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PostPosted: Sat Dec 19, 2020 1:26 am 
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Joined: Fri Jan 15, 2016 12:56 am
Posts: 8
Location: Dublin, Ireland
Good morning!

I am hoping to get some help analysing my REW measurements and advice on building acoustic treatment to finish my Control/Mixing room, dimensions 5m long, 3.6m wide, with 2.4m high ceiling at the front end, rising to 2.75m at the rear. Not quite hitting the minimum area or volume thresholds for listening rooms, I know, but I'm working with what I have. This space is mostly for my own use, composing and mixing. I own the building, so no restrictions on attaching things to walls, into rafters or studs, etc etc.

Walls, from room side to outside, are;
skimcoat//insulated plasterboard (12mm board with 25mm insulation - I know!) //timber stud packed with 100mm Rockwool RWA45//200mm cavity//hollow cinder block//plaster render.
Ceiling is skimcoat//12mm plasterboard (non-insulated) on resilient bar//vapour barrier//timber rafters packed with RWA45// 100mm cavity//Kingspan insulated roof panel. I'm happy with the isolation, so my concern now is getting moving on the internal treatment.
Floors are isolated solid concrete slabs, painted.

Electrics are complete and working. In terms of lighting, I have LED strips which I hope to mount on the rear of ceiling cloud/other panel treatment, but for now there are standard bulb fixtures installed. Ventilation for the moment is via air vents at front and rear of the room, and a fan on the outlet vent provides some airflow. There is also a window. I work in this room alone, so this is sufficient for now. I do hope to install a mini-split system at some point, but not yet. I am aware of implications and accept them for now.

I work with a large analogue console (Midas XL200, 2m x 1m), and I'm aware this causes problems in terms of reflections. It's something I'll live with and do my best to mitigate. Speakers for now are Yamaha HS80Ms, and Tannoy System 800 (passive, front-ported). Soffit mounting is something I know I should do, but it will have to wait for another day. For now speakers are on stands, right up against the front wall.

Attachment:
CR Aerial w furniture 750p.jpg


At the bottom of the pic you can see the sliding glass door into (what will be) the live room, and opposite that, at the top of the pic, you can see the opening which contains the window and single door to the outside.

There is also a live room adjacent (5m x 6m, same ceiling slope), and I will eventually record music from that space. However, for now that's my workshop for building the acoustic treatment.

Yesterday I took baseline measurements according to Stuart's instructions. I think I did it correctly, but this is my first time, so go easy! I used the Yamaha HS80Ms, a Mackie Onyx Satellite (Thunderbolt :shock: ) interface, and my dbx RTA-M measurement mic, and my Extech 407732 sound level meter. The room was totally empty, as you can see below -

Attachment:
CR Front wall test.jpg



Below is the link to my .mdat file, containing Left, Right, Left&Right, and calibration measurements. It looks like an absolute nightmare from my basic understanding, but I'm hoping that's just it being a small, empty room, and not some mistake in my measurements, or worse, something structural which would be much more difficult to remedy.
BoxtyAudioBaselineTestsv1

From reading some of the excellent info Stuart has given on other threads - I think that I will need;

-Treatment between each speaker and front wall (I've got RWA45 100mm)
-Absorptive panels at first-reflection points on the side walls.
-Corner "traps" or bass absorption at the four corners on the horizontal plane, floor to ceiling. I can afford to make these 750mm/29" wide at the face (e.g. about 560mm along each wall from the corner of the room to the edge of the trap)
-Ceiling Cloud - I've planned for an 1800mm x 1200mm (3 x panels of RWA45 100mm) timber-frame, hard-backed with 20mm ply, and some more insulation on top. I'd like to flush-mount three LED spots into this.
-Potential treatment at the wall-ceiling corners, front & back or sides, or both

Materials - I have a considerable amount of timber or varying dimensions and lengths, as well as fixings, tools etc.. I also have a fair amount of RWA45 (1200mm x 600mm) left over from another project, and would like to put this to best use - about 8 sheets of 100mm, 35 sheets 50mm, and 8 sheets 75mm.

I plan to do most of the work myself, but will have an extra pair of hands or two to do things like hang the ceiling cloud safely etc.

In terms of budget, not much! I'd like to do what I can with what I have, though I realise I will need to spend some more on materials. I would like to keep any further costs for the treatment under €1000. Mineral wool and materials for covering the treatment are the main costs I see ahead.

Regarding time - I have no actual deadline for this, but I am eager to get a working space functioning as soon as possible. Lockdown is tough on the mental health, so getting this done and having a place in which to create is a priority. The ideal is that I'm in before March, sooner if possible!

So, questions:

1. Is my budget reasonable?

2. Is the treatment I mention above a good start? I can start building the frames for this immediately if so.

3. Re: the panels behind each speaker - how big should these be? One sheet of 1200mm x 600mm? Two?

4. Re Corner "traps" - Can I use regular attic insulation like ThisKnaufEarthwoolRoll, cut into triangles and stacked as I've seen in other threads? Can this also be used for corner treatment at the wall-ceiling corners? This stuff is fairly cheap here, about €20 per roll (4 square meters or so). Basically I'd like a reasonably priced alternative to RWA45; I think I'm looking for a Gas Flow Resistivity number (which I can't find for this product), but I don't know what that number should be for this type of bass "trap"

Aside from these direct questions, if someone is available to take a look at my measurements and give me some feedback, I'd really appreciate it. I'm a little tired writing this, so if I've missed anything or you need more info, please let me know.

Finally, just a quick thanks to John and the rest of the moderators for providing such an invaluable resource for learning and inspiration. It's truly appreciated.


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PostPosted: Sun Dec 20, 2020 5:45 am 
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Joined: Tue Mar 25, 2008 3:31 am
Posts: 445
Location: Cork Ireland
Treatment between each speaker and front wall (I've got RWA45 100mm)

Front Wall treatment is often assumed. As is moving speakers away from the Front Wall. Both are urban myths. Occasionally one or the other or both may help in a complex room. More often not.

-Absorptive panels at first-reflection points on the side walls.

Definitely

-Corner "traps" or bass absorption at the four corners on the horizontal plane, floor to ceiling. I can afford to make these 750mm/29" wide at the face (e.g. about 560mm along each wall from the corner of the room to the edge of the trap)

Corners are the best place to trap LF. Note that the Ceiling/Wall corners are just as important as vertical ones.

-Ceiling Cloud - I've planned for an 1800mm x 1200mm (3 x panels of RWA45 100mm) timber-frame, hard-backed with 20mm ply, and some more insulation on top. I'd like to flush-mount three LED spots into this.

That's a minimum size but good. Hard backed is done very rarely. I would omit that and hang the cloud down from the ceiling creating an airpap 100-200mm. This will definitely make the cloud absorb to a much lower frequency.

-Potential treatment at the wall-ceiling corners, front & back or sides, or both

Sure, but priorities? It's not always modal. https://realtraps.com/art_modes.htm

_________________
DanDan FitzGerald MIOA MAES
http://www.irishacoustics.com
http://www.soundsound.ie


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