by Sandy Sims Feb 18th 2014
|About a month ago, I decided to buy an Akai MPX8 Sample player to add to my "live-but-k.i.s.s" rig for local performances to get away from GM MIDI drums for a while. This is a cool little box that can access up to 500 samples, now in 16 bit stereo .wav format, and load up to 32 megs in any 8-pad "kit", from 99 presets. For $99 I thought I couldn't go wrong.|
| Now before I go any
further, I haven't made it my mission in life to rag on Akai's development
team, nor steer anyone away from buying one of these as they *are* firmware
updatable and I'm sure some fixes are on the table, and lets face it, what
can you get for $99? A cheap cell phone, an evening out at the pub, a bus
trip (one way) to Vancouver from, uh, just north of there. This was a really
good thing for AKAI to dream up and I'm happy with it.
I know a lot of you are not, and that's one of the reasons I am posting this page so you can know there is a way out. all new products have their issues, most are fixed in the R&D stage, but, some sneak out untamed.
Here's some of the problems / annoyances I've found with the MPX8:
sample loading time. SD Card reads are faster than this, I've built
stuff faster than this and I didn't even know what I was doing. Most drum
samples are short so load in a flash, but a couple of long cymbals loading
while my fans anxiously await my next tune, I anxiously think about how it'd
be faster to load a real drum set onto the stage...
2 -NO MIDI Program Change! I was completely amazed that there is no PC recognition at all! I hadn't even considered it wouldn't be there because it defies logic. Basically, just a MIDI input that duplicates the action of the little selector know you use to find a kit. Seems logical. But then in light of problem #1 above, perhaps they just said to themselves, "It'll take too long to load, so what's the point..." or something like that. I have put in a request for that to be included in the next firmware update.
-Loop Issues, falling out of sync. This one doesn't bother me
personally, because I'll never use the MPX8 this way, but some of you had
great expectations. All I can say is "It's not a sequencer or a loop
Running Status MIDI
Inline MIDI "conditioner" on a chip $27 CAD (see below)
If you want one, you'll need a paypal account for the moment
-MIDI Running Status Blindness. This problem is a biggie for a
lot of people, including myself. I kept seeing posts on Akai's forum about
skipping notes and no notes, or occasional notes. Funny, I thought, my MPX8
works fine with all of my MIDI sources. But then I realized I had been
feeding it through my DIY drum sequencer first, even when the sequencer
wasn't playing it.
When I wrote the program (
a few months back now) for my sequencer, I had issues with my Kawai
Keyboards not playing all of the notes. It'd skip like a bugger. I monitored
and sampled etc. and concluded that whatever the problem was, MIDI-ox and
any of my PC DAW software was fixing it, as I've never had problems with the
Kawai playing a soft-synth. So Out came the scope, and I basically counted
notes I had played, then added them up on the scope. Some were missing! It
appeared the Note On/Off commands weren't always there. So I searched around
the 'net, not knowing what it was called, and found an article called
So, over the past few days, at the bequest of a fellow MPX8 user, I have designed a MIDI fix for it. (Picture above, right) It's on a PIC chip and basically started working right away. I plug it inline, turn it on, and away it goes! My drums now trigger the MPX8, as does the Kawai Keyboards. Of course being a bit of an electronics engineer, I had to add some features, and after having found problem #5 (which isn't really Akai's fault, it'd be just pre-defined for any non-polyphonic-per-pad sample player (see below)
MIDI Fix Added Features:
-I thought I had everything under control until I noticed and discovered
"Hey, sample players aren't like polyphonic GM MIDI synths at all! "
My ugly Board (which needs a box!)
|6- I've discovered yet another MIDI situation that has been messing up the MPX8. I showed up when I had the MidiFix hooked to my Korg Micro-Korg. Every once in a while a note would be skipped, well quite often sometimes. I found that when the tempo/MIDI Clock output is disabled, eveyrthing works fine, but when on the skipping happens yet again!|
| So away I went
investigating. It seems the Korg actually sends the MIDI Clock exactly
when it happens. It doesn't wait for a MIDI message to complete. This is a
nasty little problem for AKAI to solve, I wonder if they'll figure it out?
They likely won't ever be reading this haha!
Sure enough the F8's are being inserted in the middle of running status messages, talk about sabotage! I simply moved the routine that picks up meta commands (0xF0-0xFF) to a location in the program before the routine that decodes running status .
Anyway, here's the box I made because I'm being all environmental (using scrap wood) and too cheap to buy a proper box for it lol.
|I'm so happy I could share this project with you all, and I hope you've picked up some good ideas from it, or better yet buy the chip!|
MPX8 Program Change Hack:
After waiting for a couple of months, it's becoming apparent that the engineers at Akai Professional are not going to be coming out with a firmware update for the MPX8. This isn't a really big surprise to me as most of the users will be simply using the MPX8 as a sample pad/finger drum, plus they are releasing a newer product with recording ability.
So it looks extremely unlikely that I will ever get my program change firmware request, and I'll have to do a hack on the unit.
Because Akai won't offer open source or any info at all, this hack is pretty simple & superficial, but it will do the trick...
The trusty old 4066 CMOS quad analog switch is still the best choice for hacking panel switches like remote controls (I've done), and various "unknown" circuits. The worry of voltage/timing is erased using this method. There should be one switch on every button for full panel access. The pads don't need 4066's on them as they can be selected using MIDI notes already right?
I had a look
inside the MPX8, and there's certainly enough room to put in the little
board. If using an Arduino, don't have header pins attached as there is no
room vertically. Also, there will need to be the 4066 "sheild" as a
separate board so...
The Right Chip:
This Update May 1st 2014
Last Update September 1st 2014
...to Studio projects page
...to Fresh Nelly Musik!
Webmaster Sandrine Sims, Video Gena Hollingshead
Thanks to Everyone at the Akai Forum for getting my interest in this!
(C) FRESH NELLY MUSIK 2013