What is Reverb, Delay in Music Production?

by ReverbLxnd in Mixing

What is reverb in music? What is delay? This article looks at the two most common echo effects in music production— reverb vs delay

Have you ever sang in the shower and felt like you should be singing on stage?

Have you ever stepped in a stone or concrete parking garage and clapped your hands to trigger and savor that wash of sound?

Who hasn’t?

Turns out there is a reason for it.

Reverberation or, reverb, for short.

But what exactly is reverb in music?

Earlier, in this series on the absolute basics of sound engineering and music production, we looked at what is mixing, what is mastering and what is audio compression among other things.

Today we are going to continue that by looking at what is reverb and why it is the most popular effect used in music.

Let’s jump right in.

What is Reverb in Music?

Sound is a wave.

That means, it is a vibration that travels through a medium such as air, water, and solids.

If you drop a rock into a pond of water you disturb the surface of the water and create ripples called waves, which travel away from the impact. The ripples cause the height of the water to change traveling up and down, away from the splash.

Likewise, if you make a voice or clap your hands in a quiet room, you’ll disturb the air and cause ripples of waves to move away from your hand.

Sound waves behave in much the same way and have the same properties as water waves — crests, troughs, wavelengths, amplitude, frequency, speed (wavelength x frequency), and a direction.

But sound waves are different from water waves in one respect — sound waves are longitudinal, water waves are transverse.

Longitudinal means that as the waves move in one direction, say to the right, they create a disturbance in that same direction, left to right. Whereas, transverse means as the waves are moving in one direction, say to the right, they are creating a disturbance in the perpendicular direction, up and down.

The disturbance of water waves like a boat in an ocean and the disturbance of sound waves is like that of a spring.

Reverb in Music

Reverb, or more accurately natural acoustic reverb, is created when sound is reflected from the surfaces of the objects around you — walls furniture, anything that reflects sound. These surfaces cause the reflections to build up and then decay.

Reverb is the combination of the direct sound and its sound reflections.

The reflections arrive at our ears slightly later than the direct sound, but they merge together to a single continuous sound.

Reverb takes this to another level presenting our ears with countless delayed reflections arriving one after another with microseconds in between.

They unite into a single sound — this is important.

Rooms with lots of echoes used to be a common way to record singers and certain acoustic instruments like guitars. When you recorded, the mic would pick up all the natural reverb of the room.

When a musician plays an instrument, they fill the space. They acoustically illuminate every visible surface in a room.

These days we tend to record in dry rooms and apply digital reverb and delay afterward, when mixing

Artificial Reverb

You don’t have to be in an actual room to create reverb effects because there is a second type of reverb called artificial reverb.

Reverb is probably the most popular effect used in music. Almost every style of music uses reverb— some more than others.

Why We Use Reverb in Music?

Usually, at least a little bit of reverb is needed to make an instrument sound naturally in space. We use reverb to give a sense of space to the instruments, and to create beautiful or crazy special effects.

Wet vs Dry Music

Music without effects such as reverb called dry. And music with lots of effects such as reverb is called wet — depending on the degree, of course.

Drum kits in hip hop, for instance, tend to be dry whereas a drum kit in a pop or rock song from the 80s will most likely be wet.

We can adjust artificial reverb to sound as if our instrument is in a very big room or a small room.

As with any effect, you can use too much and it can spoil a good track.

Many times, either instead of or in combination with reverb, we also use an effect called delay.

Reverb and delay are two of the most common effects we use in music.

What is Delay in Music? Reverb vs Delay, Echo

Reverb and delay both create echo effects but with delay, you can create timed, specific echos whereas, with reverb, the echoes build up in a more random fashion.

Essentially, when multiple sounds of a similar level are arriving at our eardrums within 20 milliseconds of each other, we can’t pick any of them out as individual sounds. Instead, we hear the combined whole.

For this reason, longer delay times create echo effects.

Delay a sound long enough and we’ll hear the delayed sound as a separate event from the direct sound. This is not what is happening with reverb, or delay.

For both delay and reverb, there has to be a single sound with a new sonic quality.

As with reverb, you can control the delay effect in many different ways.

Medium and short delay times are used to create chorus and flanging effects.

These effects add several delayed signals into the original signal creating a single sound with a new sonic quality built on the interaction between the sound within this tight time window.

Besides just timing, for instance, you can take a single echo and make it repeat many times over. You can even make these echoes repeat at different times on different places in the stereo field creating a ping-pong effect.

This is called ping-pong delay.

Reverb With Delay

Sometimes we use delay instead of reverb, but many times we use both delay and reverb.

If we use both, it goes without saying that the track will sound really wet.

What is Audio or Sound Decay?

As we said earlier, sound is wave energy that disperses as it travels distributing its energy over a larger and larger area as it propagates.

The energy of the sound wave is gradually absorbed by the air in the room and the materials and surfaces in that room. The result is that the sound grows fainter and fainter over time. This is called sound decay.

In any space, we hear the sound plus reverb.

It’s always direct sound first followed by the reverberation as it decays to silence.

The more reflective the materials and surfaces, the slower the sound decay.

How We Create Reverb for Music Production

Reverb is created using—

  • Acoustic reverb — room tracks and reverb chambers.
  • Mechanical reverb — spring reverb and plate reverb.
  • Digital reverb.

We’ll look at each of these, shortly, in turn.

Acoustic Reverb — Room Tracks and Reverb Chambers

Acoustic reverb for studio recording comes in the form of carefully designed and cleverly captured room tracks and reverb chambers.

These room track and reverb chambers capture natural reverb in the best possible way during a recording.

The next classes of reverb are those that use some form of a mechanical system.

When to Use Acoustic Reverb — Halls, Chambers, and Rooms

Hall reverbs are probably the most versatile because you can change parameters and morph them into other things somewhat much easier.

Mix engineers tend to like hall reverb on ballad vocals, vocals with a lot of space on strings — generally, on classical instruments.

Mix engineers tend to like chambers on drums, sometimes vocals. Typically, things that might not have been recorded through a microphone, such as synths, and you want to feel like they were recorded in a live space.

Mix engineers tend to use rooms to create small spaces, such as the feeling of a guitar recorded in a small, smoke-filled club.

Mechanical Reverb: Spring Reverb vs Plate Reverb

Mechanical reverb today comes in two forms—

  • Springs i.e. spring reverb
  • Plates i.e. plate reverb

Spring and plates are mechanical systems that offer their own unique strongly flavored resonance.

While their mechanical technology is hardly cutting-edge, their sound is hard to reproduce digitally.

They are still so important to music recording that digital reverbs of today often have presets that emulate this mechanical reverbs of the past.

You’ll find that plates are springs and plates are still used widely in music production today.

Spring Reverb: How Do You Make it, How Does it Sound Like?

Spring reverbs are made of, wellsprings — usually, a network of interconnected springs.

Multi-spring reverbs make a mechanical connection between springs to trigger several interactive resonances among those springs.

You make your spring reverb by letting audio drive the springs into action and pick up the subsequent vibration. The mechanical resonance of the springs simulate acoustic reverb.

Spring reverb never sounds exactly like a room but it has certain unique and interesting sonic properties.

Spring reverb is light, portable and affordable. It is common in many old organs and guitar apps, partly this convenience.

Because of its characteristic sound, spring reverb remains an essential part of the guitar tone.

It’s a defining element of surf music, guitar-based blues, and spaghetti western music, but it is by no means limited to guitar alone.

Spring reverb is a great way to modify the timbre of an instrument.

Why it may not evoke the presence of a concert hall or a nice acoustic room, it does offer a quality of resonance that’s desirable on many tracks.

When to Use Spring Reverb

Mix engineers tend to like spring reverb on guitars to get a vintage vocal sound — for a retro vibe.

Most people don’t like spring reverb on drums and percussive elements. That doesn’t mean you shouldn’t use them every once in a while.

Plate Reverb:

Plate reverb offers an increase in sonic complexity over plate reverbs.

While springs vibrate in a relatively simple one dimensional way from end to end, a plate reverb, made up of a large plate of metal, vibrates in a more 2 dimensional way.

An audio signal feeds a driver connected directly to the plate causing it to vibrate.

Imagine a 2D room with width and height but no height.

Same as with spring reverb, plate reverb doesn’t sound exactly like acoustic reverb.

With experience, you’ll learn to identify the strong, upper mid-frequency decay characteristics of good plates, and how different they sound from spring and acoustic reverbs.

Plate reverbs haven’t been made commercially for decades. The vintage units are highly sought after, expensive, and quite massive. So it’s quite common to use a convolution reverb to add the sonic properties of an actual plate into your mix.

It’s common to use a convolution reverb to add a plate to the snare head, for instance.

Like springs, plates are desired for the distinct sonic color that modified the timbre of the instrument.

When to Use Plate/Convolution Reverb

Mix engineers tend to think of plates as pretty good for vocals.

Plates tend to build up density very quickly, you get the good part of a reverb quicker on a plate.

And with a plate, you tend to have to use a pre-delay.

Digital Reverb

To describe reverb digitally, we need a set of parameters and we need to assign them some values.

Let me warn you ahead of time, trying to describe something as ornate and expressive as reverb with just a few numbers is clumsy.

The numbers will never fully describe a reverb.

Imagine trying to describe the sound of your favorite piano, the tone of your favorite vocal mic using numbers only.

Use the digital parameters as guides but as always, listen carefully and be opinionated. Go for what you like.

One way to understand digital reverb is to look at how it reacts to a specific test signal known as an impulse. If you play an impulse in a room and record the result, you can be able to digitally examine the key components of reverb.

An impulse is a short click. A simple wave shape that snaps up, and immediately snaps back down to silence. Short and simple.

First, there is the direct sound, that is the original impulse itself.

This is followed by some early spikes of sound known as early reflections, and this is followed by a dense wash of much more complicated energy coming from the room. This is the reverb tail.

Dividing your thinking into these building blocks can help a lot in music production, even as we work with tracks instead of impulses.

The direct sound is your original, likely close-miked track. The kick, snare, the vocal, instrument. It’s the dry part of the mix.

As we add reverb to these tracks we are adding a complex kind of sustain that includes the early reflections and the reverb tail.

We’ll sometimes focus on the properties of early reflections and other times on the reverb tail.

Each has sound properties we need to get under control as we record and mix.

With these three components of reverb in mind, we’re ready to look at the three most important adjustable parameters your DAW’s reverb or reverb VSTs/plugins.

We’ll look at these in how to add or use reverb in a mix.

In Conclusion

The presence of reverb is unmistakable.

While everybody plays notices and play with reverb without much thought, making musical use of reverb effect is a much more daunting challenge presented to us every time we record.

It’s a tough concept to truly master.

As you might expect, reverb and delay bring so much life to your tracks.

They can make your music sound more dramatic. You can use these effects simply to give a sense of realism to your songs, or you can go crazy and create wild and original sounds which will make your productions stand out.

This is all up to you.

That’s if for this article but, if you’d like to learn more about reverb, delay, and other effects, have a look at our mixing blog. We are always putting out fresh, awesome content.

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ReverbLxnd

I've been a musician and brought in my stuff for mixing and mastering, I've been my own producer where I wrote, recorded, mixed and sold my own stuff. Now, I'm *mostly* an audio engineer, where I only record and mix for clients. I'm currently based in Berlin, Germany, where I operate ReverbLand out of. Got a question? DM me on Instagram or Twitter @reverblxnd everywhere, or shoot me an email reverblxnd@reverbland.com. I'd love to hear from you.

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