Pulseaudio Crossover Rack - multi-way crossover design & implementation with linux

Excellent job here!

Somebody already asked this question via PM. What exactly do you need for this? It would probably be relatively easy to add a FIR convolver plugin where impulse responses could be configured by loading some kind of PCM impulse response file (WAV or similar). Would this be enough for your needs?

It would be gorgeus for me.
My fullranges oneway need convolution.
Do you think is it possible to implement a little convolver?
I've got dozens of wave impulse...

Thank you for your impressive work.
 
Hi iperv,

currently I'm working on measurement support and this is priority number one for me. The FIR stuff is on the "nice to have" list for me though I cannot give any date as to when this will be finished. Well, incentives in any way or form may be given... :D:D
 
Hi all. I'm hoping someone can help. I'm fairly new to Linux but I'm eager to try this out with an HDMI audio extractor with Raspbian.

I'm getting the following error when trying to install Pulseaudio Crossover Rack, per instructions on the T-5 page.

When entering "sudo apt-get install pulseaudio-crossover-rack" I'm getting the following error.

E: Unable to locate package pulseauidio-crossover-rack.

Any advise?

Thanks
 
Hi iperv,

currently I'm working on measurement support and this is priority number one for me. The FIR stuff is on the "nice to have" list for me though I cannot give any date as to when this will be finished. Well, incentives in any way or form may be given... :D:D


Hi Tfive,
of course take the time you need, it would be a beautiful plus.
My incentive for you is:
good job! :D
 
Hello Tfive,
I use an active analog system and find your software very interesting. My concern is running three of four about five metres or through the wall in proximity to 240V cables.

I have a question; is it possible to use two separate USB sound cards (three to five channels) so they can be installed inside the speaker boxes and drive each speaker separately?
 
I recently found an article on this topic somewhere and the conclusion was that as long as these two soundcards are connected to the same root hub they should play in sync. I have not verified this by myself though. Software-wise this is not a problem for Pulseaudio Crossover Rack.
 
I recently found an article on this topic somewhere and the conclusion was that as long as these two sound cards are connected to the same root hub they should play in sync. I have not verified this by myself though. Software-wise this is not a problem for Pulseaudio Crossover Rack.

The cards would need to be USB adaptive to run synchronously from one controller (hub).

Thanks,
I meant having both USB sound cards plugged into the Pulseaudio box and run via an extension cable to the speaker boxes.
 
The cards would need to be USB adaptive to run synchronously from one controller (hub).

Nevertheless PA can feed two separate domain clocks via adaptive resampling of module-combine-sink. I have never tried that, probably introduces a bit of overall latency.

Do you know about the situation with two externally clocked usb soundcards (which likely use isochronous mode?!) - does this work when their clocks are synced? I tried to ask the question on the pulseaudio mailing list but never got any reply. Also Lennart Poettering did not reply to a personal email.
 
Most USB soundcards use isochronous transfer mode (AFAIR only the M2Tech hiFace v1 used bulk mode, the version 2 was back to standard isochronous asynchronous). It is just about USB signalling and packet priorities of the transfer.

But where the card gets its audio clock is another question. Cards using adaptive USB-audio standard (the inexpensive majority) derive their clocks from the incoming packets rate via PLL - thus all cards connected to a single USB controller will run synchronously, only with the deviation of PLL.

Async cards have their own clock and signal back to the driver to increase/reduce the amount of samples in future USB frames. However, if their clocks are synchronized (e.g. all clocked by a common external clock source), they will run synchronously too.

If the cards run synchronously, IMO there is no reason to use the resampling combine-sink PA module. People regularly merge their synchronously-running cards with the multi plugin of alsa to create a virtual multichannel device.
 
Hi Tfive,
Another question, please?
Can I run a package, such as Clementine, on the same Linux box and have it input to Pulseaudio which outputs to two USB sound cards? If so, this looks a brilliant solution to setting up active speakers perfectly from one box. (Apologies if it is a stupid question.)