Teensy 3.6 audio board

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Arpitha R

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Hi...
Can i use teensy audio board for amplification, filtering applications? Can it be used as audio processor?
What is the maximum output gain that can be obtained from teensy 3.6 micro controller audio board ?
 
Unsure on the gain, but suspect a more meaningful limit is the 16 bit processing path without an analog preamp. Good place to start is the tutorial video, the associated power point or just tinkering with https://www.pjrc.com/teensy/gui/ and looking in the pane on the right hand side for the various elements where the function calls are listed.

It can certainly do amplification, filtering and processing but process does require some thought and knowledge when operating within the memory and processing limits of a micro controller in place of a desktop PC.
 
Your question about amplification is a little unusual. I don't understand what you need...

On a purely technical level, an answer could be found in the SGTL5000 datasheet on the audio board page. If you look at page 2 of the PDF, you'll see there's an "MIC GAIN" up to 40 dB if you use the mic input, and another analog gain block up to 22.5 dB. There's another headphone amplifier with gain up to +12 dB.

Ultimately the amplifier can only output about a 3V peak-to-peak waveform (no matter how much gain), because everything runs on 3.3V. The headphone amp is able to drive ordinary 32 ohm headphones, but it doesn't have the current capability needed for 8 or 4 ohm speakers. If your amplifier question is about driving high power speakers, you'll need to add another power amp circuit to do that.

Of course, as you bring the signal through Teensy as 16 bit digital data, you could multiply the numbers using the mixer object. But this is done digitally. Think "digital zoom" on a camera. Too much costs quality. So theoretically speaking, you could multiply by quite a large number. But I doubt that would be a really useful answer for you.

Really, I just don't understand why you're asking. So it's difficult to give you any sort of useful answer that speaks to what you're actually trying to accomplish. But hopefully these pointers to the technical specs will help you find the info you need?
 
You might also find this tutorial helpful. Even if it doesn't answer your specific questions, it'll give you a much better understanding of how audio works on Teensy, which can really help for talking here on this forum and asking questions (which we can understand and answer).

https://www.pjrc.com/store/audio_tutorial_kit.html

The best way to learn this it to print the 31 page PDF and actually do the tutorial. It takes about 3 to 4 hours, depending on your experience with Arduino.

There's also a 45 minute walkthrough video (scroll down on that page) where Alysia & I demonstrate every part of the tutorial, and more videos where Alex Glow did much of the tutorial without prior practice & video editing.
 
Thank you for the tutorial.
I am planning to design a hearing aid with gain of 80 dB. I wanted to know if this gain is achievable using Teensy audio board. Also I am looking for digital filtering techniques and noise cancellation techniques. Could you suggest available options to achieve these ?
 
Check out part 2-7 in the tutorial for a quick intro to filters.

The library also has FIR and biquad filters (which you can find in the Design Tool, like all audio lib features), but use of those is more complex. Best to start with the simple variable filter. And really, best to actually read/watch or best, *do* the tutorial so you understand how things work. It will answer many of your questions, and give you the background to better ask questions on the things it doesn't cover.

I don't know much about noise cancellation. But I can tell you hearing aid applications including range compression have come up before. I believe some code has been posted. Maybe if you search you'll find those threads? (edit: Manitou replied faster....)
 
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