Old renewed studio needs acoustic treatment

Hi, I'm writing on this forum to ask for help mostly about the acoustic layout of the control room of an existing studio, and obviously about materials and construction howto. So no insulation questions. We took over this studio about 4 months ago, it had been almost inactive for about 2 years, so we painted it, we changed the electrical panel, we filled it with everything we had, and now we would like to use it both for rehearsals (live room) and for rec\mixing. As said before, our major concern is the control room, which for me is quite unusable (even though some quite good albums were mixed there), mainly because it's not entirely treated, it has a lot of reflections created from the parts of the walls that are not treated. So, I said entirely treated because inside the studio there were already some DIY acoustic panels placed here and there, as you can see in the photos. Before filling every wall with this type of treatment, which is cheap and quite simple to build, we thought it would be a good idea to ask for help, mainly because of the shape of the control room (completely asymmetric, I really wonder why they build it like this), and because we wanted opinions from experts (and we are not). So I am uploading photos, sketchup model, but also the sketchup project file if you need the measures. So, to sum up, what I am asking is, what can we do for the shape of the control room (full of angles and asymmetric), what can we do to make it drier, what materials should we use, and what should we do with the big live room to make it usable also for rehearsal (the small iso booth is going to be all treated, to make nearly as anechoic :shot: ). Budget.hmmm, I could say like 1000 euros, or even 1.500, but I don't have any idea of the prices of acoustic materials, obviously we'd be glad to spend less, and get the job done. We will probably scan and upload some measurements made by the previous owners and builders in the next days, made about 11 years ago when it was build, but honestly, there are quite a few things i don't get, I really would like to make a measurement by myself, but i don't have the right mic (would and earthworks qtc40 do the job?), and i only have some basics on the smaart analyzer. We'll see. Thanks in advance, and, by the way, I'm Kostas.

more attachments! :horse:

The RT Analysis I was talking about, here it is. check the name of the files to know what exactly it has been measured. These are measurements made by the previous owners of the studio (who also are those that build it), so these measurements were made with different speakers than those that we have, and maybe differently placed. This is just to give an idea of what the room "hears" like. P.S.: how can I upload pictures on the site's server (as it's stated in the forum rules), but make them clickable thumbnails and not full size images inside the posts?

Hi Kostas, and welcome to the forum! :) That's a rather "interesting" space that you have there! But not interesting in the good sense... First, I'm having a hard time figuring out which room is which! It seems to me that the control room must be the one diagonally opposite the iso booth? Is that correct? If so, that's your first problem, since that room is practically square! :shock: it measures 3.97 m x 4.05 m, and therefore has a ratio of 1 : 1.64 : 1.67. It fails two out of the three basic tests for critical listening rooms. It also seems to be asymmetrical, with a beam running down the left side of the ceiling, small pillars up the left front and rear corners, and a large pillar up the middle of the right hand wall. That room will have major modal issues at around 43 Hz, and also at 83 - 85 Hz, as well as in other areas. The response curves you posted seem to clearly show that, although the resolution is way too low to be of much use. So your first approach should be very large, very deep broadband bass trapping in all of the vertical corners of the room. But that leads to the next problem: you do not have enough space in the room for that! So you will have to use the horizontal wall/ceiling corners. I would put a very large superchunk bass trap across the right rear corner, plus large superchunks across the top of the rear wall and the top of the front wall, and also cover the entire rear wall with deep absorption, 6" (15cm) thick, and leaning forwards, so there is a large air gap at the top and a small air gap at the bottom. I would also cover the entire ceiling in at least 2" (10cm) of absorption, and in addition build a hard-backed cloud over the mix position, angled lower over the speakers and higher over the chair, with absorption on both top and bottom. That room needs about 370 sabins of absorption, and the only place you can get that is from the ceiling, which will provide only about half of what you need. The rest will have to come from the other treatment (sueprchunks, cloud, rear absorption, first reflection points, etc., but I fear there won't be enough space, even so. Then I would fix the listening geometry: get the speakers and the chair in the correct relationship and with the correct treatment. But here too you have a major problem: the front window. It is way too big. You have no choice but to cover part of it with treatment. So I would push the speakers up as close as you can get them to the glass, and put a 10cm panel of OC-703 directly behind each of them, against the glass. The gap left over between them is all the window you can afford to have. It won't be much... Then position each speaker at about 1.1m away from its side wall (therefore placing them about 1.7m apart), angled inwards at 30°, with your chair about 1.5 m from the glass, on the center-line of the room (NOT the center of the glass). That should have the acoustic axes aimed just past your ears, intersecting at 60° a few cm behind your head. Finally, you will need to more full panels of OC-703 on the side walls, at the first reflection points. Once again, that is going to cover up a large part of the window on the left wall, but there are no other options. That would be my basic approach, but that room is still not going to be ideal due to the square shape. It should at least take the room from being "unusable" as it is now, to being "somewhat usable".

inside the studio there were already some DIY acoustic panels placed here and there, as you can see in the photos.

Those are basically useless. Way too small and thin.

scan and upload some measurements made by the previous owners and builders in the next days, made about 11 years ago when it was build, but honestly, there are quite a few things i don't get,

Unfortunately, they really aren't much use at all. They are only very basic 1/3 octave graphs, which do not reveal much about the room at all. The resolution is way too low, and those are only frequency graphs, which tell you nothing at all about the time domain. And "time domain" is where the real modal issues will be revealed, as well as the reflection issues. All you can say from those graphs is that there are modal problems in the low end, and for some reason a total lack of highs! All of the graphs show a major roll-off above about 8kHz, which is hard to explain in a room like that! Perhaps the measurement mic used was simply not up to the job. Or maybe the room was very poorly treated, such as with carpets on the floor or very thin absorption on the walls. You will have to repeat those measurements with decent equipment and decent software to get a full understanding of the issues. Download REW and run that on your room, with good full-range speakers and a proper measurement mic located precisely at the mix position, and with the speakers set up perfectly, as I outlined above. Then post the actual data file produced by REW, with the results, so we can analyze it.

really would like to make a measurement by myself, but i don't have the right mic (would and earthworks qtc40 do the job?),

Measurement mics are not expensive: You can get a Behringer ECM8000 or a DriveRack RTA mic for under US$ 100. That's what you need.

and i only have some basics on the smaart analyzer.

Forget that and use REW: it is free, and does a really good job of analysis. Forget simple RTA: that's only a small part of what you need to analyze. RTA only tells you about pure frequency response, which is not much use without knowing how that changes over time. You need waterfall plots, decay plots, impulse response plots, and various ways of looking at the data to figure out what is actually happening with the room.

P.S.: how can I upload pictures on the site's server (as it's stated in the forum rules), but make them clickable thumbnails and not full size images inside the posts?

Re-size the images before you upload them so that they are no more than 700 pixels wide. That should be plenty good enough. If not, then zoom in on the region of interest and make that into a separate image, 700 pixels wide. - Stuart -

Hi Stuart, Today we were thinking maybe we should approach the CR in a different way. Why not build 2 walls to get rid of those messy corners and bring the room to a more symmetric state. During this process a small room will occur witch could serve as a computer/psu/ups room, also the possibility of a 2 door stage between the CR and the Live room could be placed, thus isolating the CR better during a recording session. I have attached some new sketches just done and the "Google SketchUp" file. What do you think ? Would it be a better thing to approach the room in this way ? Have a great weekend, thanks in advanced, Alex.

What do you think ? Would it be a better thing to approach the room in this way ?

That's a possibility, yes. The downside is that it does make the room smaller, but it would certainly make your job easier. Check the final interior dimensions with Bob Golds' calculator, to see how it works out. - Stuart -

Hello again, and thanks for the help stuart, we're slowly getting there. So, with the real measures of the room (cause in sketchup we have slightly different measure in width), and with the new shape you can see in the last sketchup model, using bob gold's calc I'm getting a good room, as far as I can understand, but if you can, just check by yourself with these measures: Room Length: 4,12m Room Width: 2,75m Room Height: 2,43m Yes, the room will be really small, we will have to get rid of the couches (hehe, too bad for the talents and talents' friends) and there will be not much space in general, but we like the idea we will have a better C-R by the point of view of acoustics. Anyway, we are working on a better model right now in sketchup, but, I was wondering right before while I was working on it, is the angle of every single surface, be it wall or ceiling, important? How much does the splaying of a surface matter? And how much "does it have to be"? Also, we ended up we will try and do it by ourselves, only with the help of a friend of ours, who is a carpenter, so the framing will be in wood mostly, but, what's your opinion about that? About the speaker positioning, which is a really crucial chapter, you wrote about it in the previous post, but we had not mentioned about the shape changes, so were is best to place theμ now? what about fitting them in a frame in the front bass traps? So can you please also help me finding the sweetspot on that room? Finally, I'm still searching for a measurement microphone, I read a lot of review and opinions on the net, it seems that even the cheapest are not so bad and will do for what I need it, but still, I was thinking of something slightly better, like an audix tm-1, not very expensive, but sensitively better than the behringer,dbx,superlux,beyedynamic.

but if you can, just check by yourself with these measures:

Not fantastic, but also not bad. That should work out OK.

I was wondering right before while I was working on it, is the angle of every single surface, be it wall or ceiling, important?

That depends on what design philosophy you are using for the room. If you are going for an RFZ design, then yes, all the angles matter.

How much does the splaying of a surface matter? And how much "does it have to be"?

THat depends on the reason WHY you are splaying it. If you are just splaying to get rid of flutter echo, then 6° on each wall (12° total angle) is what you need. But if you are going for an RFZ design, then you have to figure out what the correct angle is, by "ray-tracing".

About the speaker positioning, which is a really crucial chapter, you wrote about it in the previous post, but we had not mentioned about the shape changes, so were is best to place theμ now?

The same basic rules apply: The speakers should be positioned up against the front wall, with just enough space to get a panel of 703 in between, and they must be angled inwards 30° so they are both pointing about at the same spot about 30 cm behind your head.

what about fitting them in a frame in the front bass traps?

Yes, that is called "soffit mounting", and it is a very good idea.

Finally, I'm still searching for a measurement microphone,

The most important factors when choosing a measurement mic are: it must be omnidirectional, and it must have flat response from 20 Hz up to at least 8 kHz. - Stuart -