24 Nov
2009
24 Nov
'09
4:49 a.m.
Adrian Knoth:
On Mon, Nov 23, 2009 at 08:28:03PM +0000, Folderol
wrote:
You don't say why we should avoid analog stuff.
For me the whole point of doing this is the analog stuff.
...
The rationale in brief:
No proprietry hardware soundcard needed.
Almost all modern computers have reasonably fast Ethernet connections.
Don't know how much you already did for the hardware layout. If
possible, try to avoid analog stuff, that is, ADC/DAC. I'm also somewhat interested in the network part,
I feel IPv6 could help
a lot. It supports autoconfiguration and it has decent multicast
support, so it would be possible to broadcast/multicast the streams on
the net (LAN). This could be useful if you want to access the stream at
a mixing console for a life setup and simultaneously record it on a
computer.
At a live recording you probably have only your own gear connected to
the lan. In that case you can easily assign ip-adresses at will and to
your own taste. I don't see how IPv6 vs. IPv4 could matter at all.
That's basically what Roland's Digital Snake
offers: an onstage Ethernet
(not IP) soundcard and one or more remote devices. RockNet provides
similar stuff, there's also Ethersound, but RockNet is PC-incompatible
(400MBit/s proprietary protocol), Roland is undocumented and I don't
know nothing about Ethersound. ;)
That tells us that it should be doable. But of cause we want an open
protocol. Do you know the capacity limits of thoose systems ?
I also have some fancy Xilinx boards with onboard
ethernet, an audio
codec (including the analog jacks) and a FPGA. Though it's way harder to
mimic all the features with VHDL, it could provide stable timings. The
boards also support memory, so it would be possible to load a softcore
and run Linux on them.
Doing things with a fpga would certainly be interesting, but I cannot
do it for the moment. Perhaps you could provide designs we could
include...
If you like, feel free to Cc me or join #lad if you
think I could
contribute something.
I assume you are on the list, so I only send on the list.
Regards,
/Karl
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Karl Hammar Aspö Data karl(a)aspodata.se
Lilla Aspö 148 Networks
S-742 94 Östhammar +46 173 140 57 Computers
Sweden +46 70 511 97 84 Consulting
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