Rasberry Pi and active crossover revolution

[skyunlimited]

Ok, changing user to "root" makes some things better, i can pipe into amafir|hdmi_play2.bin. Channel mapping is wrong...

Processor load on one proc is > 70%, that is why i will try to use brutefir instaed of amafir...

Regards


Edit: Next strange thing: When I try to pipe from mpd directly into hdmi_play2.bin without amafir, get some mickey mouse sound....

 

[skyunlimited]

It is not amafir, that causes heavy load, it is hdmi_ply2.bin. At this point i think using a modified Kernel is the better solution. Even on a Singlecore Pi i can get a 2way Stereo Crossover using 8192 Taps per channel, the "limitation" to CD Standard in the output (44,1kHz 16bit) is acceptable for me.

I am using a stock Raspbian Jessie light and changed only the Kernelmodules of my modified Kernel. (mpd (44100:32:2) | brutefir. Only Brutefirs Output is set to 16 bit)

Regards

 

[AEDIO_Japan]

About Mickey Mouse Sound:
I did not experience this kind of sound,but similar experience with USB DAC.
I guess your AV amplifier is NOT compatible with hdmi_play2.bin.
So you may try to use hdmi_play2A.bin instead of hdmi_play2.bin.

About CPU consumption:
This is mainly planned for multi-core Raspberry Pi2 .If you are serious for CPU power consumption, it is good choise to use modified kernel.When you use NAS and higher sampling rate data,you may consider to use amafir and hdmi_play2x.bin on multi-core and faster speed CPU.

 

[isabido]

Hi Skyunlimeted, your Logilink USB with 6 channel output. dont dropped packets resulting in sound problems?


Aedio, its possible use hdmi_play with brutefir?

Thanks All.

 

[AEDIO_Japan]

hdmi_play is inteended to be used with BruteFIR at first development time.
Actually amafir utilized BruteFIR library, he could not map data by BruteFIR to HDMI correctly.
So to make setup easier , "assi" developed his own amafir for some reasons, I heard.

hdmi_play accepts 32bit (S32_LE) x 8 channels x 96000Hz data,even if data is 3way , leave 2channels as blank (zero) data. 2 channels in 3way configuration is thrown away.

He said if he is very familiar with ALSA/OpenMX more, he may resolve this problem.
That is "Someday in future solved" type problem ;-)

 

[keylimesoda]

There's a pull request in the Raspian GitHub to add multichannel PCM output (192k/24bit/8ch) to the ALSA driver in the Linux kernel:

https://github.com/raspberrypi/linux/pull/1166

More discussion on the topic about the HW capabilities and different implementation approaches here: https://github.com/raspberrypi/linux/issues/1000

 

[isabido]

Hi Aedio,

Amafir, does not support load coefficients equal PCM format brutefir, no?.

THANKS!

 

[jirm]

Really interesting treath here.

@AEDIO_Japan, are you triyed the HDMI 7.1 extractor 8 channels LPCM you say some posts before ?

Im very intersed in that too if really works and are able to extract (with enougth audio quality) 8 channels pcm from any HDMI source.

 

[skyunlimited]

On the Pi2 (Quadcore) you can use the USB Soundcard without any problems (all 8 channels with 65536 Taps more than enough for 44,1 kHz) , this is not possible on the Singlecore PI. Be aware, that the Logilink ist only able to output 16bit.
Regards

 

[isabido]

On the Pi2 (Quadcore) you can use the USB Soundcard without any problems (all 8 channels with 65536 Taps more than enough for 44,1 kHz) , this is not possible on the Singlecore PI. Be aware, that the Logilink ist only able to output 16bit.
Regards

16 bits is not a problem for me. But it is possible at the same time, the analog input or spdif in?

Thanks!

 

[skyunlimited]

In and Out at the same time is something i have never tested so far..

Regards

 

[AEDIO_Japan]

> Skyunlimited
What DAC did you check USB 8 channel ?
I have tried with ASUS XONAR U7 in USB2.0 mode, Unfortunately I did get clicked (many breaths during playing), though "amafir" and standard ALSA on Intel ATOM worked properly. Any other good DAC you recommend?

>jirm
read through this thread #80 or later, "assi" did develop HDMI LPCM higer sampling rate playing driver software on top of OpenMX.It was just started.
It WAS NOT extractor software , I did not write about extract. Just playing 8ch through HDMI.
HDMI extractor is hardware such as
Decoder HDMI to 7 1 Analog Audio Converter HDMI Digital Audio Amplifier Machines | eBay
I did purchase from China, but I did not get it yet. It seemed to play through "almost anything" by specifications upto 24bit/192KHz x 8ch?! ;-)

>Isabido
"Amafir, does not support load coefficients equal PCM format brutefir, no?."
I donot know this is true or not as I did not use BruteFIR yet.
I will ask "assi" about this , please wait.

 

[isabido]

As you say, I still have not been able to sound an USB sound card or my RPI/RPI2 without clicks, and always talking about two output channels. I do not want to imagine 6 channels.

I think that the only option is rpi2 HDMI or i2s (limited 2 channels) via.

 

[CharlieLaub]

As you say, I still have not been able to sound an USB sound card or my RPI/RPI2 without clicks, and always talking about two output channels. I do not want to imagine 6 channels.

I think that the only option is rpi2 HDMI or i2s (limited 2 channels) via.

Yours is the opposite of my experience!

I have been using exclusively USB DACs on the R-Pi 2 (one or more stereo DACs) and have NEVER experiences any "clicks" or other audio problems.

Perhaps the particular DAC, or its USB RX chip, is to blame? Also, the USB bus on the R-Pi isn't really up to the task of, for instance, 192k sample rate. I use 48kHz, and I find that I can get excellent sound from some (but definitely not all) very inexpensive USB DACs.

What DAC are you using and what sample rate?

 

[AEDIO_Japan]

> ChrlieLaub

2 channels is NO PROBLEM on most of USB DAC even on Raspi or Raspi2.
I have used MSB Technology DAC-IV / DAC-III or ESS9018 + Amanero Based DACs with Raspi actually that sounds good in stereo configuration.

But we are searching for multi-channels at the same timing to deliver the multi-channel (4ch or 6ch or 8ch)data to realize digital filtered data / linear delay on each channel , that requires multi-channel DAC.

 

[isabido]

Yours is the opposite of my experience!

I have been using exclusively USB DACs on the R-Pi 2 (one or more stereo DACs) and have NEVER experiences any "clicks" or other audio problems.

Perhaps the particular DAC, or its USB RX chip, is to blame? Also, the USB bus on the R-Pi isn't really up to the task of, for instance, 192k sample rate. I use 48kHz, and I find that I can get excellent sound from some (but definitely not all) very inexpensive USB DACs.

What DAC are you using and what sample rate?

I have perhaps been exaggerated, in most of the times it goes well 44 / 48khz 2-channels, but when there is a load on the ethernet often do strange things sometimes.

As we know, the USB bus is shared.

This is my dac:
UCA202 | Audio Interfaces | Computer Audio | Behringer | Categories | MUSIC Group

 

[skyunlimited]

@Isabido

do you use Brutefir? In that case try to change the Parameters in "filter_length/Partion. E.g. 8192,8 instead of 65536 , same Filterlenght but more Partions.
Regards

 

[AEDIO_Japan]

Replies and answers
(1) From "assi" BruteFIR related
BruteFIR can recognize multiple format of filter coefficients."amafir" can recognize text format only , that is compatible format with text coefficients of BruteFIR.
BruteFIR specifies filter co-efficients file in setup file, "amafir" text coefficients file name are fixed as "LF.txt RF.txt LS.txt RS.txt LB.txt RB.txt CF.txt " =>Front L/R,Surround L/R ,SurroundBack L/R,Center LFE...Not so flexible as BruteFIR.If someone can rewrite I will forward source code.

PCM format shoud be converted to "text" by "octave-signal" or similar program,if you use the same setting on BruteFIR with "amafir".

hdmi_play2A.bin can recognize "BruteFIR" outputs, at May 2015, I had given up to output linear PCM 8 channels with "From BruteFIR to HDMI with standard procedures",
I could output just 2channels with "BruteFIR and hdmi_play2.bin".
So I did write "amafir" for my own usage to perform 8 channels output from FIR filter to HDMI audio.

It might be OK on coming or latest release of Raaspbian,that is a kind of temporary and work-around base solution.

(2) HDMI Audio Extractor
Just arrived NOW! I have tested with "amafir" 3way configuration and "hdmi_play2A.bin" now , it seemed to work properly though I did not care about the sound quality but Front L/R sounds low, Surround L/R sounds mid and Surround Back sounds high, I heard.

It might be one of less expensive multi-way active crossover driving system.

 

[pidigi]

> ChrlieLaub

2 channels is NO PROBLEM on most of USB DAC even on Raspi or Raspi2.
I have used MSB Technology DAC-IV / DAC-III or ESS9018 + Amanero Based DACs with Raspi actually that sounds good in stereo configuration.

But we are searching for multi-channels at the same timing to deliver the multi-channel (4ch or 6ch or 8ch)data to realize digital filtered data / linear delay on each channel , that requires multi-channel DAC.

Isn't it possible to connect the ess9018 to the PI via I2S? In this way it is possible to use all the features of the ess9018 (multichannel, 32-bit/192kHz)?

 

[AEDIO_Japan]

Isn't it possible to connect the ess9018 to the PI via I2S? In this way it is possible to use all the features of the ess9018 (multichannel, 32-bit/192kHz)?

Physically Yes!
In actual NO. because no driver software which drives multiple I2S data streams outputs to GPIO port.
So in normal intel LINUX I connected AES-16(e) to get multiple S/PDIFs by OSS driver or ASUS XONAR U7 using USB / HDMI linearPCM.