Not exactly sure what you're trying to do but I looked into this for my pad controller (korg padkontrol) recently. I hope similar principles apply with the akai controller as well. Generally, when you press a pad, a 'note on' midi message is being transmitted, followed by a 'note off' when you release the pad and the sound stops. In the Korg, you can configure the pad to act as a switch so that you press it once and release it and only a 'note on' is sent. If you press it again and release it, then a 'note off' is sent. You need to check the akai documentation for similar functionality. That's just one way to do it, at the controller level.