downsample

Actually the connection like this : source(wav file)--->low pass filter---->buffer----->downsample------>unbuffer------>sink but the output sound have noise so my lecturer want me to move out the buffer and replace another simulink block in order achieve the chipmunk sound effect but i unsure which one is correct.

Which simulink block can use to fade while i m waiting for teh next round of sample?

Thx a lot for replying...^^