GroffStudio Recording Room (edited)

New progress at my place. Purchasing custom window from professional carpenter is cheaper than investment in good tools for making one. Anyway, making a good window is not easy and there is a high potential where things can go wrong. I got fair price (50 $ for workmanship, material not included) so I decided to purchase it rather than risk. Here's jamb and wing. Wing is sandwich of two 12.5 mm drywalls between two 12.5 mm MDFs. The jamb is with double rubber seal. Dimensions: 128 x 84 cm, weight: 40 kg. The next step was customizing the hardware for the window. I have no clue about welding but my friend Sime has tools, knowledge, experience ... and most important a good will to help me here with this. Thanks a million my friend. Sime in action at his place and final product before painting.

In the place.

In general, frames are filed (faces of lumber and drywall aligned) and caulked. I'm working on doubling the side drywall stripes. Here is one compiled photo for better overall view. Left part sucks in symmetry, I shoot it without the stand, but more or less this is the room.

Now, the first impression about functionality before adding more drywall layers on the faces. In the middle and upper range it’s quiet enough. I can’t hear sound in that part of spectrum coming into the room. Fair enough. But the lower range is awful. I can here every car engine rumble from outside. Moreover, empty room “amplify” that (like a resonator). I expected some flanking noises, but not that loud. Adding 2-3 more drywall layers would probably help with 6-9 dB in noise reduction but I’m not sure would this be enough. I have to say that I didn’t fill space between the OSB and the glass with insulation in the left (windowed) frame yet. Suppose, this wont be a crucial factor in TL. Measuring with the ears …. blah … I know … I just can’t find any affordable SPL meter here, only 200+ € and this is out of my already burned budget. Any trick in calibrating and measuring TL/NR with standard recording equipment? Even roughly, just to see where am I with all this. :roll: best regards

Hi, Guys, I’m stuck. I can’t find affordable SPL meter here. Is it possible to test what is coming from outside into my room using simple test: AT 4050 in omni, in the middle of the room, 1m in front of the monitor Playing 1 kHz sine wave 0 dB or so (maybe a pink noise instead?) through the monitor and setting preamp gain (api 512c) until reach the same level inside the DAW. After calibration, without changing mic placement and gain setting, I could record incoming noises for further analyzing. Would it show any useful data and be of any help or it’s totally moronic idea? :?: :roll:

Aloha Groff, Is there a Radio Shack/internet shopping access in your neck of the world? The 33-2055 is fairly affordable. http://www.radioshack.com/search/index. ... -2055&sr=1 Also, Rod Gervais’ book “Build it Like the Pros,” http://www.johnlsayers.com/phpBB2/viewtopic.php?t=5670 is an invaluable resource. Hope this helps, Aloha 8)

Hi kendale, I have Rod's book, of course. I'm wondering is it possible to measuring incoming noises in different way than using SPL meter to find out problematic part of the low end. If it isn't too low more mass (next two layers) should help otherwise I'm just wasting time and money. The first drywall layer is on and the low end still boiling too loud.

OK I will try another way, obviously two more drywall layers won’t make TL significantly better. Now what if I pack the bags with sand inside the cavity (B)? The depth of the cavity is app. 10''. Before that I have to make some thick hardwood construction to secure the whole thing (A). The rest of space could be filled with insulation (C). Would this „sand wall“ be of any help in blocking low noises from outside? thanks

Aloha Groff, Would the low end transmissions be entering via ground/floor flanking? Aloha 8)

It's perfectly clear to me that I can't get pro-studio high level of soundproofing without room in the room design and floating floor. Unfortunaly, except financial I have building/structural limits, permits and allowances I have to respect for multiple reasons. short resume: - can't build room in the room (weight, small room) - can't build the floating floor (arched basement under) - can't build the brick/concrete wall at windows place (not allowed) - all new structures must be non permanent or easily removable - reasonably affordable - it's live room not the control room (otherwise I wouldn’t be such a pain in the ass) Pretty tough. So, in my desperate attempt in this - single leaf impossible mission, the bags of sand comes to my mind. I expected flanking noises, yes, but not so loud like this. Actually, it's very hard to say that’s flanking only. How to sort that mess anyway? - The street is roughly 30' from the house - I have noticed that, using the palm, I can't feel vibrations on the surface of over 50 cm thick solid brick walls but it's just opposite when I'm touching the frames with drywall. - Direct sound is also clearly hearable when I'm standing in front of the frames. - In past 3 months I've noticed floor vibration just once but that was extreme situation (steam roller). - I didn't touch approx. two feet dropped ceiling much to find out how's going there but I will. - The hallway and one smaller room behind with the back yard windows are far more quieter in the low range Mr. Knightfly mentioned once that 24 cm concrete walls should make about 60 dB of STC, with 45 dB @ 50 Hz. I'm wondering how close can I come using sand barriers with similar thickness in addition to framed drywall? Thanks a lot.

I gave up on the sand bags, obviously no one use it here. I’m proceeding just with the drywalls. Two more layers on the sides. Now it's triple. The first (previously on separated pics), second and the third layer. Added mass of the last two layers really helps and made hearable difference in sound proofing. It's noticeable quieter. I'm almost happy with it. Still some subs from loudest cars occasionally comes in but I have to live with this limitation. All critical recordings could be done later at the evening time, a bit steeper on low cut filter and I hope I will be there.

The brackets for the cloud. The holes are drilled through the 55 cm thick walls.

Before wall painting I have to make the background from planks for hanging the absorbers. Removing the plaster, drilling, setting the screw anchors, preparation with mixture of sand:cement – 2:1 and the new plaster after substrate drying time.

The holes are ready.

Hi, Step by step and it's getting into the shape... The hole and conduit for cables.

Wall painting and laminate flooring.

The brackets for cloud were redesigned and mounted on the walls.

Nice progress, nice floor! So, what's with the PUR foam here eh:

Ro wrote:

Nice progress, nice floor! So, what's with the PUR foam here eh:

Thanks, The PUR foam firmly holds plumbing tube in place. I removed the surplus and dig approx. 5 cm inside the hole then tile adhesive was used for filling this perimeter gap.

I'm asking 'cuz the very open cell PUR foam is a serious soundleak. The 5cm filled part will prolly compromise.

I know the PUR sux in soundproofing, and when we come to the holes there is almost always some degree of compromise. Of course another 5 cm from the other side will help too. I choose this approach instead of wall mounting stage boxes only to keep the budget low.

Hi, Long time no post here. I made a few steps forward, so I suppose it's time for update. My biggest problem was to find dried fir wood for framing absorbers and I loose damn too much time. I was completely stacked. After many troubles, finally I've found rough B/C-class boards, witch were treated with jointer and thicknesser machines at local carpenter shop later. Next problem was resin pockets (more than hundred in 0.5 m3) some were small, others wide and deep. I boiled the resin out with the heater gun, ducts were cleaned with the sand paper and filled with the mixture of glue and saw dust. Frustrating and time consuming work.

continued

After three layers of stain (3rd was mixture of stain and lacquer) and a few days of drying, boards were ready for framing. First I made just one to see how's going, then I finished all nine frames in three days.

more pics