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I'm planning an electrical installation at home and need to know what speaker cables to lay.

So far, neither the speakers nor the stereo amplifier have been selected, but I know that:

  • The room is approximately 33 square meters large and has a high ceiling of 2.9 m.
  • The stereo floor-standing speakers will be 8 m and 11 m from the amplifier.

Does the thickness/type of cable matter in this case?

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    As far as I know, speaker cables are even less standardized than telephone, which is less standardized than Ethernet, which is less standardized than mains (120V - 240V) wiring. In other words, pretty much anything goes. I would generally look for thicker wire rather than thinner, but hopefully an audio expert will give a real answer.
    – manassehkatz-Moving 2 Codidact
    Commented Jan 12 at 15:32
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    This reminds me of the great debates a number of years ago which were finally settled (to my satisfaction) by someone doing blind testing between expensive large gauge oxygen-free copper and wire coat hangers twisted together in a string. It didn't matter. Use a gauge large enough to not introduce voltage drop at your run length and don't worry about it.
    – isherwood
    Commented Jan 12 at 16:12
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    It depends on your amp and speakers. Something like 16 ga. is usually plenty. I wouldn't use 18 or 22 for in-wall wiring.
    – isherwood
    Commented Jan 12 at 16:27
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    See this in EE. electronics.stackexchange.com/a/13927/33670 DO NOT ask the question there, do not migrate the question there, but read that (and other) answers.
    – Ecnerwal
    Commented Jan 12 at 17:36
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    @dzieciou If using sockets at both ends, you could use ordinary 2.5 mm2 mains cable for the hidden wiring, then use short pieces of stranded speaker cable at each end. You can get fancy-looking banana plugs which are not expensive, if you like - there is no need to pay lots for them.
    – Andrew Morton
    Commented Jan 12 at 19:30

3 Answers 3

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Yes, it matters. It's very important for full-range speakers (ones with deep bass), and much less so for bookshelf satellites.

Wire gauge and length affect the damping factor. In simple terms, this factor decides whether a speaker diaphragm, once it's set in motion, is free to bounce (at low DF) or only moves as the music permits. It's calculated as speaker impedance divided by (amplifier impedance+cable resistance).

Damocles' answer addresses minimum gauge for tolerable voltage drop, but if you want good low-frequency sound, you also need a high damping factor. Low damping factor results in bass blending together into a loud hum - like cheap party speakers driven too loud (though there it's due to poor diaphragm rigidity). High DF allows high-quality speakers, ones with rigid diaphragms, to produce firm brief punches, resembling a live drum.

DF=50 is considered the minimum for stage music. DF=20 is acceptable for public venues, like a cafe, where music is just background. Studio and home hi-fi sound aims for a DF of 50-100 or more. Metal and honeycomb woofers work best at very high DF, for paper it's less critical.

11 meters is a longer speaker cable run than most home setups. Using 4 mm² wire (11 gauge) and 4 Ohm, typical of floorstanders, will only get a DF=40. What I do in such situations is either get an even thicker wire - 6 mm² will do DF=55 - or double up widely available 4 mm² wire, to get DF=75.

The best way to double up, if you can't get 6-8 mm² wire, is to take two 22 m runs of 4 mm² wire (equal length for both speakers), find the middle, and braid the doubled-up cable. Strip insulation in the middle and connect the cable to the amplifier, without actually cutting it in half. Solder banana connectors to the other end, rejoining the cable. Needless to say, today, with online shopping, buying 8-9 AWG (6-8 mm²) cable outright is much easier than doubling up.

Don't worry if it's not the best-known brand; that only has a minor effect on sound, which some even question, while the impact of the damping factor is profound and well-measured.

In professional audio, to provide consistently high DF no matter how long the wire run, the speakers are usually active, i.e. the amplifier is inside the speaker cabinet. You might want to consider this option too, but 11 m is still OK for thick wires.

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  • The Wikipedia numbers in Damocles' answer are not about safety -- for that, you would need to know the power levels involved. Those numbers are about resistance, with the gauges and maximum lengths selected to give a minimum damping factor of 20, where the wire resistance is no more than 5% of the speaker resistance. As you say, higher DF would be better (within limits).
    – Dave Tweed
    Commented Jan 13 at 16:52
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    This sounds like the "Audiophile" answer. For the common Joe, it's probably overkill. :shrug:
    – FreeMan
    Commented Jan 14 at 15:05
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    @FreeMan Depends on how you define "audiophile". I'd hazard a guess that anyone installing floor-standing stereo speakers in 2024 is likely concerned with sound quality. Muddy bass is very noticeable, and a bit of extra copper isn't a big expense. In a rock concert, you'll usually find active speakers with DF>100, which helps it sound clear even at high volume. For easy background listening, it's less important.
    – Therac
    Commented Jan 14 at 15:50
  • Speaking of audiophile options: Canare 4S12F, which will give DF=50 and is specifically designed for in-wall setup, is $10/meter. It gets a lot of praise and there's no need to go higher. Off-brand cables will be cheaper, but probably no less than $5 due to the price of copper.
    – Therac
    Commented Jan 15 at 12:58
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    @FreeMan Not really, much more like the sane answer. The audiophile answer would start to rave about how 1000-dollars-per-meter cable sounds so much better than everything else below it. :-)
    – Gábor
    Commented Jan 15 at 17:08
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The potential issue with a long run of thin wire is high resistance leading to signal degradation. A typical speaker is rated between 2 and 8 ohms, so as long as the resistance of the wire is small in comparison you'll be fine. The resistance of a wire is a product of its intrinsic properties (gauge and material) and its length. Wikipedia gives this chart as a guide:

enter image description here

Since you haven't selected the speakers yet, you can prepare for the worst-case scenario and assume 2Ω. (They will probably be 8Ω in the end though). Then measure the distance of the cable run, and consult the chart.

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    Even at 8Ω, 18 gauge is a little too thin to go 10m. "Ok, so I need to narrow down selection of the hardware before laying down the cables." and have zero future proofing for something you're going to bury in a wall? - It's also nice when it's just arbitrarily bigger so that when you've twisted the end for the sixth time and five strands break off, it doesn't matter.
    – Mazura
    Commented Jan 12 at 22:17
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    @Mazura that's why conduit is a smart move for low voltage stuff...
    – Ecnerwal
    Commented Jan 13 at 14:39
  • @Mazura If you have to keep twisting the ends, perhaps adding ferrules, or using solid-core wire, or adding banana plugs would work out better. Or if the terminals are the screw-down type, fork terminal connectors could be added to the wire ends. It's got to be better than getting those strands making holes in your thumbs.
    – Andrew Morton
    Commented Jan 13 at 18:12
  • If there are two wires going to my speaker, should I take the sum of their lengths when consulting the table above?
    – dzieciou
    Commented Jan 15 at 14:31
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    @dzieciou no, that calculation is for a 2-wire cable.
    – Sort of Damocles
    Commented Jan 15 at 14:37
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Stop by your local home improvement center, electrical supply house, home audio store, or other place that sells wiring and pick up enough "speaker wire" to make the runs you need.

Also, make sure that the wire is rated for in-wall installation. There are certain insulation materials that are rated for in-wall use, many are not.

Unless you're an audiophile who claims to be able to hear the sampling rate of a standard CD and finds it irritating, your speaker cable (even though delivering an analog signal) won't be significantly degraded on an 11m/33ft run.

It's probably more important that you keep the speaker cable away from any mains voltage electrical wiring than the actual wire you use for the audio signal.

If you have a couple of options for wire gauge and the price difference isn't significant and it makes you feel better, splash out a little extra cash for a heavier gauge.

Funny, this is getting down votes, but it does answer the OP's question. His question is about the length of the run, not the purity of the audio quality. As a matter of fact, the OP specifically stated that he wasn't particularly worried about quality loss:

@FreeMan I'm definitely not audiophile, 0,001% loss in quality is not an issue for me.

It seems everyone's voting this down because it's not the "audiophile purist's proper answer". Well, go spend $100/foot on expensive wire that makes you feel better.

This is 100% correct for the OPs desire.

Oh noes, people don't like me and I've lost some pointz, whatever am I to do??

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    LFT4 is the flame spread rating they look for in my area for code on in wall low volt wires.
    – Fresh Codemonger
    Commented Jan 12 at 18:13
  • Note that if you really want something cheap, there is nothing that says you can't use NM as in-wall speaker wire :P
    – ThreePhaseEel
    Commented Jan 13 at 3:53
  • Is NM-B cheaper than speaker wire these days, @ThreePhaseEel? I haven't priced NN-B in the last 6 months, but the last batch I bought, I had to give my first-born's right leg for it...
    – FreeMan
    Commented Jan 13 at 14:03
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    This is simply untrue on every level. What's sold as "speaker wire" in most DIY stores will be 0.5mm2 at best. For 22m of cable (11m both ways) that's 0.8 ohms which is significant relative to the speaker impedance. DIY shops often also charge a mark-up for "oxygen-free" snake oil too. And that's before we look at damping factors. This isn't audiophile level stuff, it's absolute basics of Ohm's Law. Please, everyone, don't think this answer reflects physical fact.
    – Graham
    Commented Jan 14 at 15:45
  • That may be the case, @Graham, but that's NOT what the OP asked about.
    – FreeMan
    Commented Jan 16 at 12:57

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