BruteFIR reduces volume on Digi+ Pro

[reza]

Not my first post, but I don't think I have introduced myself yet:

Hi everyone, my name is Reza and I live in the Bay Area. I am not a hardware tinkerer, but I do a lot of M.L. R&D for my day job, which has a healthy portion of software tinkering to it. Up until now my audio system had consisted of playing Spotify or local network drive files through my android, streamed over Bluetooth to a NAD integrated amplifier with a builtin BT receiver, feeding a pair of passive Focal bookshelves. Everything was good. But I decided to experiment with digital room correction which brings me to my question:

Has anyone played around with this combo? BruteFIR, Volumio, RPi 3 B+, HifiBerry Digi+ Pro

There are no errors or anything, except, once I enable the BruteFIR plugin in Volumio, the sound level drops by what I guess is in the order of 20db.

Disabling BruteFIR fixes the problem. But DRC was my main motivation for picking up the RPi and Digi+.

If you have run into this issue, how did you fix it? If not, would you know of any alternatives to BruteFIR that might not suffer from the same issue?

Your help is appreciated.

 

[Guermantes]

Are you using BruteFIR3? There was some mention on github for an earlier release about a conflict with software volume and I2S DACS:
https://github.com/volumio/volumio-plugins/tree/master/plugins/miscellanea/brutefir

Check your ALSA software volume control and see if changing settings there does anything.

@Krunok is a BruteFIR/Volumio user, perhaps he can give some insight:
https://www.audiosciencereview.com/forum/index.php?threads/how-to-make-room-eq-with-volumio.5585/

 

[reza]

Are you using BruteFIR3? There was some mention on github for an earlier release about a conflict with software volume and I2S DACS:
https://github.com/volumio/volumio-plugins/tree/master/plugins/miscellanea/brutefir

Check your ALSA software volume control and see if changing settings there does anything.

@Krunok is a BruteFIR/Volumio user, perhaps he can give some insight:
https://www.audiosciencereview.com/forum/index.php?threads/how-to-make-room-eq-with-volumio.5585/

Thanks for the pointer. I was indeed on version 2. Although changing that to version 3 didn't fix the problem. Thanks though.

 

[dc655321]

IIRC, BruteFIR attenuates -6dB by default, maybe more. But, -20dB seems a stretch.

Also, @Guermantes suggestion regarding ALSA is a good one. Use the alsamixer command line program to check output levels. I've been bitten by that before...

 

[reza]

IIRC, BruteFIR attenuates -6dB by default, maybe more. But, -20dB seems a stretch.

Also, @Guermantes suggestion regarding ALSA is a good one. Use the alsamixer command line program to check output levels. I've been bitten by that before...

Yes, I saw the 6db attenuation comment elsewhere. But the attenuation I'm getting seems a lot more. I haven't actually measured it, but on the remote, I need to set it around 15db-20db higher to get same subjective loudness.

I checked alsamixer, it is set to 100, but lowering it has no effect, which I guess is expected since I have no mixer enabled in Volumio.

 

[dc655321]

Ok.
Have you looked at the spectral magnitude of the filters you're using?

 

[reza]

Ok.
Have you looked at the spectral magnitude of the filters you're using?

Oh, I should have been more clear. At this stage I'm only enabling the plugin in Volumio, I'm not enabling any of its features, including the convolution, yet. So no filters. EQ and conv are disabled.

 

[Krunok]

There are no errors or anything, except, once I enable the BruteFIR plugin in Volumio, the sound level drops by what I guess is in the order of 20db.

Check "Input attenuation" parameter in BruteFIR settings. Depending on the way your filters are created here you specify how much headroom you leave to avoid clipping. If your filters are designed only to attenuate signal you can set this paramater to 0 and you will have no attenuation by BruteFIR.

 

[reza]

Check "Input attenuation" parameter in BruteFIR settings. Depending on the way your filters are created here you specify how much headroom you leave to avoid clipping. If your filters are designed only to attenuate signal you can set this paramater to 0 and you will have no attenuation by BruteFIR.

Yep, that was the culprit. The input attenuation was set too high. The problem was that on the latest commit of the Brutefir, the settings window had some issues and didn't show up, so I couldn't tell that there was such a parameter. I went with an older commit to fix this. Thanks everyone for the help.

 

[Krunok]

Yep, that was the culprit. The input attenuation was set too high. The problem was that on the latest commit of the Brutefir, the settings window had some issues and didn't show up, so I couldn't tell that there was such a parameter. I went with an older commit to fix this. Thanks everyone for the help.

Plugin version 0.8.8 should work well with Volumio version 2.555. This is what I am using on Intel paltform and it works ok.

I suggest you avoid Volumio version 2.565 as there are some bugs in it and the BRuteFIR plugin doesn't work well with it (problems with volume control).

Btw, I'm working on a new version of plugin with the developer which will contain not only BruteFIR convolution engine but also a DRC-FIR automatic filter creation tool. This will enable users to automatically create their own DRC filters based on the sweep measurement made with REW which will then be used by BruteFIR convolution engine with Volumio. Plugin is now in beta and it seems to work fine so it will be out soon. If anybody wants to test it I will be happy to share a link to the beta distribution.

 

[reza]

Plugin version 0.8.8 should work well with Volumio version 2.555. This is what I am using on Intel paltform and it works ok.

I suggest you avoid Volumio version 2.565 as there are some bugs in it and the BRuteFIR plugin doesn't work well with it (problems with volume control).

Ah, that's good enough. I'll try that combination.

Re DRC-FIR development, that's got me curious. I'd appreciate it if you could share the link to the beta (or is it the one at sourceforge linked above?)

 

[Krunok]

Ah, that's good enough. I'll try that combination.

Re DRC-FIR development, that's got me curious. I'd appreciate it if you could share the link to the beta (or is it the one at sourceforge linked above?)

No, that one is the link to the original DRC-FIR distribution. This is the link to beta plugin with DRC-FIR filter creation. If you want to try it I suggest you uninstall your current version of BruteFIR plugin and install this one.

Feel free to send me any suggestions/error reports via private messages.