First reflections are broadband, but primarily affect higher frequencies. At least those are the ones you want damped. However, to block them at the speaker like you are doing is not what I'd do. I'd think you're losing a lot of air and hf info that's critical to good imaging and soundstage cues.
Hi Ted,
I know that is the "general perception" even amoung some acousticians (is that a word?), but it is not the case. In fact, it is just the opposite.
The "perception" of air to some is basically diffused sonic energy created by the room.
In reality, once you remove this "sonic fog", you can actually hear the subtle, and delicate sonic structure of the actual room where the recording was made (assuming it is a live recording and well miked and engineered)
And as far as imaging, taking the diffused and reflected sonics away, clarify it.
Think of it as a theater, where the idea is to reduce "reflected/dispersed" light to give you a clearer, sharper, image on screen. If you painted all the walls in a theater white, the screen images would be washed out by the reflected light.
And don't forget about the other dimension (ceiling and floor). Heck, I had my side walls treated and though the imaging was MUCH better until I realized that the marble coffee table in front of me was as big, if not bigger, culprit. A soft thick blanket or tablecloth does the trick. Wow, huge improvements, really. Same idea with an unobstructed floor.
Ditto, on the coffee table. What many (including myself some time ago) forget is that the hard surface of a coffee table is on an angle of incidence, that causes a "very strong" mid/hf reflection miliseconds after the original signal.
Generally either removing it or covering it is "ear opening".
