12" midbass driver not a real sub and can't play anything under 40Hz.


That was the same thing with my JL Audio 10w3v2s in .625 cubic feet sealed per 10:laugh:

ETA: JL Audio's recommendations for their own subwoofers suck!


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## quality_sound (Dec 25, 2005)

Because you changed where it was routed. I'll bet the RCAs were next to something like a relay bank or fuel pump and that was the noise issue.


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## VP Electricity (Apr 11, 2009)

06BLMUSTANGGT said:


> I got into it with the guys on my ricer forum a while back when they said *"NEVER run your RCA cables near your power wire because it will induce noise"*. Well, they agreed that Civics are unibody vehicles yet they tried to tell me it is different regarding running your RCAs near the sheet metal than it is near the power cable
> 
> Maybe I am wrong in my line of thinking but if one is going to suffer from induced noise, it can come from either direction meaning power or ground, correct?


Invalid analogy, isn't it? Take the amount of energy returning to ground, and compare it to the surface area of the body... I suspect that you are talking about very low EMI locally.


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## VP Electricity (Apr 11, 2009)

My myth:

The speaker is rated for 100w, so I have to use a 100wpc amp with it. 

My take on power and speaker:

The theoretical approach says it can't happen. Some people seem to have observed it. The discussion that they can go down the same side as long as they are seperated by a few inches is useless - Andy makes the case better by saying "zip tied together". 

Ive gotten away with it at times, and I have seen it happen a few times. I think it is a corner condition which has to do with the specific electrical system and the components operating on it. I don't think it's a universal, but I think it CAN happen because I think I've seen it happen, and all the theoretical discussion in the world won't overcome direct experience. (I've seen what happens when you prove an EE wrong: They say, "oh, well, that makes sense", and pretend they were right all along.)


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## MarkZ (Dec 5, 2005)

VP Electricity said:


> My myth:
> 
> The speaker is rated for 100w, so I have to use a 100wpc amp with it.
> 
> ...


The problem is that observations often fail to account for all the variables involved.

Thing is, and it's something Chad alluded to months ago in this thread... Some people are noting this noise issue when the amp isn't putting out sound. It's sitting there idle. So what's REALLY inducing the noise in that case?


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## ChrisB (Jul 3, 2008)

VP Electricity said:


> Invalid analogy, isn't it? Take the amount of energy returning to ground, and compare it to the surface area of the body... I suspect that you are talking about very low EMI locally.


I am not thinking all that clear right now, but I would think that in some instances there would be a greater likelihood of noise being introduced through the unibody panels via the ground than there would be through the power wire. After all, aren't there tons more things that are grounded throughout the unibody vehicle that can introduce noise versus the power cable that can only induce noise as current is being drawn through it?

Then again, I may read this tomorrow and facepalm myself.


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## 89grand (Nov 23, 2006)

06BLMUSTANGGT said:


> I am not thinking all that clear right now, but I would think that in some instances there would be a greater likelihood of noise being introduced through the unibody panels via the ground than there would be through the power wire. After all, aren't there tons more things that are grounded throughout the unibody vehicle that can introduce noise versus the power cable that can only induce noise as current is being drawn through it?
> 
> Then again, I may read this tomorrow and facepalm myself.


I pretty much agree with what you are thinking.

The whole damn car is full of wires, both power and ground, why is that the amps power wire is the only one to avoid? You have no choice but to run the RCA's in the car next to some sort of factory wire.


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## MarkZ (Dec 5, 2005)

89grand said:


> I pretty much agree with what you are thinking.
> 
> The whole damn car is full of wires, both power and ground, why is that the amps power wire is the only one to avoid? You have no choice but to run the RCA's in the car next to some sort of factory wire.


I think the idea is proximity and current density. Since all the current flow is focused within your power wire, and since your RCAs would be sitting right next to the power wire (if you zip tied them together), then it would be a much bigger effect than the RCAs sitting in a plane where current flow is diffused.

For people who are having issues with the two zip tied to each other, why not just separate them some? And if that doesn't fix it, how 'bout using REAL signal cable? [You know, that **** with a shield.  ]

But...for the sake of full disclosure...I'm talking out my ass right now because I usually zip tie cheap unshielded RCAs to a factory wire bundle.


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## chad (Jun 30, 2005)

89grand said:


> You have no choice but to run the RCA's in the car next to some sort of factory wire.


That factory harness kicked my ass because I tried to be "cool"


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## WRX/Z28 (Feb 21, 2008)

So where did this supposed Myth come from?

Could it possibly have to do with the proximity for a long length?


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## chad (Jun 30, 2005)

WRX/Z28 said:


> So where did this supposed Myth come from?
> 
> Could it possibly have to do with the proximity for a long length?


likely and/or possibly poor amplifier design that leaks **** up and down the power wire.


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## WRX/Z28 (Feb 21, 2008)

chad said:


> likely and/or possibly poor amplifier design that leaks **** up and down the power wire.


So maybe not so much a myth as an outdated precaution.


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## MarkZ (Dec 5, 2005)

WRX/Z28 said:


> So maybe not so much a myth as an outdated precaution.


I don't think the myth is that it can cause funny noises. I think most everyone acknowledges that there are situations where putting your signal cables near the wrong spot can be problematic. I think the myth is that you MUST run the cables along different sides of the car or you'll be fuct. That's what they teach the guys at installer school, isn't it?


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## snaimpally (Mar 5, 2008)

Myth: Ported/vented sub boxes are boomy and sealed sub boxes are "tighter".


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## chad (Jun 30, 2005)

It would take A LOT of hash to make that happen.... and I'll admit to have run some pretty crude and ****ty amps in my time.  :blush:


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## MarkZ (Dec 5, 2005)

chad said:


> It would take A LOT of hash to make that happen.... and I'll admit to have run some pretty crude and ****ty amps in my time.  :blush:


"Oh, by the way guys, I used 100ft RCAs on this job. So I coiled up the excess around the alternator..."

So have you heard anything about RF from a class D amp finding its way into the power wire? I'm pretty sure the FCC wouldn't be happy if that was part of the design, but you get some broken ones every now and then..


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## chad (Jun 30, 2005)

then the FCC would REALLY hate Honda
I can hear it coming a 1/2 mile away on the home ham radio 

Part 15 is pretty loosely worded


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## WRX/Z28 (Feb 21, 2008)

MarkZ said:


> I don't think the myth is that it can cause funny noises. I think most everyone acknowledges that there are situations where putting your signal cables near the wrong spot can be problematic. I think the myth is that you MUST run the cables along different sides of the car or you'll be fuct. That's what they teach the guys at installer school, isn't it?


I thought it was "At least 12" apart". 

I think the opposite sides of the car thing came from the fact that in the interest of speed, you usually couldn't run them apart on the same side of the car. The seats would interfere with this, and noone installing on a timeline removes the seats...


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## BASS NOOB (May 8, 2009)

as far as ported/vented its a toss up i guess ported sounds good with less power but sealed sounds better even though u need a little more power but then ported u need a big box vs sealed which is considerably smaller now i have confused myself lol


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## WRX/Z28 (Feb 21, 2008)

BASS NOOB said:


> as far as ported/vented its a toss up i guess ported sounds good with less power but sealed sounds better even though u need a little more power but then ported u need a big box vs sealed which is considerably smaller now i have confused myself lol


Tspence? Is that you?


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## ChrisB (Jul 3, 2008)

BASS NOOB said:


> as far as ported/vented its a toss up i guess ported sounds good with less power but sealed sounds better even though u need a little more power but then ported u need a big box vs sealed which is considerably smaller now i have confused myself lol


What does power have to do with any of this? I ask because I tend to overpower my subwoofers whether I run them sealed or ported If they blow, well then they needed replacing anyhow:laugh:


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## BASS NOOB (May 8, 2009)

well sed lol :laugh:


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## 89grand (Nov 23, 2006)

Ported FTW....assuming it's done right.

I've ran many sealed enclosures, but ported is better in just about every category except enclosure volume.


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## J0ne (Aug 7, 2007)

89grand said:


> Ported FTW....assuming it's done right.
> 
> I've ran many sealed enclosures, but ported is better in just about every category except enclosure volume.


I see what your saying...and I agree.


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## VP Electricity (Apr 11, 2009)

MarkZ said:


> The problem is that observations often fail to account for all the variables involved.


Not _the_ problem. _A_ problem. Just like another problem is people discounting other's observations because the observed data don't fit their preconceptions. Not _the_, just _a_...



MarkZ said:


> Thing is, and it's something Chad alluded to months ago in this thread... Some people are noting this noise issue when the amp isn't putting out sound. It's sitting there idle. So what's REALLY inducing the noise in that case?


I have already noted that this forum has many people who, while knowledgeable about system design and components, seem to be totally lost when it comes to noise troubleshooting and causes of noise in a car audio system. 

Amp is always putting out signal when it's on... else, what is a noise floor? : )


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## MrDave (May 19, 2008)

Funny thread.

I knew I'd see the "amps don't have SQ" crop up.

Running the power wire next to RCA's was a good mention.

What else can we add?

JL reps like to tell you that subs sharing air space have better SQ.

How about capacitors?


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## quality_sound (Dec 25, 2005)

I would say it's noise, not signal. Signal would be the amplified version of what was input, not what was generated internally. Hence, the SNR.


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## VP Electricity (Apr 11, 2009)

quality_sound said:


> I would say it's noise, not signal. Signal would be the amplified version of what was input, not what was generated internally. Hence, the SNR.


Can't have it both ways, though. If noise is inducted onto a signal cable before it gets to the amp, it's "signal" as far as the amp is concerned - as is the noise floor component of the upstream devices, right?


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## dkh (Apr 2, 2008)

More myths:

1. Post an issue that you need solved and expect answers to solve the issue... 

2. or answers that label you and make you want to give up... 

3. Competition can not help you improve your sounds... and, the best excuse I've read for this is along the lines of: "I'm tuning/installing for me and no one else" :laugh: More like that turd in my pants is getting too heavy to handle...

How do you learn? did someone say from errors or mistakes???


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## quality_sound (Dec 25, 2005)

VP Electricity said:


> Can't have it both ways, though. If noise is inducted onto a signal cable before it gets to the amp, it's "signal" as far as the amp is concerned - as is the noise floor component of the upstream devices, right?


It's still noise though because it wasn't in the original signal. Now it's just amplified noise.


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## InterHat (May 12, 2008)

Myth: Auditioning speakers will get you something you like when you're completely new to audio.

Telling newbies to "audition speakers and pick out ones they like" is ridiculous. When I was completely new to audio I did this and ended up buying a set of entry-level Klipsch speakers for home and Infinity Kappas in my car because I thought bright meant detailed. I completely Tspenced myself. I went to record with some of my friends who had studio monitors and I was like "HOLY CRAP IT DOESN'T HURT MY FACE TO LISTEN TO MUSIC HERE FOR MORE THAN 10 MINUTES."


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## VP Electricity (Apr 11, 2009)

I like that one. 

How about "You should ONLY buy on the Internet"? If you have a good shop in the neighborhood, give them a try... we used to have a lot of DIY customers who we took care of...


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## trebor (Jun 30, 2008)

1. A good pair of headphones are what we should all strive for as the standard for good sound.

2. Because they are the standard, all good headphones sound the same. 

3. Good headphones are dictated by price, your only fooling yourselves if you think otherwise.

4. Price is _only_ dictated by the quality of materials used.

5. Headphone manufacturers only produce one good model, because silly....there is only one standard for good sound!


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## MarkZ (Dec 5, 2005)

VP Electricity said:


> Not _the_ problem. _A_ problem. Just like another problem is people discounting other's observations because the observed data don't fit their preconceptions. Not _the_, just _a_...
> 
> 
> 
> ...


The point isn't that the amp is always putting out signal. The point is that current flow down the power wire is only substantial WHEN the amp is putting out significant power (ie. when masking pretty much makes the noise floor unimportant). So, when the amp is idle, what's the source of the noise? If it's coming from the power wire, then it has to be something...else. Something that's probably solvable.


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## BASS NOOB (May 8, 2009)

i got a myth :

10's n 12's are always better in sound n efficentcy


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## 89grand (Nov 23, 2006)

BASS NOOB said:


> i got a myth :
> 
> 10's n 12's are always better in sound n efficentcy


Than what?


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## BASS NOOB (May 8, 2009)

than 15's or 18's ss eating, reading, n typing at the same time


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## WRX/Z28 (Feb 21, 2008)

and it's back from the dead!!!


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## supermotofan (Nov 29, 2010)

Damn, I have a lot to learn.

I just spent an hour reading about all the myths that I thought were truths.

Thanks for helping me!


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## Pitmaster (Feb 16, 2010)

2 yr bump


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## Noobdelux (Oct 20, 2011)

interesting thread ppls.. but who does the writeup for the first post of whats myth/true? : P


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## Grim0013 (Nov 4, 2008)

WRX/Z28 said:


> I'd take an Ipod that had all cd files ripped to lossless over a scratched cd any day.


I've been reading up a lot on encryption and encoding lately, and this reminded me of an interesting tidbit about the error correction scheme used on CDs. They use 2 interleaved layers of Reed-Solomon convolutional encoding which can correct burst errors of up to 4000 bits. One of the interesting advantages of the method (to me anyway) is that because of the way in which the two layers of error correcting code are interleaved, the data on the physical media is distributed in such a way that a scratch will slightly affect many blocks of data (which the code can easily correct) rather than heavily affecting few blocks of data (which the code cannot correct).

It's so effective that in practice, bit errors don't matter - it's the tracking errors that cause problems. I'm not as familiar with that part of the standard (I'm more of an algorithms kinda guy) so I'm not sure what sort of damage is likely to cause scratches or how to alleviate them. I suspect that light scratches aren't bad enough to affect tracking are extremely unlikely to cause any loss of quality regardless of how many of them there are. It would seem that deep scratches are what matter. I also suspect that CD cleaners use some sort of mild abrasive to smooth and "fill" scratches to restore tracking.


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