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

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

Hi there!

This is my first post to this forum with a new account and after a long hiatus (>10 years).

I'd like to announce the first public release of "Pulseaudio Crossover Rack", a program to design and implement multi-way speaker crossovers with linux, the pulseaudio audio server and a set of LADSPA plugins.

The installation instructions can be found on the homepage, the theory of operation, available filters and lots more on the Online Help page.

Currently there are builds for the amd64, i386 and armhf (targeted at RasPi etc.) architectures only (this only concerns the LADSPA plugins, the program itself is cross platform compatible as its written in python3/PyQT). The armhf build was only tested in an emulator, so I'd like to hear back from RasPi and similar SBC owners if it actually works.

Also any usage reports, suggestions, feedback on useability and bug reports are welcome (the latter not so much ;)).

Please keep in mind that this is the 1.1 release (as I screwed up packaging the 1.0 release) - but in a sense this is even more 1 than 1.0 :D

Here's the obligatory screenshot:
screenshot_basic_2way.png


Have fun!

Jürgen

PS: There's also a Pulseaudio Parametric Equalizer available for those who just want equalization and no crossover. If there's any interest and need for discussion I can open a new thread for it...
 
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Tfive

Member
2018-06-26 6:03 pm
Straubing
That looks like great fun and just what I've been searching for.

I will give it a run tonight after I return home from work.

Can it be configured for a 2.1 system ?

I'm not exactly sure what the definition of 2.1 is... Stereo with one subwoofer?

At the moment there is a design limitation in Pulseaudio Crossover Rack: It's stereo only. I probably could add a "mono" button on the output configuration pretty easily. For now you'd have to sum up the two subwoofer outputs externally (easiest method with two resistors in series). Please tell me if my definition of 2.1 is even correct and if you would benefit from adding that mono summing on the outputs and then I will research how much effort it will take me to add this.
 

Tfive

Member
2018-06-26 6:03 pm
Straubing
Yes, 2.1= stereo mains and 1 sub-woofer.
Yes !
Your feature request is already on the 2do list. Give me a few days...

Just installed the Parametric eq on this Ubuntu workstation....shhh don't tell the boss ;) and it works wonderfully.

Installation and integration is very smooth and polished... excellent.
That's what I like to hear - thanks for the feedback! After all I will be searching for a new job as software engineer in a few days after a lengthy rehabilitation. Good to know that I can still write useful programs... ;)
 

Boden

Member
2010-03-02 9:29 am
Hello Jürgen,


The link to the server does not seem to work.


Silly question: could you -for the sake of laziness& ease- add the standard-colors for the various (Rear Left etc.etc. ) outputs of multichannel soundcards in your "Output Sink" block? I am always struggling with these...


Thanks,


Eelco
 

Tfive

Member
2018-06-26 6:03 pm
Straubing
Hello Jürgen,


The link to the server does not seem to work.


Silly question: could you -for the sake of laziness& ease- add the standard-colors for the various (Rear Left etc.etc. ) outputs of multichannel soundcards in your "Output Sink" block? I am always struggling with these...


Thanks,


Eelco

Sorry, my laptop at home, which is serving the website for cost reasons, is currently down. I will try to have it rebooted ASAP. I will try to move it to a more stable virtual root server by (not the most stable machine) the end of the year.

Could you elaborate on the coloring thing? Do you mean the multi select fields in the edit dialog for outputs or the background of the output widgets after you selected the channels?
 

Boden

Member
2010-03-02 9:29 am
The standard colors (if colored at all!) for 3.5 mm output jacks on both onboard soundcards and many PCI cards are: Green: Front speakers out. Black (or dark Blue on some older boards): Rear speakers out. Orange: Center/subwoofer out. Gray: Middle speakers out.



So, to take your own screenshot: Woofer: --- Output channels: Front Left Front Right (Green Jack) Tweeter: --- Output Channels Rear Left Rear Right (Black/Dark Blue Jack)


Adding the relevant color code would simply save me having to look up the color code, that’s all..
 

DRONE7

Member
2008-08-21 11:12 am
Superb !
I've taken my usb soundcard to work (shhh, don't tell the boss) and version 1.2 allows for mono sub out. That's great.

Interface is very intuitive and it only took a couple of minutes to load and chain the dsp's.

The pop-up boxes for user input error notifications (forgetting to name sink etc) are extremely helpful. This is so well thought out and user friendly.

Currently I am just testing on screen,as I haven't brought my amps and speakers to work...;) so I'm looking forward to tonight and trying out the audio at home.

A question...my soundcard has 5.1 output.. front,rear,centre, and sub.
When I select an output in Pulseaudio Crossover Rack for the subwoofer I can choose summing of inputs to mono but cannot select output to be sub out only.
A pop-up notification asks for 2 output channels to be configured so I need to choose centre and sub then get the option to mono.
Thus only one physical output is used but the centre output becomes redundant and unable to be used.

Is this immutable ?

Another question... The card is capable of 24/96 but the dsp seems to show PulseAudio at 16/44.1.
Can this be adjusted or is this a given ?

Thanks,
Bob
 
A question...my soundcard has 5.1 output.. front,rear,centre, and sub.
When I select an output in Pulseaudio Crossover Rack for the subwoofer I can choose summing of inputs to mono but cannot select output to be sub out only.
A pop-up notification asks for 2 output channels to be configured so I need to choose centre and sub then get the option to mono.
Thus only one physical output is used but the centre output becomes redundant and unable to be used.

Is this immutable ?

Yes, as far as I can see there is only one trick which involves remap-sink and this can only be used in two channel mode. So yes, this way you are losing one output of your soundcard. This was a surprise to me also that this hack worked with literally 10 lines of code changes. As long as there is no n-channel downmix plugin for pulseaudio available which takes two channels as input and has one output I can see no way to get around this limitation of pulseaudio at the moment.

Another question... The card is capable of 24/96 but the dsp seems to show PulseAudio at 16/44.1.
Can this be adjusted or is this a given ?

Thanks,
Bob

Actually I use kind of a hack to read the sampling rate of the pulseaudio server at runtime by reading it the first physical output. This is obviously the wrong way to do it as all the DSP/LADSPA stuff is done at the sampling frequency of the pulseaudio backbend which is usually configured system wide by editing /etc/pulse/daemon.conf .
Will look into this... The longer I think of this it should show both backbend and output sampling rate and format.
 
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DRONE7

Member
2008-08-21 11:12 am
Thanks for fixing the links !
I have installed 1.4 and now have my sound-card configured and connected.
So far I am testing on the workshop bench system and it all sounds very promising.

Just have to run through all the daily use scenarios (stopping starting suspending etc) to check for noises and continuity when resuming.

Once that passes I will take it inside to the main listening system.

Meanwhile I have started to plan a speaker project that will incorporate the xover-rack and eq.
 
Thanks for fixing the links !
I have installed 1.4 and now have my sound-card configured and connected.
So far I am testing on the workshop bench system and it all sounds very promising.

Does that mean you'r listening to a speaker crossed over py PaXoverRack? If so, you're definitely first, man. :) My SCS4s are still lurking in the basement and I will have to build a 6 channel amp first to get my setup going...

If you want you can take a picture of your test setup and I will post it on the homepage as first ever system running on PaXoverRack ;)