I recently built my own home studio by converting an old garage into a well‑isolated music room of 410 x 215 x 275cm. The isolation is great, but I'm now moving on to phase two — acoustics — and bass is a problem, especially on the notes of A, B‑flat and B, which are kind of booming.
So I am wondering how to position my Dynaudio BM6As? At first I put them along the short wall, but a lot of bass was built up, probably because of the proximity of the corners. I've already tried to put the speakers backwards, but noticed no change.
I've now got them along the long wall, which I think sounds more balanced, even though there's still some resonance on certain notes. Also, this tends to differ a lot depending on whether I sit in the exact 'sweet spot' or not. The further forward I go with my head, the more bass I get; the further back I go, the less bass I get.
In your books and in Sound On Sound, I've seen you advocate placing speakers on both the shortest wall, and the longest wall, depending on the room. So, what would you recommend for a room of my size and dimensions? Also, are the BM6As too much for my room?
SOS Editor In Chief Paul White replies: In large studio rooms, which includes many commercial studios, putting the speakers along the longest wall is quite common and has the benefit of getting those reflective side walls further away. However, in the smaller rooms many of us have to deal with, it is invariably best to have the speakers facing down the longest axis of the room. If you work across the room, the reflective wall behind you is too close and the physical size of the desk means you're almost certainly sitting mid‑way between the wall in front and the wall behind, which causes a big bass cancellation in the exact centre and, as you've noticed, causes the bass end to change if you move your position even slightly.
In a room the size of yours, working lengthways will give the most consistent results. Your room is a slightly unfortunate size for bass response as the length is almost twice the width, so any resonant modes will tend to congregate at the same frequencies.
You can often change the bass behaviour by moving the speakers forward or backwards slightly, but try to keep them out of the corners, as that just adds more unevenness to the bass end. Corner bass traps of the type you're making may help, but if they don't do enough, you could try one of the automatic EQ systems designed for improving monitoring. I don't normally like to EQ monitors but, in difficult situations, using EQ to cut only the boomy frequencies can really help.
As for your monitors, the BM6As should be fine in that room. Just make sure they're perched on something solid, as standing them directly on a desk or shelf can also cause bass resonances. Either solid metal stands or foam speaker pads with something solid on top work best and can really tighten up the bass end. You can buy the Primacoustic or Silent Peaks pads, which have steel plate on top, use Auralex MoPads or similar with a heavy floor tile stuck on top, or make your own from furniture foam with ceramic floor tiles or granite table mats stuck on top. A layer of non‑slip matting under the speakers will keep them in place.
For the mid‑range, foam or mineral wool absorbers placed at the mirror points in the usual way should be adequate, but try to put something on the rear wall that will help to scatter the sound, such as shelving or unused gear.