Unequal Cable Lengths

[Lee]

What’s the view on unequal cable lengths, such having a longer subwoofer run to a right channel speaker if the equipment rack is on the left side?

Is it a big deal? Does it matter only for speaker cable and interconnects?

 

[DonH50]

What’s the view on unequal cable lengths, such having a longer subwoofer run to a right channel speaker if the equipment rack is on the left side?

Is it a big deal? Does it matter only for speaker cable and interconnects?

Disclaimer: My answer is from a technical PoV and expected audibility of amplitude and frequency response variations, not a subjective opinion that may (will) vary.

Unless the difference is huge, like hundreds of feet, and/or very high impedances are involved, the difference will be inaudible for interconnects. Even for speaker runs, the difference between a short run to one speaker and an extra 10'~20' to another are unlikely to be audible. I did some models and showed the results of significantly unequal runs over at the hated ASR site (link to articles in my signature).

That said, for home interconnects it's a don't-care for me, but I tend to match speaker cable lengths out of an abundance of caution, mainly so the speakers (crossover actually) see the same driving-point impedance from the amplifier.

 

[DonH50]

Here is a link to the mismatched speaker cable thread:

Effect of Speaker Cable Length Mismatch

The subject of mismatched speaker wires came up recently and I said it could matter due to varying speaker impedance with the wire as a divider from the amplifier. That was based on tests done long, long ago (but in this galaxy). At that time zip cord from maybe 22 down to 18 AWG was pretty...

www.audiosciencereview.com

Here is the basic speaker cable analysis thread: https://www.audiosciencereview.com/...res-on-frequency-response.57017/#post-2082799

For interconnects, it's hard to see how there'd be a real problem for a typical home environment (unless you live in a stadium, and then you'll have other issues). I do not have a thread discussing interconnect mismatch that I recall, but here is a link to one on the bandwidth of interconnects: https://www.audiosciencereview.com/forum/index.php?threads/interconnect-bandwidth.25441/

All of these have several examples using different sources and loads to span a range of use cases. They are fairly old, more than ten years in some cases, but the basic information is (ahem) sound.

HTH - Don

 

[mtemur]

Unequal cable lengths is a big deal for all of the cables. In case of subwoofers the difference in sound due to unequal cable lengths may be less noticeable. For a full range speaker it is definitely noticeable IME/IMO.

(For normal, full range speakers) if you don’t notice a difference it’s only because the setup you’re doing this test cannot reflect those changes.

 

[dminches]

As a slight corollary to this discussion, what is the best way to deal with the extra cable you may have on one channel if you keep the lengths equal? Fox example, the interconnects between my preamp and mono blocks are both 8M but the right amp only needs 3M so there is 5M of extra wire. Should it be wound in a loose loop or does that create issues too?

 

[treitz3]

Loops will create an issue. RFI. It basically makes an antenna. If I were in that situation, I would go up and back down (or down and back up, if possible), Just try not to parallel any hidden interior wall power lines.

Tom

 

[dminches]

Loops will create an issue. RFI. It basically makes an antenna. If I were in that situation, I would go up and back down (or down and back up, if possible), Just try not to parallel any hidden interior wall power lines.

Tom

That was my concern. Thanks.

 

[Lee]

Loops will create an issue. RFI. It basically makes an antenna. If I were in that situation, I would go up and back down (or down and back up, if possible), Just try not to parallel any hidden interior wall power lines.

Tom

Yep. I recently talked to a friend at Audioquest and he was relaying a discussion from Garth saying this is a big no-no. I had unfortunately two coils in the left corner - one from my ethernet cable and one from the left subwoofer cable. I straightened them both out and it helped the sound a little bit. But it looks so much better too.

 

[DonH50]

As a slight corollary to this discussion, what is the best way to deal with the extra cable you may have on one channel if you keep the lengths equal? Fox example, the interconnects between my preamp and mono blocks are both 8M but the right amp only needs 3M so there is 5M of extra wire. Should it be wound in a loose loop or does that create issues too?

Look up the "over and under" method of coiling, and try to flip the coils so they are going in opposing directions on alternate coils. A figure-eight pattern has also been recommended, again being sure to flip the cable so alternating loops are going in opposite directions. That helps reduce common-mode noise ingress. Or just don't loop them, run a single "loop" in parallel with the conductors spaced a bit apart.

Chances are you won't have problems no matter what you do unless there is a noise problem. Do not run signal cables beside power, network, or video cables. I used some screw hooks on the back of my console about a foot apart (creating three levels) so I could run power, signal, and video cables separately and spaced apart. In the past I (to my parent's dismay) used hooks on the wall so signal cables run about a foot up and above the power cables on the floor. Interconnects anyway; speaker cables carry high-level signals, and amplifier impedances (at audio anyway) are low, so I left them on the floor but away from the power cords.

Whatever you do, do not coil the wire and leave it on top of (or under) the amplifier, as coupling from the power supply will be worst-case.

FWIWFM - Don

 

[Another Johnson]

Why not inquire of Transparent? My experience has been that they have a very large knowledge base about pairing a wide range of specific components. They’ve gone so far as to customize the geometry of terminations that I didn’t even know could be customized. It costs nothing to ask.

My sense is that powered subs tend to have high enough input impedance that the variation in load or sound due to cable length would be small. Transparent would probably make you a custom pair according to their experience, and stand behind them.

 

[Lee]

Why not inquire of Transparent? My experience has been that they have a very large knowledge base about pairing a wide range of specific components. They’ve gone so far as to customize the geometry of terminations that I didn’t even know could be customized. It costs nothing to ask.

My sense is that powered subs tend to have high enough input impedance that the variation in load or sound due to cable length would be small. Transparent would probably make you a custom pair according to their experience, and stand behind them.

good idea.

 

[ssfas]

Unequal cable lengths is a big deal for all of the cables. In case of subwoofers the difference in sound due to unequal cable lengths may be less noticeable. For a full range speaker it is definitely noticeable IME/IMO.

(For normal, full range speakers) if you don’t notice a difference it’s only because the setup you’re doing this test cannot reflect those changes.

Thanks for that information.

My speaker cables are 5m and 2m. I don't notice any difference.

I also compared a 5+5m pair with a 5+2m pair. Again, no difference.

It must be that I have a rubbish hifi system. Shouldn't have wasted the money building an acoustically treated room. Wilson speakers, Gryphon amp and some other nice things will soon be on sale.

 

[microstrip]

As a slight corollary to this discussion, what is the best way to deal with the extra cable you may have on one channel if you keep the lengths equal? Fox example, the interconnects between my preamp and mono blocks are both 8M but the right amp only needs 3M so there is 5M of extra wire. Should it be wound in a loose loop or does that create issues too?

IMO we should minimize the cable inductance to avoid picking noise - ply it in the middle and then loop it - turns are wound in opposite directions and cancel pickup. Never in a loop, than maximizes hum pick up.

BTW, the best way to minimize noise due to cable layout in a system is looking at the output with an audio spectrometer. I am always astonished when I see the peaks moving up and down just changing the cables position - the instrument is much more sensitive to hum than our ears.

 

[mtemur]

It must be that I have a rubbish hifi system. Shouldn't have wasted the money building an acoustically treated room. Wilson speakers, Gryphon amp and some other nice things will soon be on sale.

Not necessarily. Many factors beyond speakers and amplifiers can mask sonic differences between cable lengths. The AC line, power conditioner, audiophile circuit breaker, or even excessive damping with acoustic treatment could all play a role. I recommend you to investigate. There can be many other reasons that we can't think of.

 

[DasguteOhr]

What’s the view on unequal cable lengths, such having a longer subwoofer run to a right channel speaker if the equipment rack is on the left side?

Is it a big deal? Does it matter only for speaker cable and interconnects?

Just a question: why don't you stack subwoofers in the middle between speakers? 1. The cable problem is solved. 2. It sounds much better because there are fewer sidewall reflections.just an idea from me

 

[Peter Bomberg]

So here is my contrary view, I run a 18 foot run on one side and a 8foot on the other and nobody has noticed a balance or tonality difference, nor have we been able to measure a timing or spectral difference, so my comment is if you buy good speaker cables I suspect you are fine.

Disclaimer mine are silver so technically much faster than copper but I suspect the reality is close to the same for all good quality cables.

 

[DonH50]

Silver is about 6% more conductive than copper, but either is so much more conductive than other metals that it just does not matter, especially compared to losses in the crossover and voice coils. It is not "faster" than copper...

Ten feet of 12 AWG copper is about 16 m-ohms, compared to silver at about 15 m-ohms, and gold at about 21 m-ohms (yes, gold is worse than copper or silver for conductivity). Aluminum would be about 25 m-ohms. For context, an amplifier's output with damping factor of 100 into 8 ohms is about 80 m-ohms.

The timing difference between 18 feet and 8 feet is about 90 ns, well below our ability to hear, and well buried by any tiny movement we might make or a trivial difference in distance to the speakers (about 0.0001" difference in position).

 

[Lee]

Just a question: why don't you stack subwoofers in the middle between speakers? 1. The cable problem is solved. 2. It sounds much better because there are fewer sidewall reflections.just an idea from me

Interesting idea but…

1. Not sure that is best practice from a sound standpoint.

2. Wilson LoKes are not meant to be stacked.

3. We set them up to fire into the corners for sound reasons, so sidewall reflections are less of an issue.

 

[ssfas]

Not necessarily. Many factors beyond speakers and amplifiers can mask sonic differences between cable lengths. The AC line, power conditioner, audiophile circuit breaker, or even excessive damping with acoustic treatment could all play a role. I recommend you to investigate. There can be many other reasons that we can't think of.

Your response is more condescending than mine was facetious.

I have a 3-phase supply and a dedicated 100A feed (separate from anything else in the property) with 0.13 ohms line impedance. I have a fully certified IEEE 18th edition electrical installation that was double-checked by the UK national inspectors as part of my engineer's annual certification. I have a Puritan conditioner and my high-end dealer (the top dealer in the UK), who had no part in the room design and acoustic treatment, when he came to position the speakers was completely blown away about how good it sounded.

The only potential different length cable issue is the inductance, which is low (0.32 microH), capacitance is 3.87 pF.

The difference in time it takes the signal to travel due to the 3m cable length difference is at most 0.00000002 seconds. In that period of time, sound from the speakers would travel less than 1/100th of a millimetre. It's totally irrelevant.

So please explain to me what I should investigate to decide the speaker length is making any difference?

Do you have any evidence that "uequal cable lengths is a big deal"? I will assume a non-response means you don't.

The cable I tested 5+2m vs 5+5m was Belden 5T00UP. This is extremely widely used 10AWG twisted cable, probably the most popular cable for in-wall AV multi-speaker wiring, when cables are often different lengths. The inductance is 0.5 microH, much higher capacitance. I used it for about 3 months. Different lengths made no difference.

 

[mtemur]

So please explain to me what I should investigate to decide the speaker length is making any difference?

I recommend you to start with room acoustics. Actually the dampening material if you’ve installed. Acoustic sponge or similar stuff I mean. Maybe it’s something else I don’t know.

https://www.whatsbestforum.com/atta...40585&hash=f22026625260f21dd1a3683adc431e7cDo you have any evidence that "uequal cable lengths is a big deal"? I will assume a non-response means you don't.

I heard it. Every time, with every type of cable, at different lengths—it makes a difference in sound. To prove that something exists, you only need to show one example, and that’s what I’ve done. I heard it—not just once and not in just one setup.

On the other hand, to prove that something does not exist, you would have to check every combination, search the entire world, and ask everyone. Only then you could claim there is no difference between different cable lengths.

Proof of existence requires only one example. That’s logic.