Akai MPC Reference Manual page 22

Finally, let's tweak the bassline sound. This can be done in the FILTER section of the Program
Edit menu. Back to the MPC hardware!
Press the PROG EDIT button of your MPC hardware to enter Program Edit
Mode. Click on the F4 button (Flt Env) to enter the Filter page.
Use the Filter Type option to select a suitable filter type. We recommend
to work with the Low 4 type for a start.
Turn the Cutoff and Resonance knobs (Q-Link knobs Q14 and Q15) until
your bass sample sounds perfect to you.
Use the Q-Link knobs Q1 to Q4 to set the amplifier envelope. This controls
the overall level characteristics of the sound.
Do you want to add some effect, e.g. Chorus? Press F6 (Effects) and select the desired effect
type for your bassline. (Remember to turn the Inserts parameter to "ON.")
Now we've created a simple drum pattern with a bassline. But there's much more!
The Filter and Envelope display of the MPC hardware
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