On Wednesday 23 December 2009 23:52:46 Patrick Shirkey wrote:
No, the problem is one or two layers deeper in the stack. We are talking wi=
here. No matter if there is only two devices on that network or a secure=20
connection, its still wireless transmission over radio frequencies in the 2=
range. Which is per se much more affected by any disturbance then a dedicat=
cable is. Every mobile phone, every blue-tooth device, every neighbours=20
network, every iron in your ceiling will influence this. And not only with =
constant background-noise in your frequency range, but also with momentary=
scrambling and such stuff. So in the layers you can not (easily) control by=
software there is already lots of resending and rescheduling of packets. An=
all these introduce uncertainties and latencies you don't want in your audi=
transmission. Unless you can do with 100ms latency and more...
> Does anyone have an idea of how to work out the actual latency for a
The data-rate is not important. What is important is the struggle you do to=
get a payload packet out and the reception acknowledged. Wifi is very versa=
and allows usage (almost) everywhere. But you pay a high price in=20
predictability and latency.
Heck, even the wireless microphones struggle with problems and these "just"=
send some analogue data. While digital is simpler in that its only zero or=
one, its actually lots more complex on getting data out reliably.
> If we are talking about a studio setup with devices no further than 2
No, the bottle-neck is your neighbours accessing google and facebook via wi=
disturbing your signal momentarily producing gaps and xruns. And the only w=
around it is using an area where there are no neighbours.
Once the stream is stable and reliable, it will easily go below 20ms latenc=
But getting the stream to be reliable is already complicated with things li=
firewire (which has isochronous channels for exactly this purpose) and its =
complicated with usb (which has a master telling the clients when to send=20
bigger payloads to not disturb the other bus-members). Ask the jack-over-ud=
guys how difficult it is to create such stream reliably over tcp-ip network=
they take lost packets into account (which means an xrun) and advise you to=
use it on dedicated networks if you want more the the immediate experience.=
If jacknet over wifi fills your needs, use it. But if it doesn't don't blam=
on its developers, blame it on the underlying network (-technology) used.
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