SOS 's crack studio squad tame unwanted reflections, track down strange noises coming from a Mac, and make some good-sounding drums sound even better!
Paul Evans' studio is located in a couple of upstairs rooms in a building adjacent to his parents' house in Weston Super Mare — a town from which you can reputedly see the sea on a clear day! The studio comprises a control room, which is shared with Paul's dad's home office, and a second live room, in which Paul keeps his Tama drum kit set up. The windows and an unwanted doorway in the live room have been blocked up using Rockwool infill with a rubber mat taped over the top, and this actually provides some useful low-frequency absorption. Paul has covered the rubber sheet with blankets, but we noticed that there was still some mid-range reflection from it, due to the limited thickness of the blankets.
The control room had no acoustic treatment at all when we arrived, although bookshelves to one side and other furniture provided some natural absorption and scattering. Considering the lack of treatment, music played back over Paul's Yamaha HS80M monitors (which were correctly set up along the centre of the shortest wall) sounded reasonably well balanced, displaying fewer bass-end issues than we'd anticipated. Still, some room coloration was evident and the stereo imaging was quite restricted because of the unwanted reflections from the side walls. Paul had set up his monitors on metal stands, but as these weren't quite tall enough he had extended them with a stack of ceramic tiles beneath each speaker, to get them to the right height and to provide more mass. This seemed to work fine, though we recommended some non-slip matting under the speakers to keep them in place.
The studio system is actually fairly simple being based around an early Mac G5 (2GHz), a Digi 002 Rack interface and Pro Tools LE software, along with a modest amount of outboard gear, which includes a Behringer ADA8000 to provide eight additional mic inputs via the ADAT optical link. A multicore snake through the closed-off doorway links the live room to the control room and Paul has various Audix, Sennheiser and Shure mics set up around his kit, as well as a home-made 'speaker mic' in front of the kick drum to add more depth.
Sending Out An SOS
Paul Evans cut his recording teeth on an old Portastudio while helping his brother record songs, and later went on to win a BBC Fame Academy bursary in 2005, which enabled him to set up his own Pro Tools LE system. In 2006 he won Yamaha's 'Make It Break It' songwriting competition with his demo 'Forgotten Fable', and further bursary awards helped him expand his studio. Paul is also a very accomplished drummer, plays bass and percussion, and gained valuable experience working part time as an engineer at Somerset's SuperSonix studio. These days he also does live sound, web design and electronic press-kits for local bands, to supplement his income, as well as helping set up a nearby teaching studio. It seems pretty clear he's decided that the music industry is the right one for him!
After devouring a mound of chocolate biscuits and freshly made coffee, we decided to bring up all the acoustic treatment we'd brought with us — which was rather a mixed bag, as we were waiting for another shipment from Auralex and were down to our last three sheets of foam.
The side-wall reflections clearly needed addressing, but at the same time we didn't want to stick anything directly to the walls, because it would destroy the wallpaper if it had to be moved at a later date. A few months ago we'd hit on the idea of gluing a wooden coathanger onto the back of a foam panel so that it could be hung on a picture nail, and we used the same technique here. To the right of the mixing chair was a window which had a curtain rail in place but no curtains, so we hooked our panel directly onto one of the curtain rings, and the panel for the left-hand wall treatment was hung from a picture hook that happened to be there already. We positioned the panels at the 'mirror' points — the place where a mirror held against the wall would show an image of the monitor speaker when viewed from the mixing position.
A further panel of foam was hung horizontally across the rear wall at head height (when Paul was seated) to cut down on reflections from that source, and we put two impressively dense foam corner bass-traps (kindly donated by Sonic 8) in the only empty rear corner, where we'd noticed an obvious bass build-up — which was due to the boundary effect and the reflectivity of the solid brick walls. We also had a pair of 2x2 foot Real Traps panels, which can be used across 'tri corners' (where two walls meet the floor or ceiling), but we opted to put them behind the monitor speakers, to help kill some unwanted reflections there. After adjusting the angle of the speakers slightly, to aim them just behind the mixing chair, we listened to some commercial material, and all of us commented that the sound was better focused and less coloured, and that the stereo imaging had improved considerably.
Paul then pointed out some low-level digital noise that seemed independent of any level adjustments to the monitoring output or the input-gain trims on the back of the speakers. I'd heard this type of noise before and suspected the old G5's PSU was to blame, but we unplugged everything and tried to tidy up the mains wiring anyway, ensuring that everything was fed from a single power socket and that the computer, interface, computer screens and powered monitor speakers were plugged into the same six-way power strip. Originally, Paul had only one monitor screen on the system but he had a second monitor available, so after recovering its PSU from the Emarty Academy studio down the road (which Paul is helping to set up) we hooked this in too.
Unplugging the Firewire cable to the Digi 002 rack interface silenced the noise, confirming my suspicions, but although our rewiring may have reduced the noise slightly, with the Firewire interface plugged in it was still audible if you listened for it with nothing playing. Some early G5s produced a similar noise, which went away while the mouse was being moved, and downloading a piece of Apple developer software called CHUD allowed processor idling to be switched off, curing the noise. In this case, moving the mouse made no difference but we downloaded the CHUD software anyhow, in the hope that it might cure the problem. Oddly, though, we couldn't locate the preference to switch off processor idling, so perhaps this package of tools has changed since I last used it several years ago. We thought the noise might have reduced a little more after CHUD was installed, but it could equally have been that we were all just getting used to the sound. Certainly it was only audible if you put your ears close to the speakers with no music playing, and it didn't get onto Paul's mixes, but it was an annoying problem nonetheless.
Yet another niggle was that, on occasion, the Mac would go through the motions of starting up but the screens would remain blank, and it was sometimes necessary to unplug peripherals and restart to get it to behave. A possible clue was that the computer's calendar date was wrong, which Paul said had happened since he unplugged it from the mains. This suggests that the motherboard battery was discharged and in need of replacement — something that can occasionally impede the startup process on some models (as it can on some PCs).
Paul Evans: "Thanks again for coming down. I did some drum recordings the other day and the overheads sound much tighter. The vocals also sound much better, with fewer unwanted mid-range relections due to the extra foam behind where I record them.
"The stereo imaging has improved amazingly with the new treatment in the control room, and I'm going to borrow some more Rockwool from SuperSonix to make some pillow-case acoustic treatment. I have moved one of the Rockwool bags that was on the cupboard doors to above the drums, so it is across the corner of the roof, which I think works better and looks a bit neater. The bass end has tightened up nicely in the control room, considering that the speakers are unfortunately so close to the wall. In future, when recording bands at the studio, I'm going to bring them back to my house to edit and record vocals and possibly guitars and bass, since it is going to be much cheaper for me. The room now sounds nice, so I feel more confident about doing this. Now I just need to buy some good mic preamps!
"Thanks again to everyone at SOS, and to Auralex, Sonic 8 and Real Traps for providing the lovely goodies!"
Love You Live
After a spot of lunch, courtesy of Paul's mum, we turned our attention to the live room. Paul's drum recordings are amongst the best we've heard from a home studio, not least because his kit was very well tuned and the room had more than the usual amount of ceiling height, but soloing the overheads revealed some room coloration that should ideally be reduced. Fortunately Paul has accumulated a pile of Auralex foam offcuts from the commercial studio he works at, so we cut holes in the middle of a couple of square pieces and slotted them over the XLR connectors in the backs of the Audix overhead mics. Auralex make a neater commercial product based on this idea (and of course there are the SE Instrument Reflexion filters), but considering that our solution was improvised, the audible difference when we made a new test recording was appreciable. To further cut down reflections from around the kit, we filled two Ready Traps bags with 50mm, 3lbs-per-cubic-foot Rockwool slabs.
The slabs Paul had obtained were 1000 cm in length but the bags we had were 1200mm types, so it didn't look as tidy as it might. It still proved to be very effective, however, and of course the Rockwool could easily be extended or replaced at a later date. The fabric Ready Traps bags are made in the US, but as you're only shipping the covers (you provide your own filling), they're quite cost effective. They come in a variety of colours with a zippered opening at one end to insert your own locally sourced rockwool or fibreglass. We hung one each side of the overheads, using the loops on the back of the bags and simple screw-hooks.
To put Paul's remaining foam offcuts to good use, we bought in three sheets of thin 1200 x 600 mm MDF boards and glued foam offcuts onto these, to make up complete panels to hang on other bare wall surfaces around the live room. These were simply hung on nails via a single hole that we drilled in one edge of the board. They looked a bit 'ad hoc' but they worked fine and helped to dry up the general room sound. Our final trick was to run some string above the drum kit, between hooks positioned about a foot from the ceiling.We zig-zagged the string back and forth to provide support for some of the larger foam offcuts, which formed an absorptive 'cloud' above the drum kit, further reducing the reflected energy getting back into those overhead mics. We suggested Paul replace the string with woven nylon cord at some future date, as it is somewhat stronger, but the principle worked well and cost nothing to do. The audible difference, even when just speaking in the live room, was significant, and Paul commented on how much tighter the drums sounded while he played them.
Paul also explained that when recording vocals he'd been standing the singer with their back to the blanket-covered rubber sheet obscuring the window, which would reflect some mid-range back into the microphone. Putting more thick foam directly behind the singer would help reduce coloration, as would placing an SE Reflexion Filter or something similar behind the microphone. Paul still had a few foam offcuts left, and said he could improvise something with these to try next time he had a vocal to record.
By the time we'd finished, Paul seemed pleased at the improvements our simple techniques had produced, and told us that his ambition for the future was to persuade his dad to move his office out of the control room so he could have it all for himself!