Still got a weird problem

This is a continuation from my other post first of all. I changed my samples to mono to free up voices and that didn't help. But as I was troubleshooting I narrowed the problem down and was needing some help on the cause. I feed the outputs of the mpc into my laptop and used audacity to record my songs. I recorded a blank sequence with no samples at all with my other sequences that have samples. When I record spinning the wheel from one sequence to another I see the signal on audacity. When I record the blank sequence I see minimal activity on record. But when I play it back the signal get progressively louder during the blank sequence. Like some type of feddback. As my other post my problem was the volume fading up and down. I thought it was the samples I was using so I decided to just record a blank sequence and see what it would do. I believe it is the mpc because I changed cables and even used wave editor to record with the same results. This is really annoying because if I have a song with vocal samples that aren't that loud when I record. Upon playback they are louder than the drum track. Any help or advice would be greatly appreciated. It just started doing this a few weeks ago and I'm racking my brain to figure it out. If you need more description to the problem let me know and I will try to clarify them. thanks

It might be worth saving entire memory, create a .zip and post it somewhere that other people on the forum can get it so that they may be able to recreate the problem (or not).

List steps to reproduce the issue and what to listen to so that people can hear the problem for themselves.

Good luck!

I don't know if you've already tried this, but I sometimes find that effects will often mess up how the sound is recorded, and if I save the whole project, turn off the MPC, turn it back on and load the project, it will sometimes have less interference with the sounds. Also, when recording into the computer through the mic in, it sometimes does some funky stuff.

Thanks for the advice and help. I found out that the problem was because of using the line-in on my laptop. I was being lazy and didn't hook up my firewire soundcard. When I hooked up the signal through it my problem went away. Thanks for the help.