Are unequal length speaker cables really bad?

Your analysis is correct, in that if there are any audible consequences resulting from having unequal lengths, they would not be due to the infinitesimal difference in arrival time that would result at the listener's ears.

However if other parameters, such as resistance, inductance, capacitance, and possibly skin effect, are not small enough to be negligible in the longer cable (all of those effects being proportional to length) a length disparity could conceivably have audible consequences.

Whether those consequences would result in sound quality that is better or worse than if the shorter cable were lengthened to equal the length of the longer one is speculative, IMO, and most likely system and listener dependent.

For further discussion see this thread.

Regards,
-- Al

Some people believe that there is nothing better for speaker cable than lamp cord, but if you believe that speaker cables affects the sound then sound change should be proportional to length of the cable. 1/4" would not make any difference, I'm sure, but using 20' for one and 10' for another might.

Unless your cable runs are significantly different, and by that I mean more than 100 feet in difference, the length of the cables will make absolutely no sonic difference provided the cables are of sufficient diameter, 14 ga. or larger.

Do not sweat this, it is a total non-issue...

-RW-

It could depend on the amp and the speaker cable being used

As an example...
- Naim amps require low capacitance cable - using anything else can result in less than optimum sound.
- Naim also recommend a minimum length of their cable be used and of the same length.

I also recall a conversation with a Linn rep along the same lines.

However this could be a ploy to get you to buy more into their product
Iine.

As Almarg said - the distance electrons have to travel is not the issue, it is the effect the cable parameters may have on the amplifier, since it would present two slightly different loads on the left and right channels.

The bigger challenge might be convincing yourself there is no difference when you know of the cable length difference.

Try it - if you like what you hear - then it's obviously not an issue in your setup.