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OpenMPT => Help and Questions => Topic started by: Barth_Mader on October 22, 2012, 01:02:32

Title: Any way to minimize clicking sound with bidi loop on?
Post by: Barth_Mader on October 22, 2012, 01:02:32
Hello everyone. I have found a sample that I really like the sound of. I want to turn it into something like a pad, so that the note sustains longer without going out. I went to the sample editor and chose Loop>On>Bidi, but I've found that it makes this clicking sound when it loops and during playback, and it's quite distracting.

I saved the sample with that configuration and then, just now, I thought I fixed this by using a combination of downsampling and adding silence at the very edge of the start and end points but when I played back what I made so far I still heard that annoying clicking sound.

Is there a way around this or will I just have to accept it and try a different sample?
Title: Re: Any way to minimize clicking sound with bidi loop on?
Post by: psishock on October 22, 2012, 02:40:48
Well, look at the situation technically.

You will get a click either way if the sound shape on start and the end of the loop is not perfectly identical. Now, you can compensate this by finding the most similar parts on the sample and try to set your loop start/endpoints precisely, closest to this area as possible, to extend your sustain. Classic straight loops will usually work the best (it will sound most natural), unless the sample is modulated to the point where you practically cannot find a part in the sound shape that looks the same as the previous one. Even if you have to use bidi (on rare occasions it works better than straight loops), messing precisely with the start and endpoints can help you fight the annoying click.

I would never downsample a sample, it will make things even worse (artifacts, worse sounding, possible noise, etc).

So as i said, the if the sound shape is not totally identical on the start and the end of the loop you will get a click, but you can try fighting it to the point where it wont be noticeable while using in the song, by messing with your start/endpoints.
Title: Re: Any way to minimize clicking sound with bidi loop on?
Post by: Barth_Mader on October 22, 2012, 04:02:40
Thanks for the tips. I will try that. I'm very new to sample editing and stuff, so I'm not fully aware of all of the consequences of my tinkering with all the different controls. Thanks again.
Title: Re: Any way to minimize clicking sound with bidi loop on?
Post by: Saga Musix on October 22, 2012, 10:16:10
Basically what psishock said. Another thing to try is the loop cross-fader (only for normal loops, not bidi loops!), which fades the loop start and loop end into each other. This can create seamless transitions, but it won't always sound good.
Also, for bidi loops, a point of the waveform that would look smooth when mirroring the waveform around that point is always a good thing to look for, since that might promise a nice continuation of the audio signal.
Title: Re: Any way to minimize clicking sound with bidi loop on?
Post by: LPChip on October 22, 2012, 10:50:36
Actually, psishock is wrong about that for a bidi-loop the start point and end point should be at the same place.

We're talking about a bidi loop, not a normal loop.

With a normal loop, the part where the start and entrance hit the waveform should be as close (vertically) as possible, preferabely in the center.

With a bidi loop, however, the best place to put your start and entrance, is at the peak of a waveform. So if you either have /\ or \/, the center of that peak should be what you want your loop point to be. The sound goes back from that position, so if you don't use the peak, it will sound different than whats around the loop point, which can be seen as a click or abnormality in sound.
Title: Re: Any way to minimize clicking sound with bidi loop on?
Post by: Barth_Mader on October 22, 2012, 13:27:04
Thanks Saga Musix! I tried your suggestion and it helped out a lot. It's still not 100% perfect but it's pretty smooth now.

And thanks for the tip LPChip. I will keep that in mind.