http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/f2018/jjh353_bjr73/jjh353_bjr73/jjh353_bjr73/index.html We built a portable digital synthesizer capable of creating a wide variety of sounds designed by the user. The system consisted of a full octave (13 key) keyboard with two-voice polyphony, three rotary encoders for user input, a TFT LCD for visual display, and an SPI DAC for audio output. A user can play up to 2 notes simultaneously, and adjust many parameters of the system's digital sound synthesis on the fly. Wave lookup tables were used to produce different waveforms, including sine, square, sawtooth, and noise waves. Frequency and amplitude modulation were used to create more complex waveforms. For easy portability, the entire system was contained within a 18.8 cm x 10.6 cm x 2.3 cm 3D-printed enclosure. The entire project is based on the PIC32MX250F128B microcontroller.
Hi, I'm Ben Roberge. This is TJ Heard, and we made an FM synth.
So TJ's going to show you a little bit about how it actually works.
Yeah, so it's called a sound designer, where you can kind of design a bunch of different sounds.
We have a full octave keyboard that's 13 notes.
A screen that shows you what your settings are, and then three rotary encoders where you can change the settings.
So on this first screen, which is main settings, I can change the output volume, make it louder or quieter, change the octave.
I'm going to make kind of a melody sort of sound.
So if I press two buttons, I can go to the next screen.
These are the waveforms.
Some of the options are sine wave like this, square wave, sawtooth, and some noise.
I'm going to stick with the sine wave, increase the FM volume, and I can also change the ratio.
So maybe I'll do that.
Of FM2.
Of FM2, the main frequency.
So to get the plucky sound, I'll go to the main envelope.
This is where we change all the attack, decay, sustain, and release for each of the notes.
So if I bring the sustain down and make the attack really short and maybe increase the decay a little bit, we can get a plucky sound.
There it is.
Let me increase the volume a little bit.
So if I go back to the main page, increase the volume on that.
And the last setting you can change is the FM envelope.
So that's how the frequency modulation changes over time.
It'll be hard to tell what this sounds, so maybe I'll make the sustain longer.
And then bring the sustain down on the FM envelope and increase the attack and decay.
So you should hear the FM come in and come out a little longer, so it's a little more obvious.
Okay.
Very cool.
So now change it to a really low frequency FM so it makes kind of a weird wobbly sound.
So let's do that.
Bring the octave down and then also bring the FM ratio pretty far down and get more of a...
I don't know if I can bring the sustain on the FM envelope.
Okay.
So you can make quite a range of sounds then.
Yep.
I've heard you playing with it quite a lot in here.
It looks like it's pretty entertaining.
Yeah, it's in pretty good bases.
Cool tines kind of sounds.
Yeah, there's a lot of options.
Okay, thank you.
