Practice Studio Bedroom Conversion

Isolation Questions for a Practice Studio Objective: Provide enough sound isolation so I can practice my djembe hand drum without driving the rest of the house nuts, and keep the outside level below ambient to keep the neighbors happy. I'm targeting enough isolation to get the sound level to 50dB in the family room and at the property line 6' from my house. I also want to room for recording, but that's secondary to the isolation objective. Background: I have a 13' x 11' x 8' finished bedroom over the garage that I want to turn into a practice studio (sketch attached). The house is 5 years old and well insulated. Inside the untreated room the sound pressure measures 95.5dB when I play my djembe. Downstairs (and in the opposite corner of the house) in the family room, it is 58dB. My closest neighbors are 12' away and the SPL at the property line (6' away) was measured at 55.4dB. Most of the djembe's sound is mid-frequency, so I don't have a huge amount of bass to attenuate (RTA spectrum attached). I'd like to keep costs below $4k. The interior walls are 2x4 with gyp rock (1/2?) and no insulation (measured at about 31dB attenuation--sketch attached). The door is a hollow core with 1/2" gap at the bottom (measured at 9dB attenuation). The exterior walls are 2x6 with the same gyp rock + insulation, and Tyvek and Hardi plank. Windows are vinyl thermopane. Room is above garage with fairly well insulated floor. Ceiling goes to attic with a boatload of insulation (~24"?) in the attic. There's one duct and it's flexible fiberglass not sheet metal. Approach 1: a. solid door with Zero gaskets/seals (41 STC) b. cellulose blown-in insulation for all interior walls c. Window plugs (optional?) d. Acoustic treatment (I may do some recording as well, but that's a secondary requirement). I just received a contractor quote for $2,600 for the insulation and door installation, which doesn't include the door ($1,500) or the acoustic treatment ($1k). After receiving the quote, I'm reconsidering my moderate approach and thinking about: Approach 2: just going with a decent solid-core door with good seals, or Approach 3: going the other direction and ripping out the existing interior sheet rock on the east wall and adding resilient channels, rock wool, and 2x gyp rock, or a second framed wall altogether. Questions: 1) Will approach 1 or 2 get me close to what I'm looking to achieve, or will I end up ripping out walls and putting in rock wool with resilient channel and double sheetrock or a room-in-room anyway 2) Is <50 dB a good target, i.e. low enough to be below "annoying" indoors and next door 3) Will the floor or ceiling be a problem even if I upgraded the interior walls with resilient channels, etc.? 4) What about the duct--do I need a soffit or something to keep sound from traveling to the rest of the house? 5) I've read hear and elsewhere about platforms being a very good way to reduce drum SPLs--would that work in this case given the relatively little amount of bass in the spectrum? 6) I've read about the badness of 3-leaf construction, but if I didn't rip out the interior east wall, and just added another insulated wall with a 2" gap, would it still be better than what I've got now? 5) Anything else I should be doing? Thanks in advance!

"Approach 3: going the other direction and ripping out the existing interior sheet rock on the east wall and adding resilient channels, rock wool, and 2x gyp rock, or a second framed wall altogether." In an elevated environment what you need most is mass, not specifiably the decoupling in reference to how you are thinking on how to approach this. Some will tell you to use RC as a means to decouple, but the flanking of the structure cannot be overlooked as to how it will contaminate the environment. If a decoupling was to be introduced, then it would have to be nothing short of the walls, the floor and the ceiling. All of these areas would have to be decoupled. If you only do part of this, then you gain what is gained from the, let's say, walls, but you lose from the weak points of the floor and ceiling, always being mindful that the doors and windows are the weakest links, in general.

Brien, Thanks! So if I understand correctly, there's no need to do more to the east wall than I already have elsewhere, i.e. if my floor and ceiling are STC 45 and the windows are STC 40, a new door is STC 41, there's no reason to beef up an interior wall to more than STC 41? One advantage I have in dealing with flanking is that I have multilple rooms/walls that should provide some isolation between the opposite corners of the house except between the studio and the hallway. Any thoughts on whether a drum platform would help? Thanks again, Evan

Ok, I've decided to start with the door and leave the walls alone for now. Hopefully that will get me where I want to go. I am really curious about drum platforms, however. Can someone give me an idea how they work and whether they would help reduce the SPLs in the family room in my situation? Thanks.

Kotedjuga wrote:

Brien, Thanks! So if I understand correctly, there's no need to do more to the east wall than I already have elsewhere, i.e. if my floor and ceiling are STC 45 and the windows are STC 40, a new door is STC 41, there's no reason to beef up an interior wall to more than STC 41? One advantage I have in dealing with flanking is that I have multilple rooms/walls that should provide some isolation between the opposite corners of the house except between the studio and the hallway. Any thoughts on whether a drum platform would help? Thanks again, Evan

If your drum platform is something like rigid insulation on the floor, with several layers of plywood or MDF or some other kind of mass that will support you, yes that would be a very good idea.

Cool. Thanks.

Solid door with automatic bottom and gasketing arrives Tuesday. I'll let you know what $170 can do for sound isolation. :lol: