Syllaria Productions

In Part 1, I discussed ways to diagnose and minimize echo problems in your home studio. In this post, I will discuss reverb, and soundproofing to minimize extraneous sounds.

Reverb

Reverb, short for reverberation, adds a special charm to music. Because the ear can perceive the size and even the shape of a performance hall, reverb is also known as ambiance or ambience. In its simplest terms, reverb is the bouncing of sound waves off the surfaces of a room. In the extreme, a listener can even create a mental map of his environment based on bat-like capability as described in this remarkable video about a young man named Ben Underwood who is blind, but who “sees” with his ears.

The fields of physics and architecture have much to say about what makes good reverb, and how best to create it in architecture. As I am neither a physicist nor an architect, I shall not dwell on these aspects except anecdotally.

A room’s reverb can be characterized by its transient response — what you’d hear sitting in the room or performance hall when a loud impulse-type sound such as a single hand-clap is generated onstage. The transient response represents the sound waves arriving at a single point after bouncing around in the room and eventually fading out. The single, most important, characteristic parameter of reverb is known as decay time, and is typically on the order of a few seconds or less. This is the time it takes for a sound impulse to substantially fade away after bouncing off the surfaces of the room. There is a correspondence between type of program, i.e. music vs. speech, and ideal reverb times. Speech tends to run together and become unintelligible when decay times are too long. See this article for demos of this phenomenon.

Hence, ideal decay times for music are longer than those of speech.

Reverb that is flattering to a musical performance typically requires rooms impracticably large for a home recording studio, hence this series of articles focuses on addition of reverb by electronic means.

But, there are consequences for setting up our home recording studio. For two important reasons, you should consider minimizing the amount of reverb in your home recording studio.

Why Recording Studio Reverb is Bad — Sometimes

Given that good reverb adds charm to a recording, at first blush it would seem that reverb in your home recording studio would be good. But, unless the room is already ideally sized, shaped and “surfaced”, it could cause echoes as discussed in Part 1, or it could lead to a recorded sound resembling a shower stall or phone booth. Of course, a simple recording test provides the ultimate proof. Try a “straight” recording (i.e., no added electronic reverb). Play it back and listen for a natural sound that is not unpleasant. If you are satisfied that the recorded sound is natural and has enough charm or ambiance, might as well save some time and don’t read the rest of this article. If, on the other hand, you desire improvement, read on. There are two compelling reasons why room reverb in your recording studio should be minimized:

Reason One — “Tight” Splices

Unless you are fortunate enough to live in a desert or wealthy enough to afford specially constructed sound-blocking walls, exterior sounds will likely ruin many otherwise-perfect recording attempts (A.K.A. “takes”). Under carefully-controlled circumstances, it is possible to edit a recording and create a splice so as to switch from one take to another take between notes, but reverb lingering from the note before the splice can corrupt the note after the splice. Hence, minimizing the room’s decay time preserves the option of making tight splices.

Reason Two — Fidelity of Electronic Reverb Presets

Given that electronic reverb provides better options for the home recording studio than does acoustic reverb, it is important to understand that electronic reverb processors are often modelled after real performance halls, in that they emulate the transient response of actual venues. Such processors often feature named presets such as:

• Small concert hall
• Medium concert hall
• Small church
• Cathedral

Accurate reproduction of these effects assumes minimal or no added acoustic reverb from the studio. In sardonic terms, if your studio makes recordings that inherently sound like they were made in a phone booth, activating the electronic reverb might create a recording that sounds like a phone booth on a concert hall stage. Not good.

Remedy

Fortunately, the surface treatments described in Part 1 can also be used to minimize studio reverb. The only difference here is that to minimize reverb, all room surfaces, not just parallel ones, should be treated.

Soundproofing

Exterior sounds have been mentioned above as a problem deserving of some discussion. To avoid extraordinary expense, avoidance comes cheaper than treatment. If you find various sounds creeping into your recordings, this topic is of vital interest:

• Chirping birds
• Barking dogs
• Road noise
• Airplanes & helicopters
• Creaking siding & other construction materials
• Expansion pops from metal window frames
• Stomach growling (yes, it can happen)

Unfortunately, I have no silver-bullet remedies to prevent these “take-destroyers”. You can spend a lot of money making a room-within-a-room, or building denser walls. Acoustilead(R) is a construction material designed for this specific application. Sometimes you can attenuate (reduce) outside sounds such as chirping birds (especially Mockingbirds!) by hanging extra draperies or even old blankets over windows. Airplane, helicopter, truck, and automobile sounds are particulary obtrusive. Hence, you may have to punt by adjusting your recording schedule to a quieter time of day (or night). Family and neighbors may complain, but they can be bought off!

If you have something important to record for posterity, you will have to use any and all methods and resources at your disposal to surmount these obstacles.

Further Reading:

Everything You Always Wanted to Know About Concert Hall Acoustics
Quietest Place on Earth
Soundproofing 101 

– Dominic Kyrie
http://www.syllaria.com/blog

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