by Adam-V » Mon Sep 24, 2007 4:43 am
Bi-directional looping supposedly overcomes some of the issues that can occur when sampling ensemble or pulse width modulated sounds where, due to chorusing effects you just cannot find an appropriate loop point without sampling many seconds worth of audio or ending up with a pulsing sound rather than a smooth natural sound. By having the looped section of a sample first play forward then in reverse rather than just forward, the theory is that the effect is not so noticeable as the start and end points always match up nicely.
Some samplers (Earlier E-Mu samplers included) allow you to specify this mode of looping as standard functionality allowing you to pick your loop points without having to actually destructively edit the sample. If you want to achieve this in modern E-Mu's, you need to edit the sample and somehow find the appropriate loop reversal points manually. Shame really, I reckon the amount of time I've spent on some samples trying to get the loop points right could have been drastically reduced if this function was available.
I guess the need for keeping loops as small as possible just diminished and E-mu obviously decided it was no longer even necessary once RAM started to become relatively cheap and samplers could be typically expanded to 128M.
Cheers,
Adam-V