Studio SOS: Small Room Problems

Paul White takes stock of the situation.

Small rooms are often the trickiest to get right, as our visit to a TV and film composer’s new home studio proved!

Since leaving Music College with an Associateship to the London College (ALCM), singer and multi-instrumentalist Jo Bates has been touring Europe (and even Siberia, where she recently performed), recording and mixing her own music at home, as well as narrating and editing audiobooks and composing music for television.

She relinquished a place at the Birmingham Conservatoire to join the band Quill but says her classical music grounding has proven invaluable in her work for TV, film scoring and orchestral arrangements. Her output ranges from four-part harmony for male voice choir to orchestral pieces for the Discovery Channel.

We were asked for help in turning a spare room into a workable studio. Jo and her husband Phil have recently moved into a new flat, and as it was purchased rather than rented, there were no restrictions on sticking acoustic foam to the walls, as there often are on our visits!

Square Play

As we’ve pointed out before, possibly the worst room to try to turn into a studio is a cube of around three metres per side. It is worse still if the walls are very solid rather than being made of plasterboard. At 2.9m deep by 2.5m wide, and 2.7m high, Jo’s room turned out to be very close to these ‘demon dimensions’ — and it was built from solid brick. The modal resonances supported by a cube-shaped room are bad enough, and by the time you’ve put your desk in the right place in a room of this size, your seat inevitably ends up close to the centre of the room, and all the bottom end seems to vanish at the listening position. Hugh and I have dubbed this region ‘the spherical Bermuda triangle of death’, so we weren’t surprised to find that similar problems prevailed here. Somehow, though, it is reassuring to find that in an ever-changing world, the laws of physics remain dependable!

The studio setup itself was very simple, as Jo does everything on a MacBook Pro running Logic Pro, with an ageing MOTU 828 FireWire audio interface driving a couple of Yamaha HS7 active monitors. She has a Neumann TLM103 microphone for recording voice and acoustic instruments, and also uses a Roland VR-760 electronic keyboard as a MIDI controller, though we removed this from the room on a temporary basis to give us room to work and to take photographs. This normally fits nicely along the left-hand wall. Jo has also recently bought a Komplete Control S61 for use with NI’s Kontakt 5 and the Komplete 11 Ultimate sound library — but setting that up would be for another day...

As a temporary measure, Jo had set up her gear on a desk, with her speakers standing directly on the desktop. She’d hung a rug up on the front wall; as there was a little air space between rug and wall, it was having a small effect in reducing high-frequency reflections, so we left it in place. It also added to the cosmetic vibe. However, all the other hard surfaces in the room meant that the acoustic was still noticeably lively. A single-glazed window set into a very deep recess allowed some traffic noise to intrude, but Jo was already planning to have this replaced by a double-glazed unit. In the meantime, the tried and tested makeshift arrangement of big cushions and thick curtains will have to suffice.

Foam Depot

After moving all unnecessary items from the room, we were left with the desk, a small filing cabinet and a plastic storage box, both of which fitted nicely under the desk. There was also a small wooden bench seat positioned along the side wall beneath the window. While we would be doing some of our usual glueing of foam to the walls, the multi-purpose use of the room prompted us to try something a little different in the way of movable acoustics. The Auralex team have always been great at supporting our Studio SOS efforts, and a while back they sent us a pair of DeskMAX panels and a pair of ProMAX v2 panels to use when a suitable candidate came along. These seemed ideal for what we had in mind. A benefit of movable panels is that as they don’t have to be placed right up against a wall, they tend to be more effective at lower frequencies than the equivalent thickness of foam glued directly to a wall.

A set of Auralex stand-mounted absorbers could be placed at the listening position when mixing...The ProMAX V2 is based on a 2x4-foot, three-inch thick Studiofoam panel fixed to a rigid, stepped rear panel; this provides the necessary support for the foam and also allows the panel to be turned around so that its reflective surface can be used to add life to acoustic instruments if required. Each panel comes with a round-base mic stand, the pole of which is inserted into a hole passing up through the foam panel to support it. Our idea was that for mixing, these ProMAX panels could be placed at either side of the listening position to cover the mirror points, just as we normally do with wall-mounted foam. However, these same panels could also be brought in closer to the sides/rear of the chair for recording. In conjunction with a screen placed behind the microphone, they would then help dry up the acoustic for voiceover recording.

...or used to form a makeshift vocal booth when recording.For more conventional vocal recording with the singer in a standing position, both ProMAX v2 panels could be moved to the rear corner of the room where, in conjunction with some acoustic foam fixed to the walls, they could be used to create an effective temporary vocal booth.

The screen we used behind the microphone in this instance was an Auralex MudGuard, a shaped device that uses the same bonded foam/rigid backing structure as the ProMAX v2s. The MudGuard comes with fittings to allow it to be fixed to a conventional mic stand — either a normal floorstand or, more appropriately in this case, a short desktop stand. However, as we didn’t have one to hand at the time, we temporarily stood it atop the wooden box that came with the Neumann mic (Jo planned to acquire a suitable short desk stand after we left). The latest v2 MudGuard departs from the usual curved shape adopted by most Reflexion-style acoustic filters and instead uses a multi-radius convex geometry to help direct off-axis acoustic energy away from the microphone. The included hardware allows the MudGuard v2 to mount to most microphone stands, and a slotted mic mount support arm allows the user to adjust the microphone distance from the screen.

Following a similar style of construction to the ProMAX v2s, the smaller two-foot-square DeskMAX panels have a flat (rather than stepped) back, again with three-inch Studiofoam for the front surface, and this time supplied with short desk stands. We used these DeskMAX panels on top of the desk, positioned far left and right behind the speakers, and angled to help cover the room corners.

To further tame the room’s acoustics, a number of Universal Acoustics foam panels were applied directly to the rear wall.To treat the rear of the room, we had a quantity of Universal Acoustics pyramid foam, two inches thick, giving us enough to put a row across the rear of the room at head height and also to put a double row in the corner planned for stand-up vocal recording. These foam panels were glued directly to the wall. Our final spare tile was placed on the bare wall opposite the window to provide a degree of acoustic symmetry when the thick velvet curtains were closed. Hugh used the spray glue and I then stuck up the panels, having first marked a line using a spirit level to ensure that they would be square.

Stand By Me

When doing talking-book voice work, conventional mic stands have a habit of getting in the way, so I took along my desk-mounting mic arm, which is basically a budget version of the mic stands you see used in many radio stations. The stand simply clamps to the edge of the table and has a hinged, movable arm much like an Anglepoise lamp. This enabled us to get the mic in just the right position for Jo, and as it costs only £7.00 (with free delivery) she ordered one from eBay there and then. It held her TLM103 and pop screen quite firmly.

To get the speakers off the desk and to dry up any unwanted low end caused by vibrational energy being transferred to the desk’s surface, we put the speakers on two IsoAcoustics ISO-L8R200 speaker platforms, set up using the short support tubes, which put the speakers at around the right height for Jo’s ears. We’ve always found these isolating supports to make a significant difference, especially where the speakers had previously been placed directly on a desk. We also place a fabric mat on the desk to help reduce surface reflections when Jo was recording talking books, and suggested that she place her laptop slightly to one side to avoid it contributing to reflections.

Zero Hum Game

When first checking out the room before disassembling everything, we had noticed a low-level background hum from the speakers, and on rewiring the computer, monitors and interface, we found that the interface was connected to the speakers with unbalanced cables — so initially we thought the hum might be due to a ground loop problem. I had a spare pair of short TRS jack cables which we substituted in place of the original cables and that seemed to cure the problem, but then we discovered that a new hum occurred as soon as the FireWire cable was connected to the computer, even though the laptop was running off batteries at the time.

Paul tries to track down the source of that buzzing noise...Also, in trying to adjust the monitor levels, we heard some very loud pops and bangs as we turned the master output level control on the MOTU 828. Apparently, Jo had been noticing odd behaviour from her MOTU 828 for some time but, being fair to the poor thing, it was seriously old. A few minutes of furious pot waggling got it working again and the hum subsided, but Jo felt the time had come to upgrade.

As Jo only records one or two things at a time, she planned to replace it with an Audient iD14. I use one of these myself for my office system so confirmed that it would be a good choice, though as it doesn’t include five-pin MIDI, Jo might still have to use the MOTU 828 as a MIDI interface, or buy a separate MIDI-to-USB converter, which are cheap enough.

Our final listening tests showed that if Jo moved her chair back to around two feet from the rear wall, the bass level felt much more accurate than when in her seated position at the desk, but would still be essential to check mixes on headphones and other systems due to the low-frequency uncertainties associated with small, near-cube rooms. From her usual mixing position the sound from the speakers came across as very bass-light, exactly as we expected. Effective bass trapping is not really an option in rooms of this size, as it would take up far too much space. I also felt the Yamaha monitors sounded a little abrasive when auditioning known material so Hugh reset the HF level switches on the back of the speakers to -2dB, which improved things.

By then it was time to go, but in a relatively short space of time we’d managed to transform a difficult small room into a cleanly set out recording and mixing space, albeit one with inevitable limitations. The Auralex panels were a great success in providing movable acoustics and with all the absorbers in place, the room sound was much better controlled than when we first arrived.