[Noisebridge-discuss] a networked sound system idea

[Geoff Swan]

Making the assumptions that we're not talking surround sound, and that
the left and right speakers in any given pair will be relatively close
to each other...
Each speaker pair has a single TCP/IP connection (to one of the
speakers in the pair) over which it receives the stereo audio.
The speaker pair are connected to each other by a low power
(relatively) low bandwidth wireless connection (possible
unidirectional if you want to reduce costs) that is used to provide
the mono audio channel to the second speaker. This should mean that
you can very easily time synchronise the left/right pairs of speakers.
You may find that between rooms time synchronisation is less
important.

Another approach could be to have each individual speaker with a
TCP/IP connection and a low power wireless receiver - some sort of
time synchronisation transmitter can send out a ping/tick signal every
couple hundred of miliseconds or something (probably driven from a gps
for simplicity).
This setup requires that you have an audio server that time stamps
your audio streams so that they are played synchronously. It does have
the advantage though that you can probably do a surround sound setup
with very little overhead. Note that this will also require buffering
at each speaker too.

I think if you are talking relatively large speakers they will each
need there own separate power connection - that's largely unavoidable.

all the best :)

On Tue, Oct 12, 2010 at 8:00 AM, Casey Callendrello <c1 at caseyc.net> wrote:
> On 10/11/2010 11:36 AM, Moxie Marlinspike wrote:
>> I think there are commercial solutions which approximate what you're
>> talking about, too, but they're super expensive.
>>
> The one you're thinking about is probably CobraNet
> (http://en.wikipedia.org/wiki/CobraNet). However, they use a separate
> ethertype, not IP.
>
> Ignoring the IP stack allows you to strictly control buffering, which
> can really cut down on jitter. Of course, in a heterogeneous home
> network environment, there will be all kinds of crazy variations that
> complicate the picture.
>
> Nonetheless, if you want to solve the jitter / quality problem in a
> fashion other than the age-old "throw a crapton of buffer at it" method,
> crafting your own ethernet protocol can be the answer.
>
> --Casey
>
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