To round out Plugin Use/Abuse Month here on Designing Sound here are some neat tips and tricks from the 3 hosts of the Tonebenders Podcast.
Convolution Reverbs are amazing tools to have in your arsenal of plugins. Unlike conventional digital reverbs which simulate theoretical spaces with arbitrary parameters, convolution reverbs use signal processing to deploy the reverberation of a real, existing physical space. In order to make this magic happen you need both the plugin and an impulse response generated and recorded in the field. Without an impulse response (IR) the plugin alone is not very useful. Luckily, most convolution reverb plugins come pre-loaded with a library of IRs that give you a wide range of reverb settings you can put to use.
The IRs used to create those plugin presets are essentially just audio files – created out on location by either playing back a sine wave sweep or by making a loud high-transient noise that covers a large swath of the frequency spectrum – by firing a starter’s pistol for example – and recording the result. The convolution reverb calculates the relationship between the source sound and the resultant reverb created in the space. It can then apply that mathematical relationship to any other sound you patch through the ‘verb. The results are very realistic and natural-sounding reverb treatments. In post-production applications, a convolution reverb can be a life-saver for matching ADR with location audio, and making sound effects feel like they inhabit the same space as the actors. Yet for all the help they offer in making things sound realistic, convolution reverbs can also be employed to make things sound very other-worldly as well.
Every so often I find myself looking for a sound that I can not quite find in my library or even begin to figure out how to tackle. This dilemma is the sound designer’s version of writer’s block. I’ll be banging my head against the wall as my progress grinds to a halt. One strategy I resort to in this situation is to pull up a convolution reverb plugin and try to get creative with the impulse responses I load up. There are some interesting IR’s available; the precise acoustics of the world’s most revered performance spaces are there in your preset menu, alongside IRs recorded in caves, tunnels, and plastic garbage cans. Any space where an IR can be recorded can then be emulated by a convolution reverb.
There are obviously very scientific and rigid rules for those who create these beautiful and realistic reverbs, but the truth is that, since the IR is essentially just a sound file, anyone can go out and record their own IRs and load them into a convolution reverb plugin. And if you’re in search of a new sound altogether, you can throw all the rules right out the window and basically hack the plugin, because any sound can replace an IR. The weirder the better.
Now we are in experimental territory and that elusive sound effect is out there somewhere. The more out-there sounds you try, the wider range of results you’ll get. I’ve come up with a few hints as to what kinds of sounds yield interesting results. Look for things with movement to them like pitch shift or volume modulation. You also want to stick to short sounds. Longer ones can bog down the processors and just generate muddied-up sounds … but of course disregard that advice if you are looking for muddy sounds. Really, anything could work: it’s all about trying new and different ideas.
There are a few practical things you should do in order to get the best results. First up, before you import a sound into your convolution reverb, you will want to prep the sound file a bit. I always bring the sound file into my DAW and edit out any silence at the head and tail. This is important as silence will not be understood by the plugin algorithm as silence. The computer will apply a bunch of complicated math to the nothingness and create zero effect. No point in wasting CPU power like this, so top-and-tail the file extremely tightly. Apply super-short fades to the file ends to eliminate any clicks. Next, you want to make the sound as loud as possible without clipping. (Actually you can get some crazy sounds from IRs that are maxed to clipping, but normally that’s not what you’re going for.) You want to have as much data in the file as possible – because using up all the headroom available will give the algorithm more information to work with. Quiet sounds just don’t create as much of an effect. The easiest way to do this is to normalize each file. I usually normalize to -.05 dB. (Normalize each file individually rather than in a batch, otherwise you will be normalizing everything relative to the loudest of all the sounds highlighted, instead of each sound on its own.)
Once you have the sounds prepped you can import the sounds into the convolution reverb and trick the plugin into believing the sound is an IR. I won’t go into the specifics of this here, as each make of plugin will do this in a different way, with different levels of complexity, but for some it’s as simple as clicking ‘import IR’ in the plugin’s library interface. Once you have a bunch of sounds imported as IRs it’s time to experiment and play around. Here it’s important to consider both sides of the equation… meaning the sound you use as an IR is as important as the sound on which you are applying the effect. Using a rattling chain as an IR can create a great effect on a drum loop, but it just makes a sloppy mess out of a repetitive sci-fi alarm. So it’s a question of fiddling about with the combination of the IRs you create and the sounds you apply them to.
Inspiration hides in unexpected places. I found a telescoping back scratcher in my Christmas stocking and I quickly realized that when it was fully extended and whipped around, it made a great swish sound cutting through the air. So I set up a mic in the recording booth and recorded swishes until the little back scratcher broke in half. Not what Santa had in mind, but I was happy with the results. The following sounds are a few of those swishes as they were originally recorded, followed by the exact same swishes with the ‘reverb’ from a variety of unconventional IR’s.
Take a listen:
[soundcloud url=”http://api.soundcloud.com/tracks/73623258″ params=”” width=” 100%” height=”166″ iframe=”true” /]
To be honest, some of those were not much to write home about but a bunch of them will be entering my effects library for sure.
Where this trick has been particularly useful to me is in the design of slow motion or time lapse sequences. Going back to my original dilemma, where I’ve hit the wall searching for the right original sound, I’ve deployed some abstract thinking and taken a sound that relates to what is on screen and used that as an impulse response. What I’ve ended up with is a sound design element that works particularly well in sequences with skewed screen time. Using this same logic, I’ve sampled animal sounds or human screams as IRs applied to machines or vehicles, creating some original anthropomorphic effects.
Using sound files as IRs is a bit like spinning a roulette wheel as you never know which pairing of IR and source sound will work well to create that perfect new sound you’re looking for. You simply have to spin the wheel and see what you get. With practice, you’ll start getting a bead on things that will work best, but this is a technique that has been most productive for me when I didn’t know what I was looking for in the first place.
Rene Cornado had this to say (reposted from his blog):
fun with dopplers
here’s a quickie tutorial I just did with regards to how I use the Waves doppler plugin to make bys out of steady onboard vehicle recordings. In this case I used the onboards that I recorded of my motorcycle a few weeks back. Structurally, the concept draws heavily from Charles Deenan’s 100 whooshes in 2 minutes tutorial on designingsound.org
The main change I made to his process was to really work the ins and outs of each by using the faders.Some things I didn’t really discuss, but you can see how they would work are the fact that you can make stylized whooshes with this technique as well. That 100 whooshes post goes into great detail on that, though my preference is to go a little more focused than what Charles does. For example, I’ll substitute a bunch of bow waves and streams running, and get a bunch of underwater waves going on.
In the vid I’m using a controller instead of a mouse to move the faders (so that I can move several simultaneously)and I’m performing the moves in real time.skip the first 15 seconds or so. Vimeo seems to have a pause glitch in there.[vimeo]http://vimeo.com/45406187[/vimeo]My two wishlist items for doppler would be an option to make it stop at the end of the path, and 96k support.
as a modern sound designer, plug-ins are an essential part of almost any project. even with a huge tool chest of fun toys to play with, however, you can often find yourself struggling to come up with fresh, interesting ideas. as much as everyone loves spending hours experimenting with parameter settings, most schedules simply don’t allow for the kind of focused effort it takes to cull through every possible permutation of settings. wouldn’t it be great if plugins could do it for you?
well, they can.
the easiest way to allow plugins to automatically create a whole slew of new material is.. duh.. via automation. add some source material to a track, bus it out to a record input, instantiate your favorite audio-mangling device, draw some random automation across all parameters, and let it go. simple, right?
unfortunately, automation doesn’t always get the whole job done. some parameters simply aren’t available for computerized tweakage. all is not lost, however. one of my personal tricks is to use a third party application such as quickkeys (snow leopard only), ikey or keyboard maestro to set up complex keyboard and mouse movements that mimic what I would do if I were sitting directly in front of the console. do you have a favorite plugin that requires sample material to be loaded directly into the plugin itself? those can only go so far with automation, as you’re stuck using the same file for every automated pass. by using the aforementioned macros, however, you can set up a folder of interesting source and cycle through them one a time, giving each one a specified time to run through your uber-crazy automation.. all the while recording every step of the madness.
I often set this up with new plugins and let them go overnight (make sure you have enough disk space available before you attempt this). waking up in the morning presents me with a whole new library of sounds (after some serious editing, of course).
it takes a bit of set up to get everything working, but once you get the hang of it, creating huge, multi-step, dynamic-input macros will have you wondering what you’re paying all those interns for (just kidding, kids… we still need coffee ;) )
you can find quickkeys, ikey and keyboard maestro at their respective developer pages:
Super special thanks to Timothy, Rene and Dustin for putting this together for us. You can follow the Tonebenders on Twitter and make sure to visit their site to listen to all of their great podcast episodes.