Originally Posted by
Ammonite Acoustics
In a relatively small space you probably won’t want any additional acoustic absorption once some soft furnishings are in place. Bass traps that are truly effective are monstrously big things, so have a good think about whether you actually need them, and whether you are prepared to live with their bulk and intrusion. Common types of acoustic panels cannot absorb bass frequencies unless made very deep, so do be aware that panels are usually only effective at upper-mid to high frequencies, where inappropriate implementation has the worst effect on the overall room acoustic.
That aside, people almost always assume that they need acoustic absorption, when in reality they actually need acoustic diffusion to break up reflections so that they are randomised and become relatively benign. In the old days, theatres used fancy ornamentation to achieve good diffusion, and things like bookcases, record storage etc can provide good diffusion without costing anything.
Moving on, my advice is to never place absorption panels at first reflection points, because that is frequency selective and musically destructive. Use diffuser panels instead at first reflection points, or none at all. I know that Toole et al do recommend suppressing first reflections but in a small room it never works, and neither does placing absorption behind the listening position where (again) diffusion is usually a better bet. Don’t be tempted to measure the room and attempt to interpret the results in any meaningful way, unless you have access to a professional program like Odeon.
Your situation is almost certainly much simpler than you think, so tread carefully. If you think absorption might be helpful in any position, use rugs, drapes, quilts, piles of cushions etc to experiment, then you’ll have a clearer idea of what actually works, and what you like.
Since it’s an attic room, do consider isolating the speakers from the floor. When done properly, that stops structurally transmitted sound, which others in the house might appreciate, but it also means that you hear the speakers, and not the speakers plus the room structure singing along. Remove that last aspect and you might just find that nothing else needs to be done.