John Sayers' Recording Studio Design Forum Archive

Hello, my name is Jason and I intend to turn my existing attached 2 car garage into a studio control room. I have a budget of $5k - $10K, and I will be doing all of the work myself as I have a construction background.

My current control room is located in a spare bedroom in my home, located in a quiet residential area. I generally monitor at around 75-80db, with no sound isolation in place and have not received a complaint for noise in the last 8 years, so I do not believe isolation will be a huge concern of mine. My existing 2 car garage is a 8.5' x 20' x 20' structure attached to my house. It has concrete floors, 2 of the walls are adjacent to my home and consist of 1/2" sheetrock R19 insulation and 1/2" sheetrock. The other two walls are exterior walls. One has the garage door, and the other consists of cement fiber board, paper sheeting, wood studs, and 1/2" sheetrock, but no insulation. The ceiling is 1/2" sheetrock attached to 2"x4" wood studs. The fuse box is located near the door to the house, and a hot water heater is located in the corner of the room. I plan on using part of the space for a control room and leaving part of the space for storage. I have read a bit on ideal H W L ratios and chosen to use 1, 1.6, 2.33 which gives me the dimensions of 8.5' x 13.6' x 19.8'. To allow functionality of the existing garage door I plan on leaving a small enclosed pocket of space along the ceiling inside the control room to allow for movement of the garage door. I intend to mirror this pocket on the opposite side for symmetry. Because of the size and location of the hot water heater, I plan on having a hinged 6" thick bass trap located in both front corners angled to 30 degrees. I will line the frame of the bass trap with weather stripping and install a dead bolt lock to help make it as solid as possible. The left side will house the hot water heater, and the right side I will use as a machine room for my computer. I will run HVAC ducting from my homes current HVAC unit into the "machine room" and also into the new control room. For the fuse box, I intend to leave a small access hole behind one of the broadband absorbers on the side wall for access. In addition to the two hinged bass traps, the front wall will also have 2 small 6" bass traps, and a 4' x 8' x 8" slat resonator which I intend to cover with a bit of fabric for aesthetics. I will be using 4" thick broadband absorbers on the side walls, 12" thick bass trapping along the back wall, and 8 diffusers (i already own) around the back of the control room. I plan on building a two tier cloud above the listening position constructed out of 4" thick insulation. I plan on using 4" Roxul R60 for all bass/broadband trapping. For the angled walls on either side of the control room I plan on constructing a wood frame 16" OC and using 4" R60 between the studs and then one layer of 1/2" sheetrock on the inside wall, but nothing on the hidden sides. The new walls I will be constructing to separate the two new spaces will be 1/2" sheetrock, wood studs 16" OC, R19 insulation, and 1/2" sheetrock for the side, and for the front, a thin .2" thick wall with wood studs 16" OC, R19 insulation and 1/2" sheetrock. I will cover the control room floors with laminate wood flooring, and I plan on filling in the ceiling joists with either R19 insulation or blown insulation.

Proposed layout is as follows: (Download Sketchup File Here)
NOTE: Everything shown in grey in the model is made from Roxul R60, White slats are wood, white diffusers are Auralex T-Fusors, and maroon/blue are Sheetrock.


My questions are as follows:
1. Is this design worth building?
2. Are the proposed acoustical treatments sufficient and effective?
3. Is there anything I am overlooking?

Thank you for your time and your feedback!

Hi Jason, and Welcome!

I downloaded the zip file at your link, but it does not contain a SketchUp file. It only contains a few image files and a .dae file. Please post the actual SketchUp file, preferably in SketchUp 2013 format (or earlier).

There are several issues with what you describe, but I'd like to see the actual model before commenting in detail.

A couple of quick comments:

- You seem to be confusing the purpose of the front "cut off" parts of the control room: they are either speaker soffits, or bass traps, but not just angled doors that you can open to have access to things behind.

- You do not need to splay the side walls of the room: it wastes space, complicates construction, costs mote, and provides no major benefit. It's a myth. You can if you want, but you are on an extremely tight budget, so you need to simplify the build as much as possible.

- The garage door is just thin sheet metal, unsealed, with gaps all around: it will not provide anywhere near the level of isolation that you had in your bedroom. It may well even resonate and amplify some sounds.

- It would be better to permanently fix and seal the door in place and remove the mechanism and build an isolation wall behind it.

- A '6" thick bass trap' is no bass trap at all. That's just a broadband absorber, the way you describe it. Bass traps must be deep. Very deep. I often use 2 or 3 feet at the rear for bass trapping, or at least put 24" superchunks in the corners. 6" will not do much...

- I see no provision for HVAC, which is critical for a control room. That's a big oversight! Needs fixing.

- A slat resonator on the front wall is not a good idea. I try to never put anything forward of the mix position that could change the frequency response. that can go on the side walls behind the mix position if you want, but once again that's a lot of money to get it right, and your budget is very, very tight. The room likely will not need it anyway.

- "slat resonator which I intend to cover with a bit of fabric for aesthetics" ... and which would promptly kill the tuning and effectiveness of the resonance! Better take a look at the theory of Helmholtz resonators to see what that would do, and why it is not a good idea at all...

- "and 8 diffusers (i already own) around the back of the control room". What type, and what frequency ranges are they tuned to? The room is borderline for being able to use diffusers anyway: it is right on the edge of being large enough to do that, but if you plan to have a client couch at the back, then forget it. You need about 10 feet between a tuned diffuser and the ears of anyone doing critical listening, to ensure that they are not in one of the lobes. If the diffuser is tuned low, then you might need more than 10 feet: more like 5 full wavelengths of the lowest cutoff frequency. I would skip having those on the rear wall, unless they are small and tuned high.

- "I plan on building a two tier cloud above the listening position ". Better to put it between the mix position and the speakers, make it hard-backed, and angle it. Much more effective, and it accomplishes several things at once.

There's more, but I need to see the SketchUp.

- Stuart -

Hi Stuart, thanks for your reply. I created the dae file by exporting a 3D model from sketch up so it should work. In any case I'll upload the project file later. I stated my intent for hvac in the breakdown, and am aware of its necessity. There will be a wall dividing the control room from the garage door. The new wall will be the same construction as my current walls so I think it will continue to be effective. I will not be sealing the garage door shut. If I have to build two walls I will, but that doors not going away. The diffusers are auralex t fusers. I will scrap the slat resonator and just make it a broadband absorber. If it's necessary I can change the cloud design and shrink it to only cover that area above my desk. I'm not concerned with the rear listening position. Just the mix position matters to me. Also, I realize 6" r60 "doors" are not ideal, but I haven't thought of a cost effective alternative. I need access to that area, and have read that spacing the 6" of R60 that far from the wall would greatly improve its effectiveness at absorbing low end. Sorry for my ignorance in terminology. Also the majority of the rear wall will be 12" thick R60, if I need to double it I will. Thanks again for your time. I appreciate the feedback.

Hi Stuart, I have changed the file attachment to the .skp file format. Sorry it took so long. Thanks again for your time and feedback. I really appreciate your input. I know I have LOTS to learn and look forward to you guidance.

- Jason

This is how i planned on building the hinged broadband absorbers... Not sure if they should be open backed or closed. I plan on using three deadbolts and lining the back of the absorber with weather stripping to help minimize vibration.

Download skp file here

I've made quite a few changes....

1. Moved the hotwater heater to the storage space..

2. +/- 2' thick bass traps made from fluffy pink stuff at front and rear.

3. 4" thick R60 Cloud angled 6 degrees rigid backed

4. Flush mounting studio monitors, 51" front baffle, rigid backed broadband absorber above and below baffle, monitor ventilation is accounted for...

5. Pc isolation cabinet

6. Polished concrete floors instead of wood laminate

7. All walls filled with fluffy pink stuff instead of r60

8. Only using 4 Auralex T-Fusors

9. No more hinged broadband absorbers

Download SKP file here