Reader Stu Evans has a smart studio but a lacklustre drum sound. Can the team breathe life into it?
IT specialist Stu Evans describes himself as an ex-drummer's roadie who has taken up playing and recording. He has built a very smart studio in a single garage adjoining his home near Stourbridge in the West Midlands, and equipped it with Sonar DAW software running on a powerful PC. He called us in because he was unhappy with his monitoring and because he was having difficulty recording his acoustic drum kit in a small room without the sound coming over as boxy.
Stu showed us around his small studio while plying us with assorted Hob Nobs and coffee. He'd divided the garage space into two similarly sized areas, which ended up being almost square. A heavy fire-door separated the live room from the control room, in which a work-surface was fitted to the front and right walls to provide space for the equipment. The control room measured roughly 2.5 x 2.25 metres, which put the mixing position almost in the centre of the room in all three planes — something that's generally accepted as being 'a bad thing', as you can suffer a big drop in perceived bass when you're listening close to the centre of a cube or near-cuboid space. Furthermore, Stu had pushed his speakers out into the corners to allow him to fit a computer monitor either side of his Mackie Control and expander. Placing speakers close to corners tends to make bass unpredictable, with more humps and bumps in the response.
Stu had stuck up some scattered small patches of Auralex foam, which helped tame the mid and high-end reflections, but he didn't have any absorption at the 'mirror' points and there was a flat, hard surface behind him on either side of the entrance door (which was curtained off) that was reflecting a lot of energy back to him. Certainly the room had a noticeably coloured sound when we played back commercial songs.
My first thought was that Stu could buy a couple of TV/monitor wall-mounts with which to hang his two monitors directly above his Mackie Control and expander. He thought this was a good idea — but Hugh, being a little less patient, simply moved the monitor screens and stood them on top of the Mackie Control meter-bridge, leaning back against the wall. This worked fine, and with a bit of non-slip matting should be quite secure, although considering how tidily Stu had installed everything else, I wouldn't be surprised if he went for the wall-mount solution in the end.
Repositioning the LCD screens gave us space to move the monitor speakers inwards. These were a pair of Mackie HR624s perched atop a pair of very middly Wharfedale Diamond 3s, standing directly on the work-surface. Unfortunately we'd given away our last set of Auralex MoPads and the replacements hadn't yet arrived, so we cut up a piece of thick furniture foam using a bread knife and used this beneath the Mackie speakers. With the new monitor screen arrangement, Hugh was able to bring the monitor speakers into a more suitable position approximating the required equilateral triangle, angled inwards and with the Mackie tweeters at head height. The Wharfedales were still in a rather unsuitable position, but there was no immediately obvious solution to this, other than to move them to the side of the Mackies and then put them on short stands to get them to the correct height.
To tame the reflections, we used 2-foot x 4-foot Auralex foam, spaced away from the wall on blocks of three-inch furniture foam, either side of the door behind the mixing chair. The spacing makes the trapping more effective at lower frequencies than fixing it directly to the wall. A boiler cabinet was also covered with foam fixed directly to it, but to save damaging any of the surfaces we used Velcro Temp Tabs. These won't stick directly to foam, but Auralex provide some little plastic plates that you can stick on first. When we ran out of these, we sprayed Auralex adhesive directly onto the foam, then stuck the self-adhesive Velcro pads directly to that, which worked fine.
More Auralex foam was attached to the right-hand wall at the mirror point (just forward of the monitoring position), and we managed to put up a bit more on the left, though the control-room window limited what we could do in this area. Stu turned out to have quite a stock of three-inch furniture foam that had been donated to him by a friend in the business, so we stacked all the unused pieces under the worktop in the corner of the room to help with the bass trapping.
Stu Evans: "When I first built the studio, I focused on making the room as soundproof as I could. It was later that I found it hard to achieve consistent sound and soon realised that I needed to put in more time post-recording.
"The difference in the control room is striking. I instantly wanted to go over all the recordings I had made and remove all the EQ I had spent hours adding and even building into my templates. With the moving of the monitors and the changing of the monitor settings, which I had just left to 'normal', I now not only have more space on the desk but the sound has also gained some real definition.
"I never liked the bass drum sound, even though it's a good kit. I had not tuned it for some time and it was a fair point that a decent tune-up makes a whole lot of difference.
"After we tried the vocal setup in the live room with my AKG Solid Tube I was relieved that Paul and Hugh did not laugh at my home made Reflexion Filter, instead presenting me with a real one. I was very impressed with the results, and especially Paul's bedtime-story voice (a wasted talent). I am definitely going to add the foam to the live-room ceiling and see how that goes.
"I'd like to say a big thank you to Sound on Sound, to SE for that nice Reflexion Filter, and especially to Paul and Hugh for a good day and spending the time to go over my setup. A great result!"
When we played Hugh's test CD, the boxiness was much reduced and the bass end was far more consistent than we'd hoped for in such a small, near-square space. Presumably some of the low-frequency energy leaked through the partition wall into the live area, creating some natural bass trapping, and the double-glazed entrance door may also have contributed in this respect. As expected, moving the speakers in and putting foam on the side walls also improved the stereo imaging quite dramatically, so as long as Stu keeps away from the dead centre of the room when mixing, the sound should be pretty consistent and well-balanced. When moving the HR624 speakers, Hugh adjusted the settings on the back panel to the half-space bass mode (since they were away from the corners but close to the back wall) and switched in a 2dB cut at the high end.
With the control-room issues adequately resolved, we turned our attention to the drum kit. Stu played a recording he'd made using his very inexpensive Samson drum-mic kit (clip-on dynamics for the toms and snare, dynamic kick-drum mic and two C02 capacitor mics as overheads). His recordings sounded quite boxy, with a lack of focus, which is a common problem when recording drums in small rooms with low ceilings.
We investigated the possibility of removing some of the ceiling tiles and replacing them with foam, to form an absorber above the kit, but this was impractical in the time available. Stu has said he will investigate this possibility later. The space above the tiles is already full of Rockwool anyway, so it should be fairly straightforward to improve things here. Instead, I thought we could use blocks of furniture foam to screen off the back of the overhead mics, as these are the most vulnerable to room reflections. We simply made holes in our squares of foam and then poked the overhead mics through. There was also a very close side wall, to which we fixed another sheet of Auralex foam, then we put out last piece on the inside of the live-room door. We then moved the kit slightly away from the side walls, to get it away from those reflective surfaces.
Making a fresh recording showed that the sound from the overhead mics was a lot less coloured, but the kick drum still sounded too 'beach ball', with no real snap to it. The kick mic was mounted on a short table-stand and placed level with the front skin, just poking through a small hole cut in the front head. As this meant we had little room for experimentation, Hugh suggested we take it off the stand and simply place it on top of the folded blanket that was being used inside the drum for damping, to position it closer to the place where the beater struck the rear skin. We ended up with it halfway into the shell and slightly offset to one side. In conjunction with retuning the batter head, this got us a much more usable sound, with a decent snap to it, as well as a good body weight, though more time spent tuning the kit would certainly pay off. We still needed to EQ fairly radically to arrive at an acceptable sound, and as well as boosting in the expected 70-90Hz range for punch and the 4kHz range for click, we also needed to cut back at 200-300Hz to reduce boxiness. Many kick-drum mics have this type of curve built in, to reduce the need for lots of extra EQ, but the Samson model clearly didn't lean far enough in that direction.
Perhaps the most dramatic improvement you can make to a recorded kit sound is to gate the toms. If you solo the tom tracks they hum and resonate all the time, even though you may only hit them twice in the song! We gated both toms, the kick and the snare, using the fastest possible attack time and one millisecond of look-ahead, so as not to kill off any of the attack. You need to adjust the release time of the gates so you don't kill the drum sound too abruptly, but you can afford to make it slightly shorter than is natural, as adding in the overheads usually disguises this. If the kick drum lacks consistency, a compressor with an attack time of 15ms or so and a release time of around 60ms will beef it up a little. This can also help to emphasise the initial click.
I often find myself rolling some of the low end off overhead mics, but the Samson C02s seemed to pick up mainly mid frequencies and high end, so little or no EQ was needed. Pushing all the faders up revealed a less boxy drum sound, but we had to roll off quite a lot of low end from the toms (using a 350Hz shelving low-pass filter) to stop them from sounding 'lumpy'. Our extra absorbers had lessened the unpleasant impact of the room sound, so one effective way to put something more attractive back is to find a very short, lively ambience reverb program and add a little of this, either to the whole kit or just to the overhead mics. You can then add more conventional plate or room reverbs to individual drums as required. In this case we found something suitable courtesy of Sonar's convolution reverb; all the synthetic reverb plug-ins that Stu owned seemed to have too slow a build-up time.
Our final challenge was to improve the sound of Stu's recorded vocals, which he'd been doing in the live room, with a couple of blocks of furniture foam stuck behind the mic to form a kind of DIY Reflexion Filter. Today was Stu's lucky day, though, as Sonic Distribution had kindly given us a genuine SE Reflexion Filter, so after abusing the mounting hardware to make it balance better on a normal mic stand, we put up Stu's AKG tube mic and made some test recordings. The combination of the Reflexion filter and the extra Auralex foam in the room really helped, and we got the best results with my spoken word test when I had my back to the foam on the inside of the door. Hanging a duvet over a boom mic stand set up in a T-shape behind the singer (which Stu said he would definitely try) would dry up the sound even more, so he shouldn't have any further problems with his vocal recording.
Stu seemed pleased with the improvements and was very happy to have a real Reflexion Filter in place of his home-made version. The drum recordings were definitely moving in the right direction and we had a simple strategy for avoiding boxy vocals. It may be that the live room could be improved further, by substituting two or three of the drop-in suspended ceiling panels with foam slabs above the drum kit, as mentioned earlier, but that was beyond what we could achieve, given the materials we'd taken with us, so that's one for Stu to decide. And so, after polishing off his vanilla cream Hob Nobs and making a start on the chocolate ones, we had our final cup of coffee and set out for home.