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Thanks, Pensive. Not hijacking at all! I should mention that I'm located in the states. :)

Hey folks. I have 10 brand new Teensy 4.1s (no headers) that I'm not going to use. (I ordered them several months ago for a product, and then started designing a DIY teensy layout instead.) I noticed they're out of stock most places, so if anyone needs these, feel free to write me at...

Thanks, Mark! And congratulations on the MIDIPoly. It's a really cool project that I've borrowed from a few times :). That's good to know. I've read that higher values might case extra noise, but haven't experienced it yet with 20K pots. I guess I'll trust my ears.

Hi all, I'm working on a Teensy synth, and I just realized that the slide potentiometers that I want to use are not available in 10K or 5K linear format. (Almost every other variation is available but not 10K or 5K for some reason.). I'm curious what difference it makes in...

Wow. So you wouldn't have to repeat the code for each voice?! This sounds awesome. Looking forward to trying this out when I get home.

@wrightflyer What exactly would it mean to have a multi-voice audio tool? I know a lot of folks have built poly synths using the current library, myself included, that could be considered multi-voice. I'm really curious what the implications would be. Also, @manicksan, this is so cool...

Aha!!! 48 hours of debugging has finally paid off. It turns out I had a couple redundancies in the setup function that were causing a big pileup of MIDI data. Basically I was doing an initial read of all the knobs and sliders and sending MIDI data for all of them at the same time. No wonder...

Sure. I have several LEDs in the circuit that flash when the program is running (LFO indicators). When I load the program, they all go out immediately. The serial monitor logs the first few things that I print to it, so I know the program is loading, but then the serial monitor stops logging...

Thanks to you both for the feedback. I tried to extract the offending piece of code from a much larger program, but I'm realizing I left out a lot of context. (I never know exactly how much context to give or what the best way is to extract only the relevant details. I guess when you're bug...

Also, here's a video of the synth/controller, if it helps visualize what I'm trying to do. https://www.youtube.com/watch?v=VpGOdtfuOTQ

Here's the full code repo. The problem lies in the updateSlider function. I can send MIDI pitch bends over 8 channels with USBMidi, no problem. But when I attempt to do that over the serial port, the Teensy crashes. Again, thanks for any help.

Hi Pete, That code was a bit messy. Sorry about that. I just cleaned up the typos. The code reads the values of 8 different sliders and sends a MIDI pitch bend to 8 different channels based on the values of those sliders.

I'm running into an issue in a MIDI controller project I'm working on. I'm trying to make an MPE controller that will send pitch bend data over 8 channels of MIDI. But for some reason, I can only send 2 channels at a time. Every time I introduce a third channel, the program completely crashes...

This looks really cool. Thank you for sharing your work!

Genius. That's all it took. Thanks @kallikak.

Hi everyone, I'm trying to figure out something really simple--how to light an LED indicator proportionally to a Sawtooth LFO. So at the beginning of the wave, the LED would be completely dimmed, and by the end of the wave, the LED would be full brightness. I'm using AudioAnalyzePeak right...

Edit: There was no popping on those waveforms. Just my own bug in the multiplexer code. I spoke too soon. Again, thank you for your explanation and for your work on the audio library! It makes a huge difference.

Thanks so much, Mark! So in practice, sampling a square wave (or any waveform with high harmonic content) at 44.1 kSPS will reflect harmonics that should be above our hearing range back into the audible range? And that doesn't sound very musical to our ears apparently. I'm realizing you did...

I've seen a lot of posts about band-limited waveforms reducing aliasing and generally sounding a lot better than the standard waveforms in the audio library. I must say using the standard audio library oscillators can sound a bit sterile, so I'm wondering if I should explore this approach...

Thanks, Mark and Jonathan! I went ahead and added a read function (same as your getGain function) to the envelope. Now the question is, can I get a value from a waveform object that I could update an LFO indicator with? BTW, I should add that the AudioAnalyzeRMS class only gives RMS peaks...

Hi, I'm working on a synth build, and would love to add some LED indication for the envelopes and LFO. Would it be feasible to add some kind of read function to the waveform and envelope objects in the audio library? (Something similar to the read function on the DC object.) Thanks as...

Update: I just got the boards in today and the 2x20 pin with all grounds on one side is working great. Very clean signals from the MUXs. Thanks everyone for your help.

Ah! Thank you. I just added that third regulator. Knocked them down to ~100uF. I decided to put a voltage divider on the mute circuit based on this guy's recommendation. He says it provides muting as the unit powers down. Here's an updated schematic. Thanks again, Paul.

Here's my attempt at building a PCM5102A into the board with a Teensy 4.1. I think I have the Teensy pins correct, but I need to buy a pre-made board and double check it before printing this one. Any thoughts or feedback are greatly appreciated. I also built in two voltage regulators which...

Good call. I guess there's no real reason to skimp on pins, and it seems like 40pin is a more common size than 24.

Huh. I wouldn't have thought of using GPIOs as extra grounds. My current ground is just running from the voltage regulator. What exactly would using the GPIO's ground accomplish? In general is it better to bias pots that are being read by analogRead with ground from the GPIO pins instead of...

Thanks, Mark. OK, so perhaps I just need to intersperse ground signals and logic signals and all will be good. I don't think the signals will be particularly fast. I'll probably poll the MUXs about 4x/sec. Would it make sense to include several Vcc signals in the cable as well? I guess I'm...

Hey all, I’m starting to lay out PCBs for a Teensy synth and I wanted to see if I have a fundamental flaw in my design before I get too far. Any advice would be greatly appreciated. Here are the details: The project A Teensy-based midi controller/synth with a lot of buttons and knobs...

Ahh... good point about the layout and schematic in the datasheet. That's handy.

OK, great! Thank you so much. I'll probably end up laying it out on the board just because I could use the practice with PCB design.

Thanks, Frank.

OK, great! Thanks for weighing in, Paul. I guess I'm just confused on what's going on with a breakout board like the one that PaulS linked. (The other PaulS.). If I can connect the PCM1502A with just I2S and three clock signals, what's going on with all of the SMT stuff on a board like that...

Sounds great! Any ideas where I could look to find a proper schematic to use a PCM5102A with a Teensy? I'm hoping to integrate it into the PCB instead of buying a breakout board.

Hi Teensyers, I'm building a Teensy poly synth and would like to figure out how to build out my own DAC hardware. Here's a pic of the prototype board. Currently using the Audio Board, which honestly works great, but it takes up a lot of space and have more features than I need. Can anyone...

Sorry for the delayed response. I think that a relay (or pair of relays) is the only way I can conceptualize getting the PTT to work. Thanks for that idea. I'm not really well-versed in analog electronics, so I'll have to do some experimenting, but conceptually it seems doable. Thanks again...

Oh, ok. So the host pins are for powering and communicating with external "devices" plugged into the teensy. Thanks for the explanation WMXZ.

Hi all, I'm building a synth with a Teensy 4.1 and have a question about power and USB. I'd like to have my breakout board feature an external USB B connector where I can program and get send/receive midi from the Teensy (like this one) and to also feed the Teensy 5V from a 7805 regulator...

"1970's planet CB *social media* was hugely entertaining. Hooked up guitar multi-effects, yeah , waa-waa, fuzz, flanger whatever so all "on - air" setting up/testing was dumped into a 50 ohm dummy load, monitoring with another receiver." That's hilarious. Maybe I can find some new version of...

Thanks so much for all the info! I think you're right, that maybe the way to go is building the circuit into the actual mic instead of a standalone unit. I'm having a hard time getting my head around all the implications of putting the teensy in a different box.

Hey, thanks for the response! Yeah, apparently they used to put analog delay in old CBs back in the day as a kind of identifier for your voice. The CB is a Cobra 29, with a 4 pin aviation socket. Here's a pic and a schematic for that mic, which is dynamic. Could you say a little more...

Hi Teensyers, I’m working on a maker project for a friend, but am having a hard time figuring out some technical details. If anyone has any ideas on how to solve this problem I’d be super grateful. The concept: A CB radio effects box which uses a teensy and audio shield to add delay or reverb...

OK. That's what I thought I understood from Paul's comment on Teensy midi page. For newer Teensy boards with 3.3V signals, 74HCT4051 chips are best. Power the 74HCT4051 from 5V. If 74HC4051 (without the "T") are used, they should be powered by 3.3V when used with a Teensy that has 3.3V...

Thanks! I'll plan to change the bias on that 74HCT4051 chip to +3.3V instead of 5V and keep everything else the same. Appreciate it.

Hi all, Would someone be able to confirm this wiring for an analog multiplexer (74HCT4051) circuit with the Teensy 4.0? I would be reading from potentiometers biased at 0 and 3.3V, but powering the multiplexer from 5V. Thanks so much!

OK. That's really helpful, Paul. That seems like a obvious way to start troubleshooting that I didn't think of--just breaking the whole thing into parts and tuning or recording each individual section. I'll dig in more this weekend. Thanks so much!

OK. So setting lineOutLevel to the maximum value seemed to help a lot. There's still the same resting noise, but the signal to noise ratio is much higher now.

Thanks for replying, Paul. Here's the source code and answers to your questions inline: do you have any flashy lens (neopixel or ws2812s or anything like that?) No, nothing like that connected to the board. are you setting the audio board with any other functions? Nope. are you using line...

Hey Mark. I'm actually not convinced that it makes much difference in my case. Here are some audio samples I just recorded. It looks like: -running the sketch with adcHighPassFilterDisable(), the noise and the synth are much louder. -running the sketch without adcHighPassFilterDisable()...

Awesome. I'll definitely try disabling that software filter. It sounds like I'm having the same issue as the person who wrote that. Thanks!

Ahh... Good to know about the MUX. I'll either buy the Sparkfun version or just buy the component and work it into a PCB.