Maybe I should just stay out of this...
Yes, LF room modes are an issue that should be addressed in all small
acoustical spaces.
And the simplest approach is to treat the vertical corners (and secondarily,
the horizontal corners of the room with Roxul or OC705 wedge traps. Further and
more problematic anomalies are perhaps best addressed with a combination of
measurements and an appropriate ly designed Helmholtz resonator (or which
there are a variety of types requiring calculated tuning).
And this is an example of a classic room where the classic room mode
calculators are all but worthless. This room features a series of what can
be considered as coupled spaces, each reinforcing a slightly different spectrum
of modes, thus requiring measurements to identify the actual resultants which
are far too complex to model and calculate.
Additionally, assuming all of the LF modes are sufficiently addressed, 'we'
are still left with the SIGNIFICANT issue of early arriving first order reflection off of the back
ceiling. And this reflection will be a hard reflection containing much energy
and focused almost directly on the seating position which will substantially impair the quality of listening.
Thus the goal here is not to simply absorb all of the acoustic energy, thus
rendering the room dead and very small feeling. Rather the goal is to
strategically redirect the energy as much as is possible in order to reduce the
intensity of the first order early arriving reflection and to return as much of
this energy back into the space by 'breaking up' the focused specular
reflection in to a more diffuse acoustic field, and thus
contributing to a well-behaved semi-reverberant acoustic field that decays
exponentially with time - the result being that this energy will contribute to the
sense of space that is pleasantly perceived.
So, the challenge is, how do we break up the direct radiated acoustic energy
that is being reflected toward the seating position by such a large planar
surface without simply using brut force absorption and rendering the reflection
muted, and the room in large measure, dead.
Thus, while strategically applied absorption can play a role, it should be
one that is used only to the degree that is is necessary to damp the energy
that cannot be effectively diffused.
Thus the challenge, how to effectively DIFFUSE the energy using the
minimum amount of absorption necessary without spending $100K to do so (and
turning the space into a museum of modern art)! Hence the role of a bit - OK,
let's be up front here - ALLOT of creative thinking.
Nobody gets in to see the Wizard.
Not Nobody. Not No How.
The Law of Conservation of Ignorance: A false conclusion once arrived at & widely accepted is not easily dislodged, & the less it is understood the more tenaciously it is held.
Scarecrow: I haven't got a brain... only straw.
Dorothy: How can you talk if you haven't got a brain?
Scarecrow: I don't know... But some people without brains do an awful lot of talking... don't they?
Chico: Hey, wait, wait. What does this say here? This thing here.
Groucho: Oh, that? Oh, that's the usual clause. That's in every contract. That just says uh, it says uh, "If any of the parties participating in this contract is shown not to be in their right mind, the entire agreement is automatically nullified."
Chico: Well, I don't know...
Groucho: It's all right, that's, that's in every contract. That's, that's what they call a 'sanity clause'.
Chico: Ha ha ha ha ha! You can't fool me! There ain't no Sanity Clause!
Offers not good after curfew in sectors R or N,.