4mic hat stretch-lite-2018-11-13 static noise

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curl.dave
Pre-kindergarten
Pre-kindergarten
Posts: 3
Joined: Sat Jun 30, 2018 9:24 pm

4mic hat stretch-lite-2018-11-13 static noise

Post by curl.dave » Sat Dec 22, 2018 10:31 pm

I have installed the 4mic hat on raspberry pi 3 running stretch-lite-2018-11-13.
I ran the arecord example and when I play it back I get loud static and I can hear very faintly the recorded speech.
I have tried this with various releases of stretch-lite and I get the same loud static. I also tried the stretch-lite builds from https://v2.fangcloud.com/share/7395fd13 ... 6fd4792fe5 and I get the same results.

Can you help?

arecord -Dac108 -f S32_LE -r 16000 -c 4 hello.wav

also arecord -L does not match that shown in the installation instructions. Mine is missing:
capture
dmixed
array
default:CARD=seeed4micvoicec
seeed-4mic-voicecard,
Default Audio Device

arecord -L
null
Discard all samples (playback) or generate zero samples (capture)
playback
ac108
default
mic
speaker
sysdefault:CARD=seeed4micvoicec
seeed-4mic-voicecard,
Default Audio Device
dmix:CARD=seeed4micvoicec,DEV=0
seeed-4mic-voicecard,
Direct sample mixing device
dsnoop:CARD=seeed4micvoicec,DEV=0
seeed-4mic-voicecard,
Direct sample snooping device
hw:CARD=seeed4micvoicec,DEV=0
seeed-4mic-voicecard,
Direct hardware device without any conversions
plughw:CARD=seeed4micvoicec,DEV=0
seeed-4mic-voicecard,
Hardware device with all software conversions

also my .asoundrc is:
pcm.!default {
type asym
capture.pcm "mic"
playback.pcm "speaker"
}
pcm.mic {
type plug
slave {
pcm "hw:1,0"
}
}
pcm.speaker {
type plug
slave {
pcm "hw:0,0"
}
}

curl.dave
Pre-kindergarten
Pre-kindergarten
Posts: 3
Joined: Sat Jun 30, 2018 9:24 pm

Re: 4mic hat stretch-lite-2018-11-13 static noise

Post by curl.dave » Thu Dec 27, 2018 8:21 am

UPDATE: I tried again with fresh builds of stretch and stretch lite 11-13-2018 + latest update and it worked OK. But then I installed Google Assistant SDK and SEEED steps for 4mics_hat google_assistant.py, which is no longer contained in the newer 4mics_hat, and I got the same loud static problem. I will troubleshoot some more with fresh installs and try to pin down what may be causing the problem.

curl.dave
Pre-kindergarten
Pre-kindergarten
Posts: 3
Joined: Sat Jun 30, 2018 9:24 pm

Re: 4mic hat stretch-lite-2018-11-13 static noise

Post by curl.dave » Wed Jan 02, 2019 10:15 am

I did further testing and found out that my 4mics_hat board records OK for the first few minutes and then gets loud static in the recording. I looked at the wav file waveform with audacity and I can see that mics 1,3,4 have loud static, mic 2 has some static. I will be investigating further.

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