[camtarn]

> This speaker is 300 feet away from its output through X meters of copper; figure out my additional latency offset for me.

0.3 microseconds. The period of a wave at 20kHz (very roughly the highest pitch we can hear) is 50 microseconds. So - more or less insignificant.

Cable latency is basically never an issue for audio. Latency due to speed of sound in air is what you see techs at stadiums and performance halls tuning.

[whimsy]

Oh, thanks for correcting me! Now that you mention it, I'm confused by a memory I have. Wired speakers seem to be less common these days but I remember being told about two decades ago that the "proper" way to install speakers was to run out equal lengths of speaker cable (basically just jacketed copper, afaik) to different speakers even if they weren't equidistant in a room. (This was advice for home installation, not stadium-sized installations.)

Do you suppose there exists some other reason for that, like maybe matching impedance on each cable, or is this likely one of those superstitions that audiophiles fall prey to?

[rahimnathwani]

Superstition for sure.

[superjan]

For those wondering: The rule thumb here is that light travels at one foot per nanosecond. 300 ns =0,3 μsec. Electricity is a bit slower but the same order of magnitude.

[KayEss]

And by a happy coincidence it turns out that audio does about one foot in one millisecond making light six orders of magnitude faster

[entropie]

About one foot sounds very american.

[superjan]

I’m in europe so I am all in on the metric system. But “about a foot” per nanosecond is so easy to remember, understand and reason about that it is worth the exception. If you prefer something European, think of a sheet of A4 printer paper: the long side is 29.7 cm. “One length of A4 per nanosecond” is within 1% of the actual value of the speed of light.

[entropie]

> But “about a foot” per nanosecond is so easy to remember

Well, but its also just wrong. Its 12.5% to low. Thats why "about one foot" sounded absolutely wrong to me.

[dspillett]

The original comment used imperial measures, following comments kept to that for consistency.

To put things into proper units: speed of light in vacuum is approx 1.8 terafurlongs per fortnight, and electricity in wires has a pace of similar magnitude, and sound in normal atmospheric conditions shuffles along at approx 2.1 megafurlongs per fortnight.