So, just how wrong was I, anyway?

[CluelessTim]

Geez, I sure wish I found this forum a year ago, when I got the hairbrained idea to build a recording studio out of the space that was used for storing my ex's junk. Okay, some of it was my junk too, but only because I didn't have a studio to put it in.

I'll make it short. I have a funky building. I looked lots of books and articles on the 'net, and came up with some of my own ideas about what might work. I made some wrong turns, and maybe I lucked into some right ones. But just when I thought I was putting in the last nail, I discovered this forum and started getting the idea that I'm not nearly as close to finished as I thought I was.

I'm asking that you take a look at what I did, and tell me what you think I did wrong, and maybe what I did right. If you have suggestions on how I can fix the wrong stuff, I'd be most appreciative. I put up a couple of web pages to show my studio at the following url and hopefully I can include a jpeg image here. http://medianet.kellercrescent.com/Tim/ ... ayout.html

Here's the image:

The website has more images and layouts, and shows what I did for acoustic treatment--which is where I think I screwed up. Hopefully it's all clear, and hopefully the page will load okay for you. If it's too large, I can break it up into smaller pages--just let me know.

Thanks,

Tim (the clueless one)

[CluelessTim]

After seeing so many symetrical control rooms in the examples here and elsewhere, I'm wondering if symetry is more important than size. With my existing layout, I have more than 22' from near-field monitors to the back wall and back to my ears. If I turned the desk 90 degrees and built a wall to match the existing interior wall, i would have a more symetrical space, but only 9' x 17'. I arrived at the current orientation because it was more symetrical than the 90 degree alternative without a wall.

I have another question. If I rotated my desk 90 degrees counter-clockwise and built a wall, would the sound be better if I had open doors rather than closed ones in the back of the room? Would it help, or just mess things up?

I'm also wondering what to do about comb filtering. If I run a 4khz sine wave through my speakers, I can hear the sound bouncing all around as I move my head. That can't be good.

Lastly, I hope I'm not sounding completely ignorant. I'm used to being an expert in my field, which is, I suppose, why I decided to wander off in a completely different direction. I'm stunned by how much I realize how little I know. It's actually pretty exciting, if not mildly intimidating.

Thanks for taking the time to read...

Tim

[John Sayers]

Hi Tim - can I use an Aussie phrase - "No worries mate -
I reckon you did real well"

You've taken the top end reverb time down with all the panels you've added and it would have significantlly changed the sound of the room, and there's a nice ceiling shape and plenty of volume for a really good sounding room. With a room that size you would need to add a lot more treatment to make it work to it's full potential.

cheers
john

[CluelessTim]

Thanks for the thumbs up, John, if I'm reading your Aussie right. I thought I might have been a complete dill and gone too far with the panels.

I take it that in my case, the volume of the space is better than being more symetrical--so no need to put up another wall or two.

When you say that the room would need a lot more treatment to work to it's full potential, what sort of treatment are we talking about? Diffusion? More absorption? I can get more of those panels--they're cheap!

Seems to me that it's pretty hard to give opinions like that without hearing the room. Should I hire somebody to tell me what I need to know, or is it something I can figure out with some help from the good people around here?

Off the subject, I've seen some beautiful mandolins from your corner of the woods, made with blackwood and king billy. A bloke named Peter Coombe builds a fine mando.

Cheers!

Tim

[John Sayers]

well - all of your treatment is aimed at the mids and highs - the low mids and low end are still reverberating around your room. You need to add panel traps or hangers to kill the low end and possibly some slots for the low mids. The ceiling area above the console would be a good place to add hangers and you could really deaden the rear wall with some bass treatment.

cheers
john

[CluelessTim]

Hi John, and others who may be reading. I had to leave town on business for a while, so my progress has been somewhat impeded. I swept a sine wave through the big speakers in my studio and noticed that I have 3 areas where there are standing wave issues. The big one is at 67hz, then there are smaller issues centered around 315hz and 430hz. I plan to address the 67hz issue first, and then measure the room again and see where everything sits with the new treatment.

I measured the sound pressure level at more than 250 points in the room, mapped it onto my floorplan and elevation, and identified that my worst issue is directly below the control room window between the two speakers, and then in the peak of the "witch's hat".

My plan is to build a bass trap out 8" from the wall below the control room window, and replace the contents of the 4 4'x3' suspended in the peak with 3" of rigid fiberglass.

Do I need to create a sealed cavity behind my rigid fiberglass for it to be effective? If so, can I put 1" of MDF on one side of the boxes and 1/8" plywood on the other side? I am also thinking about conducting an experiment with a sealed box filled with rigid fiberglass and a rigid panel that is attached in such a way that it will move like a speaker cone. I think that I can get an efficient bass trap like this, but I have no science to back it up. I tend to follow hunches. If my experiment is successful, I will put these in the rear corners.

Also, I wanted to comment on my theory about using the stairwell as a chamber that would add some livliness to the room. It seems to work, though it is most noticeable when playing sounds directly into the stairwell. As the sound source moves away, any added echo is much less aparent.

I'm not feeling nearly as clueless on this project right now. As I experiment with recording in the space, I'm not disappointed with what I hear--though I think I can still make it better. Oh, I'm also removing the absorption in the back of the room and putting in diffusers of my own design.

Tim

--The definition of genius is one who sees relationships where others do not. It also happens to be the definition of madness.--

[CluelessTim]

I tried something tonight, to prove or disprove a theory. I put a 4' x 2' x 8" mass of rigid fiberglass in the space below my control room where I am getting the biggest bass build-up at 66hz. With an SPL of 95db, the most that I could get it to drop was 2db by positioning the mass against the wall. My conclusion? The sealed cavity is really, really, important. So much for my first thought, which was that I could box up some rigid fiberglass inside cloth bags with wood frames and suspend them across corners and in other key locations. It appears that it will be ineffective. Therefore, I will need to try the panel trap and slot absorber route next. I'll have a long weekend coming up, so I plan to pick up some raw materials and experiment with a few different designs based on a 2' x 4' form factor.

I realize I'm probably reinventing the wheel here, and I'd probably save myself lots of time and a bit of money if I would just look at the designs others have already come up with. I've heard of people recommending just piling fiberglass batts in a space to absorb bass, and I still don't see how that would work better than a mass of rigid fiberglass. If anyone understands this stuff, please enlighten me!!!

Tim