[LAU] Experiences with miniDSP AVB products ?

[Niklas Reppel]

Well mostly I'd be interested in having a somewhat modular, compact yet 
extensible solutions for
multiple channels on recent laptops.

The choice of multichannel options (esp. exceeding 8 channels) for Linux 
is unfortunately very small,
and often the devices that are compatible are not that compact.

So being able to patch together multiple devices as the situation 
requires via an AVB switch seems more than desirable ...

On 10/1/18 7:17 PM, Len Ovens wrote:
> On Mon, 1 Oct 2018, nik at parkellipsen.de wrote:
>
>> Hmm but you wrote in a previous mail that there might be a chance to 
>> make it work if sb is willing to put the effort in?
>> Are there any resources on that ? I only found a thread in the ardour
>> forums, but couldn't extract any info about where to start. (tbh i 
>> just skimmed
>> it quickly).
>
> Both put the effort in and have the hardware to test with.
>
> In my mind there are two paths one could take, jack or alsa.
>
> ALSA: in the case of ALSA one would create a driver that would start 
> up at system start or manually after start (manually could mean using 
> a GUI). The device once connected would be static. It would have a 
> fixed number of audio ports and possibly break if that device went 
> away (same as a USB device). This would be fine for many uses. It 
> would have to be all inclusive though.
>
> Jack: This case is or could be much more flexable. In this case I 
> would use the NIC's clock (assuming an i210 or similar that has such a 
> thing) and use it to time the dummy backend for jack. There would be 
> some code involved to either make this clock master or slave. I don't 
> know if this already happens with the code as it stands. The i210 has 
> some extra pins, it would be great if one of them could be programed 
> to put out wordclock as well for syncing a local audio interface to 
> the whole works.
>
> A GUI would list known interfaces that can be connected (those that 
> have the right SR at least) either as a grid (like Ardour's audio port 
> connection GUI) or as a list like qjackctl's Connections window. I 
> suspect as things get more complex the patchage style might be hard to 
> use but that is another possibility. This GUI would not just make a 
> jack connection, but would have to first start a jack client that is 
> connected to the remote device and then connect it. As many AVB 
> devices only seem to deal with 8 channel streams at a time, connecting 
> one port would mean that 8 ports would show up on the jack graph and 
> the GUI would connect any other port for that stream without creating 
> another jack client. Devices could be added or removed at any time and 
> if an AVB client is no longer needed (has no connections for more than 
> 10 seconds) it could vanish.
>
> I do not know if there is already code that allows a jack client or 
> connection GUI to advertize stream availablity to the world but, as 
> with all things AVB, that would be yet another piece of code.
>
> Going this route would also leave things open for AES67 using the same 
> clock. It would seem possible to connect to both AVB and aes67 devices 
> at the same time. Assuming a suitable aes67 jack client was available.
>
> I had thought to work on something like that and have the i210 NIC but 
> not A) another computer to act as an end point or B) (better) an AVB 
> endpoint to play with. In my case I would prefer inputs.
>
> Another solution, though probably more costly, is to purchase 
> something that has both USB and AVB and use it to access a remote 
> audio device. The Motu 8D for example (8 aes3 i/o) is 800CDN or the 8A 
> (8 audio i/o) is 1050CDN. The advantage is that you end up with local 
> audio i/o that is in sync with your remote. (well sort of, you may 
> find aes3 inputs go through a SRC stage unless you provide sync to any 
> aes3 input box)
>
> If all you want is a cheap network audio solution... an old computer 
> with 8 outs and runs jack... use zita-njbridge... be happy. Almost all 
> HDA mother boards have 8 outs for a number of years, but it may be 
> almost as cheap to use a new atom based MB with 16v PS as the minidsp 
> 8n. (or a nuc... well maybe not, they have 7.1 through hdmi but only 4 
> physical on the $200 model) Pulse also offers networked audio... but I 
> have no experience with that and pulse is known to be lossy (as in 
> samples just get lost)
>
>
>
> -- 
> Len Ovens
> www.ovenwerks.net

-- 
Niklas Reppel
www.parkellipsen.de