[EdwardT]

Hello, I’m Ed in north Alabama building a listening room.  So far, I have built a 11x16 room with an inverted ceiling 8’5 1/2” with the joists exposed (inside a Quonset bldg) on a concrete slab. The stud walls are lined with rock wool and then covered with fabric, the ceiling and floor wait to be treated. I used a simple app to test the room:



Pretty much confirms what I’m hearing so far and that's a fairly dead room. What can I try to help add a “bounce” back into my room?

[toocool4]

Wow, you have over done it a bit there, acousticians say the ideal listening room should be between 0.3 - 0.6 secs.
Can you not remove some of what you have added so far?

[WGH]

Have you explored arched diffusers for broadband diffusion? A couple companies make them.

A/V Room Service has technical articles and tested products like the PolyFlex Diffuser
https://avroomservice.com/

GIK Acoustics has a full range of products
https://www.gikacoustics.com/

[youngho]

Hello, I’m Ed in north Alabama building a listening room.  So far, I have built a 11x16 room with an inverted ceiling 8’5 1/2” with the joists exposed (inside a Quonset bldg) on a concrete slab. The stud walls are lined with rock wool and then covered with fabric, the ceiling and floor wait to be treated. I used a simple app to test the room:



Pretty much confirms what I’m hearing so far and that's a fairly dead room. What can I try to help add a “bounce” back into my room?

You could consider slats over the fabric, may want to consult an acoustician or at least read a textbook (F Alton Everest, for example) or two. Alternately, could easily consider hybrid product like Expo (https://www.rpgacoustic.com/product/expo-panels-family/) or FAST (https://realacoustix.com/products/mathematically-tuned-absorbers/fast-xposed-panel) mount in front of the fabric and rockwool.

[JLM]

Room is too small, proportions are wrong (length nearly twice the height), walls/ceiling must be covered in architectural materials, heating/cooling system not specified but must be dampened, door not specified, electrical power not specified. 

[Jon L]

The stud walls are lined with rock wool and then covered with fabric

The total surface area of absorption is way too large.  I can make my room from just-right to bit-lifeless by adding one more absorption panel, which is sitting in my hallway.  You may be able to get away with just adding good diffusors/reflectors to the soft wall, but I suspect you will likely need to remove some of that absorption. 

[GeorgeAb]

I would start covering up the paneling with something reflective such as cardboard, drywall, or tarps (something you have laying around) until the life comes back. From there you can make a plan on how to treat. For example add drywall sections or large murals. Typically WRT to absorbtion 10% coverage is minimal and 25% is considered ideal. Had the same experience as the previous poster as I had 25% coverage and removing just a couple planels and the life came back. Appears you have > 50% coverage so it is going to be a significant area to cover.