Thanks, Matt --First regarding your helpful comments and questions:1) I am running RaspiOS lite on the pi zero. It doesn't seem to have pulseaudio, unless it's installed under some other name. ("sudo apt-get remove pulseaudio" reports it's not installed)2) the alsamixer settings were correct and had worked before.3) I had tried the line bypass but couldn't know whether the board audio chain was at fault or whether it was not being set by the software via the pi.I had fastened on the dmesg not including the "mapping ok" line as an easy diagnostic for whether things were working. But in fact this seems to have been introduced by some update (via sudo apt-get update/upgrade) after the 1/21/2021 OS release -- a clean install showed success by this criteria with the new card and I think also the old one but a clean install followed by update/upgrade reverted to the previous behavior with the new card... This was true on a Pi Zero and a previously lightly used model 2B that I had around. I'll attach the dmesg results from the two software versions. I don't know enough to decipher them.Once I got over the distraction of the software and the dmesg reports, I found that in fact the audioinjector zero card had been damaged -- the old pi zero records audio with the new card with either version of the OS, but the old card doesn't work.I am not out of the woods yet. I have a new problem and have narrowed down the current version of a previous one.Both problems relate to using an approach I found somewhere on the internet for setting up a remote mic. I am using it to send ambient (nature) sound from a remote outside location to my room audio system so we can hear outside noises without opening the window when it's 20 below. This requires a high dynamic range and low noise floor to hear distant birds, coyotes, etc. I use a stereo powered condenser mic intended for a camera and a 2 stage opamp preamp (Rod Elliott p88 )This is what I was using for the sound transport over wifi and ethernet:arecord -c 2 -f dat -t raw - | ssh pi@[local ip address] aplay -c 2 -f dat -t raw -Dhw:sndrpihifiberry -The new problem is that somehow there is more than a one second delay in the transported sound compared to what is being recorded. Presumably it's made a large fifo buffer for some reason. Perhaps this has to do with changes on the receiving pi that I made when trying to diagnose the earlier problem.The persistent problem that I thought I had licked is that there is a tickatickaticka noise in the sound. I thought this was from the wireless and by separating the mic and preamp from the Pi and audioinjector i did seem to get the noise down to zero -- based on what I was hearing via the audioinjector headphone jack and the line bypass. But the noise reappeared when using arecord (and was even worse when I tried "arecord ... - " without piping it anywhere. I could hear the noise in the audioinjector headphone output as well as in the transported sound. Putting the audioinjector several inches away from the pi with a piece of grounded aluminum between the two did not reduce the noise. Clearly I need to investigate further but this seems to be either some sort of digital artifact or rf feedback from the PI's digital operations back into the audioinjector card.I may try the sox equivalents instead of aplay and arecord -- but I haven't had great luck getting sox to run yet.On Wed, Mar 3, 2021 at 2:03 AM Matt <matt@audioinjector.net> wrote:
On 1/3/21 12:51 pm, Tom Garwin via People wrote:
I feel for you, electrostatics and unknown failures are terrible.I had finally declared victory over extraneous noise in my remote microphone prototype set-up and was prettying up the power and signal wiring allowing a powered stereo microphone and opamp preamp to be separated from the pi/AI zeros -(-wifi or clock cycles may have been causing interference in the powered mic) -- but then the AudioInjector zero card stopped processing sound.
Its failure was accompanied by very strange things so it may be the Pi Zero that failed (or both) rather than the AudioInjector. I may have not taken adequate precautions against electrostatic shock to the boards.
Are you sure you've setup the mixer settings as required to select the line input ?
Specifically a set of commands to record the sound on one pi and send it via SSH and aplay it on another stopped working. I could SSH (by wifi) into the first pi and could ping the second pi and even ssh from the first pi into the second pi so this was strange. They are both on the same network with a unifi edgerouter with no intervening firewall so that wasn't the problem.
After several reboots ssh was working normally again but the sound on the pi zero was not.. dmesg shows a set of errors that seem to relate to voltages not being present --using default regulator (or something like that) and there is no final message saying the mapping is ok. I cannot capture a sound file that has anything but silence in it even though I know the AI Zero board is getting appropriate input. I also cannot get it to play anything to its output. Nevertheless the aplay -l and arecord -l show entries for the audioinjector and it is the only soundcard in the system. Alsa settings are what they were before. Of course I did not look at the dmesg output when things were working so I don't know if this is really different.
Normally Linux doesn't have a huge set of monitoring tools for the standard LDO regulators on soundcards - some of the power chips have i2c ports which are more sophisticated.
One idea which may be helpful is to enable the "line Bypass switch" in the alsamixer settings. This will route audio input directly through to audio output - at least then you can double check the input signal is coming through as expected.
So either I did something to fry the pi or the board or the both, or in trying to fix the problem I updated the OS to a configuration that no longer works.,
I suppose I could start over with a fresh os install and see if that works but at this point I am guessing it is a hardware issue and the pi zero and the AI zero are inexpensive enough relative to my time (and my inadequae software skills) that it's best to just try a fresh AI zero with a different raspberry pi before trying a new software install.
Remember with the latest Raspbian OS they have a non-robust pulse audio setup. Some people remove pulse audio entirely. You can also make sure you select the audio injector sound card using the
aplay -D hw:0
type of direct device naming methodology.
Will keep this list posted on the results -- Only posting this now on the off chance someone else has had the same symptoms.
please do.
--
Tom Garwin
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