FINALLY!! The saga begins

[proudtower]

A soffit's main purpose is to extend the speaker's baffle, forcing the woofer to radiate in half-space mode (only forward) - because of that, the "baffle extension", or flat front plate, needs to be exactly in the same plane as the woofer and roughly 3 woofer diameters in any direction from the center of the woofer cone; I don't have exact formulae for this, it's a wavelength thing; but if you make soffits that are "concave" in any way, it causes a degree of "horn effect" (focussing) which can reduce the size of the "sweet spot" so it's NOT recommended.
Steve

A concave surface (horn effect) will also screw up your frequency response.
The horn bundles sound from the driver and thus increases the on axis sound level bandlimited depending on shape and dimensions of the horn.

Bert

[MadMax]

Steve and Bert,

THANX for the clarification! In browsing around the web over the last few weeks, I've seen a few... repeat few, control rooms that are splayed at the ceiling and tapering down to the top of the soffit mounted speakers.

I read about, but no pix, of one studio that mentioned that there was "acoustic treatment" on the front wall which only allowed viewing into the tracking room as there was no place to sit in front of the console due to the shape of the wall.

I thought it rather odd as many of the classic Manzella and Berger designed (patterned) rooms are pretty well known for the classic sofa in front of the console sized control room. (although I'd suspect that it makes it a royal PITA to service a console)

Steve, I'll see if I can find a copy of Newell's book on Amazon.

One question that keeps knawing at me is whether I've allowed enough space between the CR and tracking room to do a proper job of soffit mounting.

Thanx again!
Max

[knightfly]

Found what I was referring to -

http://www.quarter-wave.com/General/BSC_Sizing.pdf

If you look on page 3, about halfway down, just below the simple formula - this is basically a mini-discussion on soffits for all intents and purposes - if you re-arrange that formula and divide 4560 by the lower Fo of your speakers, it will give you a TOTAL baffle width in inches - I did a few for reference

30 hZ = 152"
35 hZ = 130"
40 hZ = 114"
45 hZ = 101"
50 hZ = 91"
55 hZ = 83"
60 hZ = 76"

So you can see that if you had some 15" bass drivers and wanted proper soffits they'd need to be about 5-6 feet each side of the speaker for true 2 pi operation. Kinda makes ya wonder if offcenter in the middle of the ceiling would be a good spot for the sub, huh??!? :? At least the baffle would be big enough... Steve

[MadMax]

Kinda makes ya wonder if offcenter in the middle of the ceiling would be a good spot for the sub, huh??!? :? At least the baffle would be big enough... Steve

OK, I'll bite... Why not?

If I were to go 2x6 for the ceiling joists in the region of the sub and put an access panel somewhere in the control room ceiling. Front mount the driver...

Whatdayathink?

Max

[Paul Woodlock]

....
.....Of course, you could place speakers higher and aim them downward, but this introduces MORE problems and IMO should be avoided if possible -

One of the main problems of high-placed speakers is the likelihood of more early reflections off desk surfaces, bridge surfaces, etc -

???? This depends entirely on the individual room setup.

Placing speakers higher and tilting downwards can help reduce desk reflections in some cases.

another is the uneven response of the human ear at higher frequencies due to the pinnae (your outer ear) - as sound path comes from higher and higher locations relative to a path that's perpendicular to your face, the pinnae reduces high frequency response so you can't get a reliable reference as to treble content of a source. This of course will cause errors in judgement while mixing...

well you simply tilt your head upwards slightly while listening. Which also has the benefit of you not looking at the computer monitor while listening and being distracted by the GUI. This makes a good difference in practise.

Add to all that the fact that nearly everything in the studio will be in the way of a clear acoustic path to your ears, and you can't win ....... Steve

?? I actually had my soffit speakers raised up higher and tilted specifically to avoid studio equipment obsucring the monitors and the resulting diffraction.

I wouldn't hesitate to recommend having the soffit mounts higher and tiliting the soffit wall so the speakers aim at your ears.

It worked great for me.

You should geometrically draw everything out, and use tilting as a solution if you need it.

Of course if you don't need to tilt them, then fine, don't but it won't hurt if you do.


Paul

[Paul Woodlock]

Kinda makes ya wonder if offcenter in the middle of the ceiling would be a good spot for the sub, huh??!? :? At least the baffle would be big enough... Steve

OK, I'll bite... Why not?

If I were to go 2x6 for the ceiling joists in the region of the sub and put an access panel somewhere in the control room ceiling. Front mount the driver...

Whatdayathink?

Max

If you soffit mount ( mains or sub ) you'll excite the modes more efficiently. Genelec indeed recommend lots of rear wall standing wave absorption to counteract this.

If you haven't read them yet, these are the best soffit mounting resource on the Net.....


http://www.genelec.com/support/flushmount.php

http://www.genelec.com/support/faq/faq20.php

http://www.genelec.com/support/faq/faq19.php

[Paul Woodlock]

....

One question that keeps knawing at me is whether I've allowed enough space between the CR and tracking room to do a proper job of soffit mounting.

Thanx again!
Max

The plans you posted above don't show enough space for soffit mounting.

You'll need to adjust your plans to accomodate the soffits. Worth it though

Read the Genelec soffit papers I linked above before doing so


And also see my studio build diary of course. You'll need to make your soffit wall as solid and heavy as possible.

[David French]

Paul, that first link isn't working.

[Paul Woodlock]

Paul, that first link isn't working.

Cheers for that, they must have revised their publications. I need to check and update as I have those links stored.

[Paul Woodlock]

Paul, that first link isn't working.

OK sussed it. They've simply replaced 'soffit' with 'flushmount' in the link. Same article! I edited the link in my above post