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Speaker amps for headphones - Page 83

post #1231 of 2628

Very nice, Mike.  I'd like to know what speaker cable that is it, too.

post #1232 of 2628

Brunk,

 

That speaker wire is KnuKonceptz Kord Kable, in 462-strand, 10-AWG OFC.  It's sold in 5-ft lengths at Amazon:  http://www.amazon.com/gp/product/B0076SIARO

 

 

When I sent some of this 10-AWG wire to Jan Plummer, he told me I'd be better off with a smaller guage, because of a phenomenon where high frequencies end up arriving later than the lower frequencies - because the smaller wavelengths can (allegedly) zig-zag their way through a thicker conductor (where the longer wavelengths are confined to a straight-line path through the same conductor).   

 

Having a ton of respect for Jan, I'm reluctant to confess that I remain dubious of this line of thinking, as it runs contrary to a preponderance of contraction I've found online.  

 

   Quoting http://www.prosoundweb.com/article/print/myth_busting_the_truth_about_loudspeaker_wire, for example: 

 Wire is not very sexy or easy to create real marketing hooks for, but it can actually make an audible difference. The dominant mechanism is simple resistance.
 
---
 

Forget the hype, what’s important for speaker wire is that it exhibit low impedance that is resistive in nature. If the wire has a significant impedance component (reactance) that changes over the audio frequency spectrum, this can form a simple divider with the loudspeaker’s resistive impedance and cause a frequency response error.

In addition, since loudspeaker impedance will vary quite a bit over frequency, even a perfectly resistive speaker wire will cause errors. The magnitude of this frequency response error will increase proportionately as the wire’s resistance increases.  [Thick wire is good. Skinny wire is bad.]

---

Wire resistance changes linearly with length. It changes non-linearly with gauge. A convenient property of wire gauge is that the wire’s resistance will double for every 3-step increase in gauge (AWG). Conversely, the resistance will drop in half for a 3-step decrease in gauge.  
---
 
There are several strategies to manage these real losses from wire resistance. The obvious one is to throw more copper at the problem. Heavier gauge wire with lower resistance will exhibit lower losses for a given run length. Another fairly obvious approach is to locate the amplifiers as close as possible to the loudspeakers to keep the run length as short as possible. A third less obvious approach is to scale up the intermediate signal voltages.

 

And thus, the best way to reduce the influence of a speaker wire's reactance (if any) is to use a really small gauge (thick conductor) and the shortest length possible.  That way, a greater portion of the wire's total impedance becomes resistive, rather than reactive. This takes care of two of the strategies mentioned above, where the third strategy is impractical (scaling up the voltage before entering the wire, and then stepping it down at the other end).  In other words, you don't have to worry as much about frequency response errors when the resistance is kept exceptionally low.

 

I realize, however, that Jan was making a case for phase errors in the time domain, not frequency response errors caused by the reactive components of impedance, and he also said something about how the high frequencies can become blurred because, just within the treble band, they can arrive via different paths (when the conductor is thick enough to permit this behavior), but consider this:

 

Quoting this article: https://www.ramelectronics.net/understanding-av-cables.aspx

For audio signals which are relatively low in frequency [at 20Hz to 20kHz], the characteristic impedance is meaningless, since the wavelengths of the highest frequency signals are usually thousands of times longer than the cables carrying them. Because of this, reflections are not a factor. As frequency increases and the wavelength's actual length traveling through copper wire approaches the cable length, characteristic impedance becomes very important. This is very generally in the MHz range [where the shorter wavelengths can become as short or shorter than the cable lengths], and why characteristic impedance is so important for video and digital audio signals.

 

I like this argument, as it not only relieves concern for Jan's argument regarding phase issues, but also discounts the concern expressed for impedance issues on frequency response, in the first article I quoted. 

 

Here's my very rough analogy: If we were talking about shoving toothpicks through a four-inch diameter pipe that's five feet long, some of those toothpicks could get get "lost" inside the pipe, turning this way and that, arriving at the other end somewhat randomly, instead of remaining single-file with their neighbors, but if we're talking about shoving 8-foot long strips of two-by-two pine through our five-foot long, four-inch diameter pipe - they all have to take the same path through the pipe.  At even our highest audio frequencies (with the shortest wavelengths). the analog signal has no choice but to take a straight path through our typical cable lengths.  So, if indeed there's any truth to the possibility of higher frequency signals finding longer paths than the lower frequencies, through a given length of wire, that phenomenon wouldn't be a problem until we get into much higher frequencies, where wavelengths can be shorter than our cables.

 

:D

 

Meanwhile, that 10-AWG cable was just too large to make the tight turns needed in my "transportable" rig, so for this, I'm using some cheap, 8-strand, 16-AWG power cable, as shown here - but it sounds the same to my ears.  For such short runs, I really don't believe it hurts to follow Jan's advice, even though I'm not convinced in his reasons for doing so.    

 

"Travel Rig" - 44.1/16 and 96/24 WAVs on multiple 64GB MicroSD > Sony PCM-M10 Line Out > 24VDC-powered TBI Audio Millenia MG3 (5.1 Watts into 50-Ohm) > TBI Impedance Match > Audeze LCD-2 rev.1

 

Ultimately, my ears say, "I can't hear a difference!"    :tongue:    But it's fun to theorize..

 

Mike

post #1233 of 2628
Quote:
Originally Posted by zilch0md View Post
 

Brunk,

 

That speaker wire is KnuKonceptz Kord Kable, in 462-strand, 10-AWG OFC.  It's sold in 5-ft lengths at Amazon:  http://www.amazon.com/gp/product/B0076SIARO

 

Mike's take on LCR characteristics for speaker cables. (Click to show)

 

When I sent some of this 10-AWG wire to Jan Plummer, he told me I'd be better off with a smaller guage, because of a phenomenon where high frequencies end up arriving later than the lower frequencies - because the smaller wavelengths can (allegedly) zig-zag their way through a thicker conductor (where the longer wavelengths are confined to a straight-line path through the same conductor).   

 

Having a ton of respect for Jan, I'm reluctant to confess that I remain dubious of this line of thinking, as it runs contrary to a preponderance of contraction I've found online.  

 

   Quoting http://www.prosoundweb.com/article/print/myth_busting_the_truth_about_loudspeaker_wire, for example: 

 

And thus, the best way to reduce the influence of a speaker wire's reactance (if any) is to use a really small gauge (thick conductor) and the shortest length possible.  That way, a greater portion of the wire's total impedance becomes resistive, rather than reactive. This takes care of two of the strategies mentioned above, where the third strategy is impractical (scaling up the voltage before entering the wire, and then stepping it down at the other end).  In other words, you don't have to worry as much about frequency response errors when the resistance is kept exceptionally low.

 

I realize, however, that Jan was making a case for phase errors in the time domain, not frequency response errors caused by the reactive components of impedance, and he also said something about how the high frequencies can become blurred because, just within the treble band, they can arrive via different paths (when the conductor is thick enough to permit this behavior), but consider this:

 

 

I like this argument, as it not only relieves concern for Jan's argument regarding phase issues, but also discounts the concern expressed for impedance issues on frequency response, in the first article I quoted. 

 

Here's my very rough analogy: If we were talking about shoving toothpicks through a four-inch diameter pipe that's five feet long, some of those toothpicks could get get "lost" inside the pipe, turning this way and that, arriving at the other end somewhat randomly, instead of remaining single-file with their neighbors, but if we're talking about shoving 8-foot long strips of two-by-two pine through our five-foot long, four-inch diameter pipe - they all have to take the same path through the pipe.  At even our highest audio frequencies (with the shortest wavelengths). the analog signal has no choice but to take a straight path through our typical cable lengths.  So, if indeed there's any truth to the possibility of higher frequency signals finding longer paths than the lower frequencies, through a given length of wire, that phenomenon wouldn't be a problem until we get into much higher frequencies, where wavelengths can be shorter than our cables.

 

:D

 

Meanwhile, that 10-AWG cable was just too large to make the tight turns needed in my "transportable" rig, so for this, I'm using some cheap, 8-strand, 16-AWG power cable, as shown here - but it sounds the same to my ears.  For such short runs, I really don't believe it hurts to follow Jan's advice, even though I'm not convinced in his reasons for doing so.    

 

"Travel Rig" - 44.1/16 and 96/24 WAVs on multiple 64GB MicroSD > Sony PCM-M10 Line Out > 24VDC-powered TBI Audio Millenia MG3 (5.1 Watts into 50-Ohm) > TBI Impedance Match > Audeze LCD-2 rev.1

 

Ultimately, my ears say, "I can't hear a difference!"    :tongue:    But it's fun to theorize..

 

Mike

+1 Even though I may not notice a difference, it is fun to theorize and get down to this microscopic level for obsession's sake hehe. Mike, that is a very informative post, and definitely one of the better I have seen around. I really like your analogy too. I have found Mr. Goertz to have some great information on LCR of speaker cables and its impact in regards to audio, whether audible or not is a different story. Here's the link.

 

Here's a pic of my DIY version: I use a 12awg Goertz Copper Foil Inductor, unwind it and wrap in plumbers teflon tape and then sandwich a set together. These are separate strands to see how i wrapped and formed the ends. I bought an excessive 1mfd roll for $50 that I think holds about 100ft., so you can definitely get a smaller roll. Sure beats the $16/ft from him though!

 

Cheers for experimentation and learning in the process!

:beerchug:

post #1234 of 2628

Wow!  Those are cool!  They're so... crude-ilicious!  :D  They're very appealing just for how easy it would be to make - tedious perhaps, but low-skill - something I could do!  

 

I just read the explanation given at the link you provided, including this excerpt which (I'm not surprised) contradicts the page I quoted regarding how the wavelengths, even at 20kHz, are thousands of times the length of our cables, and thus, impedance mismatch and their alleged reflections aren't a problem with analog signals:

 

Quoting:  http://www.goertzaudio.com/contents/en-us/d16_MI_Speaker_Cables.html
Goertz Virtually Eliminates Mismatch
The characteristic impedance of the Goertz MI cables in the order of 2 to 4 ohms closely matches the impedance of loudspeakers. Almost all other speaker cables have characteristic impedance ranging from 50 to 200 ohms, a mismatch which causes distortion due to signal reflections. Impedance matching primarily improves the clarity of the highs and upper mid-range, but many users have also experienced improvements in the lower mid-range. The cause seems to be that signal reflections caused by impedance mismatch enter the feedback loop of many amplifiers and disturb their ability to reproduce faithfully even lower frequency signals.

 

:blink:

 

Will the expert who actually knows what he's talking about please stand up?  

 

LOL

 

Mike

post #1235 of 2628
Quote:
Originally Posted by zilch0md View Post
 

Wow!  Those are cool!  They're so... crude-ilicious!  :D  They're very appealing just for how easy it would be to make - tedious perhaps, but low-skill - something I could do!  

 

I just read the explanation given at the link you provided, including this excerpt which (I'm not surprised) contradicts the page I quoted regarding how the wavelengths, even at 20kHz, are thousands of times the length of our cables, and thus, impedance mismatch and their alleged reflections aren't a problem with analog signals:

 

 

:blink:

 

Will the expert who actually knows what he's talking about please stand up?  

 

LOL

 

Mike

Hehe yeah they aren't winning any beauty contest but it's fun to play around :) Something really cool to consider about this type of cable is that it would be perfect to run under hardwood flooring or carpet because it so flat. You would just need a few layers of duct tape for toughness. I too am curious, but i find that a 20khz length to be longer than our cables deceiving, those waves are incredibly small. It's the sub-bass waves that can be tens of feet long, not treble. Therefore i think Mr. Goertz is correct, but both share the same basic principles.

 

EDIT: Thn again, I don't really know because I'm talking about acoustics and not an electrical signal lol, whoops.


Edited by brunk - 10/31/13 at 7:52am
post #1236 of 2628

I am curious if there are any great sounding speaker amps with the Sen HD800?

post #1237 of 2628
Quote:
Originally Posted by vincent215 View Post
 

I am curious if there are any great sounding speaker amps with the Sen HD800?

I could be mistaken, but I believe Flysweep has experience in this area.

 

@zilch0md - I noticed in the Deals thread you jumped on some HD600s. What are your plans for those babies? You know you want to jump on the BH Crack bandwagon...:evil:


Edited by brunk - 10/31/13 at 8:28am
post #1238 of 2628
Quote:
Originally Posted by zilch0md View Post

 

 

When I sent some of this 10-AWG wire to Jan Plummer, he told me I'd be better off with a smaller guage, because of a phenomenon where high frequencies end up arriving later than the lower frequencies - because the smaller wavelengths can (allegedly) zig-zag their way through a thicker conductor (where the longer wavelengths are confined to a straight-line path through the same conductor).   

 

 

NVM. I'm full of schiit. 


Edited by manbear - 10/31/13 at 9:18am
post #1239 of 2628
Quote:
Originally Posted by brunk View Post
 

Hehe yeah they aren't winning any beauty contest but it's fun to play around :) Something really cool to consider about this type of cable is that it would be perfect to run under hardwood flooring or carpet because it so flat. You would just need a few layers of duct tape for toughness. I too am curious, but i find that a 20khz length to be longer than our cables deceiving, those waves are incredibly small. It's the sub-bass waves that can be tens of feet long, not treble. Therefore i think Mr. Goertz is correct, but both share the same basic principles.

 

EDIT: Thn again, I don't really know because I'm talking about acoustics and not an electrical signal lol, whoops.

 

There you go - acoustically, bass wavelengths are longer than treble, but electrically, the higher frequencies have shorter wavelengths!  I'm glad you caught that one.  Still, I remain on the fence as to who is right about reflections due to impedance mismatches at the frequencies had with analog audio signals.

post #1240 of 2628
Quote:
Originally Posted by zilch0md View Post

There you go - acoustically, bass wavelengths are longer than treble, but electrically, the higher frequencies have shorter wavelengths!  I'm glad you caught that one.  Still, I remain on the fence as to who is right about reflections due to impedance mismatches at the frequencies had with analog audio signals.

Wavelengths work the same both acoustically and electromagnetically. Lower frequency wavelengths are longer and higher frequency wavelengths are shorter. What distinguishes between acoustic and electric is the vast difference in their propagation velocities. Acoustic waves propagate at the speed of sound. Electromagnetic waves at the speed of light (though in real world cables it will be a significant fraction of the speed of light). Too lazy to do the math right now, but if memory serves, the electromagnetic wavelength at 20kHz is around nine mile long. Kind of hard to build up anything that resembles a reflection in a cable that may only be a few feet long.

se
post #1241 of 2628

May take me eons to find it, but somewhere on Head Fi I once found a post from someone who pointed out that at low frequencies (i.e. audio) it is impossible to make a cable with a constant impedance WRT frequency.

He stated that the "standard formulas" for calculating cable impedance are approximations which are valid for high frequencies (RF) but fall apart at low frequencies.

I'll try my best to find this post....................:o 

post #1242 of 2628
Quote:
Originally Posted by manbear View Post

 Electricity doesn't form a wave in space like a sound wave.

Of course it does. An electromagnetic wave propagates through space just as an acoustic wave propagates through air. How do you think radio works?
Quote:
It's a wave in time.

And space.
Quote:
It doesn't bounce around like a sound wave.

They do indeed. When an electromagnetic wave encounters something with an impedance significantly different than the wave's impedance, it will reflect off it. That's how the electrostatic shield on shielded cables works to keep out interference.

se
Edited by Steve Eddy - 10/31/13 at 9:28am
post #1243 of 2628
Quote:
Originally Posted by Chris J View Post

May take me eons to find it, but somewhere on Head Fi I once found a post from someone who pointed out that at low frequencies (i.e. audio) it is impossible to make a cable with a constant impedance WRT frequency.
He stated that the "standard formulas" for calculating cable impedance are approximations which are valid for high frequencies (RF) but fall apart at low frequencies.
I'll try my best to find this post....................redface.gif  

That may well have been me. I've made a point of that a number of times and have often cited this white paper from Belden.

http://www.belden.com/pdfs/techpprs/ciocahalf.htm

se
post #1244 of 2628

Either my computer is screwed up (probably) or that link doesn't work anymore.

post #1245 of 2628
Quote:
Originally Posted by Chris J View Post

Either my computer is screwed up (probably) or that link doesn't work anymore.

Works for me. Though my iPad isn't displaying the GIF images. Hmmm, neither is my laptop. But all the text is still there.

se
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