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by 6ren 5311 days ago
If both channels have a similar spike at the same frequency at the same time, it is probably part of the signal (not noise), so combine those, and dampen all others. This would cover your case, if the other channel had enough of the low/hi freq of the other to relate them. I reckon Shannon looked at exactly this in developing Information Theory (for telephone signals on flaky lines), and it's probably all textbook stuff now.
1 comments
JonnieCache 5311 days ago
>at the same time

The thing is, sound doesn't travel all that fast when you consider the wavelengths of vocal-range soundwaves. Those spikes are not going to arrive at the same time on the different phones.

As ever with DSP, phase problems will be the ruin of you.

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6ren 5311 days ago
nice point, but they'd synchronize with an offset. I doubt absolute time would be used to synchronize the videos anyway; they'd be matched by content.

Or do you mean that different frequencies will travel at different speeds, enough to make (e.g.) high and low frequencies arrive at different times? Whoa, apparently it does (http://en.wikipedia.org/wiki/Speed_of_sound#Effect_of_freque...) but seems to be a small effect.

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JonnieCache 5311 days ago
When setting up a big sound system, you have to delay the bassbins by up to 10ms, depending on the size of the cabinets.

Also, how do you calculate your offset? Consider that it is constantly changing.

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