This weekend I moved my home studio from one room to another. From a nearly 200 square foot living room to a 100 square foot bedroom. It’s been a long time since I’ve thought about room acoustics and because this is a common situation for home studios, I thought I’d share my experience.
This article will help you understand and overcome the challenges of a dedicated studio in a small room. It will be most helpful to those with symmetrical rooms (no weird angles) and to those that don’t need all the usual bedroom stuff, at the very least it will be a starting point to making the best of the situation.
Corner bass trap and broadband absorbers plus foam above.
The Problems
Small rooms are more likely to have acoustic problems than larger ones, primarily flutter echo, room modes and early reflections that are too short. In my room, I knew there was a very bad flutter echo problem and room modes may be a problem but were predictable. The room is symmetrical which was an advantage the old room didn’t have. The measurements are approximately 11ft long x 9ft wide x 8ft tall. There is a door and a closet on the back wall and 6 x 4 window on the front wall.
This is a guest post from Geoffrey Granka of Fresh Produce Productions. Find him online at www.freshaudio.ca and @gmgranka on Twitter.
The invention of reverb itself is impossible to pin-point in time. Gregorian monks knew it sounded great and so does anybody who sings in the shower. As soon as recording started, it was natural to record music in its most pleasing setting. Early recording engineers followed music wherever it went, frequently ending up in spacious churches and music halls. When electronic recording began to gain ground over the phonograph, interns started complaining about hauling tube tape machines to every church in the city. Subsequently, marking the first and last time anybody listened to an intern, dedicated recording studios started being built to house the gargantuan, over-heating recording equipment.
When it came down to live rooms, flexibility was the biggest concern. An 80-piece orchestra sounded great in a room with a lengthy reverberation, but it was hardly desirable for a rock band. Specially made reverb chambers were developed using a send (called an echo send) from a console, the engineer could adjust how much signal would be sent to that chamber and what channel would receive the treatment.
Note: Most audio engineering text books will refer to “echo” as a small number of repeats, each discernible. This is a misnomer in the case of “echo” chambers. Most echo chambers provide reverb, which is usually accepted as thousands of repeats that are unable to be individually picked out by the human ear.
A view inside an Echo (or Reverb) Chamber
How It Worked:
The rooms were not nearly as large as you would expect (or as they sounded). Studio architects used what little trickery they had at their disposal to exaggerate the acoustics of what was often little more than a large pantry. Echo chambers would have shellac or tile on all surfaces of the room, much like a shower. The loudspeaker (playing what was being sent from the echo send on the console) would usually be placed not facing the room, but facing a reflective wall. This increased the reflections in the room, and also decreased the amount of direct signal that would be picked up by the microphone(s). In the early days of recording the echo chambers would be mono send, mono return.
Famous Examples:
Gold Star Studios is arguably the most famous example of a reverb chamber. Phil Spector made Gold Star his home while recording the early hits of his career, and its reverb chamber played a key role in Phil’s infamous Wall of Sound. If other studios included reverb chambers as fringe benefits, Gold Star included it as a downright necessity. A cramped room where elbow room amongst musicians was a legitimate concern, the reverb chamber was the saving grace. In a Mix Magazine article, Larry Lavine testifies to the speaker in the chamber being a cheap 8-inch speaker being picked up by an equally cheap ribbon microphone (bi-directional). The chambers were a mere 2×3 feet, but the cement lining did wonders to enlarge that. You can hear this reverb on The Ronettes’ Be My Baby, parts of Pet Sounds, and other staples of that era in recording.
Try getting away with a fart in this room.
EMI Studios (later Abbey Road Studios) was a studio complex built by a record label at a time when it was hard to imagine a better business model than recorded music. There were 3 reverb chambers built inside the complex, one for every studio live floor.
Chamber One was built first for Studio Three (the smallest live floor in Abbey Road) and it made use of a single Tannoy speaker being heard by a Neumann KM53. It was approximately 11′ wide by 19′ long and was rectangular except for a diagonal reflective wall on which the speaker was focused.
Chamber Two was built to satisfy reverb needs for Studio Two (home of The Beatles). It likely made use of the same Tannoy and KM53. It’s dimensions were rather unflattering for an acoustic environment, featuring two pairs of parallel surfaces measuring 12′ x 21′. To make up for this, engineers pointed the Tannoy at one corner, and used sewer piping to diffuse standing waves in the room. Crude, but it hasn’t hurt sales of The Beatles catalogue.
Chamber Three was built for EMI’s classical studio work, mostly being done in the gigantic Studio One. It used staggered, nonparallel surfaces coated with the same reflective tiles as the other chambers. Measuring 17’8” by 12′, it was suitably the biggest chamber in the building.
Capitol Studios, located in the basement of Capitol Tower, was the frat house of Frank Sinatra, The Beach Boys, and the equally charming Beastie Boys. Its four identical trapezoidal rooms were designed by musician cum technological-soothsayer Les Paul. The rooms were built using reinforced concrete and coated with metal lath and cement plaster on the interior. Even the ceilings were sloped to ofter flutter or standing waves.
Other Famous Reverb Chambers:
Motown Records’ Hitsville USA complex is rumored to have used a hole in the ceiling as a jerry-rigged echo chamber. This wasn’t a traditional reverb chamber, it wasn’t controlled from the board, adjusted by positioning mics to pick-up the desired amount of reverb.
Joe Meek, the English producer of the 1962 hit, Telstar was well-known for using cavities in his house, like beneath the stairs or in the bathroom, to supply the reverb he needed.
An example of a staircase reverb set-up
Build Your Own:
Dave Simons over at Electronic Musician wrote a great article on his experience building a reverb chamber in the basement of his home studio.
Phase is a constant concern for recording and mixing engineers. Problems with phase can ruin your music, they can be easily avoided or corrected, but first you need understand how these problems occur.
This guide will attempt to explain almost everything there is to know about phase, what it is, how it happens, what it can sound like and some techniques to deal with it.
What is phase?
I’m going to consult my Engineering school textbook Audio In Media for this.
The time relationship between two or more sounds reaching a microphone or signals in a circuit. When this time relationship is coincident, the sounds or signals are in phase and their amplitudes are additive. When this time relationship is not coincident, the sounds or signals are out of phase and their amplitudes are subtractive.
No wonder people are confused about phase. Even I got confused at that, looking up other entries on phase in the book were even worse. I guess I shouldn’t read books.
[This article is part of The Home Recording Show Podcast, coming soon!]
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Whenever we use two or more microphones on a single source we need to be aware of phase cancellation and comb filtering. Due to the time delay of the sound waves hitting the microphone elements at different times, partial phase cancellation will occur.
Apartment buildings are not the ideal place to have a home studio, the main problem with them is the acoustics are terrible. My ‘studio’ has painted concrete walls, huge windows across one side, and is a L shape. This results in a very uneven frequency response, and ridiculous flutter echo.
For not a lot of money I made a big improvement to this situation. Rigid fiberglass is the most cost effective way to acoustically treat a room. Foam only really makes a difference with mid and high frequencies, the panels I made are effective down to about 125 Hz according to the specs of the material.
Problem: Your recording room is too large or not properly treated for vocals, you need some way of reducing the room sound before it hits the mic.
Solution: A device that helps to isolate the room from the mic, that’s much more sophisticated than making a fort out of blankets to record in.
There are several companies making room reflection reducing solutions, each with their own take on it.
1 -SE Electronics – Reflexion Filter. (List $399) The most well known out of the bunch. Expensive and heavy, but seems to work surprisingly well.
The Reflexion Filter is basically a portable device for recording live sound sources with reduced room ambience. It is an advanced composite wall which is positioned behind any microphone by means of a variable position stand clamp assembly which ships with the product. The main function is to help obtain a ‘dry’ vocal or instrument recording. This is especially useful in studios without proper acoustic treatment, but can also be used to help record takes in control rooms, where the performer also has to operate the recording device, or in rehearsal studios to reduce ambient noise.
2 – SM Pro Audio – The Mic Thing. ($319) Not quite as professional looking, but lighter and is adjustable. Available in Black or White.
The Mic Thing is a portable multi-purpose acoustic treatment panel suitable for minimizing room artifacts and improving separation during microphone recording sessions. Great for a range of applications including helping to control room ambience, minimizing spill from instrument amplifiers, or even creating temporary control rooms the Mic Thing is certainly one handy thing!
3 – RealTraps – Portable Vocal Booth. ($299) Lightweight and XL size sets this one apart from the rest. See site for a comparison with the Reflexion Filter.
Since the RealTraps Portable Vocal Booth is larger than competing products, it blocks unwanted sound and reduces room ambience much more effectively. As you sing or speak into the booth, it prevents your voice from getting out into the room in the first place. This is far more effective than trying to block room ambience and reflections after the fact.
4 – ModTrap. ($99 small $149 large) A newcomer to the market, they come in 2 sizes, and are the most affordable.
The most versatile acoustic panel in the world. ModTrap acts as an absorber to tame unwanted room reflections, and as a tool to shape your sound. What makes ModTrap so special, is that it fits directly on to your microphone stand, enabling you to place it where you need it most.
5 – DIY Vocal booth ($235) An example of what not to do, not only is it huge and bulky, it will likely increase reflections to the mic.
4 x 100 cm x 100 cm cheapest acustic foam = 10X4 + 10 (from germany) euros = 72 USD
8 x 200 cm x 50 cm wood panels = 8 x 8 euros = 93 USD
furnitures +/- = 16 + 2 + 30 (scratch) euros = 70 USD
so it’s 235 USD and 2/3 hours of “work” taking your time.
I think the both the RealTraps and ModTraps are an excellent value. They are large enough to work well for vocals or to improve isolation between instruments, they are lightweight and portable, and they are both USA made products.
