Reflections | Reverb and Delay

Reverb and delay naturally occur all around us. Reflections of audio bouncing off surfaces return to your ear and you immediately respond, without thinking, to the atmosphere and texture around you. The tone and strength of these reflections give you a natural feel for the place you are in and add a subtle texture to how you experience your environment. 

You may have heard of treated rooms where the absence of reverb and reflections is so pronounced that people literally can’t spend more than an hour in the room.  The anechoic chamber is the name of this strangely horrifying room where outer noise and reflections are absent. Only the sound of your heart beat and your voice are present. 

It can’t be overstated- reflections including reverb and delay are a natural part of experiencing our environments! So when it comes to mixing, a lack of reverb and delay actually makes the audio sound… unnatural. This is why it is critical to understand reflections and apply them correctly to mixing. Broadcast feeds will never sound natural without proper reverb and delay.

Reverb

When you speak, there is a small reflection off nearby objects and walls which we call reverb. Reverb is a sort of echo which adds dynamic and texture to your voice or sounds. When it comes to mixing, the use of proper reverb for the experience at hand is a powerful tool for improving your sound. First, start by considering the venue. Are you worshiping and want the sound of a large and rich choral hall? Are you mixing a recording and want the sound of a small or large room? Are you mixing a broadcast feed that you want to feel like a worship center or rock concert? Your answer to this question will direct you in determining the type of reverb you want. Short reverb with quick reflections mimic being close to a wall with immediate slap-back sounds. The bigger the hall or venue, the longer the delay and more spread out and airy the reflections will tend to be. Reflecting (pun intended) on the type of reverb sound you want to mimic leads you to choose the appropriate reverb. Once you choose your reverb, you can then play around with the saturation and fine tune the settings. When I mix, I like to have separate reverbs for vocals and instruments. I also like to keep my delays separate. By varying the type of reverb that is applied slightly, you can help add a more dynamic feel of reverb that sounds more natural than a completely uniform sound from a single processor. Effect processors are not created equal! Some reverbs sounds terrible and others are incredible. You will want to play around and find the effect that sounds the best for your application. 

When it comes to adding reverb, you want to add just enough that it supports the original signal without distorting or distracting. Additionally, you want to make sure that the reverb does not causing phasing issues, slightly out of phase wavelengths that clash and subtract from each other, causing the new sound to sound less full or unnatural. While reverb is an amazing tool, not all reverb options are helpful. You have to find the type and settings that work. While discussing phase issues, it is actually possible to use this to your advantage. In broadcast mixing, you can add a subtle amount of reverb to a countryman mic to help smooth out or reduce echoes in the signal. For instance, if you have a speaker in a room where there is delay and then reflections, that initial delay makes the final reflection stand out. By adding a subtle, and I mean very subtle amount of properly tuned reverb, you can help smooth out the initial silence so that there is a simple consistent reflection to the speaker’s voice. Sometimes if you really work at it, you can actually use the reverb to cancel out the room reflections to a degree. Sometimes this involves reversing polarity on the reverb signal.

Delay

Delay is the reflection of a sound that is similar to a strong echo that keeps the original signal’s message and form intact to a degree. When you hear an echo, it’s not typically a smothering of a sound like reverb, but a distinct but altered duplicate of the original signal. Delay in real life always has a certain degree of reverb in it. For this reason, whenever you use a delay effect, you want to make sure it includes a layer of reverb. Some processors include this reverb in the processing, other processors require that you add it separately. The order in which you apply reverb and delay to a signal is important. If you first apply delay followed by reverb, you will essentially be smoothing out a distinct copy of the original signal. If you apply reverb first and then delay, you will have somewhat distinct echoes of a reverb. There is a big difference! Normally delay is applied first.

Often, delay is controlled by either a tap-delay feature or a digital sync that occurs over the network between click tracks and processors used by the band. For tap-delay, a button on the mixer is assigned the task of inputting how often a reflection will take place. You may have the option to input delays in terms of 1/8th, ½ or whole notes. The tap delay controls both the timing and the spacing of the reflections. The faster the the timing, the more echos will occur.  More walls with closer proximity will be impression your ears will naturally have for such a sound. Larger, spread out reflections will give the impression of a larger venue. 

Signal Clarity

One crucial aspect of reverb and especially delay is signal clarity. You don't want to add reverb to the symbols on a drum if they aren't isolated form the rest of the kit. You don't want to add delay to a vocalist if the signal isn't isolated from the guitar or drums. Make sure that only the cleanest signal possible is getting processed to keep the output crisp and an accurate reflection of the intended original signal.

Processor Placement

Another important aspect of reflections in mixing is the placement of the processor in the signal chain and whether it is pre or post fader. Sometimes your effects processor is built right into a channel, in which case you may have a control to turn it on and off but it is built into the channel. Normally you will have either an Aux or a effect send where you route a signal copy to and the processor is then applied. Typically you will use Post-fader pickoffs for your processors. This way, when you lower the volume of a channel, the effects also are naturally reduced and the perceived ratio between the two signals, the original and the effects signal stay constant. If you choose pre-fade pickoff, then when you change the channel volume, the effect signal input will remain the same. The result is a more effects driven muddy sound when channel volume is low and a clearer unprocessed signal when the channel volume is high.

Pre-fade pickoffs for processors can be helpful though for in-ear mixes where the musician is controlling the level of mix in their ears. Having a channel that is just reverb and delay can allow musicians to mix in the appropriate level of effects for their taste and will remain unchanged by channel adjustments for FOH mixing.

With Respect to the Processor

One very important concept to understand with signal flow is where the signal is being adjusted with respect to the processor itself. If you cut off the flow of a signal into an effects processor, the outgoing channel volume is untouched, allowing the processors to wrap up and complete the full cycle of effects processing for the incoming signal. If you leave the incoming signal alone and reduce the output level of the processor, you are essentially shutting down the effects in an unnatural way. Normally reflections in real life play out and naturally decay. If you take control of the fader on the output side of the processor, you are unnaturally manipulating the output volume. For this reason, you almost always want to control the input signal to a processor, not the output.

Tones

The tone of reverb and delay adds a lot of atmosphere and texture to the sounds. Thick mid sounds will produce sounds that feel very close and cozy. High end reverb will give the impression of hard surfaces which have a clear ring to them. It will also give the impression of an environment void of obstructions like walls which would reduce the high-end sounds more than the low-end. (Think about the sound of a concert from outside a building. You’ll hear the mid and low-end rumblings without the high-end clarity.)

Normally for vocalists you will aim for a sound with some mid-range reverb but more upper range focus in the reverb and delay. If you get too low, it will muddy the vocalist's clarity and distract. Too low sounds unnatural because that sort of reverb only tends to occur when you have your head in a small space with hard walls.

Mind Blowing Application

If you want to be blown away by the advances in reflection technology, check out constellation audio systems by Meyer Sound. One of the world’s first applications of this system was at Liberty University. I heard a demo of the system and it was incredible. It took a quiet room and instantly made any sound echo and reflect as if it were in a large cathedral. While the amount of the reflections was changeable there were no individual mics on instruments. All the mics were hung from the ceiling and used advanced processors and measurements in the room to generate and project realistic reflections from small speakers hung throughout the room.

Check it out: https://meyersound.com/product/constellation/

https://www.youtube.com/watch?v=tSyY48xleWQ