30 Aug
2014
30 Aug
'14
7:42 a.m.
On Fri, 2014-08-29 at 08:12 -0700, Len Ovens wrote:
On Fri, 29 Aug 2014, Kaza Kore wrote:
Yes if it is coming from two sources of different distances you get a
comb filter but that's not what we're talking about with distance/delay
here. It's more absolute latency.
Examples I was presented at while at college/university were:
* A piano player striking a key and hearing a sound, from the downwards
motion to hearing the sound is about 6ms. Taking into account both
mechanical transference from key to string and the sound to the ear.
* For comparison this would be the same as a guitarist standing six feet
away from his guitar amplifier if we lived in a ideal world (where
electricity travelled the speed of light) but there is obviously
propagation delay plus any added by stomp boxes (s)he may have. This is
not a distance at which a guitarist finds it difficult to play!
I sometimes think the hunt for super-low latency is a bit absurd! 3ms,
to give you a 6ms round trip, should be a workable amount for pretty
much anybody and most I expect could cope with quite a lot higher (not
many working methods require the full round trip!)
But full round trip is probably also the time when delay effects (com
filter and echo) become important, such as using a PC as an LMS or FOH
mixing desk. I would consider these specialist cases though.
Just my 2c ;-)
Anyway it's probably more important to talk
about the standardised DV25 and DV50
protocol all these commercial/prosumer products use for communication that
tape/card formats. There are some Sony and Panasonic camera that do this fine
over USB so it's not impossible or a problem with USB itself. I see yours (and
apparently many others) claim to have some kind of USB Streaming but for some
reason it's not usually full quality, as you would get from Firewire. Wonder
why...
Intel says that nobody really needs that low of a latency anyway in
response some sound cards problems with one of their implementations of
USB3. (the problem was USB2 cards with USB3 ports which are supposed to be
compatable)
In recording latency is not the issue it is with live work. For recording
latency needs to known and constant and reasonably low for monitoring. I
have heard/read people who say what does it matter if you move your head a
foot or two closer or father from the speaker? But in live work if the
same audio comes from different places it is called a filter.