Another great TED Talk by Julian Treasure (watch another, and another) about architecture, acoustics and education. I can certainly relate to this, my high school had terrible acoustics and the lecture rooms in my audio school were even worse!
Towards the end of the video Julian talks about the Sound Education seminars and the free app called Study with sounds designed to mask ambient noise, help focus, improve cognition and reduce fatigue.
Mike Sorensen (@mikesorensen06) is a master cabinet maker, structural engineer and the author of the AcousticFields.com sound diffusion audio blog. I think you’ll find his research on activated carbon for acoustic absorption very interesting.
If you’re going to make a great recording you have to find a solution to the room acoustics. Like the black sheep of any family, room acoustics are somewhat left un-talked about given their unsexy nature. Yet they are key to helping you produce the best sound from your recordings whether in the live or listening room.
Some people think that throwing up a bit of foam here, dampening the sound there and generally shutting the door and turning off the extractor fan will do it but alas no. There is a big science that goes into it and I want to share some of my years of experience with you today so you can start to consider some of the treatments and how they work in conjunction with your studio space.
Diaphragmatic Absorbers
Diaphragmatic absorbers are powerful, low frequency, absorbing technologies. One must build a solid, sealed box that has a front wall that can “move” in reaction to sound pressure waves. This front wall movement slows the wave down, so that it can enter the inside of our sealed cabinet. Yes, the cabinet is sealed without any air holes. Low frequency waves that are 40 and 50 feet long do not care about some 1/4″ air holes in any type of absorber. With low frequencies we are dealing with waves of energy not rays. (more…)
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.
