On 13 December 2013 04:52, John Colvin <john.loughran.colvin@gmail.com> wrote:
On Thursday, 12 December 2013 at 18:31:58 UTC, Joseph Rushton Wakeling wrote:
On 12/12/13 19:15, Iain Buclaw wrote:
You know, I've never had that... but then again I haven't had the
fortune of being in a band where distance between the first and back
musicians is > 200 metres.  (Because sound doesn't travel *that* slow
;)

Well, it's not _just_ about the speed of sound, there are also things like the speed of attack of different instruments and so on.

Then again, ever been to a performance of one of those pieces that ask for some musicians to be placed in different locations round the back of the concert hall for spatial effects?  Things can get fun with that ... :-)


Only in the recording studio - if the time it takes for sound to leave
your instrument, into the microphone, through the walls into the
studio booth, into the mixer (and assuming digital) from the mixer to
the sound card, to the DAW software mixer which is taking the
recording and mixing it in with the playing tracks (optional live
effects processing being done) back to the sound card, to the mixer,
through the walls into the studio room, into the headphones of the
receiver playing the instrument...  is greater than 22ms, then the
person playing experiences a delay in the time he plays to the time he
hears himself in the song.  If that happens, you are not in a good
situation. =)

So, if your latency is 22ms, think of how that corresponds to sound travelling in space: you only need to be separated by about 7.5m for that kind of delay to kick in.

Delay between people isn't really the problem, it's delay in hearing yourself that's the killer. Although 22ms is the normally quoted limit for noticing the latency, it actually depends on frequency. Even regardless of frequency, i typically find that anything less than 64ms is ok, less than 128ms is just about bearable and anything more is a serious problem for recording a tight-sounding performance.

Latency between recording musicians has a strange effect of gradually slowing the tempo down. Ie, if both musicians are playing with headphone monitors or something, and there is a small latency in the system.
If you are playing together, but then you feel a 20ms latency between you and the other musician, you tend to perceive yourself as playing slightly too fast, and then adjust by slowing a fraction, the same thing happens in the other direction, so you're both constantly slowing by a fraction to maintain perception of synchronisation, and the tempo gradually slows.
It's almost an unconscious psychological response, quite hard to control in the studio.

Man, my day job works in quantities of 16ms (1 frame), and I have spent many hours resolving inter-frame synchronisation issues (16ms out of synch). Maybe I'm just hyper-sensitive, but 64ms is extremely noticeable to me. 128ms is like an eternity!
Consider, 16th notes at 120bpm (not unusual in metal, I assure you), are only 125ms apart, that more than an entire note out.
Around 4ms is what professional recording setups aim for.