Reverberation time in your studio it´s very important, besides smooth response and free reflections points RT60 should be homogeneous in all bands. If you have a long decay time in the 125hz band and are very short on 4khz, for example, you will have an unbalanced response and an inaccurate bass response.
The below picture shows the usual measurements in control rooms.
RT60 defines the time that sound decreases 60db. Generally, as smaller is the room more absorption it’s needed. Especially on low frequencies.
A good range for your room should be between 0.2s and 0,5s approximate. Depend on the type of mixing or mastering music, electronic or classic style production. Decreasing reverb time you will have a drier room, increasing reverb time you will have more liveness.
RT60 shows you the timbre and tone of your room.
For example, A room with a very short time on 4/8khz bands will sound dead, a room with a long time on 63hz will sound boomy.
“A lot of people only look at the frequency response of the room. If you have a smooth frequency response and disparate rt60 or decay times, your mixing will be inaccurate and unbalanced“
Here is a great RT60 simulator.
Bob golds calculator will show RT60 ITU/EBU Control Room Recommended.
After your room is controlled acoustically is the time for the final tweaks, where you will choose the liveness in your room.