How 'golden ratios' work in conjunction with splay

Splaying the walls (and/or ceiling) does alter the mode frequencies, but it's difficult to predict. I've seen it suggested to use an average. So if a room is 10 feet wide at one end and 12 feet wide at the other, you treat it as 11 feet wide. When the splay is large I don't know if that applies. I can tell you that splaying does not remove modes! So you still have to measure the room to know for sure what the resonant frequencies are.

It seems you're also asking about how and when rooms are splayed? A small angle like 6+6=12 degrees total is enough to reduce flutter echo, but you need more like 30-35 degrees on one side (or the ceiling) to direct reflections away from the mix position to the back of the room.

--Ethan

just the floorplan.pdf (458.34 KB) Thanks to both of you.

John, are you saying that, in your experience, a rectangular room employing one of the 'golden frequency' ratios for the control room will be no worse a starting point than the same room with each side wall splayed 6 degrees, and ceiling splayed upwards 30 degrees?

I may have the option - depending if the purchase of the property comes through - to start with an existing room of 6.25 mtrs in length, and 4.65 mtrs in width. It's a single storey house with a pressboard ceiling over 3 meters high, but if the ceiling is removed and the trusses exposed, could provide a height of well over 4 mtrs for most of the length.

Since I would anyway be removing some walls in some of the adjoining rooms to enable a large recording area (see diagram attached), I thought to also remove the side walls of the room destined to be the control room, and rebuild them with splay (see same diagram). Which brings me to another question: Down to what frequency do the splayed walls need to be effective? In other words, if I leave the existing side walls (of the 'control room') in place, and instead, build acoustical panels out of say, 4 cm thick wood and splay those down each wall of that room, would that solution (which I guess would tackle all frequencies down to at least 60 Hz) be sufficient, or is splay intended to affect bass frequencies (say, below 60 Hz) as well?

Thanks again.

Ok, thanks again for your detailed response.

Let me explain my considerations re the CR.

"I see that you have a completely coupled structure.. no double walls, therefore your isolation will not exceed 56 dB, and could be as low as 35dB, depending on how the walls are built and the materials used."

The house is on a half-acre stand, set well off the road - which itself is a culs de sac. So there'll be no transmission of noise from outside traffic. (Just, perhaps, a noisy dog or some birds). I'm not overly concerned about the transmission of low frequencies between the rooms, apart from drums, because I deal mainly with ethnic-acoustic music (especially choir work) and don't record groups that play at high volumes. And I never monitor at louder than normal hearing level when tracking - perhaps just a loudness check during the mix. So sound from my monitors won't ever enter the recording-room mics. Not to mention that my monitors are Genelec 1031s, so we're not exactly in Aerosmith territory..

What I might do with the drums is lay out some old tyres (9 to be exact) and place two large boards joined together on top of the tyres - and then rig the drums up on that decoupled stage. I did that in my studio in Israel, and it was a really effective (and very good-sounding) solution. The bass I currently record direct (simply because I don't yet have the amp-speaker setup that I'd like), but if I did add in a miked sound, I would do so from a sound lock. (I like to keep all the musicians in a single room so they can play the way they are used to playing in shows, but I don't need all their amps in there with them).

"2. The right-side door in the CR will work.. but the one the left is a BIG no-no! As is the little window on the left."

Yes, I'd much rather be able to scuttle the door and window on the left, but I'll tell you what my solution is. Generally, I'm old-school - I pay a heluva lot of attention to the way the artist(s)/musician(s) sound in the recording space before I'll assign a single mic. I use all kinds of traps in the room - especially spring traps - because I want a really nice wood-reverberant type sound. And I insist the musicians get as good a sound from their instruments as possible (I'm very interventionist on the stuff I produce myself, and will play the musicians videos of how the best musicians overseas sound). Once I have a great sound in the room, I assign mics, get the right levels, and record. So - and here's the rub - I am pretty confident that what's going on tape (actually, hard drive) is good sound, even if I don't hear optimally myself due to a problematic door & window on the left-side of the CR.

How do I overcome the problem of correct monitoring during mix time? I simply cover the door and window with a removable fitting that has the right acoustical properties - usually a sheet of rockwool on a board of selected thickness etc. Because during mix, I don't need the line of sight into the isolation booths that I want when recording. Nor do I need the artist to have easy access to any adjoining booth, as I do during tracking or overdubs. Re sound leakage while recording: The windows would not be single pane affairs, but double pane with a 6" space between each pane. And the door would be heavy duty wood filled rockwool. In other words, good enough isolation so that a) I can still hear my monitors clearly without a racket from next door. And b) that no sound from within the CR gets into the LHS booth thru that door or window.

"4. Zero room treatment is shown in the CR! and none in the tracking spaces."

There'll be plenty of treatment. All the schematic is designed to show is what hard building - 'bricks & mortar' - construction will be required.

"5. a LOT of space is lost to unuseable sections of the room due to slanted walls. (unnecessary when treated properly)"

I actually like 'coves' here and there, and employ them sometimes to get different reverberant effects - say, from the percussionist. If I put him next to a rough exposed brick-face wall, his highs might sound really nice. The recording room is big enough so that almost any size ensemble I would record (I don't do 150-piece orchestras!) would still have plenty of space. Still, your comment "unnecessary when treated properly" is interesting, and I'd like to know whether you (and Ethan) feel that placing acoustic panels on say, 60% - 70% of the target area is as good as angling the actual wall itself.

"6. Access to all rooms is not comfortable. You need better flow."

The schematic is very basic - not well illustrated at all. But if/when I acquire the property, I'll do a plan down to the centimeter. This was just to give myself an idea of what kind of modifications would be involved.

"7. Loads of wasted space in the CR due to the slanted walls."

I am DEFINITELY going to read your material "Balanced Non-Environment" criteria (2015)." I indeed have always taken for granted the slanted wall gospel, although I've been in dozens of world-class studios and many of them break all the rules - but the engineers still produce world-class records from them. Over the years I've developed a visual sense of hearing unrelated to the science; I can almost see, by looking at any room, whether the sound is likely to be aesthetic (for a recording room, theater, living room, etc) or reasonably accurate (for a control room). Interesting you mention Hidley, because while I know he nixes a vertical slant for speaker walls, I thought he does favor splays. Incidentally, I live in Johannesburg, South Africa (where the studio will be), and Hidley's greatest creation, BOP studios - a meglomaniacal project not rivaled anywhere in the universe - is 300 miles from there out in the sticks. I've never had the chance to visit it, but it will be one of my first stops when I get back to SA.

Thanks once more.

Dovis

A related question on room lengths. When acousticians/designers talk about having 12 feet long bass traps in a CR of say 5 mtrs wide, 4 mtrs high, and 7 mtrs long, are they referring to those bass panels taking up an EXTRA 3.8 mtrs of length (i.e. a CR whose effective length will then be 10.8 mtrs in my example), or do 'ideal ratios' assume all treatment will be incorporated WITHIN the 'ideal' geometry?