Studio SOS: Studio Desk & Acoustics

The room layout before Paul & Hugh set to work...

The SOS team put their DIY skills to the test, constructing a new studio desk and optimising a home studio’s acoustics.

Living south of Manchester, Graham Battersby is in the fortunate position of having retired and, now that his children have all moved out, he’s managed to wangle the largest bedroom in the house as his new studio space. His previous setup occupied the rather smaller spare bedroom, which was treated with a quantity of Auralex foam panels plus two foam corner traps, all bought second hand on eBay. So having managed to peel the panels off the walls, he was ready to fix up his new space. That’s when he called us in, as he wasn’t sure as to the best way to deploy the acoustic treatment, and with the room as it stood he wasn’t happy with the sound he was hearing, even though he had a more than decent pair of Mackie’s original HR824 monitors. He also needed to be able to record vocals in the room using his new Neumann TLM103 microphone, both for his own band, EXIT7, and for any local musicians he might attract to the studio.

Graham’s studio recording system is based around a PC running Reaper, which wasn’t giving him any problems. He also uses a Korg D888 hard-disk recorder for recording live drums on location before transferring the WAV files to his DAW. There were no weird hums or buzzes to report so no help was needed in that area, which left us plenty of time to concentrate on the room acoustics and speaker location.

After being greeted with drinks and the obligatory chocolate Hob-Nobs, Graham showed us the studio space, a rectangular bedroom measuring 3.45m wide by 3.83m long and 2.43m high. His monitor speakers were perched on keyboard X-stands either side of a computer desk firing down the longest axis of the room, which is pretty much always the best orientation in smaller spaces such as domestic rooms. His acoustic foam was heaped up ready to be deployed, and we brought along four foam corner bass traps, two from Auralex and two from Universal Acoustics.

Throwing A Wobbly

Before even starting on the room acoustics, both Hugh and I instantly homed in on the speaker mountings as being a potential problem. The keyboard stands were folded almost closed with the monitors perched on Auralex MoPad isolators on a piece of plywood resting across the top. These rather wobbly structures would do the low end no favours, so we scratched our heads looking for a simple but effective solution that didn’t involve going out and buying expensive new speaker stands. In fact, switching to my ‘born in Yorkshire’ mode, I was determined that it wasn’t going to involve anything expensive at all!

A monitor and screen platform was fashioned out of some leftover pieces of wood and MDF.Two computer screens were set up on a simple computer desk that was only just wide enough for them, so my first thought was to get something like a piece of kitchen worktop long enough to accommodate both the computer screens and the Mackie speakers, rest this on the upper level of the computer desk, and then find some means of supporting the two outer ends of this new shelf to give the speakers something substantial to sit on. Graham mentioned that he’d just put some very thick (around 25mm) plastic-coated chipboard planks from disassembled furniture out on the drive with a view to taking them to the tip, and luckily they hadn’t been there long enough to be damaged by the rain or to make the journey to their final resting place. They were around 300mm wide and by putting two end to end, we had more than enough length to make what we needed. Graham rummaged in his garage and returned with a couple of long pine slats that we could screw under our new shelf, front and rear, to join the two sections securely.

After a few minutes with a hand saw and my cordless impact screwdriver (never leave home without one!), we had our new and very solid shelf, but what to do about supporting the ends? I figured the ideal thing would be a couple of breakfast bar legs, but I’ve always bought them online when doing my own jobs so didn’t know if anywhere local would have them. Graham said they had a very large DIY store nearby so we thought it would be worth a look, and we found exactly what we needed within a few minutes. He also bought a roll of non-slip matting that we thought would be suitable to put between the existing computer desk and the new shelf which would rest across it. As time was of the essence, Hugh steered me carefully past the power tools section before I could get distracted!

The platform was set atop Graham’s desk, with some non-slip matting underneath it to minimise vibration transferral.Fortune again smiled upon us when we came to fit the breakfast bar legs, which are essentially wide metal tubes screwed into a fitting plate at one end and with a height-adjusting foot at the other. With the adjuster at around its mid-way position, the legs were exactly the right length to support the shelf ends while allowing the middle of the shelf to rest on the computer desk via the non-slip matting.

Even more fortune came in the form of double-glazing fitters: Graham had just had some double glazing installed and the fitters came back to change a handle while we were there, so we scrounged a length of 40mm-wide UPVC trim off them and used it to tidy up the front edge of our newly fabricated shelf, sticking it in place with Auralex spray adhesive. It was all starting to look quite tidy.

Just The Platform Ticket

Although Graham had his set of Auralex MoPads, which are far better than standing speakers directly on a wooden shelf, SCV Distribution had provided us with a set of IsoAcoustics ISO-L8R 155 speaker platforms, and to date we’ve been very impressed by the improvement these platforms make. They come with two different lengths of rods for connecting the base to the top, the rods simply pushing into resilient mounts. There are also two sets of spacers that can be inserted into the ends of two of the rods to angle the speakers upwards or downwards by different amounts, so we combined the shorter rods with the smaller spacers to angle the speakers up slightly. This aimed the speakers correctly towards the listening position height-wise, and we also angled them in to intersect at a point just behind the listening position.

Hugh had already checked the settings on the rear of the speakers, which were set correctly for half-space use with a 47Hz roll-off. We made sure the speakers sat towards the front of the shelf to allow the rear-mounted passive radiators on the HR824s to function correctly. The same would have been true of rear ported speakers — you need to leave a minimum of 150mm or so between the back of the speaker cabinet and the wall.

After checking the effect of the speaker platforms using some familiar test tracks of our own, Graham dug out a Bob Marley CD that had plenty of low end and he was genuinely surprised at how much tighter and more focussed the lows sounded. We also did the trick of touching the shelf surface to see how much vibration from the speakers was being passed onto the shelf and we couldn’t feel anything at all. So far, so good.

Soaking Up The Ambience

After a splendid lunch provided by Graham’s extremely supportive wife, we worked out how best to use the acoustic foam. The side ‘mirror points’ (typically in line with the engineer’s knees) are usually the first things to address, but a window to the left of the mixing position made sticking foam up there impossible. Instead we recommended partially closing the curtain and propping up a 600mm square foam tile behind it, which worked well.

To the right and slightly forward of the mixing position was a bookcase full of usefully diffusing bits and pieces, so we put an area of foam directly behind that centred at seated head height. Two 600 x 1200 mm blue foam panels went on the front wall behind the speakers, both set horizontally, and, as the wall/ceiling joint above was curved rather than at a right angle, we glued our two Universal Acoustics corner bass traps directly above the foam panels leaving a gap between them and the ceiling.

Two more 600 x 1200 mm panels went across the large rear wall, and the four matching Auralex bass traps were glued to the wall/ceiling junction directly above them. A couple of these looked a little tatty around the edges due to being peeled off Graham’s previous studio wall, but he was more concerned about performance than pristine aesthetics.

After: The front and rear walls were treated to a heavy dose of acoustic foam while the IsoAcoustics ISO-L8R 155 speaker platforms supported the Mackie monitors on the newly-built DIY desk.

With all the foam in place, Hugh ran our standard descending-semitones sine-wave bass notes test, listening for any boomy or missing notes, which would indicate standing-wave problems in the room, but we were pleasantly surprised to find the response was actually pretty even. Where there are lumps in the response, moving the speakers around by even a few inches can often help, but ultimately any large peaks and dips remaining indicate the need for more bass trapping. Of course there may not be as much space as you need for adequate bass trapping in a domestic room so it is often necessary to accept a compromise.

Repeating our listening tests confirmed a surprisingly well-behaved low end, given the minimal amount of bass trapping, and by reducing the worst of the wall reflections the foam also brought much needed focus and clarity to the monitors, with a good sense of stereo imaging and detail. In fact we were all really rather impressed by the result in comparison to what we had started with.

Striking A Chord

Paul adjusts the truss rod on one of Graham’s vintage Gibson guitars.While Hugh did a little tidying up, Graham showed me his early vintage Gibson Les Paul Junior guitars, one of which had quite noticeable intonation problems and wasn’t ringing quite as well as it should. I said I could take a look if he had the required Allen keys and spanners, which he did.

Pulling back the treble end of the bridge brought the octaves much closer to being accurate (though they are never perfect with uncompensated bridges of this type), and the lack of neck relief was addressed by slackening the truss rod nut by around a quarter of a turn. Graham said that chords played high up the neck were now much more in tune and that the general feel of the guitar was better, so we plugged it in and bashed out a few chords while Hugh stood by, daydreaming of Hammond organs.

Graham tries out his new sE Electronics Reflexion Filter.

To help with Graham’s vocal recordings, we found an sE Electronics RF-X Reflexion Filter in our ‘It’s always Christmas with SOS’ bag, and set this up with Graham’s Neumann TLM103 microphone, fitting his pop shield in front of it. We suggested recording vocals with the singer’s back to the treated rear wall as that is well away from the computer (and its fans), and would also help reduce the level of reflected sound getting into the front of the mic. The Reflexion Filter would intercept reflections approaching the sides and rear of the mic and also reduce the amount of vocal sound spilling out into the room slightly. The mounting hardware for the RF-X is much simpler and more practical than earlier incarnations of Reflexion Filter, and we demonstrated how it works best if set up on a straight stand (not a boom-arm type), and adjusted to bring the centre of gravity of the combined filter and mic directly over the pole.

By now it was time to take our leave or we’d never make the ritual traffic jam around Birmingham, where tradition dictates that we moan about the interminable roadworks while listening to BBC Radio 4.

We’d like to thank SCV Distribution, IsoAcoustics, Auralex, sE and Universal Acoustics for donating the materials that made this project possible.