Program bug, weird monophonic behavior

Hi,

I use a MPC500 as a MIDI sequencer since a couple of months. It integrates rather good with my setup (couple of synths and sound units hooked up to a mixer) but for the track I'm working on at the moment I want to use some tracks of the MPC for playing back samples of my synths and I'm experiencing a weird problem. Either I missed something extremely obvious, or it's indeed a weird kind of bug but after reading the corresponding parts of the manual and doing some searches I've no idea how to fix it...

here we go : I recorded two mono samples of my Novation Bass Station 2, each of them is approximately 12 seconds. They're meant to be played together so I created a program and assigned each sample to a different PAD. Then I used two tracks, each of them loading the program I created and playing one of the samples.

at the beginning everything works fine, the two samples play together along with the beat and the rest of the midi-controlled synths but after some time (it doesn't exceed a minute), one of them stops to play. It seems like it's not possible anymore that they play together, as if the program was suddenly acting mono or something. An interesting thing is, if I wait until the end of the ~12 sec bar, the sample which was playing stops and the other starts for the next bar (and it will switch samples again at the bar after).

If I reboot the MPC to restore the save where I configured the program and the tracks like I wanted, it works again for a short moment, then the problem comes back.

I hope my explanation was clear and I also hope I'll find a fix for this because it's really annoying. thanks for reading!

hey,

I just found out another problem which seems to be linked to this one. This thing of one source of audio interrupting another one also seems to go for the metronome.

I have one short bar with this sample I'd like to use triggered at the very beginning of the track. If the metronome is enabled when I play that back, here's what I hear :

- a really short bit of the first metronome's click, then it gets cut (after 2ms) as my sample is being triggered
- the second click of the bar cuts the sample (which should normally play longer)

i uploaded a sound snippet here for more clarity (the first 4 clicks you can hear are the COUNT IN clicks) : https://archive.org/details/MPC500BugClick

this is really weird and need to be fixed. I never used samples on this MPC before (just messed up with midi) so I don't know if the problem was there already.

it sounds like both pads are in the same mute group. set the mute group to "off" for both pads.

start with a fresh program(turn the mpc on with no cf card inserted) and avoid confusion that might arise from modifying an old program.

or if you want to play them together, you could try to put them in diferent layers in the same pad.

I already checked that they're not in the same mute group. That wouldn't explain the thing with the metronome anyway. After doing further searches on the forum I came across a couple of posts of people having the same problem as me (this thread was notably insightful : http://www.mpc-forums.com/viewtopic.php?f=18&t=130434).

So in the end it does look like a polyphony problem. I first dismissed this possibility because it seemed impossible to me that those two mono samples eat all the polyphony (I made some tests in a new sequence which just ran those two sounds). But everything leads to think it's the same problem, and according to some posts on the matter it seems like long samples tend to provoke that bug. I also read something about panning samples increasing the problem, and I did pan my two samples. Actually I remembered that I first noticed the problem exactly at the moment when I panned the samples in the program. Didn't have time to check yet but I think I'll give that up if it allows me to finish that track.

Anyway, this problem really sucks, especially as there doesn't seem to be any fix. I don't want to use this MPC for too long and go for a MPC1000 at some point but how are you supposed to sell a MPC500 which has a polyphony of one voice as soon as you run a "long" sample in it? This box is pretty cheap overall but this problem is hardly excusable.

Still opened to suggestions if there are some fixes or workarounds...

Sounds odd for sure. Have you got maximum RAM installed? Also, how have you got the truncate settings set (can't remember how to change, might be mode>pad 8 )?

Neither of the above would affect the metronome though AFAIK.

that sounds weird. how long are the samples? are you trying to use the mpc as a multittrack recorder? 'ive never tried using samples longer than 4 bars, and i wouldn't be at all suprised if the mpc500 chokes on 1 min samples, since it was never designed to be used like that.

if they are super long you could try splitting them up.

Hey and thanks for your replies / sorry for late reply (this problem put me off the mpc for a week and I started to do a tune on the computer again).

No I don't have any RAM extension or anything more than what was provided when my roommate bought it back in ~2011. He barely used it and I started to use it since like four months. Now I'm embarrassed because my plan was to get a MPC1000 and sell the MPC500 for him, but as I end up not having the money for the 1000 I'd like to buy the 500 from him first but now that I noticed this problem, I realize I won't be able to use its full capacities.

The plan was to sample some loops of my synths in order to use less MIDI bandwidth mostly for stability concerns (I'd like to use this setup to do gigs at some point and MIDI can do random weird stuff sometimes). If I remember well, the two samples I wanted to use are like 12 seconds long (four bars but the BPM is quite low).

True that this problem is weird but apparently other people experienced it (see posts linked above). When I'm done with this new computer track I'll do some more tests : first trying to un-pan the two samples (I wanted one left and one right, that's a shame if they are both in the middle but if that allows me to finish the tune then I'm sold) - then I'd like to try to run a basic beat with several samples, but all drum hits or say short samples (the idea is to be sure the main problem isn't the length of the sample).

I'm embarrassed because if I buy this MPC I perfectly know I won't use it for too long (I want to switch for a MPC1000 as soon as I can) so I'll want to sell it but who wants to buy a MPC which practically doesn't have polyphony?...

I'll probably mail Akai although I don't have any hope it'll bring anything.

it really sounds like you are doing something odd. mpc's are made to record and playback samples. if they couldn't do that then they'd be pretty useless.

midi feedback loops can cause similar problems where you run out of polyphony unexpectedly, or when your note off messages are getting lost. disconnect all midi cables then try again.

did you try making different programs for each sample?

do you have the latest OS on your mpc?

try doing some other stuff with samples on your mpc, you might be messing up something simple.

you have read the manual i assume? the manual details the things that do work...things not in the manual may have unexpected results.

Is the mpc 500 capable of working with samples 12 seconds or 4 bars long? I just assumed it wasn't an option. I guess I'll try and report back.

I still hope I'm doing something wrong but I did read the manual and tried to mess up with several options to get that work and didn't help. I did try the thing with using two programs (PAD 2 loading Sample 1 from Program 1 / PAD 3 loading Sample 2 from Program 2) but the same thing happened : everything works fine for say 30 seconds / one minute but after that the sounds start cutting each other off. If I restart the MPC it'll work again for a short time. which makes me think this is actually a bug.

you might be on something with the MIDI loop thing though, I should draw the setup to make it 100% clear to myself but it does imply MIDI going back and forth to some units, going through the computer because I need a software to program my TX81Z synth... I really don't have time today but I'll try to figure that out and also do a test with MIDI unplugged, that's a good suggestion thanks!

Not sure if this is similar to what you were trying but your post made me want to try long samples as I have not yet. So i did like an 8 bar drum loop. Then i put a 12 second string drone on one pad and a 12 second synth drone on another. Each is on its own track. It has been playing for ten minutes now with zero problems. I do have the Ram upgrade and I will say without it i could not do much of anything worthwhile on the 500. the only midi i use is the 500 out as a clock. Also i doubt it makes a difference but I make and edit my samples in the Daw. Its just easier to me. Hope you figure it out.

I do not use MIDI, however I've used this machine as a DAW and it can play a minute long sample and its gravy. No issues.

It could be an internal OS thing. I recommend to save all your work on a CF card, remove it and then reinstall OS 1.31 from Akai's website. Usually that fixes whatever hiccups it might have.