I posted this in the beginners section but really it’s a request for some tips when looping a simple sample of say, a brass synth sound - single note so I can sustain it without sounding ‘too’ artificial ?
I know the end result I’m after but need to know where I should,be setting the start & end points for a smooth loop? the guys writing for the old SNES console were masters at this !
Well some ideas come to my kind, esp. From old amiga days:
of course carefully follow the waveform and find crossover/0-line points, so the waveform isn’t interrupted. Renoise can find 0 points, as far as I remember
try ping pong looping (I guess it will sound bad on short loops)
do cross fade, so fade in the part before beginning of the loop just before the end of loop, and fadeout the end of loop (there is a tool in renoise for this)
maybe the number of waveform cycles are important, too, but I don’t remember
I know the end result I’m after but need to know where I should,be setting the start & end points for a smooth loop? the guys writing for the old SNES console were masters at this !
Yeah. It’s basically an art and craft, and takes time to get right.
Back then, limited RAM made people creative. Some of the samples from those days are still among the loops I’ve heard.
If you’re doing forward loops, enable “snap to zerocrossing” in the sample editor. Makes things much easier.
But if you do ping-pong looping (which totally makes sense sometimes), you’d want to aim for “mirrored” waveforms and not the zero crossing.
Ideal spot for forward loop (0-crossing)
___|___ |
/ \ | / \ | /
/ \ |/ \ |/
/ \ | \ |
\ /| \ /|
\ ___/ | ___ / |
| |
Ideal spot for ping-pong loop (mirrored)
___|___ |
/ \ | / \ | /
/ \ | / \ | /
/ \ | / \ | /
\ | / \ | /
_|_/ _|_/
| |
Another tip: enable the spectrum view on the master scope to see a large summary of frequencies. This will often reveal when a loop is not optimal, as the frequencies will “roll” back and forth. Also, a bad loop can introduce additional frequencies, which you can easily pick up in this view.
Similarly, it’s possible to deduce quite a bit about the waveform from looking at it in the sample editor. Zooming in and out will reveal/hide samples at various intervals, and sometimes this helps to show “hidden” movements in the sound - which is key to finding those sweet spots for a loop.
When it’s not possible to find a good spot, cross-fading is the technique to use. It’s kind of a last resort, because it involves mixing the waveform onto itself. With complex sounds this is not really noticeable, but simple waveforms (saw, square etc.) can result in drastic changes to the sound due to phase cancellation. I know there was a rather cool tool floating around here on the forum a while back which tried to improve on the built-in x-fade in the Renoise sample editor, couldn’t find it?
Cross-fading can also be done manually in the pattern editor, by mixing together samples and rendering them to a new sample. This takes time, but you can control the process very accurately.
Damn you beat me with describing the techniques. I only want to add, it is really important to use both eyes and ears when looping and trying to loop perfect. You see the wavecycles (repeated audio) with eyes, and similar looking will loop smoothest when the loop points are set properly and at “the same” crossings. Also you have to dig in deep with your ears when it comes to timbre variations, at which places the sound sounds sameish, and place loop points (with zoom/eyes) in those sections.
Ping-Pong is always only a second choice for me, it is unavoidable to have at least very slight clicks in the loop whatever you do. Unless you place the markers at (short) silence sections. Ofter the clicks will drown in the mix though.
I wish there was better x-fading for looping purposes. One where you would first select your loop points, and have them preserved. And then when timbre modulation makes the loop sound clumsy (but otherwise looped alright) you’d select a range around the loop start, and have the corresponding range around the loop end faded in and out smoothly around the selection, the loop start point being the maximum fade-in point.
The equal power crossfade tool (pretty sure that’s what it’s called) is very useful. Probably my most-used tool of all. I think that’s the one danoise mentioned. Works flawlessly in 3.1 still.
I don’t like to think how much time I’ve spent looping samples by hand since I got a second-hand S-550 in 1994. It had what was considered very good auto-looping in those days but it was terrible and I usually had to do it by hand in the end.
It varies by platform, but in Renoise, when hand-looping, it’s easiest to stick with 0-crossings, as mentioned. This becomes much more difficult with stereo samples, of course. With those, depending on the sound, I’ve devolved to the habit of just calling up the equal power crossfade tool and trying different settings until it sounds good. Note that it’s not suitable for certain sounds, especially brass-like sounds, the crossfading just makes them sound phasey and terrible. Big pad sounds, strings, stuff like that, are ideal for that tool and I’ve had success with plenty of other sounds.
I never use ping-pong unless the waveform is uniform, it just never sounds right to me, personally.
The equal power crossfade tool (pretty sure that’s what it’s called) is very useful. Probably my most-used tool of all. I think that’s the one danoise mentioned. Works flawlessly in 3.1 still.
Indeed, that was the name. Now I could find the link:
https://forum.renoise.com/t/new-tool-3-0-xfade-pow/41920
it’s easiest to stick with 0-crossings, as mentioned. This becomes much more difficult with stereo samples, of course.
If you encounter such an “impossible-to-loop” stereo sample, you could always split the sample into separate channels. I never did this myself, but at least it’s possible 