Correction! speaker #2 is at 14 feet away, not inches...sorry for the confusion |
Since the signal approaches the speed of light in your spkr. cables, unequal lengths are of no concern in your system. |
Space accordingly but keep the cable lengths identical. |
So your speakers are about 8 feet apart, right?
Well you're right about all the extra speaker cable, to say nothing of the extra money if it's decent cable. (Because if one of them would be over 10 feet, it would be good to have them the same length.)
Personally, a better way to do it, both in terms of economics AND sonics, would be to place the amps between the speakers using a longer pair of ICs from preamp to amp (I guess about 10 feet based on your information?) and then a pair of 6 foot +/_ speaker cables. Or you could place an amp next to each speaker (but using two ICs the same length) and use really short speaker cables, maybe 3 footers. That would be the best IMO.
If you can used balanced XLR ICs to connect the preamp with the amp, that is desireable, but not essential. |
Porziob is correct about the speed of light, etc. however speaker cable length over 10 feet tends to diminish the damping factor -- the amp's ability to accurately control the woofer, necessary for clean bass.
This is even more important if one is using a tube amp, since output transformers have inherently limited damping capability. That is why (unless they are just driving the high frequencies) you so often see tube amps sitting right next to speakers. |
thanks to all for the suggestions...All of the above options mentioned have already been explored. The only way the system can be laid out requires the question I have posed. "WAF" won't allow for the placement of amps out in the room, next too the speakers (my solution). Hence the need for the long runs of cable. As for the cost considerations I agree, however I already own them so my true cost is to have one of the runs shortened. If the speed of sound/light is correct? then I see no sonic benefits to the equal lengths...Correct? |
Porziob is correct. Whether you shorten one of them or not is a matter of convenience and visual aesthetics. |
Some cables like OCOS, for instance, impose no penalty for unequal lengths. I think the same is true for Silverline. See if your dealer offers any for a home audition. |
Sweet, then the question is moot. I can in fact run different lengths without loss of information. Thanks |
I wouldn't be so sure of the speed of light thing. While it is true, it is not the speed of the electricity traveling through the wires that is a concern, but the resistance, capacitance, and inductance, which are functions of length. |
A difference of 8 feet will not make an audible difference. This is easily shown with the math, but without the boring details:
Assuming the speakers have a 90 dB/2.83V-m sensitivity at an 8-ohm nominal impedance (1 watt) and that the speaker cables are 14 ft and 6 ft of #12 copper, the voltage drop to the furthest speaker will result in -0.035 dB. If you're 8-feet away from the speakers, you can compensate for this by moving that speaker a quarter of an inch forward. I didn't take capacitance and inductance into account - I don't think it will make a difference, but I could be proven wrong. |
Good work, GS. Every time you move your head while listening, you have a greater effect on the relative weight and timing of the sound reaching your ears from your two speakers than anything caused by a modest difference in cable lengths. In other words, if you think equal cable lengths matter that much, your listening chair should include a head-vise. |
Also, Pabelson, the 'moving head' effect applies to all of the other tweaks that seemingly change the sound. All of those 'differences' if even true, are swamped by moving one's head (ears) by millimetres!
Bob P. |
The key point of Gs' response was that he didn't take capacitance and inductance into account. Since these are 2 of the most important factors, nothing has really been proven. If you don't believe cables change the sound, then you also should believe that length also won't. However, if you accept the notion that cables do affect the sound, then 2x the cable length will cause 2x the sonic trait of that cable, minus the effect of the terminations. |
Honest1, I'm glad somebody else has their head on straight. Couldn't have said it better. |
Well, GS actually did the analysis for resistance. If Honest1 would like to do the same for capacitance and inductance, then we might be getting somewhere. But just saying they're "important," without giving us any measure of how important, isn't saying anything. If all doubling the capacitance does is cause a 0.2 dB rolloff at 20 kHz, that won't be audible. |
Pabelson, your thinking is not incorrect, but if you only consider these characteristics in relation to their effects (or lack of them) on frequency response curves, then you aren't going far enough.
One of the most important qualities of a good IC or speaker cable it that all frequencies arrive at the "destination end" of the cable at the same time. If they don't, then you get what is called "time smear" IE, a range of frequencies that started out together at the same microsecond at one end of the cable, arrive at the other at slightly different times. Time smear is the result of many factors, including capacitance and inductance as well as the construction materials and topology (the way the conductors are laid out.) Achieving low (or no) time smear is the holiest grail of cable designers. Its effects are not heard as sonics in the sense of frequency rolloff etc., but rather as a diminution of air, imaging, and and accurate holographic presentation of the sonic picture.
In the case of speaker cables (in addition to time smear) inductance can greatly affect damping factor (the ability of the amp to accurately control the woofer travel -- or more specifically, getting it to stop and "turn on a dime" at each end of its travel as determined by the signal. If it overshoots, you get muddy bass with no slam or (if you listen to mostly classical) musicality. Inductance not only produces an electromagnetic "drag" on the signal every time its polarity reverses, it also increases the "reactance" seen by the amplifier -- that's an equal and opposite signal generated back through the cable and caused by the movement of the speaker itself, acting like an electric generator. The amp has to work harder to drive the "real" signal against this electonic "headwind" and so the less it has to deal with the better. BTW, electrostatic speakers don't produce reactance, which is one of the reasons for their inherently good transient response (not just their lightweight diaphragms.)
As you pointed out, these characteristics are additive, and although typically small in value, have a tremendous affect on time smear (resistance and capacitance) and damping (inductance). People use all kinds of techniques to help reduce these effects (cable lifters, network boxes, etc.) but one of the easiest, especially with budget cables, is to keep the cables, particularly speaker cables, as short as possible. |
Mang: When I was trying to make my own speaker cables and installing in an asymetrical setup, I found that a difference of 20% length between the two speakers did not seem to matter much, but when the difference was 50% (8ft. length vs 12ft. length) the difference was obvious. The un-equal length differences with flat (Nordost type) cables was less obvious but still noticeable.......also cutting one set of cables shorter will hurt future re-sale value, good luck, Mike. |
Nsgarch, all that talk about back EMF might be true, but even a doubling of cable length would not result in an audible difference or a difference larger than simply moving one's head a few inches closer to one speaker. Keeping speaker cable lengths as short as possible is always a good thing, however, especially with tube amps.
BTW, electrostatic speakers might not suffer from reactance effects, but are affected by capacitance effects inherent in their design.
Bob P. |
Bob, with regard to reactance and inductance (and to a much smaller degree, resistance) I was commenting on the bass quality (damping factor) and not stereo imaging.
Unequal cable lengths probably won't effect image balance, up to a point as Mike indicated, so long as one is using well designed cables that don't have excessive timing problems. |
Yes Nsgarch, image balance will not be affected by unequal cable lengths if the difference in length is less than about 10000000:1 ratio! Bass, however, will be affected because of the reduction in damping due to the higher resistance of the longer cable, especially with amps of higher output resistance, read tubes.
Salut, Bob P. |
Bass, however, will be affected because of the reduction in damping due to the higher resistance of the longer cable, especially with amps of higher output resistance, read tubes. Which begs the question, How much? There's been a lot of cant in this thread, but not a lot of solid information. Whatever effect cable resistance has on damping factor, and therefore on bass, is easily calculable, if you know the basic physics. I'll freely admit that I don't, but I've consulted people who do, and this is what they tell me: In most systems (e.g., those with solid-state amps), simply choosing cable of sufficient gauge eliminates this as an audible problem. If you must use runs of different lengths, size your cable for the longer length, and the problem disappears. If you use a tube amp with high output resistance, then you really owe it to yourself to learn the necessary physics. |
Which brings us back to the original question - will unequal lengths of cables cause problems? The answer is NO in practice, yes in theory, but even then, can one hear the difference?
Bob P. |
First of all, I think Bob goes too far with his ten million-to-one ratio. Only really high quality cable with great timing characteristics is forgiving of differences in length, and then who cares because you're probably not going to invest in a lopsided pair of Siltechs or Purists anyway, are you?
On the other hand, the imaging performance of unequal lengths of lower priced (IC) cables suffers more from time smearing (eliminating t/s is the main cost driver of high priced ICs IMO) than unequal lengths of as much as even 3 to 1
Pabelson, Bryston used to have a really great damping factor vs. wire gauge vs. wire length chart for their amps. And if your amp is SS and (for now) you're going to use some cheap, big gauge Monster or Home Depot zip cord, stay under 25 feet for the longer run and you're done. If you have a tube amp, however, I think the best source of info (about recommended wire size vs. length) would be the manufacturer -- who could also tell you what the best you could expect out of their units would be if you used the shortest/fattest possible speaker cable (essentially a pair of jumpers between amp and speaker). One day though, when you decide you'd like more resolution, and to give your equipment the chance to be all that it can be, your not going to buy (special order probably) an unequal length pair of quality speaker cables. C'mon !!?
This is one reason folks who like to biamp often combine SS for the low end, with a tube amp for the highs and mids, where damping control is easy even for a tube amp. And it's also the reason why those who prefer no more than one amp per speaker, are always looking for the best of both worlds, usually expressed as "The most musical solid state amp ever made!" I think the darTZeel is currently the poster child for that award.
The moral of the story is: Unequal lengths? Sure, go ahead, you're likely talking about using cheap stuff anyway, so who cares?
Want better performance and better cables? Never going to need to sell them for ANY reason? Sure, buy an unequal length pair of Kimbers or whatever (you're gonna be sorry, ha ha!) |
Well, anybody who believes that cables have "timing characteristics" that are audibly relevant will buy anything. But maybe that's the idea, huh? |
Hey, I remember nsgarch in some good arguments, this isn't one of them! If speaking physics, timing characteristics are determinied by inductance only. If talking audio, then we are taking moving your head a few inches to one side of center. Oh well..
steve |
Not inductance only! Cable topology, and wire composition (not just material, but the stranding and shape are big factors) determine how fast the different frequencies propagate.
What most folks forget, is that an audio signal is a wave in a metallic (usually) medium. And although electricity (electric potential) may transmit at the speed of light in a theoretically perfect medium (ever hear of "super-cooled super conductors"?) an electric "signal" does not, and is very much medium dependent. What do you think the doctor is looking for when he/she checks your reflexes? Wants to see if your cables are deteriorating. |
And she need as rubber glove for that...?
next time I'll ask!
steve |
Oh gosh! Maybe it was my tubes and not my cables!! |
Nsgarch, you are correct in saying that different frequency voltages changes travel at different speeds in different cable compositions, BUT, the differences are only apparent (even theoretically) at RF levels, i.e. a signal at 10 megahz might be delayed vis a vis a 1khz by some very small amount, but would be inaudible anyway.
Frequency variations and Phase problems due to capacitance and inductance are however more detectable at listening frequecies, but then, again, the difference in lengths of the same cable would have to be large indeed.
'Smearing' if there is such a thing, is not caused by the construction of the cable or materials used, but by the inherent electrical properties of the cable, IMO.
Bob P. |
Bob, I think you should have this conversation with someone like Bruce Brisson (Monster, MIT cable designer -- invented the "shotgun" SE cable) I don't think he'd agree with you. I've run out of science . . . . . |
Bob, I think you should have this conversation with someone like Bruce Brisson (Monster, MIT cable designer -- invented the "shotgun" SE cable) I don't think he'd agree with you. Well, of course he wouldn't. It would be very bad for business. But that's how these cable charlatans operate. They take a basic concept, like the speed of extremely high frequency signals, and improperly claim that it applies to audio frequencies as well. That's what turns it into pseudoscience. It only works because credulous consumers are willing to believe it. |
Nsgarch, oh I think that he would agree with me, but my way of stating these things doesn't help sell cables, while his version of these same effects (or non-effects) and claim that these are audible and his solution to this 'problem' does sell cables. We are in fact saying the same thing, just disputing if the effects are audible in practice or not. Sufficiently different impedances can be heard, however.
Salut, Bob P. |
Whether either of you guys want to admit it or not, what sells anything ultimately is results, not white papers, not hype. (You remember the one about fooling all of the people some of the time etc?)
What put Monster Cable on the map way back before you'd remember, was the shotgun design with its multigauge, multilength, separately insulated stranded conductors, with dual symmetrical signal path and floating shield. (A blueprint for a new, quieter more coherent SE cable, not hype.) Before that there was only single conductor coax for SE cables -- and if I had my way, that's all you guys would be allowed to use! Shouldn't bother you though, cause everything else is just a lot of pseudoscience, right? |
That some audiophiles fall for this cable hoo-hah is evidence that you CAN fool some of the people all of the time. What put Monster on the map was marketing. And that's all the high-end cable business has ever been. |
Pabelson, why don't you do something that involves science you can trust? |
Nsgarch, I find the notion that cables should have a direction or that the 'positive' and 'negative' conductors should be of different construction or material to be pseudo science, since signals transmitted over cables (IC, speaker etc) are AC, thus flow in both directions (not at the same time of course!).
IC's can sound different if they are designed to do so, that is work with the impedance characteristics of the cable to get the frequencty response one wants and voila, a cable that sounds 'faster' 'sharper' etc.. Of course the same cable will sound different with different equipment, depending on their contributiuon to the circuit impedence characteristics (people call that synergism). Just make sure that the marketing quotes all sorts of pseudoscience to explain and justify those attributes and not the real reason (frequency response variations) why that cable sounds as such.
Salut, Bob P. |
Bob, please read the following and you will understand the reason for the importance of direction in the use of shotgun-type ICs (which is probably 80 or 90 percent these days.)
Though many mfrs. put arrows on their cables (just to look cool, I guess) the original use of them was when Bruce Brisson designed the shotgun IC for Monster Cable (which was made Monster Cable the ONLY cable to use at that particular moment in history.) He eventually left to start MIT, which he still owns. Until the Shotgun, all single ended ICs were coax -- single center (plus) conductor surrounded by a braided shield which also doubled as the (minus) conductor (a lot like TV coax today.) These ICs were susceptable to RFI pickup and ground loop hum. Bruce used two identical signal conductors in the center (double-barreled 'shotgun' - get it?) and a shield around the whole shebang. One conductor (plus) was connected to the RCA pin at each end, and the other conductor (minus) was connected to the RCA ring (ground) at each end, BUT the shield was only connected to the outer ring (ground) of the RCA plug at one end. Thus it could shield the signal conductors, and drain noise to ground, but it couldn't conduct a current and of course didn't have to carry the minus signal either. (A side benefit of the shotgun arrangement is that the two signal-carrying conductors are identical, which helps reduce time smear problems.) Bruce put an arrow on the cable pointing to the end where the shield was connected to ground (this is called a "floating" shield, because one end isn't connected to another ground point, so it, well, floats!). In order to avoid long explanations to electronically challenged audiophiles, he said "you point the arrows in the direction of the signal flow." What he really was trying to do, was make sure that the end of the IC where the shield was connected to ground (the arrowhead end) would wind up at the preamp, (which is the only component that should be grounded to the AC outlet) creating what's called a "star grounding" system, where all the components' ground noise or hum drains to ground through one point -- the preamp, and the protective shields also are all connected to ground at the preamp. WITH ONE EXCEPTION! As you can see, following the "arrow points in the direction of signal flow" rule between amp and preamp won't work! You still want the end of the IC where the shield is connected to ground, to be at the preamp. Thus the arrows on amp-preamp ICs have to point "backwards." A better rule, which I tell everybody, is "all arrows point to the preamp" and I let it go at that! Most mfrs. do use the Brisson design for their single ended ICs now. These include Audioquest, Monster, Straightwire, MIT, Cardas, some Nordost, XLO, and most of the other big names. Some exceptions are Purist and Magnan and I guess a few others, but that's another conversation.
And even though Cardas ICs are "balanced" (they don't like to say "shotgun", because it sounds like they're copying MIT, which they are!) their ICs don't have arrow because they are "double floating shielded" with each shield connected to ground at the opposite end from the other shield. So it really doesn't matter which way you orient them. So point all your arrows to the preamp and you'll get the best performance out of 90% of all SE ICs.
You still have a great deal to learn about the signal carrying characteristics of different alloys, cable construction/stranding etc., but from what you've revealed so far ("signals transmitted over cables IC, speaker etc)are AC, thus flow in both directions not at the same time of course!"), I'd say you have plenty of time ;~)) |
Nsgarch, are you saying that signals in cables (IC or speaker)are not AC?
I understand perfectly well the concept of using a shield independent of the signal carrying conductors and the need to connect it in a 'star' ground configuration. That was not my point. My point was that some people are actually saying that the 'negative' conductor should be of different material than the 'positive' conductor or that installing cables in a different direction necessitates another break- in period because the material needs to be 're-oriented', since the current is flowing in the opposite direction. That is pseudo-science. They are implying that the signal current flows in only one direction, which is wrong. The voltage signal varies from positive to negative with reference to the 'ground' and thus the current changes strength and direction accordingly. I suggest that you look at some amplifier output configurations. The ground or 0 potential is a reference point and usually at 0 volts. When the potential or Voltage goes negative with reference to the ground the current flows from the 'ground' towards the 'negative'. Now that isn't pseudo-science.
May I respectfully suggest that you look into the basics of electricity and signal conduction before making assumptions as to my age or knowledge?
Bob P. |
Bob, Mr. Abelson states "That some audiophiles fall for this cable hoo-hah is evidence that you CAN fool some of the people all of the time. What put Monster on the map was marketing. And that's all the high-end cable business has ever been."
So it seems that you have both taken the position that it's all hoo-haa. I'm good with that. And I hope you'll both be very happy with your hoo-haa systems until you hear something better, ha ha! (or was that hoo ha!) |
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mang53,
I just delt with this. I had 21 feet on the left speaker and 8 on the right due to a home theater setup and all my equipment in a walk in closet much closer to the right speaker. I had this setup for 6 years till just 2 weeks ago.
I was able to bring the left speaker down to 16 feet and then I made the right the same length at 16 feet.
There is seeming to be better balance now. Before, it always seemed as if the singers voices where more towards the left which has the longer cable. Not sure if it was the odd legth in cable.
I did role the cable up by the right speaker due to its longer lenth |
