People have been reading up on my post about the gain structure within the MPC4000 and so I did a bit more research into it.
As it turns out, you don't need to do the -24dB base point within the multi to allow full range - the problem it with the default tilt-velocity value within the programs modulation matrix.
For those who do not fully understand, I'll give a quick example.
Lets say we have a normalised sample (to -0dB) within a program. All the gains and levels within the program are set to 0dB and the overall program level set to -6dB. Volume within the multi is also set to 0dB. At this point, irregardless of the tilt-velocity value, a midi note of velocity 63 will trigger a sound at this volume below the -3dB limit (0 + 0 + (-6) + 0 + (-3)) = -9dB).
Tilt-velocity is the rate at which variations from this midi set point affect the volume. This is best explained with another graph:
Note that this graph shows relative amplitude, so shift everything down -6dB if your total gain strucutre is set to this as per the description above. Additionally, note that this graph is for linear response mode in the program.
With a tilt-velocity of 0, any change in midi amplitude has no affect. For example, this would be suitable for an organ sound. With a tilt-velocity value of 34 (the default for a new program), the dynamic range over the midi note is a massive 42dB! Bearing in mind that 6dB is a doubling/halving in volume, this is just too much. Lets say your entering a hihat pattern on the pads and you are reasonably consistent with hitting the pads at the same velocity. Assuming there is only a velocity of 20 between your hardest and softest hits, this would result in a doubling of volume between them. Remember that the pads record 128 levels of velocity, so in practice (at least for me), my range is larger than this.
From looking through the Akai Pro 0 CDROM patches I found the following tilt-velocity values in use:
* 17 appears to be a good default (used in 18/27 patches).
* Piano and bass sounds have a tilt-velocity of around 11.
* Drums are a bit more dynamic with a tilt-velocity around 22.
So my recommendation is set tilt-velocity to 17 for all new programs and work from there. This also alleviates somewhat the volume issue and avoids the -24dB volume within the multi (so you don't have a huge volume different between multi and sample modes). With a tilt-velocity of 17, and all other default settings (0db everywhere, -6db program level), only velocitys 121-127 are clamped to -3dB, which is an acceptable tradeoff.
Again, hope this helps!