I need help with a synth tone.?

I recorded a note of a synth tone that I want to use as b. However, when I map it to a keyboard and play even a few notes lower it sounds horrible and stretched out. Is their any way I can match the waveform so I have that tone sounding great on all keys? It has a distinct "nyew" sound at the beginning of each note and that is lost playing low notes. I have the .wav if anyone needs to see it.