Polyphonic Sampler Player

Created Sun, 09 Dec 2012 18:26:04 +0000 by joe4smt

joe4smt

Sun, 09 Dec 2012 18:26:04 +0000

Hello, I'm looking to use the chipKIT Uno32 for a museum project, it needs to playback 30 triggered short sounds a couple seconds each, basically piano type sounds, but polyphonic, ok to be read from an SD card. The sensors can be piezo or whatever suggested that would work best. I see that this has already been accomplished with 5 triggers from Hack a day at [url]http://hackaday.com/2011/06/08/chipkit-sketch-mini-polyphonic-sampling-synth/[/url]

Can this be easily done with chipKIT? or is there a better board? Is there anyone out there willing to help, or possibly compensated how to accomplish this? please contact me directly at joe4smt@yahoo.com

majenko

Mon, 10 Dec 2012 20:31:00 +0000

The main problem with this is the combination of polyphony and SD card. Using an SPI interface that just isn't going to happen.

Now, if you could store the samples in internal FLASH, then it would be much more feasible.

Of course, it depends on the quality of your samples - low speed, monophonic samples will be easier to get to work with polyphony, but if you are wanting 44KHz stereo samples, then in my experience two of them at once from an SD card is too much.

If you can get over the slowness of the SD card (maybe a CF card would be better?), then mixing and generating the sounds is much simpler. The example you cited does just that, and is pretty simple.

Again, if you are looking for quality sound, then I would recommend interfacing the PIC32 with a proper sound generation device, such as a cheap I²S audio codec chip. The PIC32's SPI modules have built in support for the I²S protocol and can drive those chips directly - the sound quality will be considerably better than PWM generated audio.