Speaker Cables, One side longer- bad idea?

If you have a stereo amplifier where each channel has a common ground, than you most likely will increase an inter-channel noise and distortions since different length cables have different resistance, capacity and inductance. Stereo amplifier has to be equally loaded -- it's almost like you will plug in different speakers to each channel. In dual-mono amplifier or monoblocks you will have on the shorter side slightly better details than on the longer side. This difference you will not be able to rectify with channel ballance if the one is present in your preamp.

There won't be an audible (probably not even measurable) difference with the lengths you mention. Marakanetz's comments are correct in theory, but you would only need to worry if the 2 sides were really different. I asked this question of a well-known cable maker/designer (really nice guy) at a show a few years ago and his explanation left me with the conviction that a 1.5 to 1 ratio or less should be fine. OTOH, a dealer I know has done blind tests with 5 and 1 meter runs of a mid-priced high end cable and none of his sophisticated customers have been able to tell a difference in sound.

If someone wants to illustrate the difference with numbers, that might be interesting.

Keep them equal so the cable characteristics are matched electrically and sonically.

Thanks Paulwp,

As you might have guessed, I have my stereo off to
the side with nothing between the speakers. I
need to buy new cables and decided I didn't like
the looks of a bunch of loose, extra wire for one
side. In fact, a local dealer that does custom
home installs with Transparent Audio cables
told me that they regulary messure off the length
needed and don't worry about the extra 4-6 feet on
one side.

Tom

Audiogon no longer lets us drop links into a forum so.. I've cut and pasted some interesting reading on the subject:

Equal Length Speaker Cables - Are They Necessary?

"You do know that you must match the length of speaker cables in you system to insure "an equal delay" in all channels?"

Of course, you didn’t know this until just then when the salesperson posed this "rhetorical question". On the surface, this sounds perfectly reasonable. Your power amplifier generates a set of signals that are sent to your speakers (to the right main, to the left main, to the center, to the right surround, to the left surround, to the subwoofers, etc.). This set of signals have been created in such a way to be synchronized with each other – in engineering terms, they are "in-phase" with each other. Therefore, it seems perfectly reasonable to maintain this "in-phase condition" by keeping all cables the same length. Unfortunately, this means that you will have to use the same length cable to the speaker setting right next to your equipment rack (less than 10 ft. away) as you use to the speaker setting in the back of the room (greater than 60 ft. away). As this realization takes hold, you look up at the salesperson and see this smile come cross his face – he’s "got you". You are about to spend 3 to 5 times more that you had anticipated (or budgeted) for speaker cables to compensate for the "DREADED PHASE DELAY". Even if you are an electrical engineer, you probably won’t take the time to think through the "sales pitch" you’ve just been given – it sounds so logical on the surface.

When Einstein first conceived the theory of relativity and before he attempted to codify everything with mathematics, he performed a set of "thought experiments" that helped him visualize the concept that would totally revolutionize our view of physics in the 20th century. I’m no "Einstein" and what I’m attempting to explain is not the "general theory or relativity", but I do find that using "thought experiments" are extremely useful in making complex subjects a bit more understandable. I’d like to use this approach to dispel the concept that speaker cables need to be cut to the same length to prevent audible phase delays in a HT system.

Let’s assume that you have a stereo audio system with a speaker attached to the left channel and a speaker attached to the right channel. Let’s assume that the cable between the amplifier and the left speaker is 10 ft. long; let’s assume that the cable between the amplifier and the right speaker is 60 ft. long. You are seated at a position that is equal distance from each speaker. One speaker (the left speaker) receives its signal approximately 50 ns (nanoseconds) before the right speaker. This is because the signal to the right speaker must travel through an additional 50 feet of cable (i.e., 60 ft. – 10 ft.). A good "rule of thumb" is that an electrical signal takes approximately 1ns to travel 1 ft. through a cable. According to the salesperson we met back in paragraph 2, your system has a severe phase delay problem because of this 50 ns difference between the left and right channels. With this as our premise, let’s examine our ability as a listener to detect this unbalanced condition. I will attempt to do this through three thought experiments.

In posts below:

Thought Experiment #1:
Let us assume that the sound reaching your ears from the two sources (the left channel and the right channel) is indeed out of phase by 50 ns; can the audio sensory system of a human detect this difference? Fifty nanoseconds is a very short period of time - 0.000000050 seconds. Your audio sensory system is a chemical based relay that converts the movement of your eardrum into a chemical change that eventually triggers electrical impulses to the brain. Although the brain in an extremely powerful relational computer, it is very slow compared to even the simplest desktop personal computer. Even the best human hearing is limited to an upper frequency response of 20 to 22 kHz. This corresponds to a signal with a duration (i.e., period) of .00045 seconds or 1000 times longer than the 50ns phase difference generated by the cable delay in our hypothetical system. If you were able to detect this 50 ns phase difference, your upper hearing limit would be somewhere between 20 and 22 MHz. If this were the case, you could receive most of the world’s short wave radio broadcasts directly without having to resort to a radio receiver. You will not find any physiologists that will testify that human hearing is capable of anything approaching this level of differentiation. In other words, the human ear cannot come even close to detecting a 50 ns phase difference.

Thought Experiment #2:
For the purpose of a second thought experiment, let’s assume the same setup and also assume that the human audio sensory system is capable of differentiating a 50ns phase difference between two sound sources. In our hypothetical example, energy from our amplifier reaches the left speaker 50 ns before energy from the amplifier reaches the right speaker. Therefore, sound from the left speaker should reach our ears 50ns before sound from the right speaker reaches our ears – Right? The answer to this question is almost always, "No". Speakers are electromechanical devices; an electrical current flowing through a coil surrounding a magnet moves a speaker cone to produce a sonic wave. As such these devices exhibit all of the inherent inertia effects of any mechanical system. From the time an electrical signal is applied to the speaker and the time the cone actually begins to move will vary considerable from speaker to speaker. I don’t care how much money you pay for your speakers (i.e., $10,000 each) or how well they are matched from the factory, no two speakers will "come alive" with exactly the same delay. Because of this, you have no guarantee that the right speaker which gets the electrical signal 50 ns late will not actually be the first speaker to start moving a column of air. You go to all of the trouble to cut wires to the same length, and the mechanical inertia associated with each speaker totally negates your careful preparations. In fact, there is a 50/50 chance you will increase the phase difference between speakers by timing the cables (i.e., cutting them to the same length) and make matters even worse.

Thought Experiment #3:
For the purpose of a third thought experiment, let’s assume the same setup, assume that the human audio sensory system is capable of differentiating a 50ns phase difference between two sound sources and that the speakers are perfectly matched and start moving with identical delays. In our hypothetical example, energy from our amplifier reaches the left speaker 50 ns before energy from the amplifier reaches the right speaker. The two speakers "mimic" their respective electrical signals and the left speaker starts moving a column of air 50 ns before the right speaker does the same thing. Therefore, sound from the left speaker should reach our ears 50ns before sound from the right speaker reaches our ears – Right? Again, the answer to this question is almost always, "No". To understand why this is the case, we need to understand something about how sound travels through the air. Sound travels approximately 1100 ft. in one second through the air. This means that a sound wave will travel approximately 0.00066 inches in 50 ns. This distance is equivalent to approximately 1/10th the thickness of a human hair. If you, as the user of our hypothetical sound system, aren’t capable of placing your ears to within 1/10th of the thickness of a human hair ever time you set down to listen, you are introducing far more phase difference that you could ever introduce through unequal lengths of cable. To make this point, let’s assume your ears are always within ½ inch of some nominal location everything you listen to your audio system. This would represent a phase shift that would be equivalent to having one speaker cable 3,156 ft. longer than the other speaker cable.

I don’t know how many of you have reached this point without going to sleep. But, for those of you that have, I think you’ll see the absurdity of the "equal speaker cable length" argument as it pertains to phase delay. Anyone of the above thought experiments, by itself, is sufficient to negate the "equal speaker cable length" argument. A better argument for maintaining cable lengths that are similar might be to achieve consistent damping factors between speakers. This is not to say that there aren’t places where attempting to match cable lengths is not important. If you were building a s-video cable or a set of component video cables from RG-6 cable, matching cable length becomes more critical because of the high frequency (i.e., short period) nature of these signals. Therefore, the next time a salesperson attempts to sell you more speaker cable with the "equal speaker cable length" argument, you can simply smile and say, "Thanks for this excellent piece of advice, but I think I can spend my HT budget elsewhere and get infinitely more bang for the buck."

Bwhite- Veddy interesting.

We could always move one speaker .00066 inches closer.

Wow! Science rearing its ugly head! Such nerve. Obviously the golden eared listeners can hear such phase difference, and then some. To introduce arguments using numbers, you silly person... You have to own Bose 901s, right? By the way, to put out such utterances you have to have a scientific background, no? Come on fess up. How about something on spiking every known component, I 'spose you have numbers on that too, eh? Geez, you're no fun. You probably are dead right, but most people participating in Audiogoninsane don't like this silly scientific mumbo jumbo, keep the numbers out of this, O.K.? You can use expressions and epithets such as "inner detail", "coherency", "grain", oh, and "lifting of veils" has not been used in a long time, lots of folks remember that one fondly, "slam" is always good (don't know how well it applies to phase problems, though), "back to front depth" is quite wonderful in its redundancy, well you see how this game is played now. Physics, you silly man...

Great thought piece. Where can I get a yard stick marked in nanometers? I'am sure a silver stick would measure with more sonic accuracy.

Cable lengths should be equal to preserve staging & imaging charactaristics. I guess that's what he'saying...

Hmm. Perhaps guessing again might be in order.

Nicely done Bwhite. How about multi-miked recordings with mics out of phase with each other?

Now someone want to explain the extent to which damping factors will differ one side from the other and the affect on the sound we will hear?

There are two issues that come to mind. First of all the electrical properties of speaker cable ARE to some extent length dependant and varying those parameters can effect how the amp interacts with the speakers. This is less of an issue in a 5.1 set up between the front pair and back pair since close matching is only needed with each stereo pair (the sound is really mixed as two stereo mixes plus center channel). Front to back balance will be more related to your position relative to the speaker. I agree that the phase issue is less pressing although the ear can resolve very tiny phase differences for sound localization (the comparison of the source at each ear allows an order of magnitude more resolution than either ear could accomplish alone), however since you will not be seated in the EXACT center and you may have an assymettrical room this is unlikely to make a great difference. However, different lengths within a stereo pair is IMHO a bad idea because of the resistance/capacitance issue.

Oh, I went back and read the beginning of your first post Bwhite. Attribution?

Attribution: I am not certain who wrote the document although it is as I stated, "interesting reading". Audiogon's new forum format doesn't allow for placing a URL or a link inside of a post so...I was unable to do that as a means to send readers to the actual online document.

I am at work now and the bookmark is saved on my home computer. I will post the URL this evening when I get home so that others can read the original document and indulge in some of the other rants on the webpage.

So this means I can't move my head anymore when I listen. Not one millionth of a centimetre, I gather, Well, hum... Let's see, how about a head vise (no not lice) with laser level type things to make sure the well seated (and heeled) audiophile does not move and consequently lose any of the phase accuracy of his interconnects, speakers or of his equally expensive (or more expensive is even better) speaker wires. Never mind subwoofers, there's nothing down there any ways, but 12 K cables get the imaging just right, not to mention inner detail and the greater distance between musicians in the orchestra. Magnificent, great I can hear the rosin on the bow now... it's, it's, it's in phase! Glory be to the small, dishonest, inefficient manufacturers for in these anti-scientific times, they shall rule the biz.

I may be wrong, but I always thought the standard argument supporting equal cable length had less to do with signal delay as it did with inductance, reactance, and capacitance (those terms could be wrong, it's been a few years since I stumbled through E&M). I know that for direct current a solid conductor with uniform cross section has resistance proportional to length (and inverself proportional to cross section area). As such a 60% increase in length seems like it would have fairly measurable effects on the current. I know that this is a not quite correct, complete oversimplification of the argument, but I think it's along those lines. Anyway, the final measure of course is what you can hear. Perhaps a good experiment would involve getting a ridiculously different lengths of zip wire and seeing if that makes a difference.

Raguirre, yes, as Marakanetz said above, RLC, resistance, inductance and capacitance will vary with length, or so I have been told. The question is by how much and what effect that would have on the sound. If something goes up by 50% from .011 to .016 whatever the units are (not 1.1 % distortion to 1.6, that would be audible and not what I mean,) will you hear a difference? I think not.

Now, with ridiculously different lengths of zip wire you may hear a difference because, and I rely on what others have told me since I am not an engineer, zip wire has higher measured inductance and capacitance.

The best reasons for keeping equal lengths are flexibility in rearranging your furniture and resale value. Very hard to sell mismatched cables.

Hi Bwhite, Any job openings at your company? If you have the time to post all that at work AND get paid enough to afford this hobby, I'm in.

Interesting thoughts though.

Herman - Thanks for the laugh!

Hmmm...such fun, Bry.
But I believe the difference in electrical properties of the unequal cables will result in a different LOADING of the driving amplifier, thereby slightly changing the frequwncy response of each side, and THAT's what one could hear. Certainly would be the case with a high output impedence cable running hi-value cables assymmetrically, no?
I find it safer to run asymmetrical interconnects to monos, and then keep the speaker cables equal.
Another thought: imagine coiling the extra cable up and thus creating a huge inductor acting as a high pass into one side!
OTOH the effect is minimal if very low value cables (like Nordost, etc) are used, the output impedence of the amp is very low, and the ratio of L and R sides is small.
Good night.

A++ link, Bwhite! Thanks!

I also want to point everyone's attention onto damping factor explaination on the link provided by Bwhite and make your conclusion about different cable lengths.

And than read link about Equal length of the speaker cables.

I would not recommend to make such experiments with Transperent Audio cables and suggest to use some RadioShack wire or ZipWire.

Transparent Audio cables tended to have an out$tanding quality in terms of newtrality for inductance and capacity, but I wouldn't buy different lengths of Tran$parent Audio cables since I will not ever be able to sell them!

Another vast reason that most of power amplifier manufacturers strongly suggest in the manuals to use short equal runs of speaker cables to keep as close as possible to booked damping characteristics of amp.

Different length cables will not affect sound much. Speed of light (even at 90%) through cables less than about 1 mile long won't have any audible effect on phase between both channels.

it's really the inductance and impedance of the cable that will vary. It will have some effect on imaging (ie. will create slight smearing).