On Tue, 14 Mar 2017 13:06:40 +0000 (GMT), Dave Plowman (News) wrote:

Spacing the capsules further apart would reduce the required
timing
resolution. Four mics at each corner of a 42" screen would give
ToA
differences up to a few milli seconds, far more manageable.

If you're talking echo cancellation at highish fequencies, the accuracy
needed for that is rather high too. ;-)

Echo cancellation, as in mics and speakers in the same box, only
needs event sync. Simple enough to match the wave forms between
incoming stream and that coming back from the mic(s) to maximise
cancelation. There is no need to make an absolute measurement that a
ToA range finding system would require.

--
Cheers
Dave.