In the first part of this article we talked about the nature of digital plugin reverbs and how to test to see if the one you’re considering buying (or using) is efficient – and if it is “worth its salt.”
To Convolute or Algorythe
While there are a bazillion plugins available, there are generally only two ways you can create reverb digitally: algorythmically or via convolution. Algorithmic reverb literally uses a complex mathematical model to simulate the thousands of delays at various frequencies which create reverb. These models are so good that they can even simulate the general size and dimensions of a chamber or hall. Algorithmic ‘verbs also take very little computer resources on the whole, and they’re fabulous for sweetening music or other sustained situations where reverb may want to add a special “character” to the sound. Algorythmics fall on their faces when it comes to long reverb tails. Why? Because computer models have yet to be made which keep long reverb tails “interesting” or “beautiful.” Part of what makes reverb so compelling is the beauty and mystery which comes from the sound banging around inside the giant domes of the churches of Europe or a tunnel on a motorway. It’s a haunting and mesmerizing event to clap your hands in a large parking garage and listen to the echoes. Algorhythmics have a really hard time with this. Some of these plugins make up for this by adding subtle chorus units to the signal chain. These subtle secondary effects add interest and restores a good amount of that wonder to what is otherwise cold, sterile reverb sounds.
Convolution reverb plugins also use a computer model, but it is based on Impulse Responses recorded in an actual
reverberous space. A computer than compiles the delays recorded in that space, and creates a model which, once programmed into a plugin, reacts to incoming signals in harmony with that model. As a result, you can have hyper-accurate representations of any room if you have “shot” the room with an impulse response and loaded it into your convolution reverb plugin. These are excellent for ADR or any situation where you want to recreate a space seen on screen in your mix. Take an Impulse Response of the set during “room tone recording” and, Voila! You’re golden. The trouble with convolution ‘verbs is that they’re computer resource hungry, and while they can reproduce the sound of a room with dead accuracy, they sometimes lack the character that algorithmic ‘verbs have. In the last couple of years we’ve seen the development of convolution plugins of all kinds with very efficient models that return wonderful results even when used on multiple music stems. Convolution ‘verbs usually have far fewer controls from their algorithmic counterparts, because the bulk of the control of the sound is in the loaded Impulse Response itself.
For me, I tend to use Algorithmic reverbs on music when decay times are over 1 second, and Convolution reverbs on anything with a reverb time under 4 seconds. The long convolution reverbs just take too much power and tend to artifact too much. There are several notable (and expensive) exceptions to this, but for our purposes as filmmakers, I suggest sticking to this rule.
Don’t Be Fooled By the Bells & Skin
I’ve had more than one plugin manufacturer sucker me in to buying their product on a beautifully skinned
interface or tons of bells and whistles which ended up not being that useful. Don’t let this happen to you! With an algorithmic reverb plugin you don’t need EQ built in. If it’s there, fine. But if it’s not, fine. You can always patch in an EQ plugin after the reverb on your channel. In fact, doing that gives you a lot more flexibility than any EQ I’ve seen on any plugin. Damping, however, is critical and must not be omitted. Same with stereo enhancement. Shucks. Drop a stereo widening plugin in after it. Done. A pretty interface is nice, but it needs to be user friendly and allow you get to what you need fast. For convolution reverbs you need even LESS controls – although it’s important that the plugin be able to load user Impulse Responses. If it doesn’t, then you’d better love the presets it has, because that’s all you’re going to get. If a plugin is all just skin and bells, save $400 and buy a Degas reproduction. Hang it in your studio. Again, if it has these things and sounds good, fantastic. If it sounds good and doesn’t have these things, fine.
Surround and Stereo
Sometime soon (like, maybe tomorrow) you’ll need to have a 5.1 or better surround reverb. In the Pro Members Education we teach how to use stereo reverbs judiciously to create surround reverb effects…but it’s really not the same. It’s a cheat. There’s no substitute for a good surround reverb which takes your stereo signal and chunks it out to 6 channels or more. You’ll still run the same test we described in the first part of this article to check its sonic effectiveness, but you’ll do it on all the channels. Does it feel like a true surround space? Do you have the capability to not only mute the center and LFE channels but actually have those channels not be computed (saving resources from ever-hungry surround ‘verbs)? What kind of control do you have over the input and output of each channel? Most importantly, does it play well in the system you’re running? Some DAWs don’t like 3rd party surround plugins of any kind, and Tweet: it’d be a shame to spend $600 on something which will only work in stereo on your system.
Tweet: Reverbs plugins are as necessary as faders in 21st Century mixes, and there’s no shortage of choices for any situation where you’ll need them. Do be shrewd as you make your choices, because false economy crops up everywhere and buying a cheap reverb plugin is only a good deal if it sounds better than an expensive one.
Tell us your experiences with reverbs here or Tweet about it!