5.1 control room ideas & questions

Hi, all, We've started planning (and building) a new studio in Tampere, Finland. The studio will be around 100m2, built on a concrete/brick warehouse basement. The final studio will contain 3 control (and edit) rooms and one about 40m2 live room for drums, and a sauna. We're happy with most of our plans so far, but I'd like to hear your comments on the main control room design, as we currently have two options that we can go for, and choosing which one works better seems to be a bit hard to do by guesswork only. The control room is 4.7 meters long, 4.0 meters wide and 3.1 meters high (see the option_1_top shot and raw_space screenshots). The control room is symmetrical, there's a double glass window and double doors on both side walls. The side walls are two separate 2x4 frameworks, covered with 12mm gypsum board on both sides, and filled with rockwool. The front and rear walls are concrete and brick. Unfortunately we cannot build a full-height tilted front wall with flush mounted speakers, as there are a two windows on the front wall, and two heating/water pipes going through the room, and we need to make sure there's an access to the vents in those pipes if required (the space is rented). This forces us to either build the front wall of the control room from something very lightweight material (such as cloth covered 2x4 framework) and fill the front wall with a really thick layer of rockwool (something like 60cm), or build the front wall so low that we can access the vents in the roof without problems. I've attached the two design options here, and I'd like to hear your comments which one would be more likely to work. The option 2 shot only has the front wall design in place, so it looks a bit .. ugly :) Also, if you have any comments on the rear wall - should we just fill the rear wall with 20-40cm of rockwool + cloth cover, or build it more "live" sounding with wood slats, or try to design something with two tilted sides? br, Sami

Easy: option 1. No diffraction of the sound from the speakers at the botom corners. Good luck! Andre

AVare wrote:

Easy: option 1. No diffraction of the sound from the speakers at the botom corners.

Thanks! What about the rear wall (and the roof?) - should we just go with the 30cm of 48kg/m3 rockwool with about 20cm air gap, or should we try to build them angled off from listening position and use wood or other harder materials? I know things would be a lot easier if we could soffit mount our speakers properly :( br, Sami

What about the rear wall (and the roof?) - should we just go with the 30cm of 48kg/m3 rockwool with about 20cm air gap, or should we try to build them angled off from listening position and use wood or other harder materials?

The room is total system, with each part designed as part of the whole. Have you done reverb time and early reflection design analysis? These will direct the rest of the design, including some location and quantities of absorption. Keep the questions coming until you are satisfied with understanding why each thing in the studio is done. Andre ps. Good studios are 90% design and 10% construction

ps. Good studios are 90% design and 10% construction

Andre, I wish I could say that. I spent about 4-5 months in design (actually more like a year if you add it all together), and so far I'm almost 3 years into construction... :shock: But yes, design is the key.

The room is total system, with each part designed as part of the whole. Have you done reverb time and early reflection design analysis? These will direct the rest of the design, including some location and quantities of absorption.

Yes, we've measured the reverb times (currently only for the live room) but I'll do it also for the control room this weekend now when both side walls (just the raw walls, not the angled wall units) are in place. We'll try to focus on taming the longest peaks to reasonable level. The plan is sort of "large version" of John's wall unit design with some mods - we've also measured the side walls angles so that absolutely no reflections from the speakers are directed towards the listening position, and instead of corner lo-mid absorbers we'll be using a huge amount of broadband bass trapping (hence the rockwool piles on the front wall). We'll probably be adding some removeable lightweight diffusors to the rear wall so we can fine-tune the room's sound once we've got the speaker setup in-place - I prefer to trust my ears and this way we can make sure we can add more "live" sound to the room if required. Oh, and if you know any reliable modeling/analysis software that could be used for tuning the design, let me know.

ps. Good studios are 90% design and 10% construction

I wish that was the case, we spent about two months modeling and planning the live room, and we've spent about two months building it (it's almost done by now). The control room acoustics are still in drawing board so nothing has been started yet.. br, Sami

Sami - what's the measurement from the floor to the bottom of the windows on the front wall? It is possible to build a soffit front when you have windows like that, you just build with glass where the windows are. cheers john

John Sayers wrote:

Sami - what's the measurement from the floor to the bottom of the windows on the front wall? It is possible to build a soffit front when you have windows like that, you just build with glass where the windows are. cheers john

Hi, John, The lower corner of the window is exactly 1.7 meters. The window size is 1.25m x 0.9m. The main problem is not the windows, but the water pipes on the roof, and the radiator on the front wall, that we may need access to. Also, we're using Genelec 8030's + 7060a sub as our main monitors, and they're not very good for soffit mounting due to their rounded shape (although we could probably build extra boxes around them). If soffit mounting the speakers is really really that much better option than using enough damping on the front wall (and careful placing of the sub on the front wall), we may consider doing it somehow, though. edit: looks like I don't have the front wall radiators on the "raw space" pic at all, sorry, I'll re-post a new image later.. :) br, Sami

Yes - I understand Sami - free standing front speakers, I'm suggesting you build the corner units to have an angled geometry across the front, with the heater open in the middle but bass traps in each corner up to 1.7m then glass to window top. cheers john

John Sayers wrote:

Yes - I understand Sami - free standing front speakers, I'm suggesting you build the corner units to have an angled geometry across the front, with the heater open in the middle but bass traps in each corner up to 1.7m then glass to window top. cheers john

John, Thanks for the idea - I didn't quite get what you mean, yet, though, so it would be nice if you could post some pics of what kind of traps / units you were talking about? I was thinking that the 60cm x 60cm x 130cm rockwool packs (there's a total of 14 them on the front wall!) should provide more than enough bass trapping? In this case the front wall would only be a wooden frame covered with soft fabric, so we'd have access to the front wall radiator if absolutely necessary. br, Sami

Like this. cheers john

Aaronw wrote:

ps. Good studios are 90% design and 10% construction

Andre, I wish I could say that. I spent about 4-5 months in design (actually more like a year if you add it all together), and so far I'm almost 3 years into construction... :shock: But yes, design is the key.

Sorry Aaron, that story doesn't hold water, er, sound. Just a look at your profile and intelligent posts show that you spend about 99 hours helping other people for every hour you spend on your project. If more people were like you in the world, the world would be a better place. Andre

John Sayers wrote:

Like this. cheers john

Thanks, John! I actually did consider something like this, but it made me wonder about two things: Feel free to correct me if I'm wrong :-) First, did you mean that the traps are built as tuned traps (with wood slats, meaning they have a hard, reflecting surface), or just be completely filled with rockwool with soft fabric front (which would make more sense to me?) If you mean hard surface (wooden helmholz-type resonator), if I do it like this, the angled walls are actually acting as a "mirror" right towards the listening position (as the speakers are not inside the wall), which causes phase cancellation effects on low-mid frequencies. In my design, the speakers have over 1 m distance from any hard wall, which is something that Genelec recommends when using their 8000-series products with sub (they have a crossover freq of 85hz which means that the main speakers need to be 1.1 meters away from the wall to move the cancellation dip below that frequency). http://www.genelec.com/support/tutorials.php Or do the tilted angles have something to do with preventing standing waves in the room? br, Sami

Sami - here's a pic of Funky's new studio in Macedonia - It's finished but I haven't made up a web site for it yet. The front is built in a similar way to a soffit mount in that the front has a plywood backing, behind the stud frame with a port opening at the floor and hangers inside, and the front is heavy insulation with a cloth cover. It breaks up the standing waves as you suggested but is non reflective. BTW behind the curtain is window with a heater below :D cheers john