Any tips on using audio files with Convolver? And by audio files I mean just any old audio files, not IRs.
An IR is just nothing else then an audio file. It is quasi the response of a “very sharp click” through some system, so you can basically just record a click exciting some device or space, and get the frequency and delay response of the device to use with a convolver. I will call any sound to be used “IR” in this post.
So - click like noises probably yield the closest equivalent result to an IR. Hihats are very similar for example, or records of things tapped, hit with sticks and stones, cracking, banging, whatever. As A little test, fire a click through the convolver with any sound. Like a single non-looped sawtooth cycle goes a bit into the direction. Though a proper balanced broadband impulse should make - the convolver just play back the ir sample.
Other than that, using any random sound - you can kind of anticipate the effect a sound will have. If there are tonal frequencies present, the result will be a heavy ringing in that frequency. If there are click/pop like noises, it works like a filter to the frequencies contained in those transients. If the frequencies or clicks are delayed in comparison to the start of the sample, it will also yield a delay effect to these elements. If you play back the sound normally, and watch the frequency analyser, you can anticipate a bit the frequency response of what you’re trying to use.
So here some Techniques to work with it:
One practical Tip would be to equalise the sound before with a slope eq, so the low frequencies are weakened and the high end is sharpened/boosted up. Think of the result should more or less make a flat line in the spectrum analyser, and not be too loud, the longer it is the lower the volume should be. This can reduce the boomieness that will often happen because normal samples don’t have an even frequency response graph but usually have more energy in the lower freqs.
Also you can distort the sound a lot, to add harmonics that will close gaps in the freq response upwards, and even things out a bit, and add brightness. The distortion won’t be transported to the result by the convolver. It will just make the result more even and rich sounding, a bit less defined though, but normally the extremeness of the effect is more of a problem than lack of definition, when using everyday sounds.
Put a volume envelope on the sample you are using as ir, to make it a bit click like and weaken the tail. Unless you want the heavy muddy boomy scratchy loud ringing. Look at the volume envelope of a reverb tail as a starting point. This will also make things less muddy. The longer you make your sample, the more it will go from the “filter” type style to a “reverb/echo” type effect.
Ultimately you can ofc process the heck out of the sample, chorus will be transported, filtering, echoes, dynamics, reverbs…just the organic variation will lack a bit, i.e. in a chorus. You can also sample the “ir” through your xyz superduper space simulation reverb, and have its character and position cue added to the final effect.
-Create empty audio file ( 1 second long )
-draw 1 sample click .
-process through cabinet simulator , either by clicking process fx or rendering .
-trim / maximize
-load impulse in convolver .
NOw you can see the actual impulse that is used in the cabinet simulator .
Totally useless but FUN
YOu could this with reverbs too , outcome will be totally different since this is a realtime modulated effect
Thanks for the replies. Very helpful. I’m off to try to construct some Convolver files.
there are “quick” IR’s that are simply soundfiles of a loud pop (usually a balloon) in the desired room, but that’s not a very accurate way to work with convolution, most IR’s that are traded/sold are made with a specific sine sweep instead of a pop, which then has to be deconvolved separately. this can be done natively in Reaper, and will be more of an accurate representation. of course it’s lots of fun to just mash up some soundfiles & see what comes out!
Yeah, of course quality reverb or speaker impulse responses have their own standards when it comes to making things sound pristine.
Nonetheless it can be a lot of fun to abuse the convolvers, crafting own filters/reverbs/delays from various noises. Yeah, really, you can just take some white noise, make it stereo by making left and right have different data, put a sharp envelope on it and stuff it into the convolver - to get some really unique reverb effect. Do the same with a rainstick sample - and make a reveb with lots of character. Or take a sample of a creaking door, extract single snap like sound from it, and have them color any sound into a woodlike timbre. I also like clicky percussion samples (claves, sidestick,…) that have some room on them - into the convolver, to get some kind of very colored, lively room on your drums, that won’t always work well and will need to be tuned to have a chance at all, but no clean reverb/room impulse would sound that organic. And then comes the point when you learn, that you can convolve an IR with itself or other IRs to accumulate effects by just rendering the IR sample through a convolver or with other tools…
This is more for experimental designs, of course for serious mixing tasks you will want to use serious impulses that were created with care and proper deconvolution.
Two short tips:
You can run a short clicky sound through your favorite effects/reverbs and record the output, then use that sample in a convolver.
Or you can play with firecrackers in different locations, record it with whatever you have and use that as a source.
I have found this more fun than useful though, i usually stick to my favorite IR packs when i use the convolver, which i do quite often.