Changing pitch without influencing the Pitch

[Paul]

Hi guys,   I got a little problem, i found a great Bass which fits into my Song (SySa&LD - BreathLD - 085). The song is arranged by many external Midi devices. My question is, the BreathLD Bass changes his speed also when i transpose the Note - even in small steps. I experiment with the Attack/Release/Sustain/Decay features but i cant get the Bas tied. Can somebody guide me into the right direction. I checked all the settings in Voice Edit and they are still flat, no editing done so far ! That Bass is the ideal one for my Song, but the changing in speed, spoils it.   Many thanks in advance,   Paul   P.s. If this might be the nature of the sample, does somebody know that there excist a good plug-in, proggie,  ... which could make the transposing straight ?