PDA

View Full Version : Acoustic Treatment



kimball492
28-07-2015, 01:34 AM
Acoustic Treatment - What Are We All Doing?

We talk a lot about gear, production techniques, the industry and workflows on Pro Tools Expert so it’s about time we have a discussion about our choices in acoustic treatment. Acoustic treatment is the method and implementation of materials to help control the reflections of sound within a space in the pursuit of a great sounding, well balanced room in which to record and mix in.

What acoustics do we use in your studios… and why?
Do your choices in acoustic treatment make a difference… or to word it correctly… Do our choices in acoustic treatment make an improvement to the sound in our studios?
The reason I’m bringing this up is because there is, without argument, a science to room acoustics that I believe the majority of us creative’s don’t know about or have very limited understanding in. Yet many of us, myself included, take it upon ourselves to improve the acoustic properties of our rooms with homemade treatments or pre made products we can order online. I’m going to talk broadly about a few methods of acoustic treatment I have used while listing my experiences and views on whether or not they made any improvement to the acoustics of the rooms I have worked in.

The Egg Box Theory

I have never tried it, as I always knew this to be the solution created and implemented by misinformed hobbyists. The egg box theory does nothing but confuse the novice further as many enthusiasts still get ‘acoustic treatment’ mixed up with ‘soundproofing’. Egg boxes have one purpose, to protect eggs.

The Foam Approach
I’ve done the foam thing in the past. It’s quite an addictive thing to do, as you’ll see in my picture below. With every foam tile you carelessly stick to the wall leads you believe your room is being improved tile by tile but the problem is aesthetics. Aesthetics can take over and before you know it everything’s covered in patterned foam.

The problem with foam is that it doesn’t do anything to control the low frequencies bouncing around the room. High frequency flutters that occur can be tamed with foam approach but again too much can easily take the top end out of your room. The picture below shows a monstrosity I created in 2010 in a rush. I worked happily out of what was dubbed "The Darek's Bedroom' for about three years ignoring the problems caused by the foam until I put in my upright acoustic piano. The first thing I noticed was how crap it sounded in the foam room. It sounded as though the practise pedal was stuck down. My heart sank, as I knew it was the foam sucking the top end and clarity out of the piano.
2010 - The Foam Approach
2010 - The Foam Approach

2013 - The Rethink
2013 - The Rethink

Broadband Absorption
These I believe to be a much better alternative to foam as they do more across the broader range of frequencies, hence their name. I’ve gone this route with my current acoustics mindset.

They hang on two small brackets in the wall, which means I can take them down in a second if I need to change the acoustic character of my room. This also makes it easy for if you move your studio as the damage to the wall is minimal compared to what glued foam can leave behind.

They use an absorption material inside with a one inch air gap behind. This air gap, as advertised, will do a better job for low frequency absorption.

My broadband units are handmade by a UK company called CM Acoustics. Their products are also covered in an acoustic breathable fabric, of which you can choose from a selection of colours, which is nice as that can appease the aesthetical choices that factor into acoustic treatment purchases.
2015
2015
Bass Traps
hofa basstrap
They do what they say on the tin. But, before I say anymore I want to make it clear that many professional acousticians and specialists state online that bass traps should be purpose built and tuned specifically to individual rooms to correct problems such as room modes. I didn’t go down that route so I opted to use 4 HOFA Basstraps that I have stacked and positioned at the back corners of my room. My monitors are pointed directly at those corners of the studio so I thought these would work well there. To my ears they work nicely in controlling the rumble the studio had before I put them in. HOFA say that these can also be used as monitor stands.

Diffusion

Acoustic treatment is not all about absorbing sound; it is also as much about scattering sound and managing reflections in order to get an even balance of tone and space. Diffusion scatters sound in random angles helping to disperse reflections rather than ping-pong reflections that occurs between two parallel walls. I use two types of diffusers. Both my control room and vocal booth are small with broadband absorption so I complemented them by adding Vicoustic’s Multifusers in the control room and HOFA’s Diffusers to the vocal booth to help add a small amount of life to both rooms as I felt anymore absorption would have sucked any character out of them both.

Ceiling Clouds
Ceilings are often the largest flattest surface in a room. Clouds are useful as reflections from low ceiling when tracking can be apparent. I have found having a floating cloud above the mix position to be very effective in conjunction with wall mounted broadband absorption.

Software

I own a copy of IK Multimedia’s ARC 2 affordable room correction software. I used it for a few weeks and found myself struggling to continue using it in my workflow. I found the setup of the software somewhat random with little guidance to placing the capture microphone for the room readings. After performing several attempts of capturing my room with the included room microphone the results showing in the software where different each time, which confused me as I couldn’t pick nor trust any one of the readings. I've read several articles on ARC with many glowing reviews so I still recommend it as a tool that I'm sure will work for many users.

Mike Alton, James Ivey and Neil Hester all tested the Trinnov room correction system which I’m keen to try for myself as to see three audio professionals all fall over in amazement over such a well thought out product is an easy selling point to me.



Quick And Easy Acoustic Treatment Methods
If you have space in your studio put a sofa or bed in it. They work well as they generally sit up against a wall filling a large corner where the bottom of the wall and floor meet. Their designs are soft so work as a make shift broadband absorber.

Get some bookshelves up on the wall and put lots of books up at different depths. These can work like a diffuser, scattering sound.

Advice From A Professional Acoustician
Russ interviewed Andy Munro for a Pro Tools Expert Extra Podcast sometime ago with Andy sharing some really useful acoustic treatment tips and advice.
Pro Tools Expert Podcast Extra Interview With Andy Munro

DrNomis_44
28-07-2015, 07:06 AM
I think that half the battle with acoustic treatment of a room can be won by choosing a room where the walls aren't parallel to each other, doing so will go some way towards reducing acoustic reflections that cause standing-waves, you shouldn't have to use a whole lot of acoustic dampening foam to deaden a room, a few foam tiles in strategic places should be enough, a good test of a room's acoustics is to stand roughly in the Centre, or where the Digital Audio Workstation will be set up, clap your hands and then listen and analyze the tonal quality of the room, does it sound reverberant (live) or not (dead), are there any ringing tones (these could be caused by piping hidden in walls)?, then gradually add the foam acoustic damping in strategic places till the reverberation and ringing goes away.

ultpanzi
28-07-2015, 08:08 AM
Anyone tried isocabs? Basically a soundproof box that you put your amp and mic in. I think Ola Englund (correct me if Im wrong) uses it and it obviously does a good job for him.

kimball492
28-07-2015, 01:34 PM
Hi Ultpanzi , My buddy built an isolation cab .Its a great idea, if you have neighbours or sleeping girlfriends than you just don't want to wake while your rocking out. Essentially you build a soundproof box inside and out ,and place your speaker cab inside with one or two mics pointed at different parts of the speaker.its easier to use one mic because of phasing issues.But can be done with two.

http://youtu.be/cbYqbDEV1g0
http://youtu.be/bXd0enWnQ3Y

kimball492
28-07-2015, 02:03 PM
Part 1
http://youtu.be/PYyd35LXMAU
Part 2
http://youtu.be/dahWdXkHtLk

Ola Englund
http://youtu.be/HGEk5l7O4SQ