paul@voder.UUCP (07/17/86)
>All nonbelievers please type 'n'... n >I spent several hours auditioning cables this last weekend and was really >amazed. I was listening on the dealer`s system which is quite familiar, >having the same speakers (EHS Sopranos). I also used the power-amp I >have at home, but wasn't able to tolerate its affect on the sound for the >full time. Anyway, the biggest 'find' I found was MIT-330 interconnect. > >Boy, is this stuff expensive! $115 for a 1 meter pair. But it's really >great -- I made more change in my system by putting in two of these babies >then I did getting a new piece of equipment! (new CD player) > >I'm not going to say much more about the 'sound' of the cable -- please >try it yourself -- do a little A/B with some cheap cables, say Monster >Interconnects on a system you feel comfortable with. You'll love 'em! >(PS: They're REAL transparent, but very capacitive -- they use double >John Irwin (jdi@ucbvax) I'm sorry John, but frankly I can't hear the difference between cables, at least not speaker cables. Does anyone out there know of a single reason why these expensive cables should sound better? As has been pointed out before, transmission line effects can ignored at audio frequencies (unless, of course, your speakers are several miles from your amp |-)!) The only thing I can think of is the resistance of the cable, but this can be solved pretty well just by using a heavy wire, such as lamp cord. As far as capacitance, so long as your amp can handle the small capacitive load without singing, I don't see any problems. ( A quick calc. shows that for an 8 ohm speaker, and a time constant of 40us, the C would have to be 5uF. I don't know of any reasonable length cables that even come close to this!) Much more important, I don't see how cables could add any non-linearities. So, can someone please educate me as to why one should spend $115 dollars for a meter of cable!? --- paul dietz (paul@voder) My employer takes no responsibility for my flamings, and neither do I.
crg@druxo.UUCP (GenterCR) (07/19/86)
> > >I spent several hours auditioning cables this last weekend and was really > >amazed. > >John Irwin (jdi@ucbvax) > > I'm sorry John, but frankly I can't hear the difference between cables, at > least not speaker cables. Does anyone out there know of a single reason > why these expensive cables should sound better? If Mark will forgive me, I have re-posted his article on impedence vs. frequency differences. This is an interesting article from the perspective of the amount of flames it DIDN'T receive: when it was demonstrated that skin effect was insignificant at audio frequencies there were a flurry of "told-you-so, cables don't make a difference" articles posted. I am awaiting the responses from these folks disputing Marks measurements. My own opinion on cables: the right cable on the right system can make an awesome improvement in the sound quality (both speaker and interconnects), and the only way to decide is to audition them at home, on your own system. I have had some very well respected cables on my home system that sounded terrible, but worked fine elsewhere, and vis versa. The great cable debate was properly put to rest a short time back with the following statement, which applies to every piece of audio gear: If you can't hear the difference, don't buy it. And flamers, please note: A proper, appropriate, and useful response to the net is to say that with such-and-such equipment, I was unable to hear a difference: NOT that since on my system I couldn't hear a difference, that nobody will ever hear a difference. The former tells me that if I have similar quality equipment it is probably not worth my time to audition cables: the latter tells me a little about the maturity of the poster, but certainly nothing about audio. (I guess I better practice what I preach: my system consists of a SOTA Sapphire, Accuphase AC-2, Sumiko headshell, Dynavector 501 arm, 1-m Reference Interlink, Denon POA-2000 pre-amp, 15-m Original Interlink, Acoustat Model III with Medallion Interfaces and the large RH-labs subwoffer. The Acoustats are passively crossed at 100 Hz (12 db/octave), and the RH is activly crossed (RH Labs ABX-4) at 100 Hz (36 db/octave). Amplifiers are a NYAL Moscode 600 (500 Watts/channel) on the Acoustats and a strapped Denon PRA-3000 (800 Watts, Class A) on the RH. Speaker cables are three 2-m sections of Moster Cable Powerline 2. There is also a B&O 9000 Cassette Deck and a JVC 566 HQ VCR hanging around the edges, with an Advent 6 foot projection TV centered between the Acoustats. Reference Interlink into the B&O, all other cables Original Interlink.) > OK tech weenies, here are some MEASURED impedances vs frequencies for some > real audio cables on the market. These are measurements done with a > HP 4192A Impedance Analyzer by Elite Electronic Engineering Co., Dowers > Grove, IL. They are not numbers generated by computer programs or pulled > out of a textbook. These are all cables you can buy. I'm quantizing the > numbers off plots published by Straightwire on some lit. I got at CES. > 2 Meter Interconnects (Impedance in ohms) > Brand 5khz 10khz 15khz 20khz > Randall .012 .040 .067 .114 > Interlink Ref A .010 .036 .063 .103 > VanDenHul .006 .026 .046 .087 > Distech .004 .018 .032 .050 > Flexconnect .004 .009 .014 .021 > LSI connect .000 .002 .003 .005 > 10 foot speaker cables (Impedance in ohms) > Brand 5khz 10khz 15khz 20khz > Monster Cable .040 .101 .155 > (off chart) > Monster PL II .033 .087 .144 > > MIT MH-750 .025 .074 .122 .162 > Livewire 10 .012 .045 .078 .109 > Randall 64TBC .004 .011 .017 .028 > Teflon-12 .002 .008 .015 .025 > MusicRibbon12 .001 .005 .008 .013 > Music Ribbon, Teflon-12, Flexconnect, and LSI connect are all Straightwire > products and usually cost much less than the competition. No additional > information on the test set-up was given. I use flexconnects, but I > didn't like their speaker wire. The Music Ribbon rolled off the bass, > and it and the Teflon-12 were bright, fast and lacked midrange harmonic > body, and warmth compared to my FMS speaker wires and also Monster PL II. > The flexconnect looks like a thin coax. Teflon-12 is a heavier coax using > cylindrical conductors and a teflon dielectric - probably similar geometry > to Neglex/Mogami speaker wire. The Music Ribbon is either 12 or 24 conductor > ribbon (computer) cable. The difference is that the insulating dielectric > is polypropelene and not PVC. Music Ribbon sounds and measures differently > depending upon which conductors you connect together to form a pair. > Some quotes in the literature: > "Cables tend to accentuate the portion of the spectrum where their impedance > begins to rise, while higher frequencies are attenuated. This alteration of > harmonic structure and the attendant masking of quiet information are the > result of phase-shifted musical energy filling in the space between notes. > Phase-shift also tends to make transients sound louder because their > duration is increased." > "Note that deviation of series impedance is caused by skin effect and > inductance." > Straight Wire can be reached at PO Box 78, Hollywood, FL 33022, > (305) 925-2470 > Mark Kaepplein decwrl!dec-rhea!dec-amber!kaepplein Forgive me Mark C. Roy Genter AT&T Information Systems 11900 N. Pecos St. Denver, Co 80234 inhp4!druxo!crg 303-538-4854
sjc@mips.UUCP (07/22/86)
> If Mark will forgive me, I have re-posted his article on impedence vs. > frequency differences. This is an interesting article from the perspective > of the amount of flames it DIDN'T receive: when it was demonstrated that > skin effect was insignificant at audio frequencies there were a flurry > of "told-you-so, cables don't make a difference" articles posted. I am > awaiting the responses from these folks disputing Marks measurements. > > OK tech weenies, here are some MEASURED impedances vs frequencies for some > > real audio cables on the market... > > > 2 Meter Interconnects (Impedance in ohms) > > Brand 5khz 10khz 15khz 20khz > > Randall .012 .040 .067 .114 ... > > > 10 foot speaker cables (Impedance in ohms) > > Brand 5khz 10khz 15khz 20khz > > MIT MH-750 .025 .074 .122 .162 ... My memory of EE100 is so rusty it would be presumptuous for me to claim to be a tech weenie, but when I read the original posting I thought the author was throwing in the towel! The numbers are so darned small (except for the "off chart" readings, which I can't judge without seeing the chart) that they suggest that if there _are_ audible differences among these interconnects, they're due to something other than the magnitude of series impedance. Seriously, 1. If the input of your well-designed amplifier presents a uniform impedance across the audio spectrum, then the magnitude of series interconnect impedance is less important than its uniformity with respect to frequency. An interconnect whose impedance is a uniform 100 ohms would not affect the frequency response, but the Randalls (the worst shown), whose impedance varies from .012 to .114 ohms, would: given a typical amplifier input on the order of 1e4 ohms, the perturbation would be (ignoring phase, which the posting has regrettably not provided for us) roughly 20*log10(1e4/((1e4)+(1e-1))) = -0.00009 dB. 2. Assuming a 1-ohm speaker, then the .1 ohm variation in impedance for the MIT cables (the worst shown) could perturb the frequency response on the order of 20*log10(1/(1+.1))= -0.8 dB, which may well be audible. That's a good argument for using 16 gauge zipcord, which will not exhibit this problem. 3. To claim that "cables can't make a difference" is to climb out on a shaky limb. One can surely concoct a cable having sufficiently weird reactive properties to make an audible difference. A less shaky limb is "a cable can sound different from 10 feet of 16 gauge zipcord only by being worse". > > ...Some quotes in the literature: "Cables tend to accentuate the > > portion of the spectrum where their impedance begins to rise, while > > higher frequencies are attenuated...Note that deviation of series > > impedance is caused by skin effect and inductance." This literature contradicts itself. Never mind that Kirchoff's voltage law suggests that rising cable impedance should attenuate rather than accentuate; assume that this literature is right. Then skin effect (which raises the series impedance) would _accentuate_ the highs. -- ...decwrl!mips!sjc Steve Correll