# So how does home audio work?



## trains are bad (Aug 8, 2005)

I'm about tired of spending money on car audio which is not going well for me, and I have a very nice headphone setup, but headphones fundamentally suck for most material. So I was thinking of whipping up some basic home system, when I realized I know absolutely nothing of home audio. I am in a vacuum of audio knowledge. Nobody I know has any sort of audio system beyond the basic walmart surround system. I know lots about car audio.

So, starting from the very bottom, what's a reciever actually? I assumed you'd run RCAs from your CD player to an amp, to the xover if applicable, to the speakers. What kind of processors do people use? 

Does everything just plug into the wall, and have internal power supplies?

Can you integrate surround with a Hifi stereo setup, or do they have to be kept separate? I'm really clueless how you integrate it into a Home theatre setup. How do you switch between stereo and surround? 

My source would be my computer and FLAC library, and an external DAC. 

I'm well up on car audio, I just have no idea how you do audio in your house. If you could recommend some reading or just explain home audio in terms someone that a car audio nut could understand, that would be great.


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## pervo (Aug 1, 2005)

trains are bad said:


> I'm about tired of spending money on car audio which is not going well for me, and I have a very nice headphone setup, but headphones fundamentally suck for most material. So I was thinking of whipping up some basic home system, when I realized I know absolutely nothing of home audio. I am in a vacuum of audio knowledge. Nobody I know has any sort of audio system beyond the basic walmart surround system. I know lots about car audio.


lets define two things
home audio = two channel critical listening
home theater= 5.1 channel w/ screen of course
simple enough



trains are bad said:


> So, starting from the very bottom, what's a reciever actually? I assumed you'd run RCAs from your CD player to an amp, to the xover if applicable, to the speakers. What kind of processors do people use?


in home audio "processors" are viewed as the devil
idealy one has a very high end cd player w/ top of the line DAC's(rotel 1072 is regarded as a good budget cd player)
then you go out with a nice pair of composit wires (gan be very very expensive, look at audio quest for reasonably priced high end)

then one goes into a preamp, controling switching from different inputs (ie phono, cd, dvd, etc) and acts as the only volume/gain controle
again look at rotel for a well rtespected budget version 

from there either composit or balanced cables are run to a two channel amplifier (again rotel is suggested on a budget)

no equalization is done because it is presumed that the speakers are designed well enough and one has enough knowledge on how to controle the rooms accoustics (this will take some reading as there is always something new to learn)

in short recievers are not used for critical listening
also dvd players can be used instead of a cd player when one wishes to play dvd-a or sacd's, but there is some anxiety over the extra internals so high end ones have a mode called pure dirrect wich bypasses some of the circuitry
again state of the art DAC's are needed so budget for 2000k+ if you want it to be considered 'good'
ive opted to buy a cheap dvd player (denon for $300+) since bluray is around the corner
all of my listening is done on the rotel unless it is a dvd-a or sacd




trains are bad said:


> Does everything just plug into the wall, and have internal power supplies?


strongly suggested to get a power conditioner... monster makes some affordable ones



trains are bad said:


> Can you integrate surround with a Hifi stereo setup, or do they have to be kept separate? I'm really clueless how you integrate it into a Home theatre setup. How do you switch between stereo and surround?


you can have a stand alone processor just for the surroundsound, hence utilizing some amps for stereo and 5.1, along w/ the preamp

granted it may just be cheaper to buy a reciever for 5.1 in this case
recievers are not regarded as having very good sq
for me i do only 2 channel so i just returned my denon 3806


trains are bad said:


> My source would be my computer and FLAC library, and an external DAC.


 what type of external DAC, very interested, that would alow you to save some cash on the dvdplayer... pls post some more info for my benifit 


trains are bad said:


> I'm well up on car audio, I just have no idea how you do audio in your house. If you could recommend some reading or just explain home audio in terms someone that a car audio nut could understand, that would be great.


read loudspeaker design cookbook by vance dickenson
they sell it on madisound and parts express, not to mention amazon
7th edition just came out...... that will keep you busy for a while and give you a good foundation


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## Finleyville (Jun 17, 2005)

Well, home stuff can be as simple or as complicated as good car audio systems. It all depends on your budget.

The cheapest and most basic "system" would be one of those chain store "boomboxes." There are a couple of companies that sell higher end mini-systems that come with a radio tuner, cd player, sometimes casette tape player, and two separate speakers to place a little away from the main unit. The size of these systems are about two shoeboxes. Most people use these for background music in the office or bedroom.

The next sized system would be a simple two channel stereo. A single unit called a "receiver" has an included radio tuner and accepts RCA plugs or digital inputs from CD's, tapes, and record players. This receiver has built in amps, power supplies, and such. You would then separately purchase a pair of speakers ranging in size from a breadbox (called bookshelf speakers because of their common placement on bookshelves) to tall floorstanding speakers. 
Higher end companies sometimes separate this receiver into two different parts. The preamp and the amp. The preamp acts just like a dead head unit in the car. It has all the inputs of the receiver without the power. Then the amplifier takes the music signal and sends it to the two speakers.

The most common system nowadays is the home theater system. This usually starts with the receiver. However, this A/V receiver now accepts video signals along with all the audio inputs as well. This means that you can actually connect your TV into the receiver to accept the video signal. Plus instead of only having two channels of audio (left and right) the A/V receiver now has multiple surround audio channels along with a dedicated sub channel as well. The most common configuration is a 5.1 setup. Meaning 5 fullrange channels around the room (left, center, right, rear left, rear right) with the .1 channel being the sub. Some higher priced receivers have up to 8.1 audio channels. This multi-channel output can always be condensed into your standard two channel system for music. With the addition of the surround channels naturally you need additional speakers for the surround material. 

As far as x-overs go, 99% of home speakers whether or not they have only one driver or 8+ in each cabinet all have an internal x-over inside. This means that usually you will only have one amplified speaker wire to each speaker. 


Hope this helps you on your way...


edit: I hate when someone beats your post by a second...


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## trains are bad (Aug 8, 2005)

Headroom usb MicroDac. Thanks for your help.


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## pervo (Aug 1, 2005)

http://www.htguide.com/forum/index.php4?


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## Ocelaris (Jun 23, 2005)

I'll just give my opinion about home theatre and home stereo systems... 

They are never going to be as cool as a car setup because you're in a huge room. I don't care if you have 100,000$ to put into it, it's just not going to be the same experience.

If you want to really appreciate your music, build your own speakers, and buy a decent amplifier/reciever.

I have listened to 50$-15,000$ speakers and you can build yourself some very nice speakers for a fraction of the cost, just follow someone's preassigned setup, I would reccomend the Parts Express DIY Project Showcase:

http://www.partsexpress.com/projectshowcase/homeaudio.html

And you can find some great speakers at a reasonable price if you dont mind doing some work. Build yourself 5 nice speakers, a huge ass sub, get a reciever, and you're set... I am going to go pretty nice front 2 speakers, and then probably skimp some on the rest... 

I don't think you need to blow alot on a home theatre setup, but if you hadn't realized home audio is where you get the golden ear people who have more money than a republican lobbyist, and the attitude to go with it!

It's all hype, mirrors and smoke... IMHO... Most of the stuff you read about people buying this or that or the next thing... it's like car audio in a way, if you're willing to do some work yourself, you can get much better equipment than all the buyers with all the money in the world. 

I've installed some ridiculous home theatres, and unless you're going to build a room, automate a remote control, and buy a very expensive projector... Just get yourself some decent equipment, nice home built speakers, and you're better off than most people anyways.

It's just something about my personality that makes me cringe when I hear people drone on about there perfect equipment, how it takes on a personality of it's own... I don't believe almost anyone can tell the difference between a blind AB test between 80% of the premade crap out there these days...


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## ArcL100 (Jun 17, 2005)

Ocelaris said:


> It's just something about my personality that makes me cringe when I hear people drone on about there perfect equipment, how it takes on a personality of it's own... I don't believe almost anyone can tell the difference between a blind AB test between 80% of the premade crap out there these days...



Lol, that's how I feel about people talking about Tru or similar way-too-expensive amps.

-aaron


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## Ocelaris (Jun 23, 2005)

I've helped install 100,000$ home theatres, million dollar home automation packages, and yeah, they are wonderful, but there is a point where you just say WTF were they thinking? You can do wonders with some decent off the shelf stuff if you know what you're looking for and are willing to do a little grunt work yourself... 

BTW what's your sig mean? "Audiophile grade belongs in a listening room, not a car" Just curious, as I have always liked my car system better than any home system, granted I'm still working on the home thing myself, but curious where that comes from?


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## MarkZ (Dec 5, 2005)

pervo said:


> in home audio "processors" are viewed as the devil
> idealy one has a very high end cd player w/ top of the line DAC's(rotel 1072 is regarded as a good budget cd player) then you go out with a nice pair of composit wires (gan be very very expensive, look at audio quest for reasonably priced high end)
> 
> then one goes into a preamp, controling switching from different inputs (ie phono, cd, dvd, etc) and acts as the only volume/gain controle
> ...


While it's true that some people view the above as essential for home audio, in reality it's all crap. 
1) Processors, and the EQ and crossover options they offer, are good things. It gives you the possibility of unlimited adjustment and refinement. Limitations are the devil, not processors.
2) You can't tell the difference between most DACs.
3) Wires don't contribute to the sound in a home environment, unless you're running 300 ft out to your pool area.
4) Equalization isn't only done to compensate for room acoustics. It's also done to compensate for the source material, which may or may not be recorded to your tastes (you're probably not the engineer who recorded it, so you're listening to someone else's preferences).

Ocealaris' post is probably the best suggestion for building a quality home setup. For amplification, the best thing you can do is to buy gobs of power and STAY AWAY FROM MANY OF THE "HIGH END" AMPLIFIERS, which tend to have significantly higher distortion levels than cheaper amps.


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## trains are bad (Aug 8, 2005)

> buy gobs of power


Well, one thing I learned about car audio is the same  



> Processors, and the EQ and crossover options they offer, are good things. It gives you the possibility of unlimited adjustment and refinement.


I've never understood the aversion to EQs myself. It seems to me that introducing .01%THD (a small problem) so that you can adjust for room acoustics (by comparison a HUGE problem) would be good thing.



> You can't tell the difference between most DACs.


I've been visiting some forums where that statement could get you banned.  I agree IME though


> Wires don't contribute to the sound in a home environment, unless you're running 300 ft out to your pool area.


Oh I know. I find the audiophile cabling phenomenon immensly entertaining. I'm a physics major. We use osclliscope probes that pass signals in the MHz range with very low distortion, our measurements depend on it. They cost a trivial amount. If you can hear a cable, there is something drastically wrong with it.

The thing with me and car audio, is I can't listen to music in the background. If I'm driving and music is playing I tend to turn it off. It's distracting, I can't be listening to the music and driving at the same time. Plus I drive like an old lady because of the road and engine noise. I listen to music like my friends watch movies....I just sat down and listened to Dark Side of the Moon, with my eyes closed. When I had a killer system, I mostly sat in my driveway and listened to it, which is kind of silly. I love the hobby and I'm good at it, but it's not practical.


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## DS-21 (Apr 16, 2005)

Ocelaris said:


> They are never going to be as cool as a car setup because you're in a huge room. I don't care if you have 100,000$ to put into it, it's just not going to be the same experience.


You'll have less bass, but you'll also get significantly better midbass detail because of all of those standing waves in the 200-400Hz octave in vehicles. Also, you can use much better drive-units in home audio, resulting in better midrange and treble spectral/dynamic fidelity. If you do something trite like a 7" 2-way you're not going to get much improvement. However, if you build serious speakers, say a 8-15" coax or horn on a CD waveguide with a top-notch 15" woofer for midbass per side, you will realize significant improvements over what is possible in a car.



Ocelaris said:


> I am going to go pretty nice front 2 speakers, and then probably skimp some on the rest...


I would advise against that, sort of. The front _three_ are pretty critical, with the center arguably most important of all. However, I don't think skimping on surrounds will hurt much if at all. I found sonic gains minimal to nonexistent when I upgraded my surround side speakers from KEF Q-Compacts to bespoke speakers using the same 8" Tannoy dual concentric in my front LCR. Just make sure your surround speakers have reasonably consistent directivity - like your mains, think coaxial cone or waveguide-loaded tweeter - and no glaring sonic peaks.



Ocelaris said:


> I don't think you need to blow alot on a home theatre setup, but if you hadn't realized home audio is where you get the golden ear people who have more money than a republican lobbyist, and the attitude to go with it


For speakers, you pretty much do need to spend money to get great stuff. However, as you mention the electronics needn't be pricey. I'd be perfectly confident running six figures worth of speakers off a $500 Mac mini, $220 Panasonic receiver, and wires from Parts Express or KnuKonceptz' bargain bin secure in the knowledge that spending even exponentially more on electronics won't get me a more accurate feed for the speakers.


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## Ocelaris (Jun 23, 2005)

double post...


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## Ocelaris (Jun 23, 2005)

Just some thoughts you spurred in me (trains are bad). Not that anyone was particularly asking for these thoughts, but I wanted to say them.

Car Audio is a mirror image of life. People are drawn to the ideas that make the most sense in relation to their life. 
Some people are drawn to simple answers because they have limited interest or ability to come to grips with ambiguity. 
Some are relentless zealots who are drawn to absolutes and are driven by something deep seated inside. 

Keep looking for those who are searching, and stay away from those claiming to have found the answer...


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## MarkZ (Dec 5, 2005)

trains are bad said:


> I'm a physics major.


That spells trouble.



> We use osclliscope probes that pass signals in the MHz range with very low distortion, our measurements depend on it. They cost a trivial amount. If you can hear a cable, there is something drastically wrong with it.


My *favorite* paper is the one written by Fred E. Davis published in the J.AES. He measured the reactance of speaker cables, from the very expensive to the very cheap (lamp cord). But the best part of the paper is that he included in the test group a set of jumper cables he had lying around. More papers need to include stuff out of your garage.



> The thing with me and car audio, is I can't listen to music in the background. If I'm driving and music is playing I tend to turn it off. It's distracting, I can't be listening to the music and driving at the same time. Plus I drive like an old lady because of the road and engine noise. I listen to music like my friends watch movies....I just sat down and listened to Dark Side of the Moon, with my eyes closed. When I had a killer system, I mostly sat in my driveway and listened to it, which is kind of silly. I love the hobby and I'm good at it, but it's not practical.


That's how I listen to music also, but I do it while driving.  I've literally driven my half-hour daily commute before without remembering the actual trip aside from the music. No accidents in over 10 years of driving, so I guess it's not terribly dangerous.


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## trains are bad (Aug 8, 2005)

I deliver pizza for a living, and music kills my productivity. I can't count the number of times I took the long way back to finish a song, or totally went the wrong direction, or drove 4 miles past the house I was supposed to go to. Can't do it.


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## Ocelaris (Jun 23, 2005)

I don't hear lyrics, I just hear music. Some people know words, I can't even remember the name of the song, none-the-less the words!

I grew up with the Suzuki method which trained you to listen to it and remember by ear, instead of the words... I'm not a musical prodigy, or even very good at it, but I love driving to music, and can't really be bothered to listen to it at home. 

When I'm driving, or commuting by bus/train now, if I don't have music, it drags on endlessly. 

I should really look into a good set of headphones, maybe amplified, but portable. I don't mind a gigantic headset, but i don't drive my car anymore during the week, and I miss that...


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## |Tch0rT| (May 7, 2005)

Ocelaris said:


> I don't hear lyrics, I just hear music. Some people know words, I can't even remember the name of the song, none-the-less the words!
> 
> I'm not a musical prodigy, or even very good at it, but I love driving to music, and can't really be bothered to listen to it at home.
> 
> When I'm driving, or commuting by bus/train now, if I don't have music, it drags on endlessly.


Haha I'm the same way. I still don't know the lyrics to songs I've been listening to for over 10 years and that are my favorites but I can remember most of the music. I can't drive with out music, I start to get bored and tend to nod off. The music keeps my mind active.



trains are bad said:


> I deliver pizza for a living, and music kills my productivity. I can't count the number of times I took the long way back to finish a song, or totally went the wrong direction, or drove 4 miles past the house I was supposed to go to. Can't do it.


I used to deliver pizzas and theres no way I could do that job if I didn't have a system. But yeah it does suck to have to stop in the middle of a song and start it back up a few minutes later especially if it's a good song. That's the only thing I really miss about that job, getting paid to listen to my stereo. I got out of it because it's too hard to rely on tips as income.

Ryan


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## newtitan (Mar 7, 2005)

I knwo one thing home audio is FAR more expenisve lol

im building towers, and it killing me in materials/tools alone


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## pervo (Aug 1, 2005)

newtitan said:


> I knwo one thing home audio is FAR more expenisve lol
> 
> im building towers, and it killing me in materials/tools alone


id almost go so far as to say car audio amps offer more and are better built
it is harder on a car audio amp to...wtf

preamps are another tough thing to swallow

got a "cheap" one... rotel at 499


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## pervo (Aug 1, 2005)

DS-21 said:


> For speakers, you pretty much do need to spend money to get great stuff. However, as you mention the electronics needn't be pricey. I'd be perfectly confident running six figures worth of speakers off a $500 Mac mini, $220 Panasonic receiver, and wires from Parts Express or KnuKonceptz' bargain bin secure in the knowledge that spending even exponentially more on electronics won't get me a more accurate feed for the speakers.


you are very very very very incorrect


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## pervo (Aug 1, 2005)

trains are bad said:


> I've never understood the aversion to EQs myself. It seems to me that introducing .01%THD (a small problem) so that you can adjust for room acoustics (by comparison a HUGE problem) would be good thing.
> 
> 
> Oh I know. I find the audiophile cabling phenomenon immensly entertaining. I'm a physics major. We use osclliscope probes that pass signals in the MHz range with very low distortion, our measurements depend on it. They cost a trivial amount. If you can hear a cable, there is something drastically wrong with it.
> ...


the problems with eq's in car audio is that they can introduce noise issues
in home audio digital ones provide unnecissary ad - da conversion if listening to SACD's
a good one is very expensive too, keeping in mind that the noise floor ismuch lower in home audio, so these things have much more importance... not to mention soundstageing is in a different leauge... alot of the negative opinions towards them are unfounded, most people who hands down side with passives tend to be pretty close minded-stuborn both sides have validity though


as for wires people laughed at galeleo too, ignorance isnt proof
there are some very simple and not necissarily expensive rules and geometries that have profound effects on higher frequencies- some that id be willing to bet most on here have little knowledge of... just because some factions of the hobby are dilusional about cables SQ doesnt mean that there isnt some truth.... dont mean to be harsh towards you- it is a very common opinion on the forums and is one of the very very wrong ones that gets perpetuated...
in car audio there are much much larger issues to combat, again home audio is on a different level


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## MarkZ (Dec 5, 2005)

pervo said:


> as for wires people laughed at galeleo too, ignorance isnt proof
> there are some very simple and not necissarily expensive rules and geometries that have profound effects on higher frequencies- some that id be willing to bet most on here have little knowledge of... just because some factions of the hobby are dilusional about cables SQ doesnt mean that there isnt some truth.... dont mean to be harsh towards you- it is a very common opinion on the forums and is one of the very very wrong ones that gets perpetuated...
> in car audio there are much much larger issues to combat, again home audio is on a different level


The problem with the "wires" issue is that there lacks empirical evidence to support the notion that wires can contribute to the sound. There's nothing in the psychoacoustical realm to suggest it aside from some uncontrolled tests printed without the benefit of peer-review. In the realm of physics, it's also been addressed and emphasis has been made on the geometries you speak of - most notably, the reactance of various wire types has been measured and coupled to the nonlinearities of speaker impedance and amplifier output impedance. And while the physical data has been compelling, and in fact the authors have at times even suggested that it could give rise to perceptable differences, they've never coupled the physical data with what's known in the psychophysical literature about things like discriminability and detection thresholds of human listeners. When you take that last step, it becomes pretty evident that the effects only become noticable when measuring equipment is involved, not human listeners.

There have always been objections to the psychophysical approach -- where listeners are generally asked to distinguish a difference in an ABX test or something similar. The objections have typically been the skill of the listener or appropriateness of the testing procedure (eg. one has to be careful not to merely report the null hypothesis when the conclusion is "no difference"). Fair criticisms, IMO. But they're never backed with *better* evidence to demonstrate there is a difference in sound when different wires are used. 

This is why a theoretical approach is so crucial to settling the question. While psychophysical data can sometimes be a little messy, too dependent on other variables, etc, it can usually give us an idea of what orders of magnitude these types of effects can be detectable. For instance, the .1% THD number has been thrown around ad nauseum. Unfortunately, the testing parameters often become lost in the fray. Human detection thresholds are often far greater than .1% or less than .1%, depending on the content of the signal, the way with which the distortion is introduced, and the testing procedure, etc. However, nobody has shown discriminability on the order of .001% THD. With our current level of knowledge, I think it's a safe conclusion to say that humans can't detect differences in harmonic distortion on the order of .001%.

As for wires, I may change my opinion once somebody presents me with data demonstrating that they contribute more to distortion than the output devices themselves, or to phase/frequency response more than the output zobel network. Until then, the electrical signal nonlinearities are still dominated by distortion in the source and amplfier, and electrical contributions by the speaker such as motional EMF and its very nonlinear impedance characteristics. And ultimately, using a good source and amplifier (which usually means NOT using one of the ultra-expensive ones, which are often plagued with distortion), the distortion is dominated by the speaker system itself.


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## DS-21 (Apr 16, 2005)

pervo said:


> you are very very very very incorrect


Oh, really? Show me *one* serious, rigorous listening study that has shown one whit of sonic difference between properly functioning source units, amplifiers, or wires.


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## pervo (Aug 1, 2005)

so you are saying preamps and DAC's make no difference as long as they are functional?


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## pervo (Aug 1, 2005)

MarkZ said:


> The problem with the "wires" issue is that there lacks empirical evidence to support the notion that wires can contribute to the sound. There's nothing in the psychoacoustical realm to suggest it aside from some uncontrolled tests printed without the benefit of peer-review. In the realm of physics, it's also been addressed and emphasis has been made on the geometries you speak of - most notably, the reactance of various wire types has been measured and coupled to the nonlinearities of speaker impedance and amplifier output impedance. And while the physical data has been compelling, and in fact the authors have at times even suggested that it could give rise to perceptable differences, they've never coupled the physical data with what's known in the psychophysical literature about things like discriminability and detection thresholds of human listeners. When you take that last step, it becomes pretty evident that the effects only become noticable when measuring equipment is involved, not human listeners.
> 
> There have always been objections to the psychophysical approach -- where listeners are generally asked to distinguish a difference in an ABX test or something similar. The objections have typically been the skill of the listener or appropriateness of the testing procedure (eg. one has to be careful not to merely report the null hypothesis when the conclusion is "no difference"). Fair criticisms, IMO. But they're never backed with *better* evidence to demonstrate there is a difference in sound when different wires are used.
> 
> ...


they will never contribute more distortion, the human ear also is not a good judge of distortion or volume
the human ear is very perceptive in regards to the time domain though, this is where a slight improvement can be made and id doesnt cost 1000's


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## MarkZ (Dec 5, 2005)

pervo said:


> so you are saying preamps and DAC's make no difference as long as they are functional?


I'll say this much...you'll have a hard time outperforming the playback quality of the $69 M-Audio Transit.


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## MarkZ (Dec 5, 2005)

pervo said:


> they will never contribute more distortion, the human ear also is not a good judge of distortion or volume
> the human ear is very perceptive in regards to the time domain though, this is where a slight improvement can be made and id doesnt cost 1000's


How do you mean?


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## pervo (Aug 1, 2005)

MarkZ said:


> I'll say this much...you'll have a hard time outperforming the playback quality of the $69 M-Audio Transit.


what are we looking at there
tell me its nnot a *belt drive* turntable


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## MarkZ (Dec 5, 2005)

pervo said:


> what are we looking at there
> tell me its nnot a *belt drive* turntable


It's not a belt drive turntable.

What? You still use vinyl? [ducking for cover]


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## pervo (Aug 1, 2005)

MarkZ said:


> It's not a belt drive turntable.
> 
> What? You still use vinyl? [ducking for cover]


no but the belt drive fetish makes me want to break things 
i use to dj so anything but a technics makes me wonder


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## pervo (Aug 1, 2005)

MarkZ said:


> How do you mean?


"skin effect"


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## pervo (Aug 1, 2005)

MarkZ said:


> I'll say this much...you'll have a hard time outperforming the playback quality of the $69 M-Audio Transit.


so what is that used for.... 24bit .... im listening


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## MarkZ (Dec 5, 2005)

pervo said:


> "skin effect"


The skin effect isn't really a time-domain issue though. Its nature is purely resistive. Not only that, but the skin depth is usually not significant for such relatively low frequencies (20kHz is pretty low) in typical stranded wire.


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## pervo (Aug 1, 2005)

MarkZ said:


> The skin effect isn't really a time-domain issue though. Its nature is purely resistive. Not only that, but the skin depth is usually not significant for such relatively low frequencies (20kHz is pretty low) in typical stranded wire.


ive got to go to work but i will past somke info that relates to this later


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## MarkZ (Dec 5, 2005)

pervo said:


> so what is that used for.... 24bit .... im listening


The Transit supports 24- and 32-bit playback. It's used for playing music.


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## chad (Jun 30, 2005)

pervo said:


> "skin effect"


Does not happen until the frequency rises to that of RF. At AF there is NO I repeat NO noticable skin effect.

I f there were we would be wiring our speakers with Heliax!


Heliax: http://eaulive.free.fr/repet/heliax.jpg

http://www.andrew.com/products/trans_line/heliax/default.aspx



Chad


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## pervo (Aug 1, 2005)

The Challenge Of Speaker (High Current) Cable Design
While there are many physical, electrical and magnetic phenomena responsible for distortion in cables,
there are really only a few basic mechanisms which account for the majority of the performance variations
between cables. After considering the following information and evaluating even a small variety of
different cable types, you can acquire the ability to look at a cable’s design and know pretty well whether
it deserves your further attention. Please don’t close your mind to new possibilities, just develop an
educated skepticism.
Skin-Effect is one of the most fundamental problems in cables. It is useful to think of a metal conductor
as a rail-guide. Electric potential is transferred as current inside a metal conductor and as a magnetic
field outside the conductor. One cannot exist without the other. The only place that both magnetic field
and current density are 100% is at the surface of a conductor. The magnetic field outside a conductor
diminishes at distances away from the conductor, density is 100% only at the surface of the conductor.
Something similar is true inside the conductor. Skin-effect means that current density diminishes at
distances away from the surface on the inside.
There is some disagreement as to whether skin-effect is relevant at audio frequencies. The argument
concerns whether skin-effect causes damage other than simply power loss. Since the 3dB down point
(50% power loss) for a certain size strand might be at 50,000Hz, not everyone understands the mechanism
by which skin-effect is a problem at audio frequencies (20-20,000Hz). However, the problems are
very real and very audible. This is because well before skin-effect causes a substantial power loss, it
causes changes in resistance and inductance. Skin-effect causes different frequencies to encounter
different electrical values at different distances from the surface of a conductor.
If a single strand is too large, skin-effect will cause each frequency component of an audio signal to
behave differently. Each frequency component will exhibit a unique current density profile. The result

is that some of the delicate high frequency information, the upper harmonics, will be smeared. We
hear sound that is dull, short on detail and has a flat sound stage. The energy is there, the amplitude
(frequency) response has not been changed, however the information content of the signal has been
changed in a way that makes it sound as though the midrange notes have lost their upper harmonics.
There is a textbook equation which describes the reduction in current and power density at any depth
from the surface of an electrical conductor. For copper the equation is: 6.61 divided by the square root
of the frequency (Hz) equals the depth in mm at which the current density will be 1/e. Since 1/e is 37%,
this equation tells us the depth at which the current density has been reduced by 63%. For 20,000Hz,
current density is only 37% at a depth of 0.0467 mm, which is the center of a 0.934 mm (18 awg)
conductor. Conventional use of the above formula falsely assumes that it is acceptable to have a 63%
reduction in current flow and an 86% reduction in power density at the center of a conductor. However,
this formula does not by itself describe at what depth audible distortion begins. Listening (empirical
evidence) shows that audible distortion begins at somewhat lesser depths.
There is a solution to skin-effect-using a single
strand of metal which is just small enough to push
skin-effect induced audible distortion out of the audio
range. Simple evaluation of multiple sizes reveals
that audible skin-effect induced anomalies
begin with a strand (or conductor) larger than 0.8
mm. A much smaller strand yields no benefits but
encourages the problems discussed below.
A common misunderstanding of skin-effect results in the claim that “the bass goes down the fat strands
and the highs go down the little strands.” The surface of a fat strand is just as good a path as the surface
of a thin strand, only the fat strands also have a core which conducts differently. In cables with fat
strands which are straight and little strands which take a longer route, the path of least resistance at
higher frequencies is actually the surface of the fat strands. Since the lower frequencies are less subject
to skin effect, they travel everywhere in all the strands.


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## pervo (Aug 1, 2005)

chad said:


> Does not happen until the frequency rises to that of RF. At AF there is NO I repeat NO noticable skin effect.
> 
> I f there were we would be wiring our speakers with Heliax!
> 
> ...


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## DS-21 (Apr 16, 2005)

pervo said:


> so you are saying preamps and DAC's make no difference as long as they are functional?


As long as you define "functional" properly, i.e. with FR and noise below the established thresholds of human audibility.

However, let's clear up a misconception. That's not what _I_ say. It's what the _established, peer-reviewed scientific literature_ reports without exception. People who believe in the "sound" of such components have faith-based worldview, rather than a reality-based one. Let me guess: you also deny that evolution is real.


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## Ocelaris (Jun 23, 2005)

I like your comment about faith-based worldview vs. reality-based worldview... though I think it's more commonly called logic or scientific-based... the more answers we get, the less we have to depend on belief... It was bound to happen, just when was the question... just my .02$


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## MarkZ (Dec 5, 2005)

pervo said:


> For copper the equation is: 6.61 divided by the square root
> of the frequency (Hz) equals the depth in mm at which the current density will be 1/e. Since 1/e is 37%,


And this is the fundamental problem with what you posted. It dances around the issue of skin effect and NEVER PROVIDES THE EQUATION TO CALCULATE SKIN DEPTH. How much resistance and inductance are actually introduced by a "typical" stranded wire utilizing 30 ga. wires instead of more elaborate designs? Can you answer that question based on the article you posted? I think once you answer that question for yourself, you'll see how miniscule the skin effect is as it pertains to audio frequencies. If you can't find the formula, let me know and I'll do the calcs out for you.


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## pervo (Aug 1, 2005)

DS-21 said:


> As long as you define "functional" properly, i.e. with FR and noise below the established thresholds of human audibility.
> 
> However, let's clear up a misconception. That's not what _I_ say. It's what the _established, peer-reviewed scientific literature_ reports without exception. People who believe in the "sound" of such components have faith-based worldview, rather than a reality-based one. Let me guess: you also deny that evolution is real.


so as long as you can hear the difference there is a difference but when you cant there isnt

strong statement


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## pervo (Aug 1, 2005)

MarkZ said:


> And this is the fundamental problem with what you posted. It dances around the issue of skin effect and NEVER PROVIDES THE EQUATION TO CALCULATE SKIN DEPTH. How much resistance and inductance are actually introduced by a "typical" stranded wire utilizing 30 ga. wires instead of more elaborate designs? Can you answer that question based on the article you posted? I think once you answer that question for yourself, you'll see how miniscule the skin effect is as it pertains to audio frequencies. If you can't find the formula, let me know and I'll do the calcs out for you.


im sure the difference is minuscule and down right trivial for the average person
its obvious that while current density changes rapidly the correlation to what the implications are isnt clearly stated
one thing is certain, monsters "time correct" wires are a joke
i would be very interested to see some formula's on that direct corrilation
but what you arnt seeing is that the solution is quite simple and dosent necessitate complicated designs, simply using multiple single cunductors works great... why is it that the sound recording industry uses such means but car audio dosent 

it just cracks me up that the same people who go to such futile lengths in there car installs dismiss any talk ok improving the signal pass in between thier components


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## DS-21 (Apr 16, 2005)

pervo said:


> so as long as you can hear the difference there is a difference but when you cant there isnt
> 
> strong statement


God damn it. I wish you faith-baseders would *learn to read!!!* 

(You're the one who has the reading comprehension problem right now, but you've all got it to some extent.)

I wrote absolutely _nothing_ about what _I personally_ can or can't hear. That's irrelevant. Possessing a rational mind, I realize that I am just as likely to be swayed by suggestion as anyone else. (Well not really, but in theory at least.) Rather, what I wrote is that there is a widespread consensus formed around _papers published in the relevant peer-reviewed scientific journals_ that, to the extent scientific methods can do so, says that your position is ********.

If you choose to believe in magic wires/digital bits/amps or intelligent design or supply-side economics (to name two other things commonly believed in by those with a weltanschauung that is faith-based rather than reality-based), that is of course your choice. As long as others stupidity does not affect me, I'm happy to let them indulge themselves; certainly, someone believing that wires have little ghosts in them that change the character of the electrical waves passing through them is a stupid belief that does not affect me or anything remotely important in the slightest. However, to believe such positions are anything but in complete and utter opposition to all known reality is to wholly and blatantly deceive oneself.


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## pervo (Aug 1, 2005)

yup a 48 bit track sounds the same as a 16 bit cd
my buddies studio uses hometheater in a box... of course the speakers are upgraded because he is also a scientist  
ps i run coaxial between my dvd and my plasma... custom made by an engineer for $.50


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## MarkZ (Dec 5, 2005)

pervo said:


> im sure the difference is minuscule and down right trivial for the average person
> its obvious that while current density changes rapidly the correlation to what the implications are isnt clearly stated
> one thing is certain, monsters "time correct" wires are a joke
> i would be very interested to see some formula's on that direct corrilation
> ...


Well, to be perfectly frank, there are a lot of people who go to unnecessary lengths with their audio system. But that doesn't mean that they should start including wiring with the rest of their compulsion.  

Anyway, as for the calculation, here's an online calculator:

http://daycounter.com/Calculators/SkinEffect/Skin-Effect-Calculator.phtml

This determines the wire size needed to eliminate the skin effect at the frequency provided. Entering 20kHz, it gives us the result of "18ga wire". The strands in most copper wires are much smaller than 18ga.


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## pervo (Aug 1, 2005)

MarkZ said:


> Well, to be perfectly frank, there are a lot of people who go to unnecessary lengths with their audio system. But that doesn't mean that they should start including wiring with the rest of their compulsion.
> 
> Anyway, as for the calculation, here's an online calculator:
> 
> ...


already i dont think you fully under stand it


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## MarkZ (Dec 5, 2005)

pervo said:


> already i dont think you fully under stand it


Then why don't you enlighten me?


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## DS-21 (Apr 16, 2005)

pervo said:


> yup a 48 bit track sounds the same as a 16 bit cd


A priori, it certainly _could_. It would go so far to say that it's highly _likely_ they would, if the material itself did not require more than 14 bits of dynamic range and the Nyquist frequency of both setups was the same. But of course such a statement requires actual human thought and not just the mindless regurgitation of some party line.



pervo said:


> my buddies studio uses hometheater in a box...


You may laugh at that approach, but it has its merits for modest home systems. Some of the HTIB's have decent electronics, such as TI PurePath or Tripath-based amps, and acceptable noise, FR, and distortion performance as long as one uses appropriately efficient/benign impedance speakers. (Some of them probably have undefeatable, counterproductive, EQ, but at least the cheap Koss ones that use TI PurePath amp chips don't.) Such electronics can be used creatively by those on a budget to great effect. I've done it before.


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## pervo (Aug 1, 2005)

MarkZ said:


> Then why don't you enlighten me?


well first off its 40 awg for 20k
which has a 3.44 ohm/ meter resistance

definitly not negligable

second skin effect on a multistrand conductor will go through out the wire not each individual one, introducing other measurable causes of distortion as it is forced to jump from strand to strand


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## pervo (Aug 1, 2005)

DS-21 said:


> A priori, it certainly _could_. It would go so far to say that it's highly _likely_ they would, if the material itself did not require more than 14 bits of dynamic range and the Nyquist frequency of both setups was the same. But of course such a statement requires actual human thought and not just the mindless regurgitation of some party line.
> 
> 
> 
> You may laugh at that approach, but it has its merits for modest home systems. Some of the HTIB's have decent electronics, such as TI PurePath or Tripath-based amps, and acceptable noise, FR, and distortion performance as long as one uses appropriately efficient/benign impedance speakers. (Some of them probably have undefeatable, counterproductive, EQ, but at least the cheap Koss ones that use TI PurePath amp chips don't.) Such electronics can be used creatively by those on a budget to great effect. I've done it before.


thanks for the laugh


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## MarkZ (Dec 5, 2005)

pervo said:


> well first off its 40 awg for 20k


Are you sure? I enter 20 kHz and it gives me 18ga. Are you sure you're not mistakenly entering 20000 kHz, or 20 MHz?



> which has a 3.44 ohm/ meter resistance


Nobody's saying to use only one strand of the stranded wire.



> definitly not negligable
> 
> second skin effect on a multistrand conductor will go through out the wire not each individual one, introducing other measurable causes of distortion as it is forced to jump from strand to strand


Not quite. What I think you're getting at is the change in local permeability of a single strand at the center of a bunch of strands. A fair criticism, IMO. However, since the packing fraction is pretty far from 1 in most types of wires, it's not that great of an effect. Take some litz wire, with poly coated strands, and compare it to stranded. Not that big of a difference. Not at these frequencies.

"Other measurable causes of distortion"? Such as? There's no arcing going on, if that's what you're implying. I don't know how else current (?) is "jumping" from strand to strand in a manner that's not ideal. Ultimately, it goes the way of the path of least resistance.

Frankly, at the resistances we're talking about, you're more likely to introduce inductance by twisting the wire too much than via the skin effect! I think you were more on the right track when you were talking about cable geometries explicitly. You should try to measure cable reactance some time, if you've got access to the equipment.


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## pervo (Aug 1, 2005)

MarkZ said:


> Are you sure? I enter 20 kHz and it gives me 18ga. Are you sure you're not mistakenly entering 20000 kHz, or 20 MHz?
> 
> 
> 
> ...


lol... didnt see the Khz was the units  

its my understanding that since the strands are not gas tight there is some measurable capacitence
very good point on completely undoing any benifit by creating more inductance

sure litz wire and bywiring are part of this too...
i guess one thing we could agree on is that for long wire runs or even for dedicated highs exceeding 18 gauge calls for special attention


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## MiloX (May 22, 2005)

Based on this thread alone, I am quite content to play in the 12v world.


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## leethompson (May 11, 2008)

home audio is cool!


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## Fellippe (Sep 15, 2006)

Ocelaris said:


> I've helped install 100,000$ home theatres, million dollar home automation packages, and yeah, they are wonderful, but there is a point where you just say WTF were they thinking? You can do wonders with some decent off the shelf stuff if you know what you're looking for and are willing to do a little grunt work yourself...
> 
> BTW what's your sig mean? "Audiophile grade belongs in a listening room, not a car" Just curious, as I have always liked my car system better than any home system, granted I'm still working on the home thing myself, but curious where that comes from?


Ocelaris, everyone is entitled to their opinion of course but IMHO you most likely have never heard a real quality home system. $$ spent isn't indicative of quality either...

The whole car/home debate is simple. Car can be a great platform for fun audio with the big bass boost due to cabin gain....but when it comes to really high end listening with the right type of music, it is the difference between Rolls Royce and Toyota Camry.

Not only is the high end home equipment better, but the worst case scenario home environment is still better than the best car in most cases. The best case home environment is another world of course.

You bring out your vinyl and another level is reached. There is no vinyl in car audio.

There's a certain visceralness to car audio that costs a fair amount of money to reproduce in a home but it's doable, and definitely under six figures. 

When you say that you don't always get what you pay for in high end audio, I agree fully. You do have to know what's up and a lot of what I like to call "commercial" high end is not the very best money can buy despite their six figure price tags.

And with respect to building your own speakers from raw drivers, that seems like a great idea on paper but there are two limitations with doing so. Those issues would be imaging and coherence.

You can buy all the raw drivers you want from Madisound, but getting proper coherence and imaging is very tough to do. There are many levels to this, but for the very highest levels, you need to have very good choice of speaker selection, placement, cabinet construction and crossover design. If you are at this guru level already, quit your job and get into the speaker business. 

I really think that some people have a higher capacity for appreciation of audio than others. While everyone on this site is an audio enthusiast who can appreciate good sound, clearly not everyone is a TRUE ADDICT. 

A sign of being an addict is you get excited for awhile about getting something....finally get it...it's great.....then soon after, jaded. Repeat cycle for the rest of your natural life....

It really is an addiction like drugs....you know it's not good for you and you curse yourself for the $$ spent, but in the end you can't do anything about it.


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## drake78 (May 27, 2007)

12 volt dc power supply FTW!


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## Spasticteapot (Mar 5, 2007)

Here are my observations on home audio.

1. Because you can have ideal placement of all drivers with no restrictions to the size, shape, or mass of the enclosures, home stereo equipment is almost always better than car stereo equipment for a given price.

2. Distortion is bad, CSD is worse, and box resonance is the devil. 

Distortion is the function of a driver producing sound at additional frequencies to to that of the input signal, usually caused by cone resonance - this can be annoying, but since all audio recordings are just a function of the resonances of wooden boxes, flaps of skin, and the like, it's not so much a question of "bad" as "different". 

Amplifiers distort as well. While tube amplifier distortion is often thought to sound quite good, distortion from transistor and class-D amplifiers sounds incredibly horrible. 

CSD is the driver's tendency to keep moving after power has stopped being applied. A cheap subwoofer will often keep moving even after you turn off the amp, while an electrostatic diaphragm transducer will stop so fast you can use it to make square waves. Speakers with low csd are often described as being "fast"; it was a big selling point on the original DCM Time Windows.

Box resonance is the tendency of a box to have its own resonances, which are usually quite loud and quite unpleasant. I've started mucking about with concrete and isolated baffles to keep this to a minimum, but I'm really, really picky.

3. DSP is bad...if done improperly.
The problem with DSP is that it only works with a digital signal. As such, a DSP device will convert the analog signal to digital, run it through a bunch of filters, and turn it back into analog again. 

The problem with a lot of these filters is that they are imperfect - information (in the form of audio) is lost during the analog-digital conversion, some is lost during the manipulation of the digital signal, and some more is lost when it's turned back into analog. This is why most cheap digital effects sound absolutely horrible.

However, if you use a suitably high-quality DSP device like the Behringer DEQ2496, the impact is minimal. Even better is the DCX2496, a 6-channel active crossover capable of complicated frequency response compensation and super-steep crossover slopes that keep drivers operating only at the frequencies where they distort least. Both of these devices feature digital inputs, which allow you to bypass the digital-analog conversion at the CD player's DAC and the analog-digital conversion on the input to the DSP.

4. Get a decent CD player.

I don't know about the other forum members, but I can tell the difference between a rubbish CD player and a good one. That said, my idea of a "Good" CD player is my old Denon I bought for $7 at Goodwill. Avoid cheap plastic crap with low-quality DACs and you should be fine; old Playstation 1's work well, too, if you solder some RCA plugs to the appropriate places.

5. Cables are cables.
Unless you have the sort of useless crap that comes with a $10 boom box, spending money on cables make no difference at all to the sound. The one feature you might want to look for on interconnects is shielding, which can help reduce the hum sometimes caused by RF from large power transformers.

I use MTX interconnects I paid $2 each for on eBay.

6. Don't bother with phonographs.

Some people love LPs - the feel of the vinyl, the involvement of placing the needle, et cetera. I have listened to one or two massively expensive turntables, and I thought them no better than a CD player.

The myth of vinyl's superiority dates back to the early 80s, when compact disks first went into production. Early CD players were a huge mess, with crude laser assemblies and horrible digital-to-analog converters. For a while, LPs really were better.

However, CD players have advanced quite a lot. Furthermore, good turntables cost a lot of money, especially if you factor in the cost of a phono preamp - and high-quality LPs aren't cheap either.

There is one other issue related to LPs - the quality of the recording itself. A lot of modern recordings use odd adjustments to EQ and a lot of compression in order to sound louder on cheap speakers. Back in the 70s, this was not the case.

7. Don't compress.
Mp3s generally sound awful for a good reason - quite a lot of the original analog signal was lost. If you're going to play music from a computer, use FLAC, which is lossless - none of the original data is lost. While a CD compressed to FLAC may take up over 200mb of space, hard drives are cheap enough to make it worthwhile.

8. Speaker placement is important.

Putting speakers in an undesirable location - say, up against a wall (unless they were designed for it), or on a bookshelf - can cause acoustic reflections and do funny things to frequency response. Speakers should generally be placed at head height a few feet away from any walls. It is worth noting that placing a speaker corner of a room can amplify low frequencies, which may or may not be desirable.

A bit of carefully arranged acoustic deadening - egg-crate foam works well - can help prevent sound waves from echoing off your walls, which can help sound quality.


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