# Will a cheap oscilloscope work for setting gain??



## PickleSlice (Apr 21, 2017)

Will these cheap pocket oscilloscopes work on amps to detect clipping? - https://www.amazon.com/Oscilloscope...refRID=P6B2Z2BSNT28QXAHM64E&tag=breakwindo-20

Hoping to not spend $100+ on something I'll use very rarely.


----------



## minbari (Mar 3, 2011)

Sure. Or you can take your out to dinner. Seething gains with a dmm is overkill certainly donnt need a scope

Sent from my LG-LS998 using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

minbari said:


> Sure. Or you can take your out to dinner. Seething gains with a dmm is overkill certainly donnt need a scope
> 
> Sent from my LG-LS998 using Tapatalk


From what I've been looking into, finding the clipping point of both the head unit and the amp, and then setting the gain with a DMM is the best way to achieve the loudest with no clipping. Is this not the case?


----------



## minbari (Mar 3, 2011)

PickleSlice said:


> From what I've been looking into, finding the clipping point of both the head unit and the amp, and then setting the gain with a DMM is the best way to achieve the loudest with no clipping. Is this not the case?


Here is the issue. You can set each channel up perfectly with no clipping at all. It won't ba as loud as you want it, and a little clipping doesn'tsound bad.(i don't mean pure squarewave) 

the other issue is that having each channel optimized this way is surely not going mix well and you will just change the gains to get a good audio mix anyway. So it is largely a waste of time.

Sent from my LG-LS998 using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

minbari said:


> Here is the issue. You can set each channel up perfectly with no clipping at all. It won't ba as loud as you want it, and a little clipping doesn'tsound bad.(i don't mean pure squarewave)
> 
> the other issue is that having each channel optimized this way is surely not going mix well and you will just change the gains to get a good audio mix anyway. So it is largely a waste of time.
> 
> Sent from my LG-LS998 using Tapatalk


Interesting. This is the first time I've seen this thought on this issue. 

Do you set your gains up using music and tuning by ear?


----------



## gijoe (Mar 25, 2008)

Setting gains can just as easily be done by ear if you're willing to spend a few minutes actually listening. Neither a DMM, or an o-scope are needed, and even if used they won't necessarily be any "better" or "more accurate" than using your ears. 

It's crazy how little faith people have in their ability to hear distortion caused by clipping. It's not difficult to hear (until you start to get into pretty low frequencies), and if you cannot hear it by actually listening for it, it's not bad enough to cause damage to a speaker, or ruin the sound quality.

The key step that so many people want to skip is the part where they have to shut up and listen for a minute, adjust the volume and listen some more. Really though, it's not a difficult thing to do at all.


----------



## Ifixtheinternet (Jan 29, 2016)

I'm gonna bite.

Yes, an O-scope is good for finding your deck clipping point, but that's about it. You can also easily hear when the deck signal starts to distort.

An O scope is not that useful for setting your gains.

I've tried all 3 methods.
By ear, with dmm, with an O scope.

Yes, testing with an O-scope is the most pinpoint accurate. However, we are trying to hit a moving Target.

When you use an O scope, you have to play sine WAV test tones to view the signal.

The question then becomes at what db level should the test tones be?

Opinions range from 0db to -10db on average, which is s huge gap.

The reason for this is you will inevitably be playing music with widely varying levels of volume. The maximum volume level of any track is 0db.

If you use 0db tones, you prevent any possible track from clipping, but leave a huge amount of amp power off the table.

If you use 3db tones, you prevent only the very peaks of the loudest tracks from clipping, which would probably not be noticeable.

I've gone through it all and finally threw my hands up and turned the gain up on my mids until they had enough volume to play the quietest tracks to a level I was satisfied with.

I have the 80prs, which is known to play clean to 61/62 volume, so that simplified things.

But even if you get a scope, you'll most likely circle back to doing gains by ear eventually.



Sent from my Pixel XL using Tapatalk


----------



## gijoe (Mar 25, 2008)

Ifixtheinternet mentioned something that I wanted to followup on. 

If those really loud dynamic peaks clip a little bit, it's not a big deal for a couple of reasons. Firstly, you probably won't notice, they are very quick. Secondly, if the volume is turned up loud enough to clip these portions, your ears are already trying to protect themselves from damage. They muscles tighten to protect our eardrums from damage, and we lose the ability to hear the details that we would otherwise hear. Basically, the louder you turn it up, the less detail you can hear anyway. There's no need to worry about a bit of clipping at high volumes. As long as the clipping isn't excessive, it won't be a problem, and if it's excessive it will sound like crap.


----------



## Jscoyne2 (Oct 29, 2014)

gijoe said:


> Ifixtheinternet mentioned something that I wanted to followup on.
> 
> 
> 
> If those really loud dynamic peaks clip a little bit, it's not a big deal for a couple of reasons. Firstly, you probably won't notice, they are very quick. Secondly, if the volume is turned up loud enough to clip these portions, your ears are already trying to protect themselves from damage. They muscles tighten to protect our eardrums from damage, and we lose the ability to hear the details that we would otherwise hear. Basically, the louder you turn it up, the less detail you can hear anyway. There's no need to worry about a bit of clipping at high volumes. As long as the clipping isn't excessive, it won't be a problem, and if it's excessive it will sound like crap.


Fun fact. Bmw implemented an interesting feature in their vehicles. If the computer senses you're in a crash. It will play a super loud sound through all speakers for a split second in order for your ears to close up and protect them from the loudness of the crash.

Sent from my XT1710-02 using Tapatalk


----------



## minbari (Mar 3, 2011)

PickleSlice said:


> Interesting. This is the first time I've seen this thought on this issue.
> 
> 
> 
> Do you set your gains up using music and tuning by ear?


Basically yes. Turn hu volume to 1/3 or so. Tweeter channel all the way down. Then turn up midbass and sub to sounds good. I will check with an rta to begin eqing. But only for a starting point. Then finish turning by ear. If you have T/A I think you do that before eq.

+5 on what others said. I can't type that much on my phone. 

Sent from my LG-LS998 using Tapatalk


----------



## gijoe (Mar 25, 2008)

Jscoyne2 said:


> Fun fact. Bmw implemented an interesting feature in their vehicles. If the computer senses you're in a crash. It will play a super loud sound through all speakers for a split second in order for your ears to close up and protect them from the loudness of the crash.
> 
> Sent from my XT1710-02 using Tapatalk



I remember hearing about that a few years ago (maybe on this site), that's really cool, especially if it proved effective.


----------



## PickleSlice (Apr 21, 2017)

Thank you everyone, this has been very helpful with all the new information. 

Why is it all over the internet, on many many audio sites, that they all suggest Scope + DMM is the "best" way to do this? Not asking to be contrary, just wondering where this line of thinking comes from.

I've already set it using the DMM method, where the math (if I did it right) stated that I need to adjust the voltage out to 13.03v. Speaker wattage rms (85) X 2 = 170. Root of 170 = 13.03. According to other information I've found, that should mean that I'm only doing 45-ish watts per channel, which is obviously no good. 

I'll go out this evening and adjust by ear, see how it does. Thanks again, everyone.


----------



## gijoe (Mar 25, 2008)

PickleSlice said:


> Thank you everyone, this has been very helpful with all the new information.
> 
> Why is it all over the internet, on many many audio sites, that they all suggest Scope + DMM is the "best" way to do this? Not asking to be contrary, just wondering where this line of thinking comes from.


Because people in this hobby automatically think a more technical solution is always a better solution. This hobby has a lot of engineers, and technically minded people, those people tend to want data and precision. Some of those people are so blinded by that mentality that they don't realize their ears are perfectly suited for the job. 

Many people seem to believe there is a single perfect gain setting, but as mentioned earlier, music is recorded at different levels, the perfect gain setting for one song will leave a lot of power on the table for another song, and clip a bit on a third song. There is no singular perfect setting, there is an acceptable range, and it's easy to get within that range with just your ears.


----------



## Jscoyne2 (Oct 29, 2014)

I have a slightly different opinion.

An oscope is good for a few different things.

First it's good for knowing the clipping point any gear in the signal chain that has a gain structure. For instance. Many dsps have a level setting that is around 12+db to -50db. Those dsps have a certain voltage out but only actually give that voltage when its level is close to maxed out.

So say you're headunit clips at 61/62. You run a 0db tone at 61/62 into a dsp.(not arguing 0 -3 -6 tones here). You'd now want go know both the voltage out and the clipping point of the dsp. So what do you do? You turn up the dsps level setting until you see clipping. 

AT THAT POINT. There are only two uses for using a scope on amps. First, finding the maximum output of your weakest link. That is almost always your midbass driver. Assuming your driver can handle the full potential of the amp. (remember high pass filters make a big deal here) you'd set the maximum output of your midbass amplifier. Now every other amp setting is going to either be by ear, or by mic measurement because it will be level set based on matching output with the weakest driver.

The 2nd is your bass amp. I almost never tune the bass to be level matched with the rest of the system...cuz..Bass  

Many people turn their gains way too far up to get more bass, when its a different problem altogether. Box orientation. Time alignment. Ect. This causes massive distortion and a DC signal to go to the subwoofer, leading to blown gear. 

For most amateurs and basic shops. Id advise 0db tones on bass amps to make sure that there is absolutely no way a customer can hurt gear. Then let level be set via the bass knob.


Sent from my XT1710-02 using Tapatalk


----------



## Jscoyne2 (Oct 29, 2014)

gijoe said:


> I remember hearing about that a few years ago (maybe on this site), that's really cool, especially if it proved effective.


https://newatlas.com/mercedes-benz-pre-safe-sound-pink-noise/46179/

Sent from my XT1710-02 using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

Jscoyne2 said:


> I have a slightly different opinion.
> 
> An oscope is good for a few different things.
> 
> ...


So, I have no idea how to figure out the midbass seperate from my tweeters. My components have an inline non-adjustable crossover. I have been using my headunit to manage the xover for the speakers, and have everything turned off at the amp. I have the HPF for the components set to 70 atm. I have also been considering going active, but that's a different story.


----------



## Jscoyne2 (Oct 29, 2014)

PickleSlice said:


> So, I have no idea how to figure out the midbass seperate from my tweeters. My components have an inline non-adjustable crossover. I have been using my headunit to manage the xover for the speakers, and have everything turned off at the amp. I have the HPF for the components set to 70 atm. I have also been considering going active, but that's a different story.


Simple two way. Just ear setting gains is fine.

Go active. 

Sent from my XT1710-02 using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

So what I've gathered from this thread:

I can use an oscope to find the max clipping volume level of my HU.

From there, set gain by ear using music I'm familiar with. 

I think that's the gist of it. 

Also, maybe go active


----------



## Jscoyne2 (Oct 29, 2014)

PickleSlice said:


> So what I've gathered from this thread:
> 
> 
> 
> ...


You'll hear distortion in your HU. If its a basic set up. You don't need a scope

Sent from my XT1710-02 using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

Jscoyne2 said:


> You'll hear distortion in your HU. If its a basic set up. You don't need a scope
> 
> Sent from my XT1710-02 using Tapatalk


Would I find the HU clipping the same way as using an oscope, by setting the amp gain to the lowest and turn it up until I hear it?


----------



## Jscoyne2 (Oct 29, 2014)

PickleSlice said:


> Would I find the HU clipping the same way as using an oscope, by setting the amp gain to the lowest and turn it up until I hear it?


Yup.

Sent from my XT1710-02 using Tapatalk


----------



## minbari (Mar 3, 2011)

PickleSlice said:


> Would I find the HU clipping the same way as using an oscope, by setting the amp gain to the lowest and turn it up until I hear it?


Also, can just setup amp gains to stay under 75% of the hu volume. Old school style

Sent from my LG-LS998 using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

Jscoyne2 said:


> Yup.
> 
> Sent from my XT1710-02 using Tapatalk


You guys are great, thank you so much.


Off topic question, since you answered it earlier.

Going active, should I use the head unit xover, or the amps? I plan to get a new front amp in the future but I'll probably sit on this one for a while. The amps xover HPF slope is max -12db, the head unit goes to -24db. The head unit also has individual settings for the tweeter, gain from 0 to -8db and frequency settings from 1khz to 12.5khz. Common sense tells me to use the head unit crossover, but I wanted to ask since we touched on it briefly, to be sure.


----------



## PickleSlice (Apr 21, 2017)

minbari said:


> Also, can just setup amp gains to stay under 75% of the hu volume. Old school style
> 
> Sent from my LG-LS998 using Tapatalk


I may do this, it's a good reason not to spend more money.


----------



## Jscoyne2 (Oct 29, 2014)

PickleSlice said:


> You guys are great, thank you so much.
> 
> 
> 
> ...


hu

Sent from my XT1710-02 using Tapatalk


----------



## minbari (Mar 3, 2011)

PickleSlice said:


> You guys are great, thank you so much.
> 
> 
> 
> ...


Sometimes both. You may want a bandpass on the midbass that the hu won't provide, but with hu and amp you can.

Sent from my LG-LS998 using Tapatalk


----------



## gijoe (Mar 25, 2008)

I may have missed it, but what head unit and amps are you using?

To go active you need a HPF for the tweeters somewhere from about 2khz to 5khz, and you need a bandpass crossover for the mids. Most head units and amps cannot do this, but sometimes you can combine amp and head unit crossovers to make it work. Even then, you will have pretty limited tuning options, so going active may not offer much benefit.


----------



## PickleSlice (Apr 21, 2017)

minbari said:


> Sometimes both. You may want a bandpass on the midbass that the hu won't provide, but with hu and amp you can.
> 
> Sent from my LG-LS998 using Tapatalk


That's a great idea, but I don't think I can do that with my current amp. I'd set the HPF on my HU to 80 for this example. The highest my amp HP/LP can go is 750hz. So, I'd have a bandpass setting of 80hz to 750hz, and with the tweeters coming in at 1khz, that's going to leave a 250hz gap. Am I looking at that correctly? If that is the case, looks like I'll be getting that Zapco I've had my eye on for a while a lot sooner than planned.


----------



## PickleSlice (Apr 21, 2017)

gijoe said:


> I may have missed it, but what head unit and amps are you using?
> 
> To go active you need a HPF for the tweeters somewhere from about 2khz to 5khz, and you need a bandpass crossover for the mids. Most head units and amps cannot do this, but sometimes you can combine amp and head unit crossovers to make it work. Even then, you will have pretty limited tuning options, so going active may not offer much benefit.


JVC KW740BT, which has pretty good xover settings as far as I can tell. 


```
Crossover Network: The JVC KW-M740BT lets you choose between a 2-way or 3-way crossover network for your car audio application.

2-Way Crossover: Allows you to set high-pass and low-pass crossovers for a standard Tweeter, Front, Rear, and Subwoofer speaker setup.
Speaker Size: select which size speakers are in your vehicle.
Tweeter: Small, Medium, Large, or None
Front & Rear: 3.5", 4", 4.75", 5", 6.5", 6.75", 7", 4x6", 5x7", 6x8", 6x9", 7x10" or None
Subwoofer: 6.5", 8", 10", 12", 15" or greater, None
X'Over: Select the high pass or low pass crossover settings for your speakers.
Tweeter: high pass filter (HPF)
Frequency: 1kHz, 1.6kHz, 2.5kHz, 4kHz, 5kHz, 6.3kHz, 8kHz, 10kHz, 12.5kHz
Gain: -8 to 0 dB
Front & Rear: high pass filter (HPF)
Frequency: 30Hz, 40Hz, 50Hz, 60Hz, 70Hz, 80Hz, 90Hz, 100Hz, 120Hz, 150Hz, 180Hz, 220Hz, 250Hz, Through (Full-Range)
Slope: -6dB, -12dB, -18dB, -24dB
Gain: -8 to 0 dB
Sub: low pass filter (LPF)
Frequency: 30Hz, 40Hz, 50Hz, 60Hz, 70Hz, 80Hz, 90Hz, 100Hz, 120Hz, 150Hz, 180Hz, 220Hz, 250Hz, Through (Full-Range)
Slope: -6dB, -12dB, -18dB, -24dB
Phase: Reverse (180°), Normal (0°)
Gain: -8 to 0 dB
```
And a Sound Ordnance M75-4 that I wish I hadn't bought.


```
Low-Pass Crossover Frequency	50-750 Hz
Low-Pass Slope (dB/octave)	12 dB/oct
High-Pass Crossover Frequency	50-750 Hz
High-Pass Slope (dB/octave)	12 dB/oct
```
What little I know about this, I do not think I'd be able to run a bandpass filter effectively.


----------



## Holmz (Jul 12, 2017)

Ifixtheinternet said:


> I'm gonna bite.
> 
> Yes, an O-scope is good for finding your deck clipping point, but that's about it. You can also easily hear when the deck signal starts to distort.
> 
> ...


Or another way to think of it is setting it my numbers, will have a 100W amp peaking at 100w for a O-dB tone.
And the RMS power will be at 3W for most musical content.

A cheap scope is about the same as a costly scope for this work.


----------



## minbari (Mar 3, 2011)

PickleSlice said:


> That's a great idea, but I don't think I can do that with my current amp. I'd set the HPF on my HU to 80 for this example. The highest my amp HP/LP can go is 750hz. So, I'd have a bandpass setting of 80hz to 750hz, and with the tweeters coming in at 1khz, that's going to leave a 250hz gap. Am I looking at that correctly? If that is the case, looks like I'll be getting that Zapco I've had my eye on for a while a lot sooner than planned.


Would the hu allow the lpf of 1000hz to the amp? Then set hpf on amp of 80hz.

Prolly gonna want higher than 1khz for tweeters but you get the idea

Sent from my LG-LS998 using Tapatalk


----------



## carlthess40 (Aug 21, 2018)

Well if your ever in Lake Mary I’ll help you set the amps up. I have two Scopes and the test CDs for the correct frequency’s that is needed to be generated for setting the levels


Sent from my iPhone using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

minbari said:


> Would the hu allow the lpf of 1000hz to the amp? Then set hpf on amp of 80hz.
> 
> Prolly gonna want higher than 1khz for tweeters but you get the idea
> 
> Sent from my LG-LS998 using Tapatalk


Unfortunately not. 



carlthess40 said:


> Well if your ever in Lake Mary I’ll help you set the amps up. I have two Scopes and the test CDs for the correct frequency’s that is needed to be generated for setting the levels
> 
> 
> Sent from my iPhone using Tapatalk


Hey, you're just right down the I4 from me. Thanks for the offer, I may take you up on that in the future.


----------



## rayray881 (Jul 15, 2013)

Noticed some folks from Florida. There is a sq competition this Saturday in St. Petersburg at Amplified Autosports. I’m going to demo some cars and perhaps give demos. Cheers!


----------



## minbari (Mar 3, 2011)

PickleSlice said:


> Unfortunately not.
> 
> 
> 
> ...


Well the Dayton dsp is a nice idea for $150.  can do ANYTHING you want with it

Sent from my LG-LS998 using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

minbari said:


> Well the Dayton dsp is a nice idea for $150.  can do ANYTHING you want with it
> 
> Sent from my LG-LS998 using Tapatalk


I just got home and started looking through the head unit manual, and discovered there is a 3-way crossover setting, and bandpass filter is one of the options. So it looks like I could go active no problem. Found my next project for the weekend


----------



## Ifixtheinternet (Jan 29, 2016)

PickleSlice said:


> I just got home and started looking through the head unit manual, and discovered there is a 3-way crossover setting, and bandpass filter is one of the options. So it looks like I could go active no problem. Found my next project for the weekend


I saw that too, but unfortunately in 3 way mode you don't have 24db slopes available, but you have -6db and -12db. My suggestion would be to use -12db on both sides, and flip the polarity of the tweeter to reverse.

Sent from my Pixel XL using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

Ifixtheinternet said:


> I saw that too, but unfortunately in 3 way mode you don't have 24db slopes available, but you have -6db and -12db. My suggestion would be to use -12db on both sides, and flip the polarity of the tweeter to reverse.
> 
> Sent from my Pixel XL using Tapatalk


Reverse polarity of both tweeters?

I haven't had a chance to run out and play with it yet, but I will shortly.

:EDIT:

You're right, only -12db. I wonder why that is.


```
3-Way Crossover: Allows you to set high-pass and low-pass crossovers for a complex 3-way speaker system with Highs, Mids, and Sub.
Speaker Size: select which size speakers are in your vehicle.
Tweeter: Small, Medium, Large, or None
Midrange: 3.5", 4", 4.75", 5", 6.5", 6.75", 7", 4x6", 5x7", 6x8", or 6x9"
Woofer: 6.5", 8", 10", 12", 15" or greater, None
X'Over: Select the high pass or low pass crossover settings for your speakers.
Tweeter: high pass filter (HPF)
HPF Frequency: 1kHz, 1.6kHz, 2.5kHz, 4kHz, 5kHz, 6.3kHz, 8kHz, 10kHz, 12.5kHz
Slope: -6dB, -12dB
Phase: Reverse (180°), Normal (0°)
Gain: -8 to 0 dB
Midrange: high pass filter (HPF) & low pass filter (LPF)
HPF Frequency: 30Hz, 40Hz, 50Hz, 60Hz, 70Hz, 80Hz, 90Hz, 100Hz, 120Hz, 150Hz, 180Hz, 220Hz, 250Hz, Through (Full-Range)
LPF Frequency: 1kHz, 1.6kHz, 2.5kHz, 4kHz, 5kHz, 6.3kHz, 8kHz, 10kHz, 12.5kHz
Slope: -6dB, -12dB
Phase: Reverse (180°), Normal (0°)
Gain: -8 to 0 dB
Woofer: low pass filter (LPF)
LPF Frequency: 30Hz, 40Hz, 50Hz, 60Hz, 70Hz, 80Hz, 90Hz, 100Hz, 120Hz, 150Hz, 180Hz, 220Hz, 250Hz, Through (Full-Range)
Slope: -6dB, -12dB
Phase: Reverse (180°), Normal (0°)
Gain: -8 to 0 dB
```


----------



## Ifixtheinternet (Jan 29, 2016)

PickleSlice said:


> Reverse polarity of both tweeters?
> 
> 
> 
> I haven't had a chance to run out and play with it yet, but I will shortly.


Yeah, the crossovers create a phase shift.
12db crossovers create a 90 degree shift.

So with 12db on the tweeters and mids, they will be 180 degrees out of phase from each other at the crossover point, and you will get a dip.

Flipping the the polarity of the tweeters will add another 180, totalling 360, or in phase.

That's why I (and many others) prefer -24db crossovers because they cancel out and the drivers are in phase as a result.

Sent from my Pixel XL using Tapatalk


----------



## minbari (Mar 3, 2011)

Ifixtheinternet said:


> Yeah, the crossovers create a phase shift.
> 12db crossovers create a 90 degree shift.
> 
> So with 12db on the tweeters and mids, they will be 180 degrees out of phase from each other at the crossover point, and you will get a dip.
> ...


That is really only with passives. Electronic xovers don't have the related phase shifts.

And......24db does solve the phase shift, but at the cost of 2x the slope. I wouldn't say ANYONE goes with 24db to solve the phase issues. Personally I hate 24db slopes. So steep you can hear exactly where they are

Sent from my LG-LS998 using Tapatalk


----------



## minbari (Mar 3, 2011)

PickleSlice said:


> Reverse polarity of both tweeters?
> 
> 
> 
> ...


Most likely the 24db is made by compounding 2 12db filters together. In 3-way you are using them both

Sent from my LG-LS998 using Tapatalk


----------



## PickleSlice (Apr 21, 2017)

Goddamn I have a lot to learn.


----------



## Ifixtheinternet (Jan 29, 2016)

minbari said:


> That is really only with passives. Electronic xovers don't have the related phase shifts.
> 
> And......24db does solve the phase shift, but at the cost of 2x the slope. I wouldn't say ANYONE goes with 24db to solve the phase issues. Personally I hate 24db slopes. So steep you can hear exactly where they are
> 
> Sent from my LG-LS998 using Tapatalk


Oh interesting!
I'll have to revisit that on my system then.
My tweeters play pretty low so I do have wiggle room to try other slopes.

You don't even like -24 for your sub?

Sent from my Pixel XL using Tapatalk


----------



## minbari (Mar 3, 2011)

Ifixtheinternet said:


> Oh interesting!
> I'll have to revisit that on my system then.
> My tweeters play pretty low so I do have wiggle room to try other slopes.
> 
> ...


Only if you have a strong midbass so you can't tell where the sub dies. My current system is all 12db. I just under lap the sub by 5hz. 

Sent from my LG-LS998 using Tapatalk


----------



## JCsAudio (Jun 16, 2014)

My method is based on the fact that the subwoofer requires the absolute most power in the system to recreate the lower octaves. The first step is to acquire an amplifier that has 125% or more of the power required for the top RMS power of the subwoofer. If my subwoofer is rated 600 watts RMS then I want an amplifier rated for ~ 750 watts RMS or more. Then I adjust the gain on the mono amp using the method you like best, which in my case is to use a DMM and set the AC voltage to the subs maximum RMS rating using a -3 db 60 Hz tone, but not to the clipping of that amplifier. This ensures I have headroom where it’s needed in the lower octaves. 

Then I put away the DMM and forget about setting gains to clipping for mids and especially tweeters because tweeters only require like 15 watts max to keep up with a monster sub stage and my mids usually have a HP filter between 70 and 80 Hrz and are run from an amplifier that is more than powerful enough. So then I use my microphone and REW RTA playing pink noise and match the mid-woofer amplifier level with the sub level against my target curve. I do the same for the tweeters with the mid woofers against my target curve and walla, I have a quiet balance system that sounds great and no worries of clipping. I sometimes do some final tweaks by ear as well. 

Why anyone would set an amplifier that is say rated for 75 watts RMS to it’s maximum clipping for tweeters and then trim it down in the DSP because the tweeters are playing too loud is a mystery to me.

Now playing a 60 Hz test tone through my sub amplifier and into my $550 subwoofer at insane levels and listening for distortion, nah, I don’t think so. Too risky by me. If you’re not careful you can burn the voice coils doing that.

I’d rather buy the V8 engine and chug alone at low engine RPM than buy the 4 banger and stress that thing to the max pulling the same load.

Hot topic, many strong differing opinions on this and this is mine based on my experiences and research.


----------



## PickleSlice (Apr 21, 2017)

V8toilet said:


> My method is based on the fact that the subwoofer requires the absolute most power in the system to recreate the lower octaves. The first step is to acquire an amplifier that has 125% or more of the power required for the top RMS power of the subwoofer. If my subwoofer is rated 600 watts RMS then I want an amplifier rated for ~ 750 watts RMS or more. Then I adjust the gain on the mono amp using the method you like best, which in my case is to use a DMM and set the AC voltage to the subs maximum RMS rating using a -3 db 60 Hz tone, but not to the clipping of that amplifier. This ensures I have headroom where it’s needed in the lower octaves.
> 
> Then I put away the DMM and forget about setting gains to clipping for mids and especially tweeters because tweeters only require like 15 watts max to keep up with a monster sub stage and my mids usually have a HP filter between 70 and 80 Hrz and are run from an amplifier that is more than powerful enough.* So then I use my microphone and REW RTA playing pink noise and match the mid-woofer amplifier level with the sub level against my target curve. I do the same for the tweeters with the mid woofers against my target curve and walla, I have a quiet balance system that sounds great and no worries of clipping. I sometimes do some final tweaks by ear as well.*
> 
> ...


I know what you're talking about, but I do not know how. Do you have a mic on your laptop and run REW and adjust to what is on the screen? Is it a standard mic?


----------



## JCsAudio (Jun 16, 2014)

PickleSlice said:


> I know what you're talking about, but I do not know how. Do you have a mic on your laptop and run REW and adjust to what is on the screen? Is it a standard mic?


Yes and I use this


----------



## Ifixtheinternet (Jan 29, 2016)

V8toilet said:


> Yes and I use this


+1.

Spend the extra $30 and buy it from Cross-spectrum so you get the calibration files with it, you'll need them.

http://cross-spectrum.com/measurement/calibrated_umik.html

Sent from my Pixel XL using Tapatalk


----------



## Holmz (Jul 12, 2017)

V8toilet said:


> My method is based on the fact that the subwoofer requires the absolute most power in the system to recreate the lower octaves. The first step is to acquire an amplifier that has 125% or more of the power required for the top RMS power of the subwoofer. If my subwoofer is rated 600 watts RMS then I want an amplifier rated for ~ 750 watts RMS or more. Then I adjust the gain on the mono amp using the method you like best, which in my case is to use a DMM and set the AC voltage to the subs maximum RMS rating using a -3 db 60 Hz tone, but not to the clipping of that amplifier. This ensures I have headroom where it’s needed in the lower octaves.
> 
> Then I put away the DMM and forget about setting gains to clipping for mids and especially tweeters because tweeters only require like 15 watts max to keep up with a monster sub stage and my mids usually have a HP filter between 70 and 80 Hrz and are run from an amplifier that is more than powerful enough. So then I use my microphone and REW RTA playing pink noise and match the mid-woofer amplifier level with the sub level against my target curve. I do the same for the tweeters with the mid woofers against my target curve and walla, I have a quiet balance system that sounds great and no worries of clipping. I sometimes do some final tweaks by ear as well.
> 
> ...


It makes sense to set the gain with a DMM or scope like you suggest for the subwoofer, as it is generally the one that smokes the quickest.

Then I just start at minimum for the others and crank the gain until it is good?

Or do I use REW and crank up the gain until the bottom of the nulls hit the target so that the DSP only needs to remove a bit of gain at the peaks?
But generally sending full strength to the amp, and the amp gain is pretty low so the hiss is absent.?


----------



## JCsAudio (Jun 16, 2014)

Holmz said:


> It makes sense to set the gain with a DMM or scope like you suggest for the subwoofer, as it is generally the one that smokes the quickest.
> 
> Then I just start at minimum for the others and crank the gain until it is good?


 Yes, maybe 1 db more and trim in the DSP for a little bit of adjustment within the DSP. 



Holmz said:


> Or do I use REW and crank up the gain until the bottom of the nulls hit the target so that the DSP only needs to remove a bit of gain at the peaks?


 I would have already EQ'ed before level adjusting at this point and I ignore nulls if they are due to cancellation. If I cannot get the null to clear than I make the left and right sides match so I don't hear it pull to one side during certain notes. My overall max net boost is never more than 1 db in the DSP but individual boost can be more. I do this to avoid clipping the amplifier and or getting weird sonic conditions that can result from over boosting. And again I'm using an amplifier that has more than rated power so to keep power delivery as clean as possible but also driver THD in relation to xmax.




Holmz said:


> But generally sending full strength to the amp, and the amp gain is pretty low so the hiss is absent.?


 The way I see it, the lower I set my gains but meet the required power, the lower the noise floor, which is what that hiss in the background is really. 

I see it as if you are trimming a lot within the DSP than you have the gains on the amplifier too high. I'd rather trim with the amplifier gain and reduce noise floor than trim in the DSP and have more hiss/noise floor.

Hope this helps. It is the method I have found works best for me and will admit I am by no means an expert hear.


----------



## KG089 (Mar 31, 2019)

And for who said ‘setting a 100rms amp to 0db tones will net like 3W rms with music’
Okay so then what if listeners typical music is like 0db peaks up til about 1K 
And they are setting their mids gain which play from 80hz - 3.5k 
If the MUSIC above 1K is less than 0db what is wrong with setting your gains to play less wattage where there IS less wattage 
So then the 100hz -1K wont blow your spkr due to distortion and neither will above 1K 
You can’t make the tweeters play louder than a song has the music at either 
Well you can I suppose but then you wouldn’t be listening to the song at the levels it was recorded or produced at now would ya .... 

Matter fact since I’m bringing this up how does an auto tune set gain levels when using a dsp with the function how does it autoset levels and gain structure


----------



## minbari (Mar 3, 2011)

If you are playing music that has regular peaks at 0db, it will sound like ass. No dynamics left.

Sent from my LG-LS998 using Tapatalk


----------



## Holmz (Jul 12, 2017)

KG089 said:


> And for who said ‘setting a 100rms amp to 0db tones will net like 3W rms with music’
> Okay so then what if listeners typical music is like 0db peaks up til about 1K
> And they are setting their mids gain which play from 80hz - 3.5k
> If the MUSIC above 1K is less than 0db what is wrong with setting your gains to play less wattage where there IS less wattage
> ...


I think that the first part is me...

If 0-dB is full scale, then yes... for music the RMS value is typically ~15dB below peak.

Generally the power for the tweeters is ~15%, the mid range is ~35%, and woofers ~50%.
For car audio and home theatre the subwoofer would be gobbling up the majority of power.


----------



## KG089 (Mar 31, 2019)

Holmz said:


> KG089 said:
> 
> 
> > And for who said ‘setting a 100rms amp to 0db tones will net like 3W rms with music’
> ...


 I mean that sounds about rite I have 150x4 to tweets & mids - tweet gain is down to about 100w mids to about 125w 
Rms of my tweets and mids being 75 & 100 
But since they are both crossed over active I felt safe although as far as I knew thus far mids do/can reach 0db level tweets hardly ever will I did set my gains with an Oscope I doubt an extra 25w on either would kill anything 
My midbass are getting 180w a side 
Subwoofer about 650W 
My midbass sensitivity is about 5-6db less than mids/highs 
Anyways yeah I kinda forgot everything above a certain freq typically is way less power 
Kinda a mind**** 
Out of curiosity does anyone have fft graphs of a few popular classic rock/jazz/metal/pop/rap/r&b etc


----------



## Holmz (Jul 12, 2017)

KG089 said:


> I mean that sounds about rite I have 150x4 to tweets & mids - tweet gain is down to about 100w mids to about 125w
> Rms of my tweets and mids being 75 & 100
> But since they are both crossed over active I felt safe although as far as I knew thus far mids do/can reach 0db level tweets hardly ever will I did set my gains with an Oscope I doubt an extra 25w on either would kill anything
> My midbass are getting 180w a side...
> ...


Well you may get an extra 25W (peak) to the tweeters, but the RMS will still be ~5W or less.
Then if they are getting an extra 25W peak, then you need to turn up ether midrange or mid base to get them louder so that the music is not overly bright.
However if the MR or MB is already turned up, then you either need to have it clipping more, or maybe not want the volume knob twisted as a hard.

The MB has 180W/side available.
How much do you think gets delivered in an RMS sense?


----------



## KG089 (Mar 31, 2019)

Holmz said:


> KG089 said:
> 
> 
> > I mean that sounds about rite I have 150x4 to tweets & mids - tweet gain is down to about 100w mids to about 125w
> ...


 Well ..
Lol as I’ve already stated now I’m kinda lost 
By something I already knew 
But completely slipped my mind with me being technical 
I always tended to believe my mb received a fair share of the full 180 most the time since bass & midbass notes approach the 0db mark 
I set mb & sub with 0db tones 
I’m sure there are plenty of notez that don’t approach rms 
But when it comes to mb & sub 
And possibly mids too..
I’m sure there are plenty of notes that infact do


----------



## Holmz (Jul 12, 2017)

You are on point... The sub and to a lesser extent the mid bass can play louder, and the crest factor is lower with heavy bass.
But it is likely still way less than 180W, unless it is really loud and the MB is heavy and constant.

Which also goes to show that the 100W RMS amp for the tweeter or midrange may only closer to 1W RMS, one still needs at least 20W (or more) to have the headroom for the fast/sharp impulses.


----------



## KG089 (Mar 31, 2019)

Holmz said:


> You are on point...
> Which also goes to show that the 100W RMS amp for the tweeter or midrange may only closer to 1W RMS


 Why is he here lol 
?


----------

