I did, a few years ago, when I had several loudspeakers at home for testing.
Thanks for the info, DVV! Just for the sake of completeness, can you list any of the speakers and components you tested with?
JMLab/Focal, Bowers&Wilkins, B&M Acoustics, Infinity, JBL and AR speakers, of various sizes, quality and prices. It was a group test I was doing, that's why I had them all at hand.
JMLab/Focal make their own drivers, so do B&W, so does AR, but JBL, Infinity and B&M Acoustics all use drivers originating from Son Audax, itself a part of the Harman International emire (as are JBL and Infinity).
As for the cabling, I used many flavors of van den Hul, some AudioQuest, Jamo and garden variety power cables. Cross section ranged from 2.5 sq.mm to 5.5 sq.mm; 5.5 sq.mm are two parallel runs of 256 strands each, and it's capable of passing along at least 200 amperes of current. To the best of my knowledge, no amp made in the world today can deliver anywhere near that kind of current.
In everyday life, that's the cable I have on every speaker; its official van den Hul designation is 352 Hybrid. It uses OFC copper, which is silver plated, and mixed with carbon fibres (hence "hybrid"). I have yet to hear a better cable which costs less than 30 times its price for a 5-6% improvements (the last was made by Kimber, but cost like 50 times the price).
After about two weeks of experimenting, I could not name one instance when biwiring helped any, assuming only I used decent cross sections (i.e. with enough metal to carry the required signal properly).
Can you define what you determined "decent" to be, and did it vary with the driver type (woofer, mid, tweeter, etc.)?
Thanks![/quote]
Well, to be blunt, I could not notice ANY difference that I could swear was really there and not in my head. None whatsoever. And I use a variety of amps: Karan Acoustics KA-i180 (2x180/250W into 8/4 ohms), Harman/Kardon 680 (2x85/130W into 8/4 ohms), Harman/Kardon 6550 (2x50/70W into 8/4 ohms, but SEPP) and Yamaha's AX-592 (2x100W into 8 ohms). Plus my own designs, but since these are not available commercially, so nobody but me can compare them to anything, I tend to leave them out and use them for my own reference only.
All of them except the Karan have been pushed quite a bit more into pure class A; for those interested, there's a text I wrote some years ago on the topic on the TNT site (
http://www.tnt-audio.com ). I still get regular mail on the topic.
Must have hit a nerve.
I should also add that I support the wide bandwidth school; this is to say that if my audio circuit doesn't hit 1 MHz, it's junked promptly. My line level electronics hit 10 MHz, and if I continue to do this, sooner or later I'll get into the FM range.
But seriously, I'm talking about INTERNAL response, I always add an input filter to make sure that the electronics are always faster than the fastest signel that can get into them, thus practically eliminating TIM, TID and SID. What's left over is of purely academic value. But this can (unfortunately not always) really open up the sound, make it easy and flowing rather than struggling along in a congested manner. Consequently, I'm very likely to hear what there is to hear.
There was nothing to hear with biwiring that was different to using single quality cabling. And although I just turned 51, I can hear 18 kHz ten out of ten times. While the powered JBL subwoofer makes sure I get to hear what goes on below 50 Hz.
Before you ask - yes, I tend to be meticulous in tests, that's what I'm paid to do (however with different technologies, PCs mostly), and I spare no costs to create a level playing field for one and all. My room is at 24 deg. centigrade, 40% humidity 365 days a year. Power is strictly controlled.
Cheers,
DVV
