GroupDIY

General Discussions => Truth Table => Topic started by: ChrioN on April 04, 2019, 06:01:31 AM

Title: DIY MPC type sampler - What platform/system?
Post by: ChrioN on April 04, 2019, 06:01:31 AM
First off - My programming skills are poor, I've been doing some Arduino codes, and also reading up a bit on C++.

I thought it would be fun to make a little sampler, similar to the Akai MPC.
Not as comprehensive in functions of course, but similar in terms of basic functionality.
Sample, edit sample, assign sample to pad, pushing pad tells midi sequencer where to play that corresponding sample, and so on...
Its basically a midi sequencer with added functionality of recording, editing and storage of  48khz 16bit audio.

As I've been doing some Arduino codes, I thought this would be the perfect system to run this on, except its not.
Too little RAM to store the samples on! 64MB would be enough, but the largest RAM on a Arduino compatible board I've seen is 16MB IIRC.
It doesn't appear to be a demand for more RAM on the micro controller hobby scene it seems, as many of the popular MCUs have the capability to interface with 256MB and up.

I would love to do this project with a micro controller, but I would avoid making my own PCB if I could.

Alternatives? Moving up to one of those credit card sized computers running linux?
The MPC Live runs on a RK3288. That certainly solves the RAM issue.
But I don't know how well they support encoders and buttons, and more importantly, audio latency.
Any ideas? The reason I ask the question is to know what I should start reading up on.

Fun reading regarding the internals of the MPC Live: https://niklasnisbeth.gitlab.io/mpc-internals/
Title: Re: DIY MPC type sampler - What platform/system?
Post by: iampoor1 on April 04, 2019, 11:41:18 AM
Raspberry Pi
Title: Re: DIY MPC type sampler - What platform/system?
Post by: dirtyhanfri on April 05, 2019, 12:04:13 AM
There’s a project similar to it for the raspberry, it’s from the creators of the non official but much better OS for the MPC 1000 / 2500, JJOS.

I’ve seen some videos in YouTube but can’t remember the project name now, if you search for JJOS surely you’ll find videos from it.

Maybe it fits your taste, it looked kind of primitive when I looked at it.

Maybe there’s a way to connect buttons to the GPIOS of the raspberry and make them work with the software.

A DIY MPC is something always been around my mind, the biggest problem is the software I think...
Title: Re: DIY MPC type sampler - What platform/system?
Post by: ChrioN on April 05, 2019, 02:23:41 AM
You are talking about this:  JJ-Sequencer (http://"http://www7a.biglobe.ne.jp/~mpc1000/jj-seq/")

Maybe I should've been more clear about one thing. I want to make this an embedded thing. Power the unit up and in a second or two the unit is operational. I won't be having a big HD monitor hooked up to this, I will be using a couple of small 128x64 monochrome LCDs to show needed information.

It does seem like I have to scrap the microcontroller based sampler idea and move on to something running some version of embedded linux. Maybe a realtime one. Any useful tips or such?

 This one  (http://"https://www.youtube.com/watch?v=_nBK8sAl9nw")uses a raspberry pi together with a fairly powerful microcontroller. Pretty impressive, but I believe theres a hefty amount of latency, which to me is unacceptable.
Title: Re: DIY MPC type sampler - What platform/system?
Post by: Rob Flinn on April 05, 2019, 07:31:18 AM
Look at www.ucapps.de.    They will probably get you half way there.  They have sequencing & sample playback hardware.  Their latest kit runs on the STM32 or LPC17 platforms which are very powerful.  They already have SDCard readers in their designs too which would be ideal for sample storage.
Title: Re: DIY MPC type sampler - What platform/system?
Post by: ChrioN on April 06, 2019, 02:52:25 PM
I certainly had that goldmine in mind  ;D
Title: Re: DIY MPC type sampler - What platform/system?
Post by: Niketouille on April 11, 2019, 03:38:32 PM
You need to keep in mind that : playing real time audio + graphic user interface need some ressources and quite fast code with eventually an RTOS. 8 bits arduino are no really well fitted for the task. Eventually have a look at something with 32 bits cpu. Stm32 are now quite well documented and tons of libs are available
Title: Re: DIY MPC type sampler - What platform/system?
Post by: ChrioN on June 10, 2019, 03:19:21 AM
Going to go with a Beaglebone Black + Bela!
Title: Re: DIY MPC type sampler - What platform/system?
Post by: mhelin on June 10, 2019, 04:27:28 PM
A Linux SBC like the Atomic Pi might be the easiest way into sampling workstation. Atomic Pi is running Intel Atom X5-Z8350 CPU with 2 GB RAM, and has got a programmable XMOS audio processor (with XTAG connector, though in 2 mm pins so you need an adapter cable) with 4x I2S inputs and a 2x5W Class-D power amp. There are also some 3v3 GPIOs available. I think this board is no more manufactured and so is surplus (according to a rumour 28 000 pcs was manufactured for some robot, it was actually Kuri - https://www.heykuri.com/explore-kuri/) but there is plenty of stock available.

https://digital-loggers.com/api.html

Available on Amazon:
https://www.amazon.com/Atomic-Pi-High-Speed-Peripherals/dp/B07N298F2B/ref=sr_1_1?keywords=atomic+pi&qid=1560198194&s=gateway&sr=8-1
Title: Re: DIY MPC type sampler - What platform/system?
Post by: ChrioN on July 31, 2019, 09:06:33 PM
Atomic Pi looks great. However, hard to get here in Sweden.