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Studio SOS: The Cube

Community Centre Project
Published July 2013
By Paul White

A recomissioned Apple Mac G4 and MOTU Traveller interface, along with some generous donations (including monitors from Alesis), formed the basis of a fully operational multitrack recording setup.A recomissioned Apple Mac G4 and MOTU Traveller interface, along with some generous donations (including monitors from Alesis), formed the basis of a fully operational multitrack recording setup.

With a non-existent budget and some serious acoustic problems, it took some quick thinking and a generous helping of goodwill to give this revitalised community centre a functioning recording studio.

The Cube is a West Midlands youth centre that recently came under threat of sell-off from the local authority. However, thanks to the efforts of a group of local people who organised to support its continued existence as a social facility, it is now in the hands of a trust and is being renovated on the tightest of tight budgets. The aim is to provide a multi-function centre that includes a performance hall, meeting room, cafe, rehearsal room and small recording studio. Most of that is already up and running, while renovation work carries on.

We were initially called in not only to try to improve the acoustics of what is, frankly, a very difficult space, but also to piece together a viable recording system from bits and pieces owned by the trust or donated to them. As the facility was within easy travelling distance of my home, I decided to tackle the job in stages, bringing Hugh Robjohns in later, after all the basics had been completed.

The trust had come into possession of a G4 Mac running Logic 7, which was pretty ancient, but it still worked, so it was decided that it would do the job — and visitors could always patch in their own more up-to-date laptop systems if they had them. The G4 came with a Mk1 MOTU Traveller Firewire interface, which offers four mic/line inputs and four further line-only inputs, as well as the capability for expansion via an ADAT port. We also found a grime-encrusted Mackie mixer and a box of XLR and jack cables — but no monitors and no mics, other than some well-used dynamic live-sound models.

Donations Welcome

A subsequent donation of a Studio Projects B1 capacitor mic provided a main vocal mic, but that still left us some way off a complete system. Jon White (no relation), who manages the Cube, said that users should bring their own headphones, since if the Cube provided them, they'd probably be broken within days! He did, however, dig out a USB controller keyboard that worked fine as soon as it was plugged in. This was just as well, as the studio was out of Wi-Fi range at the time of our visit and the G4 didn't have a wireless network card fitted anyway, so updating the software would have been time consuming if it had been necessary!

Because of the limited hard-drive space on this fairly old Mac, I suggested that the trust members phone around the local computer repair shops to see if they could beg or buy any cheap external Firewire hard drives to use for audio storage.

Given the almost non-existent budget of the trust, I called Numark Alesis in the UK to see if they had any B-stock speakers we could buy at a knock-down price — but once I explained what we were doing, they very kindly sent us a pair of 520 Actives free of charge, which was very much appreciated. I also had a pair of Silent Peaks MDF-on-foam speaker isolator platforms in my Studio SOS kit, and cutting one of these in half using my bandsaw left me with two speaker platforms that were exactly the right size for the Alesis 520s.

Having surveyed the available gear, the emerging plan was to to use the Mackie mixer's two stereo outputs (the main and alt buses) to feed the four line-only inputs of the MOTU Firewire interface (inputs 5-8). This, along with the four preamps built into the MOTU Traveller, gave us eight-track microphone recording capability. The old G4 wasn't going to deliver much in the way of fancy software instruments without maxing out, but it was quite happy doing basic audio recording and hosting a few essential plug-ins. Since the main aim of the studio was simply to allow bands to record their efforts and for musicians without recording gear of their own to gain some basic recording experience, the G4 would be able to handle the task quite adequately.

Window Of Opportunity

Before: The Cube's manager, Jon White, in the shower room that would soon form the heart of a recording studio.Before: The Cube's manager, Jon White, in the shower room that would soon form the heart of a recording studio.

My first visit to the Cube revealed a high, narrow space next to the rehearsal room that would be used as the studio control room. Dimensionally, the room was almost a cube cut in half vertically, so I knew we'd have some serious standing-wave issues, especially given the very solid construction of the space (which had once been a shower room). Still, it was the only available space for the studio, so we had to work with it. Jon knew that a control-room window would be needed, so he arranged for volunteers to cut a hole in the wall facing the rehearsal room, into which was fitted a heavy wooden frame left over from some earlier venture. I suggested making a hole lined with waste pipe in the wall between the control room and the rehearsal space to accommodate the necessary cabling. This could then be filled with foam offcuts or expanding foam once the cabling was in place, so as to reduce sound leakage from the live room. On my next visit, the frame had been fitted with a double-glazed unit set at an angle, and the hole for the cabling was also done. I had envisaged a piece of 1.5-inch waste pipe but they'd put in a piece of five-inch down-pipe, which would need a good roll of foam to seal.

Door Control

The door separating the control room and rehearsal space was reasonably heavy, but it had no catch and was not sealed around the frame, so sound simply poured in around the edges. It also had holes in it where previous locks and handles had been fitted. I told Jon that once they'd fitted a suitable catch, I'd bring some tools and fit new wooden closing strips with seals to get the door as airtight as possible. A double door will always work better, but there was little space to build one here.

In the end, we settled for heavy-duty domestic weather-strips to use as seals on three sides of the door, and then fitted a strip of thick carpet under the door to help seal the bottom, but without introducing a trip hazard, which a further wooden sealing strip would have done. Another strip of carpet was then glued and tacked to the lower edge of the outside of the door so that it would butt up against the piece we'd glued to the floor when the door was shut. This worked reasonably well, and though the sound isolation was far from perfect, as much sound seemed to be coming through the door as around it, so the sealing was clearly working. A rather nasty old rug was cut up and glued to the inside surface of the door to add a little damping.

Jon also asked me about sound leaking out of the rehearsal space to the rest of the building. Access was via a corridor around three metres long, which also serves a kitchen area, so I suggested building a stud partition with a doorway in the corridor. This wouldn't help sound leakage into the kitchen space, but the airlock thus created should improve leakage into the rest of the building to a useful degree. Again, this was agreed, and a couple of weeks later it was done and worked perfectly.

Plan Of Action

The control-room window looks out through onto the rehearsal space, but it is set into one of the control room's longer walls. It would be disastrous to set up monitors firing across a room with less than two metres between the speakers and the opposite wall, so it was decided to put a desk at the end of the room to house the recording system. The concrete floor at that end had shower trays cast into it and wasn't flat enough simply to stand a desk on, so we asked Lee, the volunteer carpenter, to fix a couple of wooden battens to the side walls, onto which we could rest our desk surface. This was done leaving a gap of 250mm or so between the desk and the end wall to accommodate cabling. Surplus carpet squares were later used to cover the desk top, providing a tidy, non-slip surface. A budget eight-way XLR-to-wall-box snake was used to link the control room to the rehearsal space, the plan being to run a separate headphone extension cable through the same hole for monitoring purposes. I managed to dig out a six-channel headphone amp that I'd designed and built as a readers' project back in the mid '80s when working for Home & Studio Recording magazine, so I gave this to Richard to integrate into their system.

The rehearsal room had already been treated using a number of fabric-covered Rockwool bass traps hanging around the walls, and there were two spare, which we decided to hang on the rear wall of our control room. The remaining walls were then treated using a mixture of Auralex and Universal Acoustics foam that we had available, including a few corner bass traps. Foam panels were glued to the wall behind the monitors and also to the mirror points on the right-hand wall. The control-room window took up most of the immediate left-hand wall, so small Auralex foam tiles were arranged all along the top edge of the window. This tamed the excessive 'bathroom' liveness of the room, but we knew we'd still have some low-end issues to sort out, because of the room's size and construction. Most of the corner traps went along the top edge of the front wall, with a couple more near the back of the room, although we didn't have enough to completely tame the room's errant behaviour.

Testing, Testing...

Even after the team had positioned acoustic foam on the walls in all the usual places, the shape and dimensions of the control room meant that it still had some significant acoustic problems.Even after the team had positioned acoustic foam on the walls in all the usual places, the shape and dimensions of the control room meant that it still had some significant acoustic problems.

After wiring up the system and confirming that the ancient G4 still worked (albeit with the noisiest fan I've ever heard!), Hugh ran his test CD, and we also ran a sine-wave chromatic bass-scale test to check for excessive peaks or dips in the room response. And did we find one! We performed this test after fitting all the foam panels but before fitting the bass traps. At around 105Hz, the audible signal level leapt up dramatically (affecting both lower A and A-flat notes), and no amount of moving the monitors around made any impression on it. It was so bad that when we made a test recording of speech in the room, the combined effect of the room resonance on the speech being recorded, and again on playback, produced a hideous low-frequency honk that had me wondering if the mic was faulty! It wasn't. Although this peak was reduced by a few decibels after we fitted the bass traps, it was still a serious concern and would preclude actually recording anything in the control room (not that the noisy computer fan would make that a good idea anyway).

As an experiment, I set up a parametric EQ plug-in as a notch filter and adjusted it to give a subjectively even level across our chromatic sine-wave scale test. I had to use between 15 and 18 dB of cut to level things out! I also added another less severe dip an octave higher, at around 210Hz. Now, I don't like the idea of using EQ to try to fix room acoustic issues when monitoring, especially ones of this magnitude, but in this unfortunately sized space there was no room for effective bass trapping, other than possibly in the ceiling, and as the more serious musicians using the facility would probably be taking their work home to mix, it was a case of pragmatism winning out.

That left us with a choice: either set up a Logic template song with a plug-in notch filter in the output, which would have to be bypassed when bouncing mixes or listening on headphones, or look for a suitable hardware equaliser that could be placed in the monitor chain. My suggestion was to look out for an affordable 31-band stereo graphic EQ to put before the speakers, but in the meantime I left my EQ setting in the Logic template song so that it would be active by default but could easily be bypassed when necessary. Subsequent sessions confirmed that this approach was quite workable.

My next visit was to install some balanced jack cables to connect the Mackie mixer's main and alt outputs to the MOTU line inputs 5-8. However, on my arrival it transpired that the MOTU interface had ceased to function, and it was feared that money would somehow have to be found to buy a new one. Fortunately, Sound On Sound's Dave Lockwood remembered that MOTU interfaces could sometimes be cured of apparent death by doing a factory reset — so after a very quick Google search for the procedure, I pressed the buttons, dialled the dials and the thing sprung back to life, to sighs of relief all round! Because of the noisy G4 cooling system, I also took the opportunity to relocate the Mac to beneath the desk.

By the time the installation was done and tested, Jon had managed to find a couple of DAW-savvy local musicians, Jake and Richard, to help run the studio, so I spent a while with Richard, showing him how to translate his existing knowledge of Cubase to working with Logic (Jake seemed to have a good working knowledge of Logic already). Richard told me that he planned to install hooks for cables and other basic niceties, as well as reorganising the PA in the rehearsal space, and he also managed to get a combination lock fitted to the studio door to prevent unauthorised tampering before I signed off on the job.  

Reader Reaction

Richard: "The original room was horrendous, and although it is still not perfect, at least we now have a working studio where we can record up to eight sources at the same time, with the option to expand to 16 in the future by adding a Behringer ADA8000 expander or similar. This is all the more remarkable as it was all assembled from existing equipment, other than the monitors which Alesis kindly gave us. The integration of the Mackie mixer gave us four more mic inputs, and the acoustic foam cleaned up the overall sound immensely. We'd like to thank Universal Acoustics, Auralex, Silent Peaks and Alesis for their kind contributions to this project. They have helped to fill gaps in essential equipment that was needed to start things up.

"Last, but definitely not least, we would like to thank Paul and Hugh from SOS for the large amount of time, work and assistance that they have given the Cube studio project. What was once an old shower room is now a functioning recording space that will allow the young musicians of this area to learn and improve their knowledge of the whole recording process”

Published July 2013