TimeStrectching causes slap-back echo artifacts
Created by: harryhaaren
Issue reported via email by Protein Kyn: continuing discussion here:
I have a problem with luppp. There is an echo!! I connect master left & right in the system and I heard an echo. I take a simple loop and I play it with Luppp and with VLC. In attach 2 files : 1 with Luppp (luppp.mp3) and the other with VLC (vlc.mp3). I don't know why there is an echo and I don't know to remove it. https://drive.google.com/file/d/0B13cNMKDQczybjRoX3FfRTVuZVlHZGtvVmJEZWQ1T1NFQjFj https://drive.google.com/file/d/0B13cNMKDQczyWVJmUFdPbFBxVWNZb2VXOUlzWkVHWW11U18w
The "issue" that you're seeing is that Luppp is time-stretching your loop (perhaps badly, what version of Luppp are you using? There was a bug there that has been fixed...)
The time stretching algorithm currently used in Luppp is not a high-quality one, which causes this "slap-back" echo when extreme stretching is applied.
Is the BPM of the song similar to the loop? Does the problem go away if you load the loop, and then right-click->"Use as tempo"?