Does the audio cable gauge have a bearing on sound quality?

wet-paint

Hi folks, Got a bit of an ICE query.

The backstory: Had a Pioneer Head, sub, two woofers and two tweeters in my old car, a Fiesta. All was groovy, it sounded great. A mate installed it, and as part of doing so, he upgraded the cable from the head to the door woofers, as the standard cable couldn't power them.

I changed cars, to a Polo, and brought the kit with me. Got a professional installer to put it in, and while everything works, it's now super top and bottom end heavy, the tweeters and sub work fine, but there's quite drastically reduced mid range from the door woofers. I know they're working, if I turn them up max, I can feel them moving, but that's the thing - when in the old car, I never had to turn it up past 2/3 volume. Now, it's up nearly to the max to get it good and loud.

When I handed the car over, I asked the installer if he was upgrading the cabling to the doors, and he said he wasn't. I just presumed that meant that the new car had superior cabling than the old, and that the existing wires were capable of supplying enough power,

Now, I'm not so sure. While they do work, an idea has wormed its way in to my head that while the cabling is sufficient to make the speakers work, they're not good enough to make them work at full capacity.


So yeah, my question is this - does upgrading of the audio cable have an effect, even on speakers that do already work on the existing cable, and can a situation arise where cables are strong enough to get a speaker moving, but not be good enough to actually make them work to their full potential?

I'm trying to figure out whether my sound quality would benefit from having the cables upgraded, even though the speakers do still work.


I know it's a bit wordy and long winded, but any info you can provide would be gratefully appreciated.
Cheers, WP

Popoutman

Note - a lot of people will have issues with this answer, but the science and engineering check out.

Short answer:
Once the cable is above a certain (small) size, it has absolutely no effect on quality.

Longer answer:
Two things to consider: EFI and resistive losses.
All cables in a car will pick up EFI from things like the alternator, various motors, HID ballasts and the like. Most of the EFI will be in the RF region and will not be audible even if it can be measured at the speaker terminals. In an ideal world properly earthed+screened cables in conjunction with well-designed and screened speakers would be the answer, but oddly enough that's not done in car audio. Where EFI does come into consideration is feedback from the speaker cables back into the amplifier circuits where it can affect the signals. Not that easy to guard against that except by careful design and construction of the amp circuits and one would hope that this would be covered by sourcing from reputable suppliers. One method of reducing EFI pickup by cables is to use twisted pair - aka bellwire
Resistive losses (either by resistive or inductive methods) can pretty much be ignored when working in the voltage and current ranges found in car audio. If you can measure the cables getting warmer when under use then the gauge is too low and you would need to increase the cable cross-sectional area.

Based on numbers from here: http://www.sengpielaudio.com/calculator-cross-section.htm here are soem back-of-envelope calculations for the difference changing the cable would make.

Lets assume that you are reaching 100db volume with your current setup and let's say that you have 0.75^2 cable as the speaker cable. Increasing the cable size to 4^2 cable would reduce the power loss in the cable from 2.0% to 0.4% - meaning that you get about another 1.8% of current through the speaker coils.

That's not even 0.2dB - and you'd be very hard pressed to be able to tell the difference.

If you are not getting the volume you are expecting, check your connections for corrosion, check your speakers for water damage in the doors, and check for wear through the insulation where signal may bleed to earth.

In general once you are using ordinary bellwire for your audio you are doing more than enough and it's actually better for keeping a clean signal because of the twists.