Orchestral Positioning: Reverb in theory

Reverb is a big and crucial topic when it comes to orchestral music so I’ve decided to split this article up into several parts in order to not overwhelm the reader. The first part deals with the basics — what is reverb, how does it apply to the sound of an orchestra, what stuff to look out for and finally some explanations of common reverb terminology.

Effect reverb vs orchestral reverb

First off let’s talk a bit about why beginners use reverb the wrong way, or are shy about applying it. The most probable reason is that reverb is commonly thought of as an effect, i.e. something slightly gimmicky that should be used only on occasion and under special circumstances to add a bit of extra size and width to a certain part. Definitely not something you would put a lot of on each and every instrument in a mix. This thinking is actually perfectly valid for pop and rock mixes. Especially today when mixes tend to be really (even overly) punchy and in your face, reverb is something you should use sparingly unless you’re going for a 1980’s type of sound.

But orchestral music is a completely different beast. If you want your compositions to sound as huge and majestic as you imagine them you should forget everything you’ve learned about using reverb ‘properly’. In a virtual orchestration reverb is not just a special effect. It’s both a positioning tool and the glue that makes everything stick together and sound like a whole. You could even go as far as saying reverb is an instrument in its own right, and just like all other instruments it needs to be tuned and tweaked and carefully orchestrated so that it sits well with everything else. Yes, it’s really that important.

Good reverb is crucial

That’s why it sometimes makes me sad to hear people pay so little attention to what reverb they’re using. I mean, why go through all the work of composing and recording a virtual orchestral piece when you’re going to feed it through some grainy, tinny, abomination that makes the whole thing sound like cats fighting in a sewer pipe?

When you select a sampled instrument, do you just pick whatever you first come across, even if it happens to be a 100kB soundfont from 1995? No you (hopefully!) don’t, you use the best samples you have. The reverb is just as important and there is simply no reason why you shouldn’t be equally picky when choosing it. There’s a number of really good inexpensive and even free reverb plugins so “it came with my DAW” or “I don’t have anything better” are not valid excuses.

If you don’t consider yourself capable of telling a good reverb from a bad one, look around the web for clues or simply ask someone knowledgeable for advice. But you should really train your ears to pick up on the nuances of different reverbs and what the various reverb parameters do. Audition a bunch of different plugins, listen carefully to the characteristics of their sound and experiment with different settings. Pay special attention to how they sound applied to different instruments. Percussive sounds and instrument with lots of high end are great for determining if the reverb sounds tinny and shrill, for example. Whatever you do, don’t audition reverbs with sustain string samples only. Almost any reverb will sound good on sustain strings.

Reverb as a positioning tool

Main_Auditorium,_Copenhagen_Concert_Hall

Copenhagen Concert Hall

I mentioned in the previous article that reverb is a positioning tool, just like panning. This is best illustrated with an example. Imagine you and a friend standing in a large, empty room. If your friend speaks to you with his mouth only an inch from your ear, you will hear his voice the way it sounds coming out of his mouth, and very little — if any — of the reflected sound waves from the room. If you move back a distance, the dry sound of his voice gets fainter and the more you hear of the room. If you position yourselves at opposite sides of the room, you will hear more of the reflections than the dry sound.

This is the fundamental principle behind using reverb for positioning. It’s really very simple, yet something most people don’t consciously think about. So, consequently, you will need to apply the right amount of artificial reverb to your sections to make them sit in the right Z-axis spot.

Examples

Giving tips on how much reverb to use on the different parts of the orchestra is even harder than panning. It depends on how much of a recorded ambience the samples have, as well as on the settings and characteristics of the reverb being used. That’s a ton of unknown variables right there. But in VERY loose terms, I would suggest something like this as a starting point, with “x” being a completely arbitrary parameter. Experiment with reverb on the first violins until they sound good to you, then use that value as a reference point.

1st violins – x amount of reverb, more than brass but less than percussion
2nd violins – same as 1st violins, or slightly less
Violas – slightly less than violins
Celli – same as violas or slightly less
Basses – same as 2nd violins
Trumpets – less than strings, more than woodwinds
Horns – same as 1st violins
Trombones/tuba – slightly more than trumpets
Flutes/clarinets – to taste (see below)
Oboes/bassoons – to taste (see below)
Percussion – as wet as possible without sounding bad

Projection, section size and diffusion

The difficult thing about reverb levels is that instruments project in different directions, which affects the percieved wetness. Trumpets and trombones project forward towards the listener so you should use less reverb on those than you might think considering their seating. The opposite is true for horns, which project backwards/downwards, so in that case use a bit more than what the seating indicates.

Section size is also a tricky matter. Take woodwinds for example. These instruments are seated in the middle of the orchestra, which theoretically means they should be wetter than strings and drier than percussion. Still, woodwind sections are small with a less diffused sound and I sometimes find that using a lot of reverb makes them lose definition. So my best advice is experiment with different reverb levels — while keeping some good reference material handy, of course — until you feel that the winds sit in the right place without sounding too smeary and unfocused.

Just like with setting the panning, you should trust your ears and not slavishly follow the numbers your DAW is showing you. If an instrument or section sounds wrong, even though it theoretically has the correct level of send reverb, do not hesitate to adjust its wetness one way or the other to make it sound right. As long as it sounds good, screw the numbers.

Reverb jargon demystified

Let’s finish off by having a look at some of the different terms and parameters you will encounter on your quest for the perfect orchestral reverb. They’re usually not quite as esoteric as they may seem.

Predelay
This one’s easy but important. How long does it take before the reverb kicks in? Keep it below 50ms to avoid lagginess in the reverb sound and slapback echo effects.

Time
Sometimes labeled T60 (i.e. the time it takes for the reverb tail to fade down to -60dB), this parameter sets the overall lenght of the reverb. Decrease to get rid of smear and blurriness, increase for a lusher, bigger sound.

Early Reflections
This is best described as a flurry of fast initial echoes reflected from the surfaces closest to the sound source. ER’s are not to be underestimated as they are what cue our ears in on the size of the room. Decrease to put instruments further back, and vice versa.

Late Reflections (or “tail”)
This is what ER’s transform into when they have been bouncing around the surfaces in the room for a period of time, becoming so diffused and blended with each other that they’re a wash of sound rather than discrete echoes.

Size
Not all reverbs have a Size parameter, but in the ones who do, this usually puts you in control of the overall scale of the simulated space. Most likely it’s related to amount, width and complexity of ER’s.

Distance
This one’s a parameter sported by some reverbs. Usually it controls the balance between early and late reflections.

Diffusion
This parameter controls the complexity and density of the reflections. A completely empty room with flat, symmetrical walls (e.g. a squash court) will have low diffusion, whereas a room filled with various reflective surfaces (e.g. a church) will have high diffusion. For a typical orchestral sound you’ll want medium to high diffusion.

Damping
Damping is what happens when a room contains various soft surfaces that absorb high frequencies. Like curtains, soft furniture, or people. Increase to get rid of ringing and harshness in the high frequencies. Decrease for more brilliance and more pronounced reflections.

Low cut, High cut, Highpass, Lowpass
These are simply EQ filters, useful for removing (or adding) high and low end in the reverb.

Frequency multipliers
These parameters put you in control of how long high and low frequencies will ring out, relative to the specified reverb time. This is physics again: in a real space, high frequencies die out faster than low ones. The typical warm orchestral hall sound has a quicker decay in the high frequencies. To avoid muddiness and low-end rumble, don’t overdo it. E.g. setting low to 2x will double your reverb time in the bass/low mid register, meaning a modest 2s reverb will have the low frequencies ringing out for 4 seconds!

Next: Orchestral Positioning: Reverb in practice

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