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I can also recommend Sonic Visualizer for looking at spectrograms :)

Formatted as code it might do. Also the frequency response of the mic can be found in the SPU0410LR5H-QB datasheet. According to WMXZs test the frequency response of the ADC in the SGTL5000 is fairly linear until 60kHz at 192kHz sampling rate before slowy falling off. Of course the frequency...

What a lucky coincidence that we are all working on more or less the same project :D very nice! That sound like a simple enough setup CorBee for generating tones. I will see if I can throw together something similiar to it. Also thanks for the tip about using AudioSynthWaveformSineHires! I...

Hi Frank! Thats fantastic news! Congratulations! Sounds like you're getting some nice results. Maybe I will give the mic preamp you linked a try. Smart idea to take 3,3V opamp! :rolleyes: I had a quick look in the data sheet. I was told that for amplifying signals in the ultrasonic range the...

@WMXZ: Thats great news. Thanks for confirming! And thank you again for making the effort of testing the chip and sharing your results! Much appreciated! @CorBee: That is very interesting! So our results seem to line up :D If you have a working design/schematic for a pre-amp I would be very...

Haha no worries. Yes that would be nice :) I looked at your code for changing the sample rate and it seems far more elaborate, than what I've been using. Your code is nicely documented and you seem to have a deeper understanding of the chip. Maybe it would be worthwhile to turn it into a single...

Hi Frank, Thanks! Yes well in theory I should be able to explain why downsampling also introduces a frequency shift, as I did learn this is university... but I can't remember properly. You are definitly right that a proper downsampler has to do a LP filter to avoid aliasing. The code I wrote...

Wow thank you so much! It's really nice that you took the time to check! For me it's great to know that using a sample rate of 192 kHz doesn't change the SNR significantly. Only minor thing that I have to note: Almost none of the axis in the plots are labeled, which makes them difficult to read...

Sorry, I don't quiet understand the question. So for the first tests I have used a cheap, shitty EMY-62NL101 electret mic which only goes up to 12k. That one is quiet noisy when used with the Teensy Audio shield mic input. (could be because its cheap, could also be how I set the mic gain, not so...

Hi Frank, thanks for pointing me to your project. I have already seen it and it's what convinced me to buy the Teensy 3.6 + audio shield and try it for my project! :) really cool stuff! I've just got around to upload my code as well. I've already done something similiar to what you are...

Weeeeeeelllll hahaha :D I was actually planning on using 192kHz as sampling rate... Thanks for the fast answer! Good to know I'm kinda on the right track. So what I want to do is to record ultra sound (at 192kHz for a resolution of 0-81kHz) and then transpose/scale it down to the audible range...

Hello everybody! I have some technical questions about the Teensy 3.6 in combination with the audio shield. So I would like to do quiet lot of big FFTs, then do some spectral processing and finally iFFT the signal. If possible I would like to do it in real time, but if thats not possible at...

Thank you so much :o :D There is a couple of things I would like to tweak. - Using the proper size typedefs (ie int16_t, int32_t etc.) so that the integer width is guaranteed - Adding multi channel support - The files are displayed as containing 32-bit float, eventhough I write 16-bit...

Hello everybody! I am working on a little project and needed a way to store audio on a SD card. All I could find was code that either writes raw samples or some god awful spaghetti code attempting to write WAV files (sorry...:rolleyes:). So I decided to write a simple class that nicely abstracts...