Post your questions, opinions and reviews of the MPC1000. This forum is for discussion of the OFFICIAL Akai OS (2.1). If you wish to discuss the JJ OS, please use the dedicated JJ OS forum
By Txrrxbxss Mon Aug 27, 2012 7:36 pm
Hi,

I've noticed something a bit strange which started happening yesterday and that I can't figure out.

While using the MPC1000, I noticed that hitting one of the pads very fast (like an extremely fast snare roll) would stop the playback of a much longer sample (say 5 seconds long) playing on a different pad.

Voice overlaps are all set to POLY, and the Mute Groups are all off...

I also had drum triggers set up on a tom and a snare, which where fed into the MPC via an Alesis drum trigger interface, as well as a Roland SPD-11. Because the phenomenon initially occured whilst using these, I tried using the pads directly on the MPC to see if the same thing happened - it did.

I then unplugged the Alesis and the Roland, and tried again using the pads directly on the MPC. The problem was solved.

When I plugged the Alesis and the Roland back into the MPC, the problem had vanished... For a while at least. Suddenly, playing a really fast snare roll once again made the longer samples stop whilst they were playing simultaneously.

Could this be something to do with the re-trigger settings on the Alesis? I can't figure it out...

Any ideas would be great, thanks in advance!
User avatar
By sciguy Wed Aug 29, 2012 2:14 pm
It's probably a polyphony limit issue.

The MPC has a maximum of 32 note sample polyphony. What you're doing with the snare roll is eating up polyphony slots, until it has to stop the longer sample.
This can be especially noticeable, and something you really need to pay attention to, when you've got more complex sequences.

As for the problem existing with just the other stuff plugged in, I dunno, but try some of the tips below first (specifically #3)

Some tips to help not to use up polyphony:
1. Convert samples to MONO. Obviously not every sample, but many drums, for example, don't need to be stereo samples. Stereo samples take up 2 polyphony slots.
2. Clip samples as short as possible. If it's a long sample, it'll be a while until the MPC can re-use the polyphony slot when the sample is finished.
3. Make individual pads MONO. Probably the best solution in your case. It will cut off the previous hit of the snare when you hit it again, so that the entire snare roll will only take up 1 polyphony slot. (or 2 if it's a stereo sample)
4. Use mute groups where you can. If you have multiple variations of a snare or hat for example, they could probably be in a mute group, so that they all only use up 1 polyphony slot.
5. Turn off INPUT THRU. It uses up 2 slots of the available polyphony.
6. Resample layered pads. If you've got more than 1 sample assigned to a pad, resample the Main Out for that pad. Each sample layer uses up more polyphony slots, so resampling can make it only use up 1 slot.
User avatar
By Roger Nodge Wed Aug 29, 2012 4:33 pm
sciguy wrote:It's probably a polyphony limit issue.

The MPC has a maximum of 32 note sample polyphony. What you're doing with the snare roll is eating up polyphony slots, until it has to stop the longer sample.
This can be especially noticeable, and something you really need to pay attention to, when you've got more complex sequences.

As for the problem existing with just the other stuff plugged in, I dunno, but try some of the tips below first (specifically #3)

Some tips to help not to use up polyphony:
1. Convert samples to MONO. Obviously not every sample, but many drums, for example, don't need to be stereo samples. Stereo samples take up 2 polyphony slots.
2. Clip samples as short as possible. If it's a long sample, it'll be a while until the MPC can re-use the polyphony slot when the sample is finished.
3. Make individual pads MONO. Probably the best solution in your case. It will cut off the previous hit of the snare when you hit it again, so that the entire snare roll will only take up 1 polyphony slot. (or 2 if it's a stereo sample)
4. Use mute groups where you can. If you have multiple variations of a snare or hat for example, they could probably be in a mute group, so that they all only use up 1 polyphony slot.
5. Turn off INPUT THRU. It uses up 2 slots of the available polyphony.
6. Resample layered pads. If you've got more than 1 sample assigned to a pad, resample the Main Out for that pad. Each sample layer uses up more polyphony slots, so resampling can make it only use up 1 slot.



Dope info :nod: I haven't run into these kind of issues before but there's about 3 or 4 things from this list I'll start doing to be proactive.
By Txrrxbxss Wed Aug 29, 2012 5:47 pm
Hey,

Thanks so much for providing all that information, I will defintely try those things, but there's every chance that those are the issues, and not the other hardware connected to the MPC. I thought there could have been some kind of conflicts to do with the MIDI messages they were sending, but probably not.