sunnysal Posted October 29, 2001 Share Posted October 29, 2001 The article talked about the need for impedance matching in audio cables and made an interesting argument for the fact that much of the differences heard in cables is actually due to the impedance characteristics and not to materials, etc. any thoughts? looked darn interesting to me...regards, tony Quote Link to comment Share on other sites More sharing options...
Tron Posted October 30, 2001 Share Posted October 30, 2001 I don't claim to be an expert (I'm no electrical engineer), but don't various types of materials (metals) have varying impedances? If so, then the materials directly relate to the impedance of a cable system, no? Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted October 30, 2001 Share Posted October 30, 2001 Impedence is an "active" component. The metal used to make a cable determines some of the static characteristics, such as resistance, but it is the construction method that will determine the characteristic impedence. The characteristics of the metal chosen for the conductor will change some of the constants used in the calculation of impedence, but the material (copper, silver, various alloys) will have much less of an overall impact on the reactive behaviour of the cable that will the construction method (twisted, untwisted, Litz, braided, twin-axial, twin lead, etc.) ------------------ Music is art Audio is engineering Quote Link to comment Share on other sites More sharing options...
sunnysal Posted October 30, 2001 Author Share Posted October 30, 2001 it is true the material will affect impedance, as will numerous other factors...impedance is the AC equivalent of resistance (for DC) isn't that right?...anyway the facinating aspects of the article were related to this guy's measurement of echoes within cables (!) and his demonstration that by careful impedance matching these echoes could be eliminated (reduced)...It was a VERY persuasive article and put the impedance matching issue way up in priority over the material of the cable, that was what I was trying to get at...Ray, I would be really interested in your thoughts about the article...regards, tony Quote Link to comment Share on other sites More sharing options...
discorules Posted October 30, 2001 Share Posted October 30, 2001 If you look carefully at the article he performs the measurements using cables 100 meters long and I think some of these meassurements occurred at very high frequencies or very short pulse reponses. The key thing is the unrealistic cable lengths which makes this article somewhat dubious. These lengths are longer than a football field. In addition, I saw no comparison between regular and exotic high dollar cables. In that same issue, the magazine reviewed high dollar cables. I suspect the cable test gives the impression that the cables reviewed has merit. I'm not buying it. Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted October 30, 2001 Share Posted October 30, 2001 Hi Tony! I read the article. I've seen several other articles that attempted to provide some quantitative measurement of various cable parameters that could be related to perceived audio differences between cables. There was an extensive analysis in HiFi News and Record Review some time back... just checked their website, can't find the months and year... anyway, the article measured the impact that different cables had on the leading edge of a square wave. They evaluated, like, two dozen different cables. I've also read articles in Audio, going back a few years, that looked at the distortion of complex waveforms transmitted down a bunch of different cables. My take on all of these is that someone is saying "Damn it, ** I ** hear a difference, there's got to be some reason for it, so let's measure anything we can think of and see if there's a correlation between what the measurements show and what I hear." So far, I don't think I've seen any definitive link between some measured value and the associated cable's sound. I do know that I hear differences between different cables, whether interconnects or speaker cables. If I try to do a quick, A vs B comparison and articulate whether this cable has a "better" high end, or that cable sounds "smoother" or more "transparent", I get absolutely nowhere. What happens is I'll be listening to a familiar recording after making some kind of equipment switch (different cable, different amp, whatever) and I'll notice that I perceive somthing different about the recording. For example, take Ronnie Milsap's recording of "Lost In The Fifties Tonight (In The Still Of The Night)". There's a male group singing "shoo-be-boop" in the background. Up to now, I've heard that chorus as three guys standing in a line behind Ronnie. Now, all of a sudden, I realize it's four guys, and they're not standing in a line behind Ronnie, they're standing in a circle around a microphone, off to the right and a little behind him. Which one is correct? I don't know, but that's not the point. The point is, I heard it DIFFERENTLY when I changed, uh, whatever it was that I changed. Is the difference due to a slightly altered frequency response curve? Lower noise floor? Higher noise floor? Greater channel separation? Lower channel separation? Extended high end? Rolled off high end? I have no idea. But it's a difference that's very real. I go back to the other component, play the same cut, and yep, now it's three guys standing in a line. These are the types of differences I hear when I switch cables, and I've no idea what characteristic of the particular cable might account for this type of perceptual difference, let alone how to test for or measure it. Ray ------------------ Music is art Audio is engineering Quote Link to comment Share on other sites More sharing options...
JonM Posted October 30, 2001 Share Posted October 30, 2001 I'm with discorules on this one. His test lengths were unrealistic, and his test signals were 10 kHz square waves, whose first harmonic is above most people's ability to hear (let alone their higher harmonics, and to get a square wave, you need a lot of them!). He glibly said a 1 meter cable's problem will be 1/100th the 100 meter cable's, but that means its reflection will come 100 times sooner, and let's see his oscilliscope show *that* on the waveform's leading edge. In fact, in any normal length of cable at any normal audio frequency, the wavelength of the signal in the cable is much greater than the length of the cable itself, and such mismatches can be ignored. The theory of transmission lines is well known (I studied it in school many years ago, and it was old stuff then). The author (affiliated with an engineering school, if I remember) should have known that at audio frequencies and in normal cables of a few meters, this simply doesn't apply, and the factors you need to look at really are the lumped constants of the preamp output impedance, cable R, L and C reactances, and the following power amp's input impedance. I.e., it's a simple RLC filter. (And his solution to a nonexistent problem was to add additional electronics - another op amp or two. A previous Stereophile had a more convincing article saying how except for two particular designs, all common op amps are bad for the sound. Gotta love it - if you were looking to Stereophile for consistent guidance, forget it.) What bothers me is that Stereophile pubishes this sort of stuff apparently without technical review. But then Jonathan Scull, their senior editor, never claimed to be technical. A scholarly journal it ain't - Audio used to be, but now all we have really is the Journal of the Audio Engineering Society, and that's way above most people's heads (including mine most of the time). Quote Link to comment Share on other sites More sharing options...
Prana-Bindu Posted October 31, 2001 Share Posted October 31, 2001 I love this mystery. I was reading somewhere recently ( somewhere in here (forum?) ) about a quantum effect called phononic energy that is supposed to be generated by the signal going through a conductor and is converted into electrical energy at points of different impedances. It was a discussion about what these things called Bybee Filters have done to Dan Wright's home system. By the way, he's modding a P-3A for me this week to patch up the digital weak link in my system. I can't wait.... Back to the point: I found a couple of definitions of "phonon" on the worldwideweb: A quantum of crystal lattice vibrational energy. Phonons are analogous to the quanta of light, i.e. photons. phonon , quantum of vibrational energy. The atoms of any crystal are in a state of vibration, their average kinetic energy being measured by the absolute temperature of the crystal. In certain phenomena it becomes evident that this energy is divided into discrete bundles (see quantum theory); the energy bundles behave like particles in some respects and are termed phonons. These effects are most apparent at low temperatures where only a few phonons are present. For example, interactions between phonons and electrons are thought to be responsible for such phenomena as superconductivity. Ray: perhaps the dudes in the white lab coats have come accross something with which to measure these mysterious differences? If measurements become useful, I'll name my first kid Phonon. The second one would thereby HAVE to be named Phonoff.... So, assuming this phonon phenomenon (ha!) is in substantial ephect, maybe the closer impedances match, the less phononic energy is converted to electrical energy (noise). In other words, the magnitude of the dipherence in impedances has a direct relation to the magnitude of converted phononic energy being phed back into the signal as electrical energy. That would work nicely. Phfffssss!! ------------------ May the bridges we burn light our way.... Quote Link to comment Share on other sites More sharing options...
ckt Posted October 31, 2001 Share Posted October 31, 2001 I did not see the article. Wonder if they left the cable on a reel, or did they spool it off and spread it out? And how did they match for testing purposes ? Ironically, there is a trend in audio transmission for long distances to use a very low impedance source and a medium terminating impedance. It gives a lot more bandwidth than matching. Come to think of it, its kinda the same for an amp and speakers. Most amps have a very low source impedance. I reckon thats why we had all the discussions on damping... Quote Link to comment Share on other sites More sharing options...
Tron Posted October 31, 2001 Share Posted October 31, 2001 Well, I didn't read the article and don't really care to now since it seems the technical accuracy of it has been questioned. After absorbing the content of the replies to this post and taking notice of the quality of the information provided, who needs a magazine like _Stereophile_ anyway? Off to read more about the "phonon phenomenon." Quote Link to comment Share on other sites More sharing options...
Andy W Posted October 31, 2001 Share Posted October 31, 2001 I'd like to see: 1. The musical instrument that can produce 10kHz square waves (function generators don't count). 2. The air molecules that can carry them. 3. The microphone that can transform square waves into an equivalent electrical signal. 4. The recording/playback devices (analog or digital) which can store them and regenerate them. 5. The loudspeaker which can reproduce them. 6. Again, the air molecule thing. 7. The ear that can discern between 10kHz square waves and those with rounded edges. Until then, I don't need anything more than a length of adequate gauge zip cord. -Andy W Quote Link to comment Share on other sites More sharing options...
KLIPSCHHOG Posted October 31, 2001 Share Posted October 31, 2001 Finally a REALIST! I nominate Andy W. for President! ------------------ LSU PAINTBALL- We'll cover you with our balls! Paintball players do it 'till their balls break! 1 Pair KLF-30's Sonic Frontiers SFL-1 Pre-amp Carver TFM-45 Amp Teac AD-4 CD Player ***Needed VPI HW Series Turntable*** Anybody Sellin'? Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted October 31, 2001 Share Posted October 31, 2001 Here's a link to a rather exhaustive speaker cable analysis conducted by Nelson Pass (of Threshold and Pass Labs fame) some years back. Makes for some interesting reading. I'll post other links as I stumble across them. http://www.passlabs.com/articles/spkrcabl.htm ------------------ Music is art Audio is engineering Quote Link to comment Share on other sites More sharing options...
Kevin S Posted October 31, 2001 Share Posted October 31, 2001 I am sure that I am asking for trouble from those of you that understand the Nelson Pass article better than me from an electrical standpoint, but here I go anyway. My take on the article was: 1. If a cable has a benign combination of inductance, capacitance and resistance, it will have little effect on measured or audible performance if the length of the cable is short. 2. The longer the cable run, the thicker the cable needs to be to minimize resistance and measurable and audible effects on frequency response. 3. If you mess around with the inductance of a cable intentionally, you may get a different "sound", but you might blow up your amp! Since the frequency response charts shown in the article appeared to be 40 foot runs of 18 guage cable, I thought I would look up some wire guage recommendations relative to length etc. from a far less esteemed source (Radio Shack) to see what they recommend. In a book entitled "Installing Home Theater" from 1998, they specifically recommend against 18 or 22 guage wire. Here is what they recommend for runs of up to 100 feet when connected to 8 ohm speakers: 25 watt amp-16 guage minimum 50 watt amp-14 guage minimum 100 watt amp-12 guage minimum They recommend that you use the next thicker wire if you have 4 ohm speakers. So from this laymans viewpoint, if you use 12 guage cable, and your run is less than 100 feet, you've pretty much covered your bases. To be honest, these conclusions regarding thickness and length are the same as I remember them when I started in this hobby about 30 years ago. And I suspect that these conclusions were known to someone at Bell Labs in the early part of the century. So when Monster Cable started out all of those years ago promoting their thicker wire, that was probably a benefit to the average consumer. Most everything else that has transpired since then is (to put it mildly IMHO) scientifically suspect. ------------------ L/C/R: Klipsch Heresy II Surround: Klipsch RS-3 Subwoofers: 2 HSU-VTF-2 Pre/Pro/Tuner: McIntosh MX-132 AMP: McIntosh MC-7205 DVD: McIntosh MVP-831 CD Transport: Pioneer PD-F908 100 Disc Changer Turntable: Denon DP-72L Cassette: Nakamichi BX-1 T.V. : Mitsubishi 55905 SAT/HDTV: RCA DTC-100 Surge Protector: Monster Power HTS-5000 Quote Link to comment Share on other sites More sharing options...
Audio Flynn Posted November 1, 2001 Share Posted November 1, 2001 It seems that Stereophile is compelled to find undetectable differences to justify the price of the componenets it reviews through many hours of setup and testing. I do not expect them to invest much time responding to the letter from a guy who listened to K Horns for the first time and thought they sounded great with a 20 year old Kenwood receiver. I like Stereophile somewhat but Sensible Sound is much better grounded in reality. Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted November 1, 2001 Share Posted November 1, 2001 One thing that we must remember is to keep an ample supply of Q-Tips and Ear Wax Remover handy before every listening session. Did you know that a mere 0.5 mm wax build-up causes a 10 db drop in the nose/noise ratio, and if not uniformly applied to, and irrigated in, both ears, it causes an imbalance in the brain's RBL (red blinking light) circuitry that could vent off resistance as heat and blow your head off? I remember in Algebra's linear equations those things were measured at the end of the equation (e.g., y=mx+b+(sum of mind melting errata)), but they can accumulate and be significant. Also if your two year old is watching "There Goes a Bulldozer" with Construction Foreman Dave, AND rev'ing all his Tonka toys at once, well, so much for all the above anyway. You'll be deaf before the end of the Yankees' game tonight. No, I'm not drunk Just find this discussion to be intellectually stimulating yet comical in a nice way. And if I had to be stuck with a GUY on a desert island, it would be JonM because he's the smartest guy I've ever met, hands down. We'd be off the island in about 12 minutes, floating away in Lazy Boy comfort. ------------------ If you don't like what is coming out, you wouldn't like what is going in." -PWK- --------------------- Klipsch 1968 ALK Cornwall "II"s (LF/RF) ALK Belle Klipsch (Center) Klipsch Heresy (RR/LR) Klipsch KSW-12 sub Sonic Frontiers Anthem AMP1 (driving Cornwalls) Sonic Frontiers Anthem AMP1 (driving Heresy's) Denon AVR-4800 Toshiba SD-3109 DVD Quote Link to comment Share on other sites More sharing options...
cc1091 Posted November 1, 2001 Share Posted November 1, 2001 This message has been edited by cc1091 on 11-01-2001 at 11:34 PM Quote Link to comment Share on other sites More sharing options...
cc1091 Posted November 1, 2001 Share Posted November 1, 2001 If you'll allow me to get a little off subject: Until about two years ago, I thought that all I needed for my speakers to sound their best was a good amp, good sound sorce, and a reasonable gague "monster" type cable (Radio Shack brand or any other..including Monster). When I had finally purchased all the items that I thought would make for good sound and I was still hearing a small amount of distortion and having stereo imaging problems, I started the great equipment hunting expedition (you know, buy a few new pieces because they sound good in the store, only to bring them home and be disappointed). Finally a local stereo store listened to my problems and suggested a high end wire ($400 per 8' pair!). I doubted the sales guy's integrity and thought he was just out to steal more of my money. Then he offered to let me take the cables home with me for free. If I didn't like them, I could bring them back with no charges. So I took him up on the offer; brought the cables home; plugged them into my system and...WOW! The guy at the store said that they need some time to break in, but I was already in love with the crisp, clean sound. The imaging was perfect. After a few days, the bass broadened, and the treble smoothed out into a nice mellow and even bandwidth. I don't know what the article said, I don't put a lot of stock in the explanations about why certain wires work better. I only know that my ears were happy when using the cables. If you get a chance to borrow a pair of MIT Terminator 2 speaker cables (or a better model), do so. I think you will hear a positive difference. Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted November 2, 2001 Share Posted November 2, 2001 CC, I don't disagree at all. My last post was simply to break up a thread that had gone nicely pedantic. A little comic relief sometimes gets everybody focused. My personal experience is similar to yours ... after getting a Denon amp, a pair of nice matching tube amps, some vintage Cornwalls with Al K's WONDERFUL networks, a ALK'ed Belle for a center, some mint Heresy's for surrounds, and new cabinets to put all these into, my buddy said, "You're not done yet!" I said, "What? I just dropped $7 grand for speakers and electronics, and I'm not done?" He said, "Yeah ... you got to get rid of that zip cord you're using for speaker wires, and pitch the Rat-Shack RCA cables ..." He said (like you), "A nice pair of 8' speakers cables will cost about $500 ...", to which I said, "I'm going to need 200' to wire this room ..." Well, we comprimised, and I bought 200' of Audioquest Type 2+ cable, terminated them ourselves (actually, he did all that for me) ... And I bought another $575 worth of Kimber Kable PBJ interconnects (not the best, but very nice). Installed them all and threw the switch ... and all I can say was "WOW!" It was like someone removed the two or three blankets that had been covering them. Definitely worthwhile. So ....... I concur with you and the folks above ... just needed to poke a little fun at ourselves, even though there is enough brainpower in the post (myself excluded) to put MIT's charter in serious jeopardy. ------------------ If you don't like what is coming out, you wouldn't like what is going in." -PWK- --------------------- Klipsch 1968 ALK Cornwall "II"s (LF/RF) ALK Belle Klipsch (Center) Klipsch Heresy (RR/LR) Klipsch KSW-12 sub Sonic Frontiers Anthem AMP1 (driving Cornwalls) Sonic Frontiers Anthem AMP1 (driving Heresy's) Denon AVR-4800 Toshiba SD-3109 DVD Quote Link to comment Share on other sites More sharing options...
Colin Posted November 2, 2001 Share Posted November 2, 2001 I had the brown version of the Fulton cables mentioned in Nelson's article around here somewhere - have not used them in years - I listened to Khorns on some old tube equipment twenty years ago and still remember being very impressed - enough to learn the name and buy some big old Cornwalls years later - I played the Cornwalls with a little boom box once and they still sounded great - the voice of the speaker does not change dramatically without major changes in the front end equipment - a Cornwall still sounds like a Cornwall - I too hear differences in the cables I compare, but the price/performance ratio is way out of whack, but what do I know? I use $500 used speakers for my mains, not $20,000 Wilson Watt Puppies - I, for one, will respect some one else's opinion as just that - another opinion, and I will invest the time to respond to a guy who thinks Khorns sound great with a 20 year old receiver ... ------------------ Cornwalls & Klipsch subs; leather couch & feet up; lights out & tubes glowing! This message has been edited by Colin on 11-02-2001 at 11:52 AM Quote Link to comment Share on other sites More sharing options...
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