Wednesday, 12 March 2014

Building a Studio

Last year I was commissioned to build a small educational studio for a creative arts institute in Norway. Working in an established office building and on a Spartan budget you’ll have to stretch your imagination. In this post I’ll let you in on the process, my decision-making and show you some images.

The size of the over-all space is ideal for a project-studio, song-writing suite, radio, multi-media or education-studio.

In the building where we set up the facility there were two rectangular offices available side by side. One of the ideas the building’s owner had was to use them as a live room and a control room. The idea was good enough but the long rectangular rooms would not have provided nice acoustics. Instead I chose to knock down the wall and opened up the space for two reasons: (1) to get more space around our ears when mixing, (2) and to easier accommodate a whole class for bigger projects. The separate entrance doors from the hallway to the offices proved to be sound-doors with -35 dB SPL even damping. We kept them and thus had separate entrances to the live and control rooms, but having to go through the hall outside.

After knocking down the wall we built a small live room for vocal-recording, acoustic guitars and the likes. It was constructed to be big enough to stand inside with a long scale bass guitar and still have some space between the walls. We were also looking at the idea of bringing in a vocal booth on wheels, but we didn’t have enough clearing under the roof. Another idea was to dampen down a corner of the room and use a screen around the microphones, but this obviously wouldn’t have been as effective as a separate room—albeit, it could be a good idea for a small project studio.

In the roof above the doors we had an incredibly noisy ventilation channel. To cope with the ventilation we created a small air-gap, used a thick layer of Rockwool and two layers of plaster. It was very effective in containing the noise. Since we didn’t have the space or the budget to build a room-within-the-room we insulated all the walls and covered them with plaster. The plaster that covered most of the surfaces is a perforated type. The perforations with the insulation behind helps do dampen the sound (quite similar to a Helmholtz resonator) while the plaster it self creates some reflections. This is exactly what I wanted as the room gets a nice natural sound with hardly any echoes or notable reverberation, but it doesn’t sound totally dry either. The perforated plasterboard is more costly than regular plasterboard and it had to be ordered from Denmark. But the extra cost was about the same as the extra soundproofing would have been if we were to build the walls from regular plasterboard. The sidewalls in the main studio were set up conically prevent any standing waves. They were closer together at the front than at the back, but visually it could hardly be seen. With clever design and really skilled carpenters (cred to them!) we ended up having very few parallel surfaces in the entire facility. The floors were covered with carpet tiles (on top of the existing concrete) and at the front of the studio I chose a wood floor, both to throw in some acoustic irregularity and for easier use of office chairs. Additional damping-foam was fitted only where our ears told us we needed it, which turned out to be an impressively modest sum total of 5 bass traps in the live room. The live-room walls were covered with 40 mm. tiles for suspended ceilings. We glued these on and they were acoustically very effective (and affordable). They dampen reflections but not fully as much as regular sound foam.

The doors in the original offices damped sound relatively flat at -35dB SPL. Our carpenters did three things to improve them. (1) They tightened up the locks, (2) they put in new draft-excluders and (3) they covered the inside of the door with 40 mm. tiles for suspended ceilings. The latter dampens the reflections back into the room from the door, but it did in fact help a little on the overall exclusion of sound from the hallway as well. 

In front of the workstation there were two large windows. It is off course a nice thing to get proper sunlight into the space, but I was sceptic to the prospect of having large studio monitors that close to the windows. My concern was mostly that the glass could start resonating at the low frequencies and give a false impression of bass levels in a mix. Subsequently I spent a lot of consideration whether to get monitors with front or rear bass-ports. Initially I wanted them at the front to avoid the windows, but after several rounds of good research and consultancy from the speaker distributor we ended up with a pair of speakers with rear bass-ports. The distributors monitor expert meant that since bass frequencies are not really directional, front or rear ports wouldn’t make a difference. As much as I generally agree on this I have experienced that bass ports can create “wind” quite far from the speaker cabinet at loud volumes. However, round bass ports create a sphere of air-pressure while long flat bass ports and other odd shapes spread the air-pressure out better. Since we were looking at Eve Audio’s SC 207 (flat rear ports) I was convinced enough to give it a try. Either way, the distributor said I could return the speakers if I wasn’t happy, a great offer that sealed the deal. After mounting and tuning the speakers I was more than happy with the outcome. The big windows turned out not to be a problem at all. (I have written more about the SC 207 and other Eve speakers at two other posts.)

The workstation

A normal configuration for a studio this size is often a live-end-dead-end design. In a live-end-dead-end studio it is common to have the lowest roof height and most damping at the same end of the room as where the speakers are. The studio I designed is the opposite of this for several reasons. For one I wanted the work-position to be close to the windows to get the natural lighting to flow through and we had already lowered the roof at the other end of the room due to the ventilation channel. The other reason is that I like to have some space around my ears when I mix and at the front of the room (read: where the speakers are) was really the only place left where we could have it. Due to this it was important to avoid any sharp angles at the back of the room. Where there was a difference in roof height we made a slope between the surfaces instead of a 90-degree angle (see picture below). Still, in the perforated plasterboard with Rockwool behind this didn’t really provide any undesired reflections. This way we kept the acoustics of the space very natural. The ‘strawberry on top of the cake’ was a big sofa behind the workstation. The world’s most used bass-trap! ;)

Odd angles and perforated plaster board.

The window to the vocal booth consists of one 6mm and one 8mm glass plate set at apart at an angle. Two different thicknesses makes it more sound-proof. The same principle goes with double walls.

If you want artists to thrive in a studio-environment you have to think about the look and feel of the space. Gear won’t be enough to make musicians feel at home. Light became a huge consideration, especially as this studio also were to double as a classroom. We had three light-sources: two big windows, two large low profile lamps in the roof above the workstation (approx. 50*50 cm.) and LED downlights at the back of the room and in the live room. For the electricians that worked on the project I had four requirements for any lights installed: (1) Lamps would have to have no acoustic noise from transformers or similar (transformers were to be placed outside the room if there were any); (2) lamps, transformers or dimmers would have to make no electronic interference (we skipped dimmers all together); (3) lamps would have to be tightly closed so no rattling noises would occur at loud bass-volumes; and (4) lamps in the tiny live-room would have to be LEDs to not fry our singers.

The entrance. The door is treated with additional 40 mm tiles for suspended ceilings. Since the shadow from the sunlight fall into the entrance space we chose to liven it up with some colour. Initially we intended photo-canvases depicting the tropics on the walls and the blue against the oak details would echo the sea and sky against sand, wood and ropework—in case you're into interior design :)

Around the workstation I had several electric circuits installed. Two of these consisted of a series of sockets with individual switches. This way the speakers could be shut down separately from other equipment. This is useful to avoid damaging speakers but it is also a pedagogical measure to teach students to avoid sending unwanted transients to the speakers. Having all the equipment powered through two switched circuits also makes it quick and easy to power up and down the studio.

Switched and separate circuits makes it easy to power up and down the studio.

Interior of the vocal booth.

Inventory list

(Since we built this studio the UR824 has arrived on the marked along with similar USB models for Focusrite et al.)
PreSonus Blue Tube DP V2 (set up with one channel for mic- and one for line-recording)
CGM Table

Eve Audio SC 207
Sony Sms-1p (To provide a home stereo contrast to the SC 207s)
Beyerdynamic DT 770 Pro

A selection of microphones from AKG, Røde and Shure—covering large and small membrane condensers and dynamic microphones.


ProLyd in Norway has been my supplier of equipment throughout the building process (which also included another studio and a class-room). I’d like to send a big shout to Cristhopher Briggs and the staff there for excellent help and advice.

I’d also like to send a shout to the guys at the contractor Primahus who actually had built a recording studio before (what are the chances!), and a shout to Rosenborg Malerteam who provided paint, flooring, colour samples and really good assistance with the look of the room. Both of these contractors went above and beyond!

A shout also goes to Audun Røstad at Ambolt Audio for letting me bounce my acoustic design ideas off of him.

Sparkling wine (non-alcoholic) for the students and staff at the official opening.

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