[Tom Powers]

Hello All,

So I converted a room off the house to be a mixing room (I can master in it, but the vast majority is mixing work).  While I’m not tearing up the world wioth Barefoots or Dutch and Dutch, I am using the Dynaudio LYD 48s with the Dyn 9s sub… and in a 13×13 ft room, it is a nice balance.

I was able to bring in some acoustic design folks I’ve worked with in the past to get this room into shape.

We tore out all the drywall and replaced it with acoustic gypsum which before and after seemed to make a world of difference on it’s own.

I had put up the cloud, and had the primary reflections taken care of with acoustic art panels, and really treated the room…and I went too far. The room sounded dead and lifeless and not at all like studios I had worked in over the years.

My major mistake was putting up treatment without measurements to guide me on what was needed.

By taking multiple readings with REW , and pulling out a lot of the treatment, the room sounded better and the REW graphs still looked good. By the time I was done, I had some bass traps in the corners (real heavy dense foam they brought in…which surprisingly worked) to deal with an issue at 120hz and then the acoustic art stayed up on the right and left, but the back wall untreated and the cloud taken out sounded so much better.

My question is… does it make sense that the use of the acoustic gypsum drywall results in less acoustic treatment on the walls?

All insight is appreciated

[Phil Koenig]

Please post a link to the specifications of the acoustic gypsum.

[Tom Powers]

Here’s what the Invoice said the Drywall is…  Quietrock 545

Which I found online here:

https://www.quietrock.com/products/quietrock-545

 

 

[Phil Koenig]

6+ lbs/square foot?  Wow.  Heavy stuff; over 190 lbs per 4×8 sheet.  Glad I didn’t have to install it.

You have an unusual situation: Almost none of the in-room sound escapes, even without absorbers inside.  So there is very little baseline data to form a comparison.  There are on-line calculators around that can estimate (untreated) room response based on dimensions and wall/ceiling construction materials, though at this point it would be an academic exercise since you already have the stuff installed.  If it were me, I’d just accept the “win”.

[Bob Olhsson]

What I always saw in studios was building a sandwich of 5/8-inch sheetrock and 1/2-inch sound board.

[Phil Koenig]

Bob,

I’d think that would be cheaper (drpending on installer labor costs).  And far easier to install.

[Norman Varney]

Tom,

I stay away from QuietRock due to the cost and hassle. You can do better with other materials and methods. That kind of mass is mainly going to help with sound transmission between adjacent spaces, not improve your reverberation times or room modes in the listening space.

You should always measure and adjust to get controlled and linear RT times. Depending on the room size, for critical listening spaces I want the reverberation times to fall between 0.25 – 0.4 seconds from 125Hz. and up, with a slightly ascending decay from 125Hz. and down to about 0.7 seconds. It’s all about the right treatments, in the right locations, and the right quantities.