Studio SOS: Seth Folen

Small rooms are always challenging, but there are some fundamental principles that can help you keep problems to a minimum.

Seth's setup before the SOS visit: there was no acoustic treatment, and the location of the mixing position was resulting in prominent bass resonances.

Seth Folen is a composer, drummer and Cubase user who found himself struggling against the acoustic constraints of a small room with very solid walls. His Bournemouth‑based studio is set up in an upstairs room of a large Victorian house, measuring around two metres wide by three metres long and three metres high. His Alesis Monitor One Active MKII monitors were aimed across the short axis of the room, and he had them at about the right height, on good-quality Atacama speaker stands, but, as is invariably the case when working across the width of a small room, the bass was very inconsistent, and there were some spectacularly prominent resonances on certain bass notes. To make matters worse, his seating position at the desk placed his ears almost exactly at the mid-point between the front and rear walls, resulting in a significant lack of audible bass.

Seth hadn't installed any acoustic treatment, other than a heavy rug covering part of the wooden floor, and all the surfaces were highly reflective hard plaster, lending the studio an obviously coloured sound and diluting the stereo image to almost nil. Fortified by coffee and chocolate Hob Nobs, we did a little planning.

It's All In The Planning

Clockwise from top left: (1) The Rockwool panels Seth had already purchased were flimsier and less rigid than the ones we usually use; (2) Hugh used a bin bag as a means of shoe‑horning the panels into the covers; (3) The panels in their Ready Traps covers; (4) Paul White hangs a finished panel at the right‑hand 'mirror point'.

Hugh and I measured the large desk to make sure it would fit across the width of the room (which it would), before trying to convince Seth that his monitoring woes would be less severe if we moved everything so that the speakers fired down the longer axis of the room: this would still put his listening position close to the centre of the room, which can be a real problem area for bass in a small room (especially one where two or three of the dimensions are equal), but from our initial appraisal it seemed like the lesser of two evils. Fortunately, Seth was in full agreement and his recording system was relatively simple, which meant we wouldn't have to do much rewiring.

His PC sat under the desk, along with an M‑Audio Delta 44 audio interface. An SM Pro TB202 preamp sat on top of the desk in a rack shelf, alongside a Soundcraft Compact 10 mixer which served as both a monitor controller and a headphone amp. Seth's setup was completed by a Studio Projects C1 capacitor vocal mic and a budget Maplin pop screen.

Once we'd moved the desk around, we found that we just had room to fit the Atacama speaker stands at each side of the desk, but moved these a little forward of where we'd normally site them, to avoid the speakers being placed directly in the front corners — which would emphasise the low end even more and further aggravate the room-mode resonances. Some spare Auralex MoPad foam wedges were used to angle the speakers down slightly, and the stands were angled inwards to put the tweeters in the right position with respect to the mixing seat.

Dispensing The Treatment

As with any ported speakers, it's a good idea to experiment with foam in the ports in order to achieve the right sound for the room and speaker position.

Before we conducted any further listening tests, we needed to treat the reflective walls to each side of the listening position, and to damp down the rear of the room to some extent as well. Because the walls are rendered with old‑style lime plaster, we decided that nails and screws would be a poor choice for hanging the acoustic treatment: they tend to fall out, taking a chunk of wall with them. Fortunately, the room has a picture rail running around the walls about 500mm from the ceiling.

Seth had already bought some 1200 x 600mm Rockwool slabs, but these weren't as dense or solid as those we normally use, and were quite fluffy and difficult to handle. As luck would have it, we had a few Ready Traps velour bags left over from a previous Studio SOS, so we decided to use them. These are designed to be filled with more dense and rigid Rockwool, and our previous installations have looked quite tidy. Straps are stitched to the back to help hang them, and the bag is closed using a concealed zip fastener. Getting the rather floppy 50mm Rockwool sheets into the bag was a bit of a challenge, made only slightly easier by slicing a bin bag to use as a slippery sleeve between the bag and Rockwool. We slid the bag over the top of the Rockwool and then pulled it down along with the cover, before finally pulling it out of the cover and zipping it closed. The end result looked a little like a failed taxidermy exam, although better than we feared it might look — but the important point was that it certainly still acted as a decent absorber.

Seth FolenUsing picture‑rail hooks and loops of string, we hung two panels on the side walls at the 'mirror' points, to intercept early reflections from the monitors, and used two more to treat the back corner, so that it could also be used for recording vocals, in conjunction with the SE Reflexion Filter and wire‑mesh pop screen that had kindly been provided by Sonic Distribution.

This modest amount of treatment made a huge difference to the liveness of the room, and our standard test material confirmed that the big bass resonances had improved slightly — but not enough for us to feel completely happy. We experimented by moving the monitor stands further forward, away from the corners, and we also tried putting the monitors on the table, but as there was no real difference we went back to mounting the monitors on their stands.

In smaller rooms where the low end is causing problems, it's sometimes possible to tame the situation by placing absorbers in the bass ports of the monitors. This damps the port and converts the ported cabinet into something more closely resembling a sealed one. As a result, the bass response changes and outputs less energy, but with a smoother and possibly greater extension. Alesis suggest that socks are OK for this purpose, but we rolled up some spare acoustic foam and plugged up both ports in each monitor. Surprisingly, this worked rather well, tightening up the low end and reducing those modal hot‑spots quite significantly: they were still evident, but massively better than before, and we thought this quite a good result in such a potentially troublesome room. We all noticed that the stereo imaging was now rather good, with plenty of left‑right separation and a stable phantom-centre image, thanks to the hanging absorbers at the mirror points.

Something For Later

Seth's studio after the SOS visit. Usually the first thing to try in treating your room is placing foam at the 'mirror points' to intercept reflections from the speakers that would otherwise reach the listening position and blur the stereo image.

Seth also asked us for some advice about installing proper bass trapping, and we came up with an idea he could try later without making any permanent changes to the room. Bass traps require a lot of depth of foam or mineral wool, and they need to go in corners — so we suggested that Seth get a couple of lengths of wood that he could use to span the width of the room by resting them on the picture rail. This simple structure could then be used to house a couple of packs of Rockwool (with the polythene packing removed) wrapped in cotton sheet, in such a way that they'd fill the whole width of the room at the top of the back wall, between the picture rail and ceiling, and with a front‑to‑back depth of 600mm. Not only would this be an inexpensive option, but it could further flatten that bass hump to a useful degree, as well as providing additional mid-range and high-frequency damping.

Recording & Mix Advice

Having done the best we could with the room, we turned our attention to some songs. Seth said he was having trouble getting the vocal sound he wanted, citing Nine Inch Nails as an influence. He'd set up some gentle compression and a 50ms mono delay plus a splash of reverb, so I had a tweak to see what could be achieved. He wanted an audible vocal-slap effect, so I increased the delay time to 105ms and gave the reverb a 105ms pre‑delay. The reverb decay time was shortened to under 0.5 seconds, the density turned to minimum and the EQ juggled to keep the reverb bright but with a reduced low end, to stop it getting too messy. Blending the delay with the delayed reverb gave a very lively vocal sound, further enhanced by an 'air' EQ boost at around 8kHz, and dipping the 180Hz region slightly to reduce some boxiness. I suggested that Seth try a higher compression ratio (around 8:1) to give the rocky vocals more impact. He seemed happy with the result, and said that it was closer to what he'd had in mind originally.

A basic vocal 'booth' is pretty easy to construct using an sE Reflexion Filter and a couple of acoustic panels in the corner behind the vocalist.Our final task was to assemble the SE Reflexion Filter, once again folding the hardware mount back over itself to keep most of the weight over the centre of gravity of the mic stand. After fitting Seth's C1 mic and his new SE pop screen, we made some test speech recordings with Seth standing with his back to our treated corner. The combination of Reflexion Filter in front of the mic and Rockwool behind gave us a well‑controlled, dry sound that responded well to processing. We confirmed this by checking a test recording over headphones.

While there's no 'silver bullet' solution for small rooms with strong resonant peaks, we were pleased that we'd managed to reduce the problem to a more manageable level, and we left Seth with the remaining two empty Ready Traps bags to fill and add to the side walls if he felt the need. The main lesson here is that the smaller the room, the more important it is to have the monitors aimed down the longest axis, and even if you can't afford comprehensive acoustic treatment, a couple of foam or Rockwool panels on either side at the 'mirror' points will do a lot to dry up the sound and improve the stereo imaging.