No, that didn't actually work either. I picked up some cheap (10/$1.00) electrets on Aliexpress that are a CZN-15e https://www.sunrom.com/p/czn-15e-omnidirectional-electret-condenser-microphone-9x7mm-with-pins-9767-capacitive-sensitivity-58 (just a data source) Expendable microphones that aren't bad. Got one working on prototyping board, too much hum. On pad-per-hole breadboard I set another up with a 1 transistor preamp then another transistor as emitter follower to get the output impedance down to about 1000 ohms. With that I can get signals of about 1 volt peak-peak as checked on an analog oscilloscope. But this is now too much to feed into a microphone input so I want to use a line input. And that brings me to trying to figure out Alsa syntax again. I don't remember what I might have changed in some file somewhere to get it using the microphone input on the USB sound card. It seems probably smarter to specify devices via command lines to arecord since I have multiple microphones, sound cards, computers. This worked: arecord -f S16_LE --channels=2 --device="plughw:2,0,0" --rate=44100 junk.wav But for the micropbhone input, now I want the line input. amixer -c 2 scontrols Simple mixer control 'Speaker',0 Simple mixer control 'PCM',0 Simple mixer control 'PCM Capture Source',0 Simple mixer control 'Line',0 Simple mixer control 'Mic',0 Simple mixer control 'IEC958 In',0 (Why are they all 0?) I think a 1-line script to amixer followed by 1 line to arecord is what I want. I'd be more comfortable with numbers in binary or hex than all this parsing of prose. On 7/20/20, Alan Corey <alan01346@xxxxxxxxx> wrote: > OK, > arecord -f S16_LE --channels=2 --device="hw:2,0" --rate=44100 junk.wav > does work. It's not pretty, I have to amplify in Audacity about 40 > db. My coupling capacitor seems to be leaky, I see DC on the waveform > and I get some motorboating. But I did it twice and both times > worked. What I did for a signal was just wet a finger and touch the > center conductor of the soundcard input, which captures hum. I did a > pattern of touching it and not touching it, what I see on the screen > roughly matches what I did. So I need to build more amplification. > > On 7/20/20, chris hermansen <clhermansen@xxxxxxxxx> wrote: >> Alan and list, >> >> On Mon, Jul 20, 2020 at 9:45 AM Alan Corey <alan01346@xxxxxxxxx> wrote: >> >>> When I do >>> arecord -f S16_LE --channels=2 --device="hw:2,0" --rate=44100 >>> junk.wav >>> >>> It doesn't complain but the recording is silence. Something may be >>> turned down or off in the mixer. Or I'm recording the wrong >>> subdevice. hw:2,1 and hw:2,2 don't seem to be found. If I amplify >>> (40 db) in Audacity there's not really anything there. >>> >> >> Alan have you tried running "alsamixer" in a terminal window and >> inspecting >> the settings? >> >>> >>> I'm using a bare electret cartridge with a 3.9 k resistor from 4.2 >>> volts in from a lithium cell, and a 1 MFD coupling cap. I'd expect to >>> see something when I tap on it, but nothing. >>> >> >> Do you have a voltmeter to watch what happens on the output of the >> capacitor and ground when you tap? >> >>> >>> >>> On 7/20/20, Alan Corey <alan01346@xxxxxxxxx> wrote: >>> > Hmm, none of these are 1 channel. I do want 2 channels but so far >>> > I've got 1 electret cartridge on prototype board trying to figure out >>> > how much amplification I need. >>> > >>> > USB Sound Device at usb-3f980000.usb-1.5, full speed : USB Audio >>> > >>> > Playback: >>> > Status: Stop >>> > Interface 1 >>> > Altset 1 >>> > Format: S16_LE >>> > Channels: 8 >>> > Endpoint: 6 OUT (ADAPTIVE) >>> > Rates: 44100, 48000 >>> > Interface 1 >>> > Altset 2 >>> > Format: S16_LE >>> > Channels: 2 >>> > Endpoint: 6 OUT (ADAPTIVE) >>> > Rates: 44100, 48000 >>> > Interface 1 >>> > Altset 3 >>> > Format: S16_LE >>> > Channels: 4 >>> > Endpoint: 6 OUT (ADAPTIVE) >>> > Rates: 44100, 48000 >>> > Interface 1 >>> > Altset 4 >>> > Format: S16_LE >>> > Channels: 6 >>> > Endpoint: 6 OUT (ADAPTIVE) >>> > Rates: 44100, 48000 >>> > Interface 1 >>> > Altset 5 >>> > Format: S16_LE >>> > Channels: 2 >>> > Endpoint: 6 OUT (ADAPTIVE) >>> > Rates: 96000 >>> > >>> > Capture: >>> > Status: Stop >>> > Interface 2 >>> > Altset 1 >>> > Format: S16_LE >>> > Channels: 2 >>> > Endpoint: 5 IN (ASYNC) >>> > Rates: 44100, 48000 >>> > >>> > >>> > >>> > On 7/20/20, Clemens Ladisch via Alsa-user >>> > <alsa-user@xxxxxxxxxxxxxxxxxxxxx> wrote: >>> >> Alan Corey wrote: >>> >>> arecord -f S16_LE -d 10 -r 16000 --channels=1 --device="hw:2,0" >>> >>> /tmp/test-mic.wav >>> >>> Recording WAVE '/tmp/test-mic.wav' : Signed 16 bit Little Endian, >>> >>> Rate >>> >>> 16000 Hz, Mono >>> >>> arecord: set_params:1345: Channels count non available >>> >> >>> >> I suspect recording always uses channels. >>> >> Please show the contents of /proc/asound/card2/stream0. >>> >> >>> >> >>> >> Regards, >>> >> Clemens >>> >> >>> >> >>> >> _______________________________________________ >>> >> Alsa-user mailing list >>> >> Alsa-user@xxxxxxxxxxxxxxxxxxxxx >>> >> https://lists.sourceforge.net/lists/listinfo/alsa-user >>> >> >>> > >>> > >>> > -- >>> > ------------- >>> > No, I won't call it "climate change", do you have a "reality >>> > problem"? >>> > - >>> > AB1JX >>> > Cities are cages built to contain excess people and keep them from >>> > cluttering up nature. >>> > Impeach Impeach Impeach Impeach Impeach Impeach Impeach Impeach >>> > >>> >>> >>> -- >>> ------------- >>> No, I won't call it "climate change", do you have a "reality problem"? >>> - >>> AB1JX >>> Cities are cages built to contain excess people and keep them from >>> cluttering up nature. >>> Impeach Impeach Impeach Impeach Impeach Impeach Impeach Impeach >>> >>> >>> _______________________________________________ >>> Alsa-user mailing list >>> Alsa-user@xxxxxxxxxxxxxxxxxxxxx >>> https://lists.sourceforge.net/lists/listinfo/alsa-user >>> >> >> >> -- >> Chris Hermansen · clhermansen "at" gmail "dot" com >> >> C'est ma façon de parler. >> > > > -- > ------------- > No, I won't call it "climate change", do you have a "reality problem"? - > AB1JX > Cities are cages built to contain excess people and keep them from > cluttering up nature. > Impeach Impeach Impeach Impeach Impeach Impeach Impeach Impeach > -- ------------- No, I won't call it "climate change", do you have a "reality problem"? - AB1JX Cities are cages built to contain excess people and keep them from cluttering up nature. Impeach Impeach Impeach Impeach Impeach Impeach Impeach Impeach
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