If you are using time stretch on drum loops, most of the time you are still going to hear a change in pitch regardless, from the programs and gear I've used anyway.
You need to select the "Don't change formant" or something like that when you timestretch the sample. I'm gonna look into that and get back at ya tomorrow, aight?
I do it all the time, no stress
I've been checking it out and it really is a failsafe method. If you timestretch it, it shouldn't change the pitch at all. You might end up with some dirty artifacts on the sound, but no change in pitch. I got things mixed up when I was talking about formants and all of that.
If you're really curious about how you do this, just do a "print screen" (one of the buttons on the keyboard) and send me a picture of the layout of the timestretch plugin. I'll figure it out for you.
It sounds like you have just pitched the sample down/up in speed, so the tempo as well as the pitch were changed...The concept of timestretching is the ability to change the length of a sample and not the pitch.
Anyways. There's a million different ways to accomplish this so if you're stuck as fuck just holla at me and I'll help ya out in some way.