Detecting Sound Loops

[tehachapifan]

Maybe it's the drummer in me, but this is one area that I wish could be addressed better with sound files in general...which is being able to pick up on and hear the sound loop(s). I mostly hear this with diesel sound files when the loco is at idle and, if it's too noticeable, I'll often unload the file. While I've never attempted to build a sound file and would have no idea how to, I've found that some files loops are really noticeable while others aren't. I have one sound file in particular loaded in a loco where there is absolutely no trace of a diesel idle sound loop whatsoever, which makes me wonder what kind of attention can or can't be given to the looping of a sound sample when building a sound file. Are there tricks or techniques that can be used to smooth the transition? On that one really good file, it almost seems like there's a subtle and random echo-type effect that runs over the top of the diesel idle sound that eliminates any trace of looping, but I can't say for sure. Thoughts? Anyone else wish this was addressed better?

Edit: Right after posting this I realized it reads like I'm only talking about the moment in time the sound sample loops from end back to the beginning. My comment/question extends beyond that to include any repeating/rhythmic sound(s) that tips it off as a loop (make sense?).

[DKS]

Disguising sound loops is an art. Likely the quality of the loop is a consequence of the budget for building the sound library. Having worked as a sound engineer on and off, I'm also very sensitive to loops. Echo effects are one way to disguise them, but the better approach is to use a good long source file, break it up into multiple pieces, blend them together using carefully-timed crossfades, make a few of these assemblies from randomized segments, then assemble them all into one big loop with another crossfade. It's a lot of work, but the result should be worth it.

Another trick is to make an extremely short loop from one or two cycles of the sound. This too can be detected, but it's less annoying than the longer loops.

[tehachapifan]

Thanks for the reply and info, DKS! Interesting to find out the echo trick is an actual thing.

Something else I find interesting with a loco idling somewhere, is how sometimes me standing in a different place around the layout will reveal a repeating sound that I hadn't heard previously. I recall a few times with certain sound files where I think I hear my cat meowing repeatedly, for example, then to discover it's coming from the idling loco. Then, it goes away when I move again. Sound is complex stuff, I guess.