Can't hear microphone in Audio Tutorial

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rforbes

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Hi,

I'm working my way through the Audio Tutorial. Aside from some SD card issues, things have been working well--hardware test checks out, I can play music, samples, etc. However with the Microphone Test I hear nothing...the headphones are totally dead. I tried upping the mic gain to 63; still nothing.

I'm using the electret mic that comes with the PJRC Tutorial Kit. I've checked the mic polarity against the datasheet (+ to Mic pin, - to GND), and checked the continuity on my cable (I have it on a 3 foot cable instead of directly mounting to the Audio Board). I've looked at the pads where I soldered the headers in; they look good.

One thing that seems suspicious is that there is no voltage across the Mic/Gnd pins...aren't condenser mikes supposed to be biased?

Any troubleshooting suggestions? I suspect I must have omitted something obvious....

Rob
--------------------------------------------------------------------
The hardware:
Teensy 4.1
Audio Shield Rev D, on a 14-pin stacking header above the Teensy
PJRC Audio Tutorial Kit (wired by me)
Arduino 1.8.13
Teensyduino 1.53
-----------------------------------------------------------------
The sketch code:

void setup() {
Serial.begin(9600);
AudioMemory(8);
sgtl5000_1.enable();
sgtl5000_1.volume(0.5);
sgtl5000_1.inputSelect(AUDIO_INUT_MIC);
sgtl5000_1.micGain(32);
delay(1000);
}

void loop() {
// do nothing
}
 
...never mind, its working now. The tutorial doc shows the input object named "i2s2" so I had dragged an i2s2-type object instead of an i2s-object, oops.

Rob
 
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