Choosing the absorbent filler for Acoustic Panels is one consideration to be decided on. Whether it be a Sustainable Substance as a by-product from one Industry or a product produced from a by-product from another Industry is for the individual to choose.
A choice might be made for simply wanting a Natural Material only within the home, or wanting to support an industry promoting by-product usage and being participant in reducing impact in other Industries.
As a rule of thumb, Fibrous Filler produced as a Glass Wool that weighs approx' 35Kg/m3 is documented for having valuable absorption properties for a broad frequency range, this same guideline may transfer to other Fibrous Fillers Materials as well.
Fabric Covering / Acoustic Fabric Covering are also going to need to be decided on as a Fabric Covering might be the ideal aesthetic, but not be as suitable as a Acoustic Fabric. For either Fabric, choices made will effect the efficiency of the Built Panel. I use a Fire Rated strengthened Paper as my Panel Covers and as a covering for a few other structures produced in the room.
Placement of the Panel, not just the siting in the Room, but also how the Panels is positioned to the Wall > Ceiling will optimise their use within the space of set up. Hard Back to the Wall > Ceiling is not the optimised, being set up Off the Wall > Ceiling and being better able to Absorb reflected sound from a Hard Surface has merit as a design within a room, but this can mean support legs for a Panel to make this happen.
I have my best results in my Room when Panels are not hard against the Wall, where the Bulk of the Panels are Floor To Ceiling in the Room Corners, with the Panels creating Triangular Cavity in a Room Corner.
Some places between Speaker and Listener can only have the Panel hard against the Wall, between the Speakers directly in front of the listener and behind the Listening Position, I have opted for the Hard against the Wall position.
Once when on a Hard Floor, (no soft covering) a Soft Material Temporary Used when using the system tidied up the energies released into the room, a secondary glazing system certainly rattled a lit less on certain tracks. If a Temporary Panels was produced due to the room aesthetic not being made less attractive, such a Panel could be tried on the floor in between the Speaker and Listening Position.
The Between the Speakers, Behind the Listening Position and Side Wall Absorbent Panels have Diffusion Panels mounted on the Absorbent Panels.
Diffusion Panels can be a feature in a room and be quite attractive, but can be costly.
Alternatively, there is ratio info available to self built Diffusion Panels, which can be a design produced that is noticeably more robust/cheaply produced than many seen. The robust design is easily concealed behind the absorbent panels fabric cover. The Frame of the Absorbent Panels can the designed to enable the Diffusion Panel to be Rigidly Attached and have Fibrous Filler put behind it.
Not limiting oneself to how a Panel Set Up can look in the Room will get the most valuable results. Some Panels in a living space might be best if designed for a Temporary use and easily removed / reinstated by design, the Dimension may be one that is making it easy to conceal the Panel behind another furnishing when not being used.
Additionally, one design for a room that is immediately able to be put in place is for if inanimate object are placed in the Listening Space. Ornaments in a room, Doors on a Display Case, can be effected by energies transferred through sound being produced, sitting Ornaments on a damping materials such as a small pad of Anti-slip Mat or a few 1/2 Pea Size BluTak Pads will really tame these for producing anergy that is audible. A tiny ball of BluTak on a Cabinet Doors Corners is able to tame resonance being created, which can be audible.