Help with resources for synthesizer project

A

aranis22

Member
Trying to make a pretty basic but functional synthesizer aimed at kids to learn sound design with. It should have a spec sheet good enough to make common sounds like a piano,flute etc. "Jeannie" by Rolf at TubeOhm was quite inspiring, but is very advanced for my knowledge of sound synthesis. The Audio tutorial for the audio library has been useful. I've been able to get basic implementation of a filters, envelopes. Values like ADSR and cutoff frequency are adjustable with potentiometers. I am struggling with implementing LFOs and other features similar to the Jeannie synth. I want to make a waveform bank similar to "Jeannie". I am not too familiar with polyphony and multi-voice synthesis, but I do want to make the most of teensy's capabilities for this project.

Can someone provide a sort of "spec list" of what kind of synthesizer is achievable with the teensy, with some cheap discrete hardware? Is there another example synthesizer project made with the teensy ? Something similar to vital is what im trying to achieve.
Something I definitely want to replicate almost exactly from "Jeannie" is the display menu. This is also the biggest challenge since the whole interface will I have already made a post on it here. Any help there is also appreciated.

Features like a sequencer, MIDI IN/OUT will be implemented much later when I have the sound synthesis part down.

Any guide, resource or learning platform is appreciated. Or, if there is another forum that is more active, or a discord server, I'd love to join that too.

Thanks in advance.
 
Hello,

I have built many synths for kids workshops. Teensy can do a lot ! Here are some links :
Minitouch 1
Minitouch 2
hang

I have also built "vintage like" synths with big knobs, with educational approach. I attach a example of a control panel design at the end (in French !)
If you think I can help, we can go further, steps by steps.
Emmanuel


control panel.jpg
 
This is amazing! Thanks so much for sharing.
Some questions:
- how did you implement the LFO with the audio library?
- For the notes, did you just add an envelope at different frequencies? What I mean is, did you use the noteOn/noteOff functions to implement the keyboard? I really like how you made everything in the same scale. Really avoids mistakes for kids!
- How exactly did you implement the presets? Did you assign each parameter to a certain value?


last question unrelated to your projects:
do you have any idea on how to implement a sequencer with the teensy? I am looking to add a step sequencer to mine.


just a brief note on each answer is suffice. I do not need code, just a way to implement it

Thanks in advance
 
Hi,

- LFO
Use one oscillator at low frequency (0 to 30 hz for example). Then use its output to modulate notes frequency, amplitude, filter frequency, PWM...

- notes
The trick is to use an array that stores all the frequencies of the 127 midi notes. Here is the idea :
1 - say key #60 is pressed
2 - associated frequency is found thanks to the frequencies array (note 60 = 262Hz)
3 - notes oscillator is set to 262hz
4 - noteOn message is sent to the enveloppe

This is the basic way to manage monophonic synth.
There is an amazing tutorial here :
link

You have think simple. If you want, I can help you to implement a simple monophonic synth with all the logic. Then you can evolve to a more complex project. Polyphony is quite a challenge if you're not familiar with C++ pointers and object programming.

Emmanuel
 
Hi Emmanuel,
Apologies for the late response. Have been busy with school

Can you provide a resource for where C++ and OOP are used for polyphony?

I would love the help to develop the monophonic version first. I already have a 8 step sequencer that sounds good with the help of chatgpt. But for now its just selecting a basic waveform (sine,saw etc) and having a keyboard from 8 pushbuttons. The keyboard has octave up/down and a scale type selector pushbutton, similar to what you have in your project.

From this, I want to add many features that a typical synthesizer has. The idea is to have something where they can make any sound from scratch and learn basic synthesis. How can I make a flute, piano or guitar sound? What waveform do I select to start? How can i adjust the envelope/lfo/filter to get the sound I want?

I am still confused on what are the basic components of a synthesizer, so If you can run down the basic properties that would go into a synth that make these sounds, do let me know.
Thanks in advance
 
Hello,

You really should start by the tutorial by Notes and Bolts.
Another very good ressource :
http://thewessens.net/synthbook/#preface
There are plenty of examples using teensy and audio design tool.

Please, take time to do these tutorials, there are just great. Then come back to me if you want.
Emmanuel
 
emmanuel63 said:
Hello,

You really should start by the tutorial by Notes and Bolts.
Another very good ressource :
http://thewessens.net/synthbook/#preface
There are plenty of examples using teensy and audio design tool.

Please, take time to do these tutorials, there are just great. Then come back to me if you want.
Emmanuel
Click to expand...
Hi Emmanuel,
I have been working on my synthesizer over the past month. I have implemented much of Ken Wessen's constructive synthesis tutorial onto a project. Again, thank you for this valuable resource. Notes are triggered via an additional envelope, and it implemented as you described in your older post.

Things like Velocity sense, Overdrive, pitch are not implemented from the features of the "mentor" synthesizer of the tutorial (image below):
1730659803861.png


At this point, I want to make my synthisizer "patchable" or have presets. What I mean is I want to make it so that I can set certain parameters at get a certain type of sound, such as a piano or a flute.

In your Minitouch, you have much of these settings, but your sound generation comes from a sound preset, not an oscillator. In the second version, you have some software that allows for tweaking the sound

Below are some examples:
Source
1730660309208.png


Source
1730660339479.png


Right now I have two oscillators, that can be morphed between a sine,saw,triangle, or square. How can I make a richer sound?

Also, what is the point of polyphony other than playing more than one note at a time? From what I can tell it is just a way to play chords. Does it help in any way for sound synthesis?

I know this is alot of questions at once. Please take your time to answer them. Thanks in advance!
 

Attachments

  • 1730660335322.png
    1730660335322.png
    112.4 KB · Views: 9
You must log in or register to reply here.
Back
Top