Close

Focusing on sample sequencing

A project log for Wee Noise Makers PGB-1

Open source pocket groovebox

fabien-chouteauFabien-Chouteau 09/24/2017 at 21:282 Comments

When I started this project, my main idea was to do a music synthesizer, i.e. algorithms that create sounds out of thin air (or from sin tables actually). I added an SD card to the design to also be able to play pre-recorded sounds (samples). But at the time I was considering this as a bonus feature and I didn’t know how well the hardware would allow me to play those samples (how many in parallel for example).

As I started to implement the sampling feature in the software, I realized that it was actually possible to read 10 samples in parallel from the SD card (thanks to STM32F4’s 4-bit mode SDIO support and DMA). At this time I also talk about Wee Noise Maker with my friend Raphael, he told me that a sampling is really a fun way to make music. He was right:

From this point I decided to focus the software development on the sampling and sequencing features.

Discussions

Fabien-Chouteau wrote 10/16/2017 at 23:34 point

Thanks Frank, so far the project is mostly streaming audio from the sdcard to the DAC. I think the STM32F4 will allow more than that, for instance I'd like to have FX (reverb, delay, filters, etc. ) for each track. I also want to do re-sampling to change the pitch of samples.

It will also be possible to use the same hardware to do pure sound synthesis (vs samples) but this will be a different firmware.

  Are you sure? yes | no

Frank Buss wrote 10/15/2017 at 23:06 point

Many famous music are using samplers, you can do a lot with it. For example YELLO used a Fairlight CMI III. Someone is trying to sell their system for a ridiculously amount of money http://tinyurl.com/ycwhuspv But still cheaper than the original price. Could be done all with one Raspberry Pi today.

BTW, looks like the "Streichfett" synthesizer uses just one ST32F303 and the internal 12 bit DAC for audio generation. The specification claims 128 voices polyphony, it is amazing what can be done with such a small microcontroller. I wonder what someone could do with a STM32F4. Teardown of the Streichfett and demo later in the video:

More demos:

  Are you sure? yes | no