Noob with an idea for a audio sample playing instrument

[enomis]

Hello All,

I recently stumbled across this website and forum while trying to find information for a project idea. I am an architect and musician so I'm new to designing at this minute scale. I appreciate your patience with my questions and hope, if nothing else, to learn something along the way. I have worked with the visual programming language Max MSP but realize that probably won't help me much in dealing with hardware.

The thread I stumbled across is this one:

https://www.electro-tech-online.com/threads/audio-recording-playback-using-pic.41586/

Project Idea:

Essentially I am interested creating a polyphonic audio (wav 16bit 44.1 khz) sample playing instrument that can play audio samples that are organized on a removable flash memory card. The audio would be added to the flash drive and organized using a computer so the design of the "instrument" would only have to take into consideration playback and not recording. Ideally the polyphony would be around 20 voices minimum.

Triggering of the samples would be accomplished via an external MIDI controller. So a MIDI note ON message (ex. Note 64) would trigger the audio sample with the corresponding file name (note_64.wav or similar). A note OFF message would stop playback. Additionally (if possible) there would be a basic controllable envelope applied to start and stop of sample playback. Output would be through either one (mono) or two (stereo) 1/4" unbalanced jacks.

There are some other details I would be interested in adding but I will leave it there for now realizing that I am already asking a lot.

From what I have gleaned in my readings there are a number of hurdles to jump:

- Polyphony - keeping track of note on and offs and triggering the right sample as well as taking into account what happens when the maximum polyphony is reached.

- Audio mixing - how the audio from multiple voices played simultaneously gets mixed before output

- Buffering the audio samples for playback with minimal latency

- Interfacing with MIDI - taking a MIDI signal and converting to instructions to send to a micro controller etc.

I realize I am probably way out of my depth but I am curious to know if this is even doable using off the shelf (readily available) parts that a hobbyist would have access to. I have looked at Arduino and it's related offerings but it seems to not have the power or capacity to do what I am looking for.

Your help is much appreciated

 

[Nigel Goodwin]

Aren't there already polyphonic MIDI sample playing machines? - many keyboards for a start.

 

[enomis]

Hi Nigel,

Thanks for the response. Most products out there that allow the type of flexibility I am looking for are software and not hardware based. I am interested in a portable (small) device that can be played from a keyboard outputting MIDI to avoid doing it with a computer (with relevant software) and an audio interface. Also, the keyboards that allow your to keymap audio are very expensive and usually require that the samples be encoded in a proprietary format.

 

[Mr RB]

There used to be plenty of dedicated MIDI "samplers" I had a couple of rack mounted units that would do that. They would record X amount of samples, at full 16bit stereo quality then assign the sounds to MIDI notes and play them back under MIDI control.

These days that level of functionality is already incuded in so many musical devices I don't even know if you can still buy a "sampler" as such.

For a couple hundred dollars you can get a full 16bit audo quality digital multitrack with hard drive recording, and it will definitely have sampling and MIDI assignment included.

 

[Jon Wilder]

I can help with getting a PIC micro to decode the MIDI note on/off messages into whatever messages need to be sent to the playback device if that's what you're looking for. I would just need to know what messages the playback device wants to see in order to play the samples.