Hello,
I have a Raspberry 4, Amp100 and a DSP module running. I am performing a room measurement according to instructions. The created profile looks good, there is nothing unusual to see. As soon as I activate the profile, I hear a low frequency rumble when playing a song. It is not possible to use the program like this.
What can I do to change this behavior?
Thanks for your help.
What are the filter settings calculated by the Room equalisation module? Please post a screenshot.
First I was running DSP Programm 11. But there was hiss in the high frequency (Without room equalization). Now I am using DSP Programm 13.
Looks not bad. You can try enabling/disabling each filter and try to find out which filter is causing this.
Thank you for Quick response. I've tried to disable each filter. Actualy the rumbe is present if even only one of the filters is active. It is an irregular rumbling sound. If I turn the last filter of, than it is not present anymore.
the noise is there as soon as I add any filter. So it has not directly something to do with room equilization. What could be wrong than?
Hmm, right now I can't say. Might be some problem with the filter coefficient calculation. I need to check if we can reproduce it somehow, but "rumble" is hard to get. Do you have some recording of this?
Here are two files, recorde with my mobile.
https://mega.nz/file/itMGmLDR#kf9H29VNwzlLGaoNvLunfkSRASDnwXCbNzZw1hf43-w
https://mega.nz/file/boUEwLQR#w4NV_egvRmvkvNxAIq53H4vdpiYPxi6DFeyEpnLeDYs
These recordings were made with a Peak Filter set on 100 Hz, 5 db, Q 5.
The problem reminds me to Clives Post here: DSP Low Frequency Artefacts – HiFiBerry
Tried to install DSP Programm v11. The rumble is much lower than. Unfortunately there is hiss in the higher frequencies than.
Ok, we'll look into this. My guess is that there is some problem in the filter coefficient calculation.
Hello,
could you already find a solution?
Maybe someone else had this problem and could solve it?
A solution is very important to me, otherwise I see no sense for me in the DSP module.
Many thanks in advance
Jan
Unfortunately I can't reproduce it here.
Please enable and disable the filter as shown above (100Hz, Q=5, +5db) and run the following commands with the filter enabled and disabled:
dsptoolkit get-checksum
dsptoolkit read-dec 273
dsptoolkit read-dec 274
dsptoolkit read-dec 275
dsptoolkit read-dec 276
dsptoolkit read-dec 277
Disabled:
dsptoolkit get-checksum
7E8C1487A53969AA24991E5903E15D53
# dsptoolkit read-dec 273
0.00000000
# dsptoolkit read-dec 274
0.00000000
# dsptoolkit read-dec 275
1.00000000
# dsptoolkit read-dec 276
0.00000000
# dsptoolkit read-dec 277
0.00000000
Enabled:
# dsptoolkit get-checksum
7E8C1487A53969AA24991E5903E15D53
# dsptoolkit read-dec 273
0.99863708
# dsptoolkit read-dec 274
-1.99897599
# dsptoolkit read-dec 275
1.00038177
# dsptoolkit read-dec 276
-0.99901885
# dsptoolkit read-dec 277
1.99897605
Thank you for response.
Hmm, very strange. Everything is fine. However, with the same settings is running perfectly fine here.
Do you only have one Amp100 available or do you have another board like another Amp100 or a DAC2 Pro that can be equipped with the DSP add-on?
No, unfortunately the only thing I have is an Amp60, but this will not help in this case.
If you assume a hardware problem. Will it be the DSP-Module or the Amp100?
Also I think of the fact, that as I installed DSP Programm v11, the rumble was much lower, but there was some kind of hiss in the higher frequencies. If I could get best of both...
The DSP-Module and the Amp100 were bought new, and I have a fresh HifiberryOS installation.
I don't really assume anything. I simply don't known what's happening in your setup. It seems that the DSP is doing something that it shouldn't. However, the program and the filter settings are correct. Therefore, I think the only way to debug it is in our lab. I can't really say if this is some unknown hardware or software problem.
I have a solution that works for me now for now:
Now the DSP behaves as desired.
Unfortunately, I do not really know exactly what I have done here. Especially whether it can be a permanent solution.
What would you recommend? Should I send the device to you to have it checked once? Or do you have any other Idea?
Regards
Jan
Dear HifiBerry team,
do you have a solution for me to make the whole thing a little more stable?
After each update or restart I have to perform the procedure (dsptoolkit write-reg) again. I also do not know if it workaround will be possible permanently.
Regards
Jan
Unfortunately there isn't really some well-integrated way to do things on every boot. We will add something like this in the next release.
For now, you could simply add the command to /opt/hifiberry/bin/reconfigure-players (just at the beginning)
