I'm working on the sound effects for my computer game, which is something I've never done. Many of the effects need to be able to be looped seamlessly so that the beginning matches the end. For instance, if I have a plane engine sound, I need to be able to make like a loop-able clip that I can play. But I don't know how I would go about doing this. The only software I have at my disposal is Logic Pro, which I've only used for music, and freeware audio editors like Audacity. Does anyone have any suggestions in making seamless audio loops?

I don't have any "tips", but obviously, the waveform should start and end at the same point
to make it loop. I suggest leveling out the start and end of all your waveforms to zero, so
you can combine any of them without much problem.

I've done quite a bit of this and can point you in the right direction. You need to get an audio editing program that allows you to set looping points and edit the wave form. I use Sound Forge Pro for this. Now it is up to Sound Forge 9, but make sure you get the professional version. The cheaper version (at least for 8) didn't support looping points.

From there, all you need to do the edit the waveform to make the starting and ending loop points match up. If they don't match up well then you'll get bumps, wobbles or clicks in the sound when it is looping.

I could probably write a whole book on this, but try getting the program and then reading the manual first. From there, you're going to have to spend some time just experimenting with the software and seeing what is possible.

A few quick tips:

1) The shorter the loop, the more obvious it becomes.

2) Instead of just focusing on the exact looping points, try and make the starting and ending portions similar as well. This will help make the SFX seem more seamless.

3) Have fun!

I hope that helps,

Nathan

Everything Nathan said...yes!

Audacity is fine for seamless waveform editing

BUT!

don't just get edit them at zero crossing points, make the wave form continuous. So at the very end try and clip off the waveform as it's coming up (compression) from below the zero crossing point and snip off everything after it goes above zero. Then the beginning of your file should start at zero and then raise above the zero crossing point (rarefaction).

This will play seamlessly, with no cuts, hiccups, or artifacts.

Speakers translate these digital waveforms into analog vibrations, so when the "line" goes below zero, the speaker pushes in, when the line goes above, the speaker pushes out. Making the beginning and end of your files at zero is technically accurate for a seamless loop, but you are asking the speaker to do something a bit out of it's comfort zone and are likely to hear pop or some other audio anomaly (unless the sample is already full of distortion and other artifacts if you don't follow the laws of compression and rarefaction.

Big words, but just make it end going up and begin going down, meeting at zero.

Well, this sound is a little bumpy in the middle areas now, but I've combined your advice with just adding compression to squeeze the dynamic contrast in the wave form. It's a little weird cause the only good engine sound I found that was free had like a whooshing as the plane flew by, so after all the compression it took to flatten the sound, it lost a lot of it's oomph. Then I went to Audiri, and I got the beginning/end to hook up. They hook up perfectly, the only slight problem is that there was a slight pickup that happened in the middle of the sound, and you can only hear it now that it's looped. But when you change the playback speed as the engine slows up and down, you can hardly tell.

Thanks

I'm surprised nobody mentioned cross-fading here. It's a perfect tool for smoothing out the loop points in many cases.

As for compression making the sound lose the 'oomph', perhaps you compressed too much. Using a good curved knee on the compression with no extra gain compensation will mostly leave the louder parts alone. I'd advise playing around with it to try and keep the quality of the original sound.

Crossfading is the way to go.

Quote: Original post by Kylotan
I'm surprised nobody mentioned cross-fading here. It's a perfect tool for smoothing out the loop points in many cases.

Me too. It's probably easiest and most effective way to do looping sounds.

- Piotr

Copy the end over to the start on a separate track, just like you would do with a photo, then set it to bleed into the start by adjusting volume envelope inversely. I'm not into SFX, that's just the method that can be used in music sometimes. I know that there is an option in FL Studio to do this, you just set it to "wrap remainder" when rendering it.

I use cross fades all of the time, and yes they are very helpful. However, you still need to be mindful of the waveform's shape and data at the looping points. Even with a good crossfade plugin, you can get some bad wobbles or archives that will hinder the seamless effect you're going for. This is why I detailed those other steps first and then apply a crossfade. This will give you a much higher quality loop.

You can also zoom way in, I mean WAY in to where you can see the individual periods of the waveform, and the do some cut and pasting to make things match up. This is particularily helpful when dealing with live recordings of musicial instruments which can produce wave forms with great variance.

Hope that helps!

Nathan