Tremolo Effect - Digital Audio Processing with STM32 #3 - Phil's Lab #51

Mixed-signal hardware design course: phils-lab-shop.fedevel.education
Real-time digital processing (DSP) of audio data using an STM32 microcontroller in C on custom audio-processing hardware. Third video in series, covering the tremolo effect. Essentially, amplitude modulation of the audio waveform using a low-frequency oscillator (LFO). In this video, we'll be using a triangular waveform modulator. Including live guitar demo.
[SUPPORT]
Free trial of Altium Designer: www.altium.com/yt/philslab
PCBA from $0 (Free Setup, Free Stencil): jlcpcb.com/RHS
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[LINKS]
DSP Playlist: • DSP
STM32 Playlist: • STM32 Firmware
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First DSP Video: • Digital Audio Processi...
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[TIMESTAMPS]
00:00 Introduction
00:41 Previous Videos
01:02 Altium Designer Free Trial
01:20 Hardware Platform
01:57 JLCPCB and Git Repo
02:20 Test Set-Up and Hardware Overview
03:20 Tremolo Effect Overview
04:22 Tremolo Block Diagram
05:43 Tremolo Equation
06:16 Generating the LFO Triangle Wave
07:43 Tremolo.h (Header)
08:50 Tremolo.c (Source)
11:07 main.c
12:30 Time-Domain Analysis (WaveForms)
14:28 Frequency-Domain Analysis (WaveForms)
16:22 Guitar Demo
ID: QIBvbJtYjWuHiTG0uCoK

[@luismiguelfrancisco824]

This is completely amazing! I never thought that one day i would understand this.

[@isaacclark9825]

I love this content. More audio processing stuff, please!!! I have been subscribed for a while, but I have just clicked a notification bell for the first time ever.

[@PhilsLab]

Thank you very much, Isaac! A lot more DSP/audio processing content to come :)

[@szymon4602]

@@PhilsLab Please prepare something about Q-constant transform :)

[@siddharthkothari]

Im genuinely convinced there's something common about electronics and guitar as a hobby. Almost every electronics guy I know, including me is into guitar and at times diy guitar pedals. All that aside, brillant video!

[@bot5am]

facts

[@mr.shredder5430]

this guy is amazing very talented, some day when i finish all your courses i might me able to make my own anyway thank you for your time and sharing knowledge

[@madrigo]

A thanks to Phil, I'm finishing my Bachelor's work with an extra effect. Reverb next and you'll be responsible for my finished synth and degree sir! hahahaha thank you so much for making this content free for everyone man, this is a golden class with superb didactic. Cheers!!!

[@DonQuichotteLiberia]

In my mind, you are a true renaissance man. Great knowledge across the board, and an excellent teacher. Thanks for making these videos.

[@PhilsLab]

Thank you very, very much!

[@markworkman6544]

The SMITH's "How Soon Is Now" made this effect "famous"

[@deivedwilliam2386]

That's so good my friend. Congratulations 👏🎉

[@PhilsLab]

Thank you! :)

[@shashankshetty4617]

Great video

[@jj74qformerlyjailbreak3]

That’s pretty slick bub. I knew I bought the AD2 for a reason. And this guy already did it. Great job. God Bless.

[@gino.avanzini]

Love the final clips demonstrating the effects on the guitar!

[@PhilsLab]

Thank you, Gino!

[@zetaconvex1987]

Top quality video! I like how you present everything with no fudged explanations whilst still keeping it within the bounds that us mortals can understand. This series is shaping up to be the best practical DSP on KZbin.

[@PhilsLab]

Thank you so much!

[@mello.felipe]

That's really inspiring! Thanks for sharing your knowledge with us!!!

[@PhilsLab]

Thank you very much, Felipe!

[@jugal4607]

amazing stuff as usual

[@PhilsLab]

Thank you very much!

[@MrIgorek123]

Awesome video dude! I learned a lot, keep it doing!

[@KSITREVS]

Great video Phil, look forward to seeing more :)

[@PhilsLab]

Thanks a lot, Trevor!

[@velvetsound]

Thanks Phil. Keep them coming!

[@PhilsLab]

Thank for watching, Jason!

[@leiferickson3183]

Wow! great project and great sound too!

[@PhilsLab]

Thank you, Leif!

[@Bianchi77]

Nice info, thanks :)

[@diemaschinedieviereckigeei2941]

Wow! The intro genuinely made me think it's a song from Portishead for a second! If you'd started singing to it with a sad high-pitched voice, the illusion would have been perfect.

[@PhilsLab]

Haha if I only I could sing.. :D

[@karama5478]

Awesome!

[@PhilsLab]

Thank you!

[@tomislavtropcic2855]

Makes me wanna buy an guitar and experiment with it myself. Very cool.

[@PhilsLab]

Well, I think you definitely should get one! ;)

[@Mel-mu8ox]

Found this after listening to the scream in Love death + robots not sure if this is what they used or just one of the things used but was great to see what it does in wave form :D

[@alejandroismael2109]

Hermoso!

[@marcelhensen6847]

Thank you Phil. Please follow this up by a concise two hour video on how to actually *buy* an STM32 chip 😆

[@PhilsLab]

Haha yes.. I think that video may have to wait one or two years :D

[@markworkman6544]

VERY COOL......

[@PhilsLab]

Thanks, Mark!

[@micheleciaramicoli7139]

Love this shit bro

[@PhilsLab]

Thanks, Michele!

[@VSThrasher]

Your videos are always amazing, Phil! Thanks a lot for sharing your knowledge with us. I'm kinda rusty on C embedded applications (then, I'm sorry in advance if my comment sounds stupid =D), but I was wondering if make lfoDir a int8_t variable isn't enough for the application and why don't use unsigned integers for both lfoCount and lfoCountLimit? I mean, it would save some bytes on this struct. What do you think about it?

[@PhilsLab]

Thanks, Vitor! Yeah, it doesn't make sense in this case to use a float for the LFO variables. I was messing around with different modulation waveforms (sin, etc..) so needed float for that, just ended up not changing it before recording!

[@joanlopezjimenez8336]

Greate Vídeo!!! I just want to try to design my oun bass pedal (or guitar). Maybe the next video could be an explanation of Fuzz Pedal 😏

[@PhilsLab]

Thanks! I'm planning on making a video on guitar overdrives/distortions - I'm afraid not a fuzz, but close :)

[@stm3252]

Is there anything you can't do when it comes to embedded system?

[@renatofilho9985]

what value did you put on the clock configuration of the stm32 IDE? and what pins did you select

[@Tarnith]

Great video! Am I correct in thinking that if you band limited the control signal more significantly, or possibly oversampled the modulation processing (or both), you would reduce the modulation distortion? My assumption being the harmonics are generated by the overly sharp transitions at the -1, +1 points? (in the modulation wave)

[@PhilsLab]

Thank you! The harmonics are due to the triangular waveform, who's Fourier series is composed of odd-harmonic sinusoids. See: mathworld.wolfram.com/FourierSeriesTriangleWave.html

[@CristiNeagu]

Do you think you'll ever be able to implement impulse responses?

[@PhilsLab]

You can check out the FIR video on my channel, which is essentially that. I've tried out (short) impulse responses for speaker emulation but for long convolutions the microcontroller struggles quite a bit.

[@crosswick]

At the time this video is published, unfortunately JLCPCB doesn't have the microcontroller and codec in stock for the LeDSP module... also there is no firmware on the github for it (yet?)

[@obregr]

good as alwwwwwwwwwwwwayas

[@PhilsLab]

Thank you, Gregor!

[@jango9973]

How often do you solder on your own components? I'm finding that most of the chips I want to use on JLPCB are out of stock but would like to have them assemble the whole board.

[@PhilsLab]

I try to never solder anything myself these days (unless I'm fixing a mistake, trying out different components, etc.). JLC now offers components acquired through third-party distributors, so maybe that can help out?

[@nickst2797]

Great! How many bits are the DACs?

[@PhilsLab]

Thank you, Nick. The CODEC goes up to 24 bits I believe, but I'm running it at 16.

[@nickst2797]

@@PhilsLab Thank you very much!

[@sarbog1]

Very cool....... do you play Blues?

[@PhilsLab]

Thank you, Stephen! I mainly play 80s rock (Extreme, Ozzy, ..). :)

[@Adin_Prastyo]

Hey bro..I've never seen someone on KZbin make a preamp for an acoustic guitar....can you do that bro.thanks bro..my greetings from Indonesia .. If you can make a playlist about audio, effects, guitar ..

[@PhilsLab]

Hey Hamba, I'm afraid I don't really have plans for an acoustic guitar pre-amp, but definitely loads more to come for the electric guitar :)

[@JA-ur8ob]

Hey Phil, may you please make a Twitter account?

[@haythemjelassi4766]

could you please make a tutorial and explaine in it how to make an echo cancelation algorithme on the DSP of STM32 for intercom application ?