Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 3 of 3

Thread: MIDI Sequencer / Sampler

  1. #1

    MIDI Sequencer / Sampler

    Hi, I'm new in this field and I have a project in mind that is probably beyond a beginner reach, but I am willing to learn and build it step by step.
    I have a background in programming, but I'm a newbie in the hardware aspect, apart from some basic soldering.

    The project I want to create is very similar to this one, from forum user Pensive: https://www.pjrc.com/beats-by-teensy/
    Although I think he didn't finish the project.

    If you are familiarized with the Akai MPC that is basically it.
    This are the specs I have in mind:
    - 12 bit audio sampling.
    - Manipulate samples: trim them and changing the pitch.
    - Assign the samples to 8 different buttons and being able to trigger all of them at the same time (polyphony).
    - 96 ppq sequencer with quantize and swing functions and BPM variation.
    - Store sequences.
    - MIDI controller.
    - If possible, the input and output would be 1/4 jack (line) and stereo.
    - 16x2 LCD.

    I have some doubts about feasibility of it.
    First of all, I don't know if it is possible to handle all the sequencing work with the Teensy. I have thought of using a Raspberry Pi, but I'm not sure whether a microprocessor would cause latency problems.
    Another issue is the sampling rate. I know is like going backwards, but I like lo fi samplers. And as far as I know the Audio board records at 16 bits and dropping the bitrate is not an easy thing to do. I know too that the Teensy 3.6 has the capabilities to do sample at 12 bits by itself, but I don't know how easy would it be to use the built-in input and output. I was looking up something like the ISD1820, but I don't think it is compatible with the Teensy.

    I was thinking of something similar to Pensive's setup , with a Teensy 3.6 instead the 3.1.

    Summing it up, do you think it is possible to achieve such a project? And if so, what do you think the requirements would be?

    Thank you for your help!

  2. #2
    Senior Member Pensive's Avatar
    Join Date
    Aug 2014
    Location
    Basingstoke, UK
    Posts
    553
    If I was to offer some advice;

    Making the sounds is easy.

    Sequencing and pattern sequencing to a high resolution is full of challenges.

    Can I suggest for Phase 1 - you make the device send midi events out over USB every time it does _anything_ sound related.

    And then you can make it respond to those same events and use an external midi sequencer. That way you will get a long way forward quickly.

    Youíll basically have built a midi sampler with integral keypad.

    If you feel like it later you can then add a pattern engine.

    I bit off too much - honestly I would have finished it if I hadnít started a company - this chewed up my every spare minute for nearly 3 straight years.

    But I digress. Break it up into bite size chunks - each a successful project in their own right. This is the premise of Agile software development you might be aware of and itís equally true in hardware

  3. #3
    Thank you for your advice Pensive.

    I think that is exactly what I would do: break it up into small chunks and learn in every step what is needed. As you say, the Agile philosophy based on sprints is much more rewarding and helps a lot when the project is big.

    My main concern was about how to focus it and your advice has been very explanatory.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •