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I've created an SD looper with overdub, I've written about it here. It's using the technique described above. Reads from one file and writes to another, switching the files at the loop point.

Thanks very much KurtE!

Does anyone know why the video hasn't embedded?

Here's a demo video of where I am with the development of my looper module, which uses a Teensy 3.5 (and a PIC chip). Loops are recorded to the SD card, so length is virtually unlimited. Also...

Gotcha, thanks! I did actually add pads for smd resistors on the data lines on my PCB. I shall experiment with different resistances (including 0R).

Not strictly connected, but I managed to get the I2C and I2S working between Teensy 3.5 and WM8731. I'm not using any resistors in series on any of the data lines. See image in last post of this...

Hmm not sure why that image didn't work..

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Unable to make any progress with my PCB, I went back to the drawing board (well, vero board), and built my circuit from scratch from the schematic I attached further up this thread. It worked! I2C...

Ah, that makes sense, thanks Theremingenieur! Seems a little wasteful, data-wise, but as long as it's to be expected.

In that case though, I'm at a bit of a loss to explain why I don't see any...

I'm using Teensy 3.5, and for me the I2C side seems to be working perfectly. I'm using @blackaddr's BALibrary, and have commented in the error checking on the I2C transaction and every one seems to...

Yup, that's definitely on my list of options! Only getting very limited to time to spend on it at the moment though..

I'd be interested to hear how you get on with this, Derek. Were you able to confirm if the I2C setup transaction from Teensy to WM8731 completed successfully? If so you are in the same boat as me....

I tried your BALibary, and 'commented in' the serial output. The I2C appears to be working fine, I get SUCCESS on all Wire transactions. At least the chip is alive and working in some capacity. So it...

That's very helpful, thanks Paul!

Thanks @blackaddr I had another look at this last night. It turns out my schematic *is* slightly wrong. CSB and MODE pins were connect to GND net, NOT AGND or DGND, so were basically connected to...

Thanks @blackaddr, I plan to try this out next. Does my schematic look correct to you?

Interesting reading, thanks Paul! I'd be really interested to hear from anyone that has got the WM8731 codec working in slave mode (Teensy as IS2 master) using the teensy audio library.

Ah yeah, thanks very much, Paul! I hadn't even considered that. I've fixed this now, and it solves the issue with Serial.print(). Still no sine wave though. :( Do my connections look correct in the...

I'm trying to make a new Teensy 3.5 based PCB which uses the WM8731 for audio in/out. I've had an enitire prototype PCB made (they're so cheap nowadays it seemed easier), but I've only populated the...

Ah, thanks very much! At least I know I'm headed in the right direction now!

I'm still not sure on the answer here. But, I'm assuming (from my experiements) that the current Teensy SD library is not re-entrant. Therefore I should not be accessing files within an interrupt AND...

I'm writing a looper effect which requires recording to one audio buffer (a file on the SD card), whilst reading from another (a different file on the SD card). The 'play file' is read during an...

So, as predicted, it was all my fault! I was trying to do too much in a single audio effect update() interrupt. Basically I was trying to write to the SD card inside the update, which just takes too...

Thanks, Paul! My effect is connected AudioInputAnalog so I would expect to always receive input? I suspect it's down to something else I'm doing wrong. I'm writing to the SD card, and communicating...

Under what circumstances does receiveReadOnly return null? The library documentation says it's possible, and that you should treat this like a block of silent audio. I'm writing a looper effect which...

I'm writing an Audio Effect which is an SD recorder/looper with overdub. I'm using the source code for AudioPlaySdRaw audio effect and the Recorder.ino from the Audio examples. It's pretty much...

A more recent video showing off some of the new features of my AudioFreeze module. The module is based around the Teensy 3.5. It samples small loops of sound and allows you to adjust playback speed...

Yes, the order is important. The ADC object MUST be initialised before the audio object. I wrap them in a struct so the intialisation order is clear. https://github.com/cutlasses/TeensyBoardTestV2
...

Yes, I managed to fix it. See the code here for an example https://github.com/cutlasses/TeensyBoardTestV2/blob/master/TeensyBoardTestV2.ino Basically, the ADC library seems to affect both ADCs on the...

Yes, that would work I think. I've had PCBs made, so ideally I'd like to find a software solution, but it's a good backup plan!

Actually, what I said above isn't really a fix. It DOES successfully change the voltage reference of ADC_1, and the Teensy doesn't crash, but it seems to screw up the audio library, and no sound is...

I've solved this issue now (copying this from another thread I started for the sake of anyone else who has this issue)

Think I've fixed it! The issue was this sequence of events.

1. ADC class...

Think I've fixed it! The issue was this sequence of events.

1. ADC class is constructed, setting its voltage reference to 3.3V for both ADCs
2. Audio library initialises, setting voltage...

Thanks for the reply, Paul. I'm using the ADC library, and setting the ADC 1 ref voltage with that (see below for simple example). I assumed that would do the same thing as you suggest, e.g setting...

I'm trying to make use of both ADCs on the Teensy 3.6 using the ADC.h library. One will be dedicated to the audio library, and the other will be used to read the value of potentiometers.

As I...

I'm trying to use this ADC library in my sound projects. Should it be possible to run the Teensy sound library on ADC_0, whilst reading values from potentiometers etc on ADC_1? If the answer to this...

Here's a video of my WIP Eurorack module the Glitch Delay.


https://www.youtube.com/watch?time_continue=1&v=sdTysy3dD84

more details here: http://www.cutlasses.co.uk/tech/glitch-delay/

The...

Ah yes, I obviously didn't search very well :) Cheers for the assistance anyways..

I see, thanks for the help! Is this issue documented somewhere? I would have thought it would be quite common.

That makes sense, thanks very much! What state is the Teensy in when this happens? Resetting the Teensy (via the on-board button) makes no difference once in this state, the power must be cycled.

I have used a Teensy 3.6 to build a DIY eurorack sound module. I have a curious issue with power where sometimes the module will just not start up (say 1 in 3). This never happens if I power it via...

Not sure if this is of interest to anyone else, but thought I'd share it. When developing Teensy audio effects I struggled to write anything vaguely complex without some form of debugging tools, and...

Thanks very much for this! I'm now pretty sure that the 5V offset from the regulator is responsible for the noise, as I went back to my breadboard, and as soon as I disconnected it the noise went....

For reference, this is the power circuit I'm using, adapted from Radio Music module. I’m actually using 10uF for C6 instead of 1uF. Not sure how much difference that makes..

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Many thanks for your help! I shall report back when I've had time to try this out.

It's white noise. The noise seems to go when an audio signal is present. AGC is Auto Gain Control? (had to Google ) I don't have that, no. Just a simple pass-thru in the audio library. It's a PCB,...

There was noise on the 5V line actually. I was using a voltage regulator only regulated up to 100mA, and I was drawing slightly more than this (Teensy 3.6, plus PIC, plus LEDs), and showed some noise...

Thanks for your help and suggestions everyone! I had read both of those links beforehand, Paul. I decided to use op-amps for the input rather than a potential divider, as I thought this was better to...

Here is my circuit design which is intended to take Eurorack modular audio (-5V..5V), and convert it to the range (0V..1.2V), for the Teensy 3.6 ADC. The first op-amp is in an inverting summing...

Thanks, Paul. From what I can see from the code, this defines LBCF, which is a feedback comb filter which also includes a low-pass filter on the feedback loop?

I wanted to start very simply with...