@Tfive - that's why I said in my previous post "you are right". Me neither can hear any resampling artefacts and your argumentation already convinced me in 100%
When the time allows (weekend most probably) I will make fresh install of Ubuntu 20.04 LTS and install your soft to try. Certainly I will back to you afterwards with tones of questions 🙂 🙂
One of the first question cross my mind is how to use equaliser together with the crossover (to equalise bandwidth between 20Hz to around 40Hz where my cabinets got already -3dB drop down)
When the time allows (weekend most probably) I will make fresh install of Ubuntu 20.04 LTS and install your soft to try. Certainly I will back to you afterwards with tones of questions 🙂 🙂
One of the first question cross my mind is how to use equaliser together with the crossover (to equalise bandwidth between 20Hz to around 40Hz where my cabinets got already -3dB drop down)
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First of all you might want to stay away from 20.04 as it seems to have a premature pa version bundled and it seems to have problems with ladspa plugins. Might want to try 19.04 instead. Or Linux Mint, my Dimension for desktop use.
Secondly you can also insert as many eq blocks as you like into your crossover chain, for example on at the very beginning before splitting signals. That way you can modify the overall sound of the chain. No need to use the separate eq program at the same time.
Secondly you can also insert as many eq blocks as you like into your crossover chain, for example on at the very beginning before splitting signals. That way you can modify the overall sound of the chain. No need to use the separate eq program at the same time.
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@Tfive - so your software is similar in concept - various "blocks" (I know not the same - just to imagine principle) like Windows VST Host, correct? With that differance it is limited only to filters and EQ. Regarding Ubuntu - I want to stay with this distribution as I am most fluent in that (never used other distribution actually and start my journey with Ubuntu 8.04 many years ago 🙂 ) But thank you for advice - I will go with 19.04 then.
Yes, it's probably similar to vst host.
And Linux mint is based on Ubuntu. So all the base things are almost identical. If you're finally feed up with Ubuntu you might look into mint's direction. 😉 if not, PaXoverRack should run just fine on Ubuntu too.
And Linux mint is based on Ubuntu. So all the base things are almost identical. If you're finally feed up with Ubuntu you might look into mint's direction. 😉 if not, PaXoverRack should run just fine on Ubuntu too.
@Tfive - regarding distribution: let me ask the question other way round - did you use Mint to develop the software? The reason of that question is following: since Kodi Media Center interface is full-screen type one can't see what system sits below anyway so it is completely irrelevant for me which distribution will I use. BUT from functional point of view it makes the biggest sense to stick to the exactly the same distribution as software was originally developed in/for - in other words to the distribution you are using.
Yes i used mint to develop. But under the hood Ubuntu and mint should be so similar that no problems should arise. I also regularly test on other apt based distros. They all worked fine except the one with problems, Ubuntu 20.04.
BTW I also run mint and Kodi on my htpc. I read some questions about kodi a few posts back, so to summarise: kodi will use the crossover just fine as PaXoverRack will set it's input sink as default sink.
BTW I also run mint and Kodi on my htpc. I read some questions about kodi a few posts back, so to summarise: kodi will use the crossover just fine as PaXoverRack will set it's input sink as default sink.
@Tfive - sounds that's exactly I need 🙂 But I prefere to go with Mint then as if I will potentially need any support from you it will be easiest for you if we "speak the same language" - having the same system distribution 🙂
@Tfive As I didn't installed your software yet I can't check myself so I would like to ask you: will it work with 3x stereo PCM2706 INSTEAD multichannel card? In total we have 6 channels but from 3 USB devices. For testing purposes I made set which is USB hub and 3 times cheap Chinese PCM2706 card. See picture
Well, I see no reason for syncing. But perhaps I miss something so please clarify. I mean we stream via USB digital data simultaneously to identical devices with identical latency so what is the potential problem?
You mentioned that you had a USBstreamer... If those DACs have i2s input you can create a 8ch DAC with it.
PCM2706 are USB-adaptive devices, they will generate synchronous clock PLLed from the common USB signal. OK.
But three devices connected to a serial bus receive their data at different time. The time difference between first and third device will be at least 2 packet lengths, i.e. 2 x 48 audio frames at 12MHz, i.e. for 16 bits 2 x 48 x 16 x 2 = 256us. In reality probably more (USB frame overhead).
However, the PCM2706 datasheet says:
That would mean all three chips will be synchronized by the common SOF packet and playback should start at the same time. Provided the USB HUB does not introduce time shifts between its outputs (probably not).
But three devices connected to a serial bus receive their data at different time. The time difference between first and third device will be at least 2 packet lengths, i.e. 2 x 48 audio frames at 12MHz, i.e. for 16 bits 2 x 48 x 16 x 2 = 256us. In reality probably more (USB frame overhead).
However, the PCM2706 datasheet says:
That would mean all three chips will be synchronized by the common SOF packet and playback should start at the same time. Provided the USB HUB does not introduce time shifts between its outputs (probably not).
I do. I created this set just for curiosity, for the few dollars. If it would work I would like to develop same with superb interface Amanero
I didn't think about that. Wouldn't it be true if one USB would serve for all 3 DAC? Theoretically we could go for 3 separate USB's taken directly from motherboard not from hub. Then data package shifting wouldn't be problem anymore. Do I think right?
The PCM2706 datasheet suggests the data shifting within the USB frame should not matter because the FIFO output startup is gated by the next SOF packet which should arrive to all the connected devices (connected to the same hub) at the same time.
3 motherboard USB ports does not mean 3 independent USB controllers, every USB facility contains USB root hubs. The actual layout is listed in lsusb -t tree view.
Nevertheless splitting the data to 3 distinct USB controllers would definitely ruin the synchronization - different clocks (though likely PLL'd from a single system clock), independent SOF generation/delivery.
IMO your arrangement with USB-adaptive soundcards and PCM2706s gated at the common SOF could work correctly.
3 motherboard USB ports does not mean 3 independent USB controllers, every USB facility contains USB root hubs. The actual layout is listed in lsusb -t tree view.
Nevertheless splitting the data to 3 distinct USB controllers would definitely ruin the synchronization - different clocks (though likely PLL'd from a single system clock), independent SOF generation/delivery.
IMO your arrangement with USB-adaptive soundcards and PCM2706s gated at the common SOF could work correctly.
Should be easy to try with a scope and at least two PCM270X/PCM290X boards. If you use pulseaudio you should be up and running with two or even three of these in no time, just assemble a filter chain with a single split to two/three outputs and no filtering.
I'm a little sad to announce that you guys should also stay away from linux mint 20. it ships the same buggy pulseaudio version as ubuntu 20.04 does, and that breaks pulseaudio crossover rack. I'll be trying more stuff over the next days, trying to find out if there's a general problem with pulseaudio 13.99 or the version shipped with ubuntu 20.04. I'll be filing a bug report against either pulseaudio 13.99 or the packaged version in mint/ubuntu, whichever turns out to be the culprit. We'll see how all that turns out.
Just for your record Tfive Manjaro has Pulse Audio -13.0-3 -
packager - Jan Alexander Steffens (heftig )
Build date - 11/01/20 ( UK dating )
I do not have anything Pulse Audio installed and ALSA works exceedingly well.
packager - Jan Alexander Steffens (heftig )
Build date - 11/01/20 ( UK dating )
I do not have anything Pulse Audio installed and ALSA works exceedingly well.
Hi, I would like to know how, if at all, kernel version influences the crossover performance? Particularly I am asking for low latency kernel. Does low latency kernel install/update make any sense?