Most people in the audio community are aware of the use and importance of reverb in the recording/mixing/mastering pipeline but when it comes to differentiating between the two main types of reverb the details start to blur. Today I’m going to explain a bit about the two types of reverb and discuss the pros and cons of using each.

The first form of reverb we’ll look at is algorithmic reverb. An algorithim is a mathematical process used to explain and emulate something in real life. Algorithmic reverb is the traditional and oldest form of reverb. The elements that make up a reverb are studied and then using these data as a model, hardware or software reverb is engineered that allows the user to affect these elements in order to control the resultant sound. Although there are numerous different algorithmic reverb units on the market there are certain characteristics and controls they all share. For an example we’ll look at the Waves TrueVerb interface-

One of the first common controls is Room Size. Room Size should be self-explanatory…the larger the room the stronger the reverb effect. The next control is Pre-delay which refers to the amount of time before the reverb effect begins…imagine recording through a mic in a room. Before we would hear any reverb from the room we would hear the direct sound at the mic, Pre-delay lets us emulate that. Another common control is the Wet/Dry Mix which here is split into three controls- Direct- the dry sound or pre-effect sound.
Early Ref- called early reflection, this refers to the first thing heard as a sound reflects off a surface- more along the lines of an echo or slapback effect.
Reverb- this is the full wet or affected sound.

Algorithmic Reverb is perhaps the easiest to control and use.

Now we’ll dive into Convolution Reverb. Convolution reverb uses real spaces through the manipulation of impulse files or impulse tones depending on how they are referred to in the reverb. Impulse tones are created by recording a test tone in a real physical space and then removing that test tone. What’s left is then applied as a modifier on your digital audio. For an example I’ll share the interface from Waves IR-1-

Convolution reverb units have fewer user controls but they have much more detail and accuracy. Generally, convolution reverbs are only used when realism is desired and processor power is not in question. Some reverb plugins let you create your own impulse tones and there are third-party developers that market impulse tones. The tones themselves are quite large files so hd space is another factor to take into account.

Well that’s it for this time…hopefully you’ll come away from this with a better perspective on reverb and be more prepared to use the tools rather than let the tools use you!

-Bill