The future is here! I used to follow various audio forums several years ago, it was just analog stuff back then but due to various reasons it all fell into slumber, now being back here it's like having traveled in a time machine into the future seeing people nowadays playing around with massive DAC's and powerful DSP projects, we are experiencing some exciting times.
I admit not being well versed in Linux at all, yet, but a BruteFIR optimized distro would be super cool, and I had a little look around among Linux stuff such as the TinyCore distro SU (skyunlimited) mentioned in above post, that looks like a very interesting candidate, on top of it possibly with a low latency patched/tweaked kernel!
And it's apparently free of that pesky S y s t e m D init as TinyCore comes with a much slimmer Sys-V-init, which is a good thing, and provides for an even lower latency too.
A cool thing is, TinyCore loads into the RAM even from a USB stick, and after it has booted up one can pull out the stick, all in all having checked their FAQ it seems like a slim, fast and sane distro to build on.
Yes, VM = Virtual Machine, haven't played with it for years but having tried in the past I found it easy to use thanks to an intuitive GUI, but probably needs some further setup to allow host-guest OS communication.
https://www.virtualbox.org/
SU that's pity to hear, but where are your threads so we can have a look into what you have done?
Just a comment on the low reception rate, I simply guess you were ahead of the time, but during the recent years Linux has caught much more attention, perhaps in part also due to Win 10 controversies.
Nonetheless it would be appreciable if you could share further thoughts on it.
It was a project in the german Diy Hifi Forum . That was 5 years ago. All Links are down in the meantime. These Times there were only a few non active Threads here in this Forum concerning Brutefir.
This Project is pretty outdated. BTW changing the Kernel in TinyCore is not that easy.
I am now using Raspberrys and Orangepis for Brutefir.
Just take a look at this Thread, i suppose there are not more than 3 users, that will become Brutefir-users in the Future. So i would say restarting such a Project is not worth the time.
Regards
This Project is pretty outdated. BTW changing the Kernel in TinyCore is not that easy.
I am now using Raspberrys and Orangepis for Brutefir.
Just take a look at this Thread, i suppose there are not more than 3 users, that will become Brutefir-users in the Future. So i would say restarting such a Project is not worth the time.
Regards
I was at the point of attempting to get Brutefir running on a BBB when life events delayed the project. I would like to get going on it again for the purpose of 2 channel phase correction. It will be correcting for Linkwitz-Riley crossover curves generated and executed via IIR filters running in ALSA. This may seem simple (even though I haven't done it yet) but there is a wrinkle...
I would like to swap the filter configurations on the fly so that different music source files at different sampling frequencies are each correctly modulated. [The IIR filters in ALSA do this.] I would not attempt anything higher than 96kHz, and I'm wondering how many taps I can achieve with the BBB, along with the IIR filters still running correctly. With the SoX convolver I can run a simple EQ with 2048 taps at 48kHz. I don't know how many taps would be minimum for correcting IIR crossover phase - would 1024 suffice?
*IF* there is just not the CPU power i need in the BBB, then I'd like to try running FIR filters within Logitech Media Server. Anybody done that?
If you are curious, I have a thread running on LADSPA filters in ALSA on the BBB: http://www.diyaudio.com/forums/twisted-pear/277564-ladspa-filters-digital-crossovers-bbb.html
Any comments or ideas on adding xo phase correction would be *greatly* appreciated!
Cheers,
Frank
It's not just the script writing I can do that bit even if my electronics are a bit more challenged
I'd like to run Brutefir for an active crossover on a reasonably powerful Linux SBC or even mini PC but the difficulty for me is getting six channels of 12s or spdif output from said box. A BBB with more horsepower would be nice ...
What kind of output do you use? I would like to use the Pi3 HDMI output for something like 4 channel or 6 channel output. So far I have tried using Jack server, Calf plugins and Qjackctl to set something up. I have had it working at one point, not since, and I can't set output channels at more than 2. If you know a way to use more channels from the HDMI output, I would be very happy.
There's a Dutch hobbyist who made a GUI to control Brutefir. It's set up as a php server (I think), you access the localhost page and you have get a graphical interface where you can set notches, filters etc. Basically the whole host of biquads. You can load convolution files as well. Nice thing. He had an .iso with a full distro (ubuntu minimal and brutefir/GUI) as well. Not sure of the status of the project.
ADAT and HDMI can transfer multiple channels but not beyond 48k bitrates. USB can though, as can mutiple simple spdif outputs.
Yes. I am having trouble setting up the required database though, and after solving that I will still have only two channels if there is no access to more. The interface looks nice and simple though.
Is that a Pi specific limitation? 48 kHz is still OK compared to your basic 2x4 miniDSP unit which runs at that samplerate.
Maybe this interesting for someone here:
http://www.diyaudio.com/forums/soft...e-7-1-av-receiver-over-display-port-hdmi.html
Regards
Guenter
http://www.diyaudio.com/forums/soft...e-7-1-av-receiver-over-display-port-hdmi.html
Regards
Guenter
Nope, the limitation not Pi specific, it is written into the standards for ADAT and HDMI protocols whatever hardware is used.
If you want high bit-rate multi channel digital then USB manages this and we have DIY hardware available at sensible prices. There is a new (sort of super-ADAT) audio protocol called MADI but availability is limited to some super-expensive pro-audio stuff. DVI is the new, quite ideal looking, super-HDMI standard and includes specifications for hi-def multi-channel audio but I have never seen this implemented or available anywhere except in computer monitors, it hasn't even made it into common use as an HDMI replacement for home cinema stuff yet.
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My blu-ray player supports 6 channels at 192kHz through HDMI. Can't find out what my receiver can receive, though I remember seeing 96kHz coming by when playing a blu-rayaudio disc. Are these devices negating standards, or using the DVI standard? Come to think of it, I did come past that in the receiver's manual. Aha. Nevertheless, I'd be quite happy with a superflexible open-sourcy cheap RPI DSP with a usable HDMI-output.
Hello Guenter,
Thanks, your story with interesting sceenshots is what got me interested. Not all of KXstudio is available for RPI, but enough or equivalent of it is. At least there is jack server, a way to manage connections, the calf plugins, mediaplayers. If there is an easy way to crack open HDMI output, there will be lots of DSP-playtime ahead.
My blu-ray player supports 6 channels at 192kHz through HDMI. Can't find out what my receiver can receive, though I remember seeing 96kHz coming by when playing a blu-rayaudio disc. Are these devices negating standards, or using the DVI standard? Come to think of it, I did come past that in the receiver's manual. Aha. Nevertheless, I'd be quite happy with a superflexible open-sourcy cheap RPI DSP with a usable HDMI-output.
Ah, yes, Well, maybe no
For general audio use you will probably want to use standard uncompressed PCM audio and you are limited by the bandwidth allocated for this in HDMI to 48khz per channel.
That said there is a special case, where you are both sending from and to commercial AV equipment incorporating proprietary Dolby/DTS decoding, sending compressed and encoded audio down the HDMI pipe for uncompressing and decoding at the other end. This does indeed allow 192khz and would be a potential DIY solution if you were happy to pay the $10,000 annual license fee required.
P.S. earlier on I was talking about DVI as a HDMI replacement. DisplayPort was actually what I had in mind. too much stuff, too many standards ...
For those of you who are interested in 6 or more channels of output from the HDMI port of a RPi, I helped a nice fellow get it working. It requires some patience and familiarity with ALSA. The purpose of that effort was implementing an IIR crossover using LADSPA filters. These are fairly lightweight and the RPi can execute a stereo 3-way crossover up to 192kHz, IIRC.
Here is a link to his instructable: Raspberry Pi Music Server with Built-in Crossover and DSP
And here is a link to the thread where I helped him: http://www.diyaudio.com/forums/twis...rs-digital-crossovers-bbb-12.html#post4631927
It seems to me that almost anything one wanted to do with FIR processing could just as well be done on each of the two stereo channels before they are divided by IIR filters rather than during/after crossover filtering. Phase correction especially, though EQ wouldn't be a problem either. That is the direction I'm headed with my BBB player - hybrid filters to optimize the SOC computer's resources. In that objective I think that there is significant common ground among different SOC minicomputers here because the ultimate route of output is fairly trivial compared to the common issue of CPU load limitations.
Bottom line: I can help with ALSA, and it doesn't matter if the hardware is a RPi or BBB or whatever...
Here is a link to his instructable: Raspberry Pi Music Server with Built-in Crossover and DSP
And here is a link to the thread where I helped him: http://www.diyaudio.com/forums/twis...rs-digital-crossovers-bbb-12.html#post4631927
It seems to me that almost anything one wanted to do with FIR processing could just as well be done on each of the two stereo channels before they are divided by IIR filters rather than during/after crossover filtering. Phase correction especially, though EQ wouldn't be a problem either. That is the direction I'm headed with my BBB player - hybrid filters to optimize the SOC computer's resources. In that objective I think that there is significant common ground among different SOC minicomputers here because the ultimate route of output is fairly trivial compared to the common issue of CPU load limitations.
Bottom line: I can help with ALSA, and it doesn't matter if the hardware is a RPi or BBB or whatever...
Here is a link to another option for multichannel output from the RPi. This one doesn't use HDMI.
https://www.kickstarter.com/projects/1250664710/audio-injector-octo-surround-sound-for-the-raspber
https://www.kickstarter.com/projects/1250664710/audio-injector-octo-surround-sound-for-the-raspber
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