Forums > MaxMSP

6-channel uncompressed audio over network

August 24, 2009 | 2:40 pm

Hi everyone,

I’ve searched the forum and read (amongst others)
http://www.cycling74.com/forums/index.php?t=msg&goto=150540
which is quite close to my question.

The difference is that i would like to send 6 channels of audio from multiple sources (6 channels per source) to a single machine which only relays the sound to 6 speakers.

I’m not looking for a shoutcast or oggcast external or internal, because that would mean that i would compress my audio, which I do not want.

The reason for this is because I want to play ambisonic files without any loss of quality but over a network (if i’m repeating myself too much, please say so.. I’m just trying to explain my question in more detail)

Perhaps ambisonic isn’t the best way, but it has excelent positioning capabilities.

I tried netsend~ 1.0 alpha 11 but I don’t know how old this version might be. At least it works better than jit.catch/jit.net.send and the release/receive patches, but they give a sort of ‘clicking’ sound (which is not because of my hardware setup).
Alas, the netsend~ and netreceive~ (without catch and release) don’t work smooth either, though somewhat better..

the forum post I referred to is about 2 years old now, and i was wondering if there is a better version perhaps, or a new patcher that someone else made.

I also tried the wormhole vst, but this seems to drop the audio once in a while and it only seems to work with 2 channels, and having 3 vst’s open for each pc that has to connect isn’t really the best of ideas.

Any input, idea, link or comment is welcome!


August 25, 2009 | 11:40 pm

Howdy,

I just did a quick calculation, unless I’ve made a mistake 6 channels of audio is just over 1MB per second and gigabit ethernet should handle 125 MB/s so I doubt that amount of data is the problem.

I don’t know how to help however. If the amount of data is the problem the you could code up a lossless codec if you’re feeling adventurous. I’m not sure why no one has done this already!

This would halve the amount of data. Have you tried transferring 3 or 4 channels to see where the threshold is? You could just compress one or two channels if you could get away with it.


August 26, 2009 | 1:22 am

CobraNet is the best uncompressed, multi-channel, digital audio format I can think of. You can send 64 channels of uncompressed audio over one cat5 cable on a 100Mbit network (32 channels in each direction). The audio is packetized and sent over standard Ethernet networks. However, CobraNet is not routable and therefore cannot be used to send audio over the internet. It can only be used in a LAN. Latency is usually around 1.33 to 5.33 milliseconds.

You’d have to get a cobranet audio card for each computer if you wanted to fool around with it. Or, if you already have a multi-channel audio card for your computer, you can just find a cobranet a-d converter. There’s a pretty good wikipedia article on cobranet that goes over how it works.

Audio channels are digitized and assembled into "bundles" of up to 8 channels per bundle. Most CobraNet cards can receive up to 4 bundles and send up to 4 bundles (some can only do 2 and 2). So, you could theoretically take your 6 channels of audio from each source, throw them in a bundle, and send them on their way. The receiving computer could receive 6 channel bundles from up to 4 different computers.

Here’s a PCI card that’ll do 16 channels in both directions:

http://www.audioscience.com/internet/products/sound_cards/asi6316.htm

Not sure if it’s in your budget…

I know Whirlwind makes cobranet A-D’s and D-A’s, and so do a lot of other manufacturers.

Good Luck


September 8, 2009 | 1:42 pm

Thanks to all of you for replying,
the problem didn’t lie in the netsend~ protocol, but rather in the modem.
The connection was made through a modem with wireless capability. After a while we figured out that whenever anyone was using wireles functionallity, our entire bandwidth would drop down.
Thus, we plugged all the pc’s to a switch, and put that switch in the router (for internet only) so it would route all LAN traffic via the switch.

This solved our problem for 95% !
We still have a tiny hiccup once in a while, but it’s really allot better.

Thanks again for all the help.


March 4, 2010 | 1:06 pm

Hi Daft, hi list,

We’re looking into the same kinda thing: sending around multichannel uncompressed audio.
Netsend~ sounded good and I’m sure i got it working before. It doesn’t work anymore though. Have you done any fiddling with it? We’re connected through a router which should work fine I guess.

any thoughts why it wouldn’t work?

regards
Woody


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