0

Additional Parametric Eq channel in GUI

Daniel

January 09, 2025 11:22

None

Follow

Hi there,

I'm trying to setup active 2.1 system with active crossovers, and so far it's going good. The speakers are 2-way stereo + Subwoofer. I have DAC + DSP.

I was able to successfully create a custom dsp profile in SigmaStudio, attach 2xMerus ma12070p digital amps to Serial out 1 and Serial out 2 via p6 header as 2-way amps, and I've used existing RCA out to send the subwoofer signal. I can set the speakers crossovers in the GUI via IIR_A/B/C/D registers.

It's a nice setup and the sound is great!

The only thing I'm missing is additional "Parametric Equalizer" entry in GUI for setting my subwoofer crossovers and equalizer if needed.

Is there any way I can set more than 4 channels Parametric Equalizer in the GUI?

I'm using hifiberry-os at the moment.

• Facebook
• Twitter
• LinkedIn

11 comments

• 0
  
  HiFiBerry team January 09, 2025 15:36

  The UI is limited to 4 channels.

• 0
  
  Daniel January 10, 2025 07:35

  thats a bummer.

  Is there an easy way to set the filters to this custom IIR register, lets call it IIR_SUB, using command line tools like dsptoolkit? I can't find a way to use e.g. apply-rew-filters to a custom IIR register?

• 0
  
  HiFiBerry team January 10, 2025 07:44

  Depends what's "easy" for you. You can define any meta data in the XML file. 
  
  BTW: When you use HiFiBerryOS, you should not do filter changes outside the UI. The best way is probably to define your filters directly in the SigmaStudio UI.

• 0
  
  Daniel January 10, 2025 08:02

  ah, yeah, about that - I've added some default filters (low pass, and one peak filter), and it seemed good when I used sigma studio, but later after deploying and using it for a bit I noticed that's something is wrong:

  
  note - I know that changing sample rate can screw up the filters, but I use the the same sample in sigma studio as the defined in the .xml file (48khz).

  1. Do you know why that filter might go crazy after deploying or using the GUI?
  
  2. Can you tell a bit more about "you should not do filter changes outside the UI" - can you tell more? In context - that's a separate IIR_SUB filter register, not used in GUI so far, other than A/B/C/D
  
  3. re command line "easy": I mean run some command that applies different filters to my IIR_SUB, e.g. different low pass (and maybe some peak filters) than default in the deployed dsp profile. I don't want to open Sigma Studio every time

• 0
  
  Daniel January 10, 2025 08:10

  Here's how I modified the sigma studio project - I used default dac+ dsp v15 profile and added one more IIR filters in the speaker eq section. Then routed it to the proper output and signal in the main section.

  

• 1
  
  HiFiBerry team January 10, 2025 08:22

  The UI was not designed to handle or interpret filters created outside the UI. Therefore, it might not interpret these correctly.
  
  If you add seperate filters with new metadata, the UI won't touch these. However, the UI knows what filters are configured and will write these to the DSP when starting.
  
  There is no command line option to apply a single or multiple filters to a given memory cell. You would have to add this functionality to dsptoolkit.

• 0
  
  Daniel January 10, 2025 15:51

  Okay. And are there any reasons why my default IIR filters might be screwed up if they are not used in GUI (e.g. is sample changing)? or I should look for an issue elsewhere?

  Edited by Daniel January 10, 2025 15:57
• 0
  
  HiFiBerry team January 10, 2025 15:52

  What do you mean by "screwed up"?

• 0
  
  Daniel January 10, 2025 16:00

  see my screenshot from REW recording the subwoofer response: I didn't change the filters, but subwoofer started giving a weird response later.

  I think experienced something like that when sample rate didn't match, but I'm not sure here.

• 0
  
  HiFiBerry team January 10, 2025 16:13

  If you expected a flat response: I can't comment on this. However, the UI won't touch any filters that aren't defined in the metadata.
  
  BTW: I would reduce the number of EQs in use. While it looks nice to have an extremely flat frequency response, this is usually not the best way to do it:
  1. Frequency respoonse won't be that flat if you just move to the side by 30cm. Extreme optimisation on one position might mess up frequency response on other positions more.
  2. The more filters you use the more changes will also be there in phase. 
  
  In my personal experience, 3-5 filters are usually enough for almost any room. That's the reason our own room eq works with less equalisation than REW. Personally I would try to bring frequency response within +/-3db and not even try optimisations >8kHz.

• 0
  
  Daniel January 16, 2025 07:21

  thanks, I totally agree, the amount of eq bands is as the default program for DAC+ DSP v15. I don't use them all.

  I don't expect a flat curve. The issue was that the filters applied at the setup (and measured with a reference microphone), later caused a different output (measured again). I'll double check if that happens again and let you know.

  Edited by Daniel January 16, 2025 07:21