Length of Speaker Wire

No, they don't need to be the same length.

Just be sure to use some decent cable, don't be sorry later. I'm not suggesting that expensive stuff, just no junk. I used 14 Ga. for my surrounds. 12 Ga. really jumps up in price and I don't think it's necessary for surrounds.

Yet another audio "myth".

The myth is that the signal take s time to travel across the wire. And that is TRUE. IF you are talking miles of wire. Most people don't use that much for a home setup.

Use as large a size as you can-and keep it as short as you can-but don't worry about inches. Leave some slack-just not 10' of it.

Yes at audio frequencies wire length time delay is not significant, in fact a joke. Now at hundreds of MHZ or higher, it is critical. Even your modern computer motherboard has timed wire lengths on the PC board.

However you should still keep the distance matched within 10% if longer than 10 feet on the main speakers, surrounds are not critical in this respect. The reason is the wire does have resistance and you don't want the voltage drop on one channel to be audible versus the other.

Here is the unofficial AVS Forum guide to speaker wire:

http://www.roger-russell.com/wire/wire.htm

Note my 10% above 10 feet is purely an educated empirical judgement. I have done no tests or measurements to verify it.

Before I was active on AVS, I posted this exact same question to the then Sound and Vision forum Nov-2007 and was advised the keep long runs within 10% , even for surrounds, since the trend was same amp power to all channels.

right or wrong, I did this, and it was a PIA, keeping the "extra" wire from 120v source, crossing at 90 deg to 120v source, wrapping in non circualr pattern, etc.
For 7.1 speaker in 14.5 ft x 18.5 ft this meant lots of "extra" (wasted) wire, I used 14ga 4c wire.

RH side wall, extra wire for RH side surround tucked above door frame, this was the most wasted wire, as its counterpart wrapped along the whole back wall to the LH wall.


Back wall, extra wire for RH back surround looped as shown


I'd like the definitive, engineering, objective fact based response to bring closure to this Q once and for all.
It shows up every few months.
I'm not a subject matter expert, so defer to others who are on this.

Now you know why I recommend that people go to 12 gauge. If the longest speaker cable does not cause an audible change, then neither will any of the shorter ones. If none of the cables cause an audible difference, then no audible difference #1 is the same as no audible difference #2, etc. , and the lengths of the cables don't matter. 12 gauge gives you almost twice the assurance that the cable is not causing any audible change.
Edited by arnyk - 2/15/13 at 1:24pm

The answer is there is no easy answer. If you hold it to resistance as the only factor (which it is not), you would have to take into account cable Z, amplifier output Z and loudspeaker Z, all as a function of frequency.

Since it would be nearly impossible to accurately answer this question for every variable in a given installation, the easiest answer to insure a balanced sound from all channels is to keep all lengths and spec of speaker cables as equal as possible. To be easier, in less critical systems the front 3 channels should be the same length, and the rears the same, with left to right differences being held to a minimum to maintain soundstage balance.
Edited by Joe Skubinski - 2/15/13 at 7:40pm

WOW that was a bunch of crap.

If, that is, one is trying to sell wire. Then one wants to confuse people into believing all sorts of crap, to break down their resistance to even the most outlandish claims.

If one is not a wire marketer, the answer is very easy. The correct length of wires for speakers is long enough to reach from amp to speaker, with a little play to allow movement. And each wire should be of appropriate thickness for the minimum impedance of the loudspeaker and the maximum power the amplifier can generate.

I would LOVE to challenge you to a blind listening test regarding wire length.

If you can REPEATABLY pick out the cable that is longer-either by signal delay or level-then you have a much better set of ears than everybody I know. And I hang around with audio professionals-some at the highest level in the industry.

Actually the power of the amplifier does not enter into any speaker cable calculation that I have ever seen.

The only variables are length-speaker impedance and to a small amount the output impedance of the amplifier.

If you know of a formula that takes amp power into consideration-I would love to see it.

Now when you start to get into the MONSTER amps-the size should be of decent size (generally 12 ga is fine for short to med runs)-but I highly doubt anybody using a 14,000 watt amp would be using 18ga wire anyway. if they are-they amp should be removed from them because they are not deserving.

If he dose take on it, that will mean the end of his retail business. Think about it, if your income source is about to be wiped out, would you willingly let it?

I think that is why a very obvious demo is never seen at audio shows, which is a DBT involving cables, amps or DACs. Same reason why all of the high end audio writers and manufacturers pooh-pooh DBTs. Commercial suicide!

Why know the truth-when just making it up as you go is so much more fun

---

Also, much easier. You don't have to learn anything. You don't even need acute ears, because it's all an act.

I've always cut to length...  (just to present my viewpoint)

 

That said...  wouldn't a coil of wires to take up the extra length bring other potential issues to the table that a straight/short run wouldn't?

 

I was always had the understanding that a coil of wire could pick up some noise or become an antenna or something goofy like that simply because it's coiled up???

Well yes, it's all about the resistance. However as usual Mr. Skubinski wants to apply RF theory to speaker cables to foster sales.

Not with a passive speaker. Of course mathematically we can show the phenomena, but it will be far from audible.

We did a deep dive on WBF Forum on the effects of cable including that of inductance. An interesting theory was put forward that we need to model the speaker as a true complex load and not just a resistor as is commonly done when discussing cables. That did show differences with respect to cable parameters that was not visible when just modeling the speaker as resistor. I built a "Spice" (electronic circuit simulation) of a prototype speaker and actual measurements of speaker cable including its resistance, capacitance and inductance. Then I changed the parameters to see how the response changed with and without the cable. You can read it by clicking on the first link in this google search: https://www.google.com/search?q=site%3Awhatsbestforum.com+cable+theory+page+3&rlz=1C1SNNT_enUS374US375&oq=site%3Awhatsbestforum.com+cable+theory+page+3&aqs=chrome.0.57j58j60.7948&sourceid=chrome&ie=UTF-8

Here is a sample graph showing the before and after the cable waveforms:



Suggest reading the thread as it was a fun journey with no one on the defensive, allowing a good discussion with real data. If you don't want to bother, the quick summary is that if you keep the cable resistance low, then the impact of inductance becomes negligible. Otherwise, there can be .1 dB or so difference in the audio band per above graph. That said, the point made regarding audibility is right that these are very small differences and likely not heard. Just to be on the safe side, follow the first rule of being a man: if a little bit is enough, more is better and use the thickest cable you can manage.

Most women would tell you the same thing.

Common sense says cut them to the length you need.

'Loudspeakers: For Music Recording and Reproduction', by Philip Newell and Keith Holland- Chapter 6: 'Effects of Amplifiers and Cables', is a brief and reasonable summary of some research into how cables and amplifiers affect sound, and each other.

http://my.safaribooksonline.com/book/-/9780240520148

http://amzn.com/0240520149

I'll give you one from personal experience. Subwoofer with 4Ω nominal impedance, 45' cable run, 1kW of power.

In that circumstance, the 14AWG wire I intended to use would have resulted in less than half a dB loss, but it doesn't meet the 300 circular mils per amp of current rule of thumb. (Why 14AWG? That's what I had on hand.)

Generally, I agree with you, though. At home, outside of a multisub system powered by a central amp (or amp stack) power isn't generally a factor one needs to consider in any speaker power calculation. And perhaps even in the above case it needn't be considered even though on paper it's marginal.

....and the OP is asking if it will make an audible difference to a HTiB. Can't we all agree that for the OP's situation the simple answer is just NO.

my answer is no. I have 2 5.1's set up and each wire was cut to length. Without any doubt, the answer to the OP's question is no.

But unless you are running SINE WAVES into the loudspeaker (most people don't) then the "average" signal level is "generally" about 1/8th the continuous-or 125 watts for a 1000 watt amp.

Wire capacity number are figured using constant current draws (such as lights). A dynamic current draw (such as audio) is very different.