Hi
I have a pi 4B running Raspbian and recently bought DAC+ DSP. The sound is excellent and I am happy with it, but every time i boot up there is a very loud thump from the speakers followed by 2 very loud clicks - loud enough to make everyone jump with fright.
Is there any way to prevent this?
Thanks
G
Are you using DSPToolkit?
kind of a noobie, so not that i know of. running kodi on the Pi if that has an impact
You didn't install it? Did you deploy any DSP program on the DSP by yourself?
The first thing i did when the DAC arrived was use the hifiberryOS to boot up the first time and check everything was working. I updated the DSP version to the latest option listed and then saved it.
Then i switched back to my Raspbian card, which I had already been using with Kodi, and followed your instruction for Linux setup here:
https://www.hifiberry.com/docs/software/configuring-linux-3-18-x/
That's as much tinkering as I did.
Do you see the same behaviour when booting HiFiBerryOS?
I just switched back to the hifiberryOS card and yes, it has the same loud pops and clicks, and in fact a few extra thumps too.
I should add that this only occurs when booting from cold - powered off/on from mains. Issuing a reboot command does not cause a problem.
What amplifier is this connected to? Our DSP programs shut down the output if nothing is playing. This can result in these pops with some amplifiers.
The amp has never had issues like this with any other sources, and there are no other pops and clicks from the system when in use - eg between tracks, during movies, etc. It is only on start up from mains off.
I just did some further testing using HiFiBerryOS - if i set the volume to zero and then save the settings to memory, then there are no more pops and clicks on booting up, so it seems directly linked to output of the DAC. This could be a viable workaround if i were only using HiFiBerryOS, but when i then switch back to Raspbian there is no audio output.
Is there anyway to access the (now muted) hifiBerry volume setting from Raspbian? Then perhaps if i could figure out a way to mute it for the first 60 seconds after startup to silence those sounds i could have a workaround for this?
You need to install DSP toolkit:
https://github.com/hifiberry/hifiberry-dsp
Then install a DSP profile and you can use commands like
dsptoolkit set-volume
I thought you might say that... I'm struggling with how to create a profile. I've installed dsptoolkit. I'm trying to follow the guidance here: https://github.com/hifiberry/hifiberry-dsp/blob/master/doc/dspprofiles.md
i've installed SigmaStudio, and then trying to use an "existing project and adapt it to your needs."
I opened the QuickStart sample file in C:\Users\Administrator\Documents\Analog Devices\SigmaStudio 4.7\Projects\Sample Schematics\AD1940.
I can see it's a very simple schematic but it's not clear where to go next- i've obviously never used this software before - all i want is to be able to execute a mute/delay/unmute command against the DSP, but this seems like overkill, with the potential to screw up my dsp.
Is this the right approach? any pointers to help with this?
Thanks
You don't need to create a new profile, just use the one that comes with HiFiBerryOS.
i can execute the commands using hifiBerryOS but when i try on Raspbian i get the response: "Profile doesnt support volume control". Is there something that needs to be enable to allow this?
Hi folks - is there anyway round this "Profile doesnt support volume control" issue?
Thanks
You need to install a profile first on the system you want to the it with. Without a profile, dsptoolkit doesn't have any idea how to control the volume.
hmm - that takes it right back to my earlier post then - i tried to follow the instructions to do just that, but then got rather stuck. You replied that i didnt need to do that.
You should not CREATE a DSP profile, but just install the one that you also installed on HiFiBerryOS. You can find these profiles on Github:
https://github.com/hifiberry/hifiberry-os/tree/master/buildroot/package/dspprofiles
So here's my update.
It took a bit of trial and error/backup and restore, but i was eventually able run dsptoolkit and install profile dspdac-12.xml from that link.
The mute/unmute didnt seem to do anything at all, but setting the volume did. I set the volume to 0.001 and used the store command to save it to the board. I then created a script to run on boot that waits 40 seconds after startup and then sets the volume to 1 (100%).
This was sufficient to prevent all the pops and clicks on startup I was experiencing.
However, i have a new problem now. approx 5 seconds after any audio stops there is a deafening thump from the speakers. Again, if i reduce the dsp volume the thump reduces too. This suggests to me that it is a function of the the dsp.
I didnt have this problem before i used dsptoolkit to install dspdac-12.xml - i had used HiFiBerryOS to install "v12" previously and only had the issues on bootup, never during/after playing audio.
You mentioned that "Our DSP programs shut down the output if nothing is playing" - presumably this is the cause, though it's strange that it can be volume controlled. Is there anyway to prevent this from happening?
Thanks
I'm not aware of any 5 second timer in the DSP program. This might be cause by ALSA power management. Try disabling this.
https://github.com/hifiberry/hifiberry-os/blob/master/buildroot/package/hifiberry-tools/snd_soc_core_disable_pm.conf
Not sure i understand where to add that line/file. I'm using Raspbian but the path for that link is for HiFiBerryOS - do i just create this file with that text and save it in the etc folder on Raspbian?
Thanks
I'm not sure, but I think kernel level configuration files go under /etc/modprobe.d on Raspbian. Just check if the directory exists and create the file there if it does. If this directory isn't there, it might be somewhere else under /etc
Have a look here how to read kernel module parameters:
https://serverfault.com/questions/62316/how-do-i-list-loaded-linux-module-parameter-values
i created the file in the directory but it had zero effect. i tried setting it to different values but again no effect. any other ideas? This is really killing my setup :(
Thanks
i should add that I checked the parameter value has definitely been set using
modprobe --showconfigwhich outputs this:
options snd_soc_core pmdown_time=-1
But it does not seem to have any effect on the thump i hear 5 seconds after every time the audio stops.
Actually, just for the heck of it, I installed profile dspdac-11.xml. With this profile i no longer have the thump/pop when pausing the audio!
At present i have dspdac-11.xml installed, but stored with volume set to 0.001. options snd_soc_core pmdown_time=-1 and the cron job on startup sets the volume back to 1. So far this appears to have removed all the issues. When i have time i'll remove each of these settings to see which are or are not present on v11 vs v12.
What are the differences between 11 and 12? what will be lacking if i leave the dac with v11 and don't upgrade?
Thanks
If v11 works fine for you, just keep this. We change things from time to time, but there is no changelog of the DSP profiles.