Room acoustic improvements are the least done, but generally the most impactful improvements in sound quality for any system. It’s amazing how much the space is involved in how music sounds. I shoot photos for musicians’ PR and albums, and I’ve heard what cuts sound like as recorded, in studios designed to prevent sound from invading any microphone other than the one intended. It’s so bizarre sounding - surreal and completely off-putting. A lot of reverb and decay is added to albums recorded in those acoustically dead studios to make them sound like our ears expect them to sound.
I’ve done room acoustic work in our main listening area. First with things that are “normal” for a room - curtains, rugs. Next step was deadening the corders with bass traps, one of which is behind my open audio equipment rack (if it was behind a solid rack it wouldn’t do anything) and another that’s the color of the walls tucked under a corner table.
Third step was getting diffusion to break up room mode sound reflections. We have a number of large complex wood carving/statues from Bali, Tibet, etc. When we set them up on the bookcases and tables in the room, you could hear the difference. It was striking enough that we even tried different pieces in different places just to convince ourself that it mattered that much. That was a “bridge too far” - the quantity and location of the big wood carvings mattered more than which one was where.
Last step, catching the last nasty reflections from the walls behind the speakers. You can now get acoustic panels that have art printed on the surface. Acoustic panel sellers have a large collection of stock art you can use. We used my own photographs (I sell through galleries)… although we had some “spirited” discussions about which photos to use, since we’re going to be looking at them for many years. Because my speakers are dipole for bass, cardioid for mids and highs, damping the whole area behind would have wrecked the sound for that particular speaker design. We did some large panels, hung to start just at the level of the tweeters. Before we hung them, we leaned them up against the wall behind the speakers, and yeah, it was bad, almost reduced bass but boomy, flat mids. But up on the walls, good.
When we lived in an apartment in Singapore, the main living room dining area had marble floors, hard plaster walls, and 10 foot windows all along one side of the room. The echoes in there were so bad if you were on a phone call the person on the other end couldn’t make out what you were saying. That was how we ended up with the speakers we have now - even after rugs and curtains and soft pillows on furniture and rugs for wall hanging, the room still had a lot of “room mode” amplifications of specific frequencies here and there. Regular speakers just didn’t work - moving them forward, back, etc changed room modes but didn’t stop them. Having the woofer open all around, with everything above in a cardioid radiation pattern, killed all the room mode problems. That was my education in how much acoustic treatments matter.
