Hi Milla, and Welcome!
The room i have is 3.87m wide x 4.23m long and 2.38m high
A reasonable size, and the ratio is OK too. There shouldn't be anything out of the ordinary with modal response there.
All walls have 3 layers of firecheck gyprock and the ceiling has 2 layers.
On the inner leaf, or the outer leaf? Or on both leaves?
The floor has carpet (Im going to put in a square section of timber flooring under the mixing console chair area.
Actually, it should really be the other way around! There should be no carpet on the floor (since large areas of carpet do nasty things to acoustic response, and also psycho-acoustic perception), with just a small section of carpet under the mix position, if needed.
i have put in a window that is 1.30m wide by 1m high which is at an angle of 5 degrees pointing down.
The angle isn't necessary for any acoustic reasons, and in fact could damage the room isolation (because the MSM gap is now smaller at the bottom of the window than at the top, and the smallest distance for cavity depth is what defines isolation). But if you already have it in, and you are getting enough isolation, then that's fine.
my computer will be on a small desk on wheels
Are you SURE you want to do that? Changing the position of furniture can change the acoustic response of the room. You'd be hearing different things with the desk in different positions... It would be better to have it fixed in only one position.
I feel this restricts me from having the walls fanning out from behind the console like in many of your studio designs on this forum.
Those are only really needed if you are going to do a proper RFZ design for the room, and it seems you are not doing that, because the room is already finished. That door does, indeed, limit your options. If you did want to do an RFZ room, then the options open to you are to either move the door (which is probably not as big a job as you might imagine), or to flip the room 180° so it is facing the other wall. That would allow you to do it, but of course then you'd have your back to the window, and no place to put your rear wall treatment, which is critical for control rooms. So I'd suggest moving the door, if you want an RFZ design. If that's the case, I'd also suggest soffit-mounting your speakers, which is a big part of a successful RFZ design in any case!
If you don't want (or can't) get an RFZ design, then just go with a plain rectangular room, which can also work very well provided that you do the correct acoustic treatment for that.
I also have a bunch of Polymax Acoustic insulation made by Martini CSR Australia left over, enough to cover all the walls 150mm deep (If it were needed). I have MBA 32kg per/m3 sheets at 100mm thick and 50mm thick
That could be useful for your first reflection points, but not much use for your rear wall or superchunk bass traps. The low frequency characteristics just aren't that good. You will need something like OC-703 for that. To give you an example, 75mm of OC-703 has a coefficient of absorption of 0.53 at 125 Hz, compared to 0.4 for your stuff, and 1.19 at 250 Hz, compared to 0.85. (I'm assming ASTM-A mounting in both cases, even though the Polymax specs don't say. If it was E-405 mount, then the OC-703 specs are even more impressive, with 0.66 at 125 Hz.)
So you'll need to get some better stuff for your bass trapping and rear wall.
I'd love some advice on how to go about laying this room out acoustically for a great mixing environment if possible?
On a tight budget, I would keep it rectangular, keep the speakers on stands (they must be very massive! Extremely heavy), and set them up as follows: 114 cm from the side walls, which implies they will be 161cm apart (I am talking about the acoustic axis of the speaker, of course: not the edges of the box). Adjust each stand stand so that the acoustic axis is about 1.2m above the floor, rotate the speakers about 28° inwards, and set up your chair so that your ears will be about 172 cm from the front wall when you are mixing. Adjust the speaker stands so that the rear edge of the speaker cabinet is about 10cm from the front wall (which leaves just enough space to put in some good absorption behind it, to help a bit with SBIR control). That geometry will set the intersect point for the speaker axes about 30cm behind your head., and places your ears at about 142 cm from the speakers. An easy way to get the speaker toe-in angle correct is to set up a mic stand with the arm vertical, so that it is 172 cm form the front wall, exactly on the mid-line of the room. Set up a laser pointer on top of each speaker, exactly above the acoustic axis, and exactly perpendicular to the front baffle (if you don't know where the acoustic axis is on your speakers, ask the manufacturer, or just assume that it is about 90% of the distance between the center of the woofer and the center of the tweeter: That's not precise, but close enough). Now turn each speaker so that it is pointing at the mic stand, and the laser hits the middle of the mic stand arm, while at the same time the acoustic axis of the speaker is the correct distance from the side walls. When the lasers on both speakers are hitting the same spot on the mic stand, then you have the angles correct.
That's not ideal (the sweet spot will be a bit narrow), but it's about the best compromise I could come up with for that shape and size of room. It's pretty darn good, though!
With the speakers set up like that, try tweaking things just a a little each way while you play music that you know really well, to see if you can get a noticeable improvement. For example, move the speakers a couple of cm further apart or closer together, and/or change the toe-in angle by one or two degrees. You might get a useful change, but I'm betting there won't be much difference. When you have them in the best position, confirm once again that they are both at identical distances form the side walls and front wall, and they are both aimed at exactly the same point, about 30 cm behind your head.
Now that you have your geometry correct, put the desk, console and other furniture in the room such that it is all comfortable for you, without moving the chair at the mix position! In other words, move the console, rack gear and computer desk until you can operate them comfortably with the chair in the correct position.
Now do a measurement of the room response using the REW acoustic software (which is free!) and a good measurement mic (should cost around US$ 100). Do make sure you fully calibrate REW before you test! You'll need a quality sound level meter to do that (also around US$ 100: avoid the Chinese toy junk ones that go for under US$ 50): Post the MDAT file from REW some place where we can download it to do the analysis, then we can suggest what treatment you will need. Do the first test with no treatment at all in the room: that's your "baseline" test, and it reveals all of the "ugliness" of the room's acoustic response, which is what we need to see in order to figure out your treatment. When you measure, set up your mic exactly where the middle of your head will be while seated at the mix position. Make sure you are not in the room while the test runs (use the "delay" feature to give you enough time to get out, close the door, and a few extra seconds for things to settle down after you leave).
From what I have picked up Im thinking of building pannels on my walls on the left and right side of my console where my line of sight (while using a small mirror) reflects back to my monitor speaker cone,
Yes, you will definitely need those. Those are your "first reflection points". You could use the Polymax XHD stuff for that, 100mm thick. Make the panels big: at least 1.5m high and at least 60cm wide. If you can spare the room, then space them away from the wall by another 10 cm, or more of you can.
And don't forget the first reflection point on the ceiling! That's a big one, and VERY important. I would probably hang hard-backed cloud up there, in your case. Make it wide and deep, and put at least 15 cm of XHD in there, then another 10cm at least on top of the hard back.
and having the pannels angled by at least 12 degrees towards the back of my room.
Not necessary. That would just take up extra space in the room, and it is already narrow. Just leave them flat against the wall, or angle them a bit if you want, but it won't make a huge difference. 12° is the angle for splayed walls to get rid of flutter echo, but you don't¿t have the space (or the budget) for that, and absorption panels do the same job.
I plan on lining the walls with the insulation to deaden the room
Not a good idea!!!! A dead room sounds terrible! The concept of control room treatment is to make it
neutral, not dead. You want the frequency response and decay response to be as smooth and neutral as possible, with the overall decay time in keeping with the room volume. There are equations for calculating all that, but with a room that size I'd shoot for an overall decay time of around 200ms, or as close as you can get to that (it will probably end up less than that, unfortunately, but we can try to improve it).
So do not cover your walls with that stuff! The correct approach to control rooms like this where there are so many unknown factors, is to start with the baseline test, then do a series of measure - treat - measure - treat - measure - treat until one of three things happens: 1) you get perfect response, totally flat in both frequency and time domain, except for a 20 ms ITDG, followed by smooth and even decay across the entire spectrum. (This is the least likely of all outcomes, but it is the goal you are shooting for). 2) You run out of money. 3) You run out of patience. Number two is the most likely outcome...
also to have corner bass traps like in my photo's in above post.
Definitely! You will most certainly need those, and probably more besides in the other room corners. It's a small room, so it will need heaps of bass trapping. But don't use the Polymax stuff for those: wrong characteristics. See if you can find proper Owens Corning OC-703. That's what you need for those things.
Im still a little unsure of some asspects of weather/ how to build the right diffuser for my back wall
No. Your room is not big enough to be able to have diffusers on the rear wall. Or at least, not tuned diffusers (such as Schroeders, skyline, QRD, binary, etc). You need at least 3m between your ears and the diffusers for that to be possible, and you won't be able to get more than about 2m or so. Maybe 2.4, best case, but still not usable. Your best bet for rear wall treatment, is just 15 to 20 cm of OC-703, or something similar. You could do that just for the top section of the wall (1m above the floor, upwards to the ceiling) if you wanted, but doing the entire wall would be better.
and weather or not i need to include resonator's
Perhaps... but only REW will reveal that!
- Stuart -
