RE: TIME PERCEPTION and LOOPING

["Jeff Larson" <jeff.larson@sailpoint.com>]

> My suggestion is to take one's instrument and plug into a digital
> delay set to 100%, no repeats, and dial in 5ms, then play a bit.  To
> me it's very noticeable and very undesirable.

A factor to consider in this experiment is whether you are playing an
instrument that makes a clearly audible sound as you play.  If you are
playing an acoustic guitar through a 5ms delay this is easily
detectable as a phase shift because you can hear both the live and
delayed signals.

If you were playing a synth or an electric guitar with an amp loud
enough to mask the acoustic sound the guitar is making, this effect is
much more difficult to detect.

When discussing latency and looping it is also  important to distinguish
between real-time audio and looped audio.  Latency is critical if you
are playing a soft synth or using an amp simulator, where the sound of
your "instrument" is being delayed as you play.  With looping, we're
usually talking about a device that records real-time audio and plays
it back many milliseconds in the future.  It is possible for this
device to shift the playback of recorded audio backwards to compensate
for latency so that overdubs happen exactly where you expect them.

As an extreme example, let's say the latency of a particular computer 
and sound card is 1 second.  If the software can properly compensate
for latency, as long as your loops are longer than 1 second you will
hear absolutely no effects of this latency.  

If however you like to make bee noises by recording and overdubbing
into a loop of 10 milliseconds, then latency will be a problem,
at least for the other bees.

Jeff

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