Room Treaments - Where To Begin...

+ 2 GIK

My recommendation would be to read up on the subject whether online or your local library.

An Acoustics Handbook would likely be too rigorous and delve into theory with formula and equations focusing on a physical principle that defines 1/100 at a time of the whole concept of Room Acoustics.

Look for something like HIFi Systems for a balanced practical understanding of what treatment is and how it is applied in a listening environment.

Then start to ask informed questions working toward a solution that is applicable to your circumstance.

Maybe someone here could recommend a suitable Title ...

Room treatment needs to address three main items:

1. Bass reverberation time
2. First reflections
3. Slap echo

For (1), large bass traps in corners. For (2), absorptive panels at sidewalls and ceiling first-reflection points. For (3), provide absorption/diffusion on parallel surfaces until a walking-around clap test doesn't result in any pinging. The thicker panels you use for (2) and (3), the more they will help with (1).

In general, avoid panels that are purely absorptive, as they tend to unbalance the room, absorbing HF more than LF. Panels like the GIK Alpha, RPG BAD, or most products from ASC incorporate some sound scattering and will control excess reflections without over-deadening.

GIK and ASC give consultations -- last time I looked, it was for a small refundable fee. It's worth it. I found it useful to get two opinions, then decide myself how to proceed. Expect it may need some experimentation.

Another great resource is the series of YouTube videos by Jesco. They are aimed at mastering and recording engineers, but there is much that the home audiophile can take from them.

+3 GIK

It is more difficult to correct what you haven't yet measured/heard.