RUNE Audio and Brutefir (Convolver for Roomcorrection)

[Da Alchemist]

Rune Audio and Brutefir on QuadCore Pi (Pi2)

First Thanks to hondagx35 for his great work and support. I never would have done it with his support, because i am a completly Noob to Arch Linux.
What it is all about?

Brutefir http://www.ludd.luth.se/~torger/brutefir.html is a Convolver and can be used for RoomCorrection and active Xover (with Multichannel soundcards). The single Core Pi was far to weak to run a Convolution and a Streamer but the Quadcore version is doing it without any hazzle.
Impulse Files for the Convolution can be build with Rephase, Porc, DRC or even RoomEQWizard (after Exporting the EQ-Filters Impulse Response and converting them with SOX from WAV to PCM).Of Course there are commercial Solutions like Acourate.

So apart from the PI2 and hondagx35`s Image we need to install a Version of MPD thats supports Pipeout and we need to install Brutefir.

Hondagx35 build these to Packages so it is easy to do; ssh into yor Pi and get them here : the-new-4-core-raspberry-pi-t862-150.html#p5733

after that: pacman -U mpd-rune-0.19.6-1-pipe-output-armv7h.pkg.tar.xz

The same for Brutefir and
pacman -U brutefir-1.0m-1-armv7h.pkg.tar.xz

Open sudo nano /etc/modules-load.d/raspberrypi.conf and uncomment the line snd-bcm2835 with "#"

Now we have to tell mpd to feed Brutefir so we have to edit the mpd.conf. For security Reasons we will first make a Backup of the original File in rune´s home

sudo nano /etc/mpd.conf

and disable all lines, section beginning with "audio_output" (#)

and add these lines

audio_output {
type "pipe"
name "brutefir pipe"
command "brutefir -nodefault /home/.brutefir_config 2>/dev/null"
#command "aplay -f cd 2>/dev/null"
format "44100:32:2"
}

If there is someone who wants to try out Brutefir , I could upload some example Filters and a simple brutefir_config for the start.

Regards

[ACX]

Thank you for reporting your experience and the instructions!
Any thoughts about the sound quality? How much does the filter affects PRaT and soundstage?

[Da Alchemist]

Brutefir is only a Convolver so Soundquality is depending on the Filters you use with it. Filters could be build e.g. with DRC http://drc-fir.sourceforge.net/doc/drc.html; Exported and converted EQ Filters from RoomEQWizard;
PORC https://github.com/zzzzrrr/porc ; Rephase (instructoion from MiniDSP http://www.minidsp.com/applications/adv ... e-fir-tool) or with the commercial Acourate http://www.audiovero.de/en/acourate.php

In any case you have to make Measurements of your Situation ( I did that on a Raspbian running the RommEQwizard and using MiniDSP´s UMIK1) So actually i am running two Sd Cards, the Filters are generated on my Desktop and copied via Network to RuneAudio.

I would say the Result is superb...

Regards

[jonas18z]

Yes. But is there a simple switch on/off from gui so you can compare? Will this be integrated in the 0.4?

[Da Alchemist]

Filters are switched in Brutefir via CLI and Scripts ( Manual http://www.ludd.luth.se/~torger/brutefir.html#bflogic ). At the moment I log in via SSh and execute the Scripts. It would be nice if there is a Page with some Buttons to execute some customized Scripts...
(The Name of these Scripts could be given by Rune Audio, the User decides what he puts into this Scripts)

Correction with Brutefir is not a One-Click Solution, Filter-building needs some Experience. I am working with Brutefir for over 5 years now and still learning .....

I do not think, that Brutefir will make it to 0.4 but I wish that there is the Chance to use it (MPD compiled with Pipe-out....)

Regards

[jonas18z]

Do you know any good simple tutorial for BruteFIR to make a Roomcorrection?

[sonnius]

Hi Da Alchemist,

Could you post some sample configs please?

Thanks,
Rob

[tux]

Hi!

Thank you very much for all this useful information shared in this topic.

Just one question. Is there any workaround in for brutefir in order to operate with multiple sample rates?

It would be really interesting if you shared with us your config files!

Last but not least, I see that you don't use jack. Am I correct? I am asking because in most of the tutorials found, jack is usually used.


Cheers,

Michael

[Tinitus]

Hi Da Alchemist,

thanks again for your sharing your experiences with us. If I understand it correctly you build your filter files with REW using a UMIK-1. The filter files are .wav files if I am not mistaken and you use sox to transfer them to PCM (so brutefir demands pcm-files)? Then you transfer them to your brutefir configutration file? I have read that the upsampler build into mpd is not the best so if one only wants to use on filter one could pipe out to sox first and convert everything to a fixed sample rate (do not know whether Pi2 or C1 have enough computing power to convert everything to 24/192 before handing this over to brutfir. Of course if you have maximum 24/96 that would suffice as a fixed sample rate (or you downsample 24/192 to 24/96). I for one think that you do not really need 24/192, 24/48 should already be enough. If RuneAudio will work on the C1 I would have to find the snd-device line in the conf file (umless this is neccessary to disable the output to the audio jacks (C1 does not have them). Then configure mpd for pipeout and install brutefir and load the filters I did creat with one of the various programs. I for one would be more interested in your target curve than your filter files. Filter files only work for a specific set up (speakers/room) the target curve is universal (the filters tweak the sound in order to reach the target curve). Is building your own target curve in REW easy and comfortable?

Best Regards

Tinitus

[theSuede]

Hi all!

I'm also a total newb to ARCH/PI2, but I have ample experience with audio filtering techniques and room correction / loudspeaker correction solutions on other platforms if someone has question about that in particular.

I still haven't figured out how to actually couple all the modules together, since each time I reboot the system or restart Rune it resets the:
audio_output {
..params...
}
-back to the default (Alsa/HDMI) from the Pipe setting...

It would be good to have an actual walkthrough of the setup, from mounting the rune img in the PI2 for the first time.
I would gladly volunteer to write/format the piece nicely - if I only knew how to do it in the first place... PI2;Rune/MPD;Pipe;BruteFir;HDMI/USBDAC

(one of the neverending problems with Linux solutions - there are a million solutions, none are intercompatible, every one takes a few hours to test through - and that after spending hundreds of hours getting to know the used flavor of Linux that's used for the base...)