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R/E/P => R/E/P Archives => Acoustics in Motion => Topic started by: Brent Handy on April 06, 2008, 04:03:08 PM

Title: Darn kids and their questions
Post by: Brent Handy on April 06, 2008, 04:03:08 PM
Has there been a study or an experiment on this?

It is common practice to splay walls out on the sides of the control room.  There are studios with the front walls leaning in and out.  We all know why, blah, blah, blah.  Has anyone knowledge of a designer/builder splaying the side walls, but also leaning them in or out?  Foller me fellers?
Title: Re: Darn kids and their questions
Post by: jimmyjazz on April 07, 2008, 03:00:46 PM
Are you asking about side walls that are splayed front-to-back AND floor-to-ceiling?  In general, I would say that non-parallel walls do help mitigate flutter in the middle and high frequencies, but they don't necessarily improve low frequency performance.  All rooms resonate, but calculating the resonant frequencies and associated modeshapes for non-rectangular rooms gets very tricky.  

I think a lot of designers prefer to stick with more easily analyzed shapes, which in some sense is letting the cart drive the horse, but at least one can feel fairly confident in a design before it is built.  The same is not necessarily true with a crazy room geometry.
Title: Re: Darn kids and their questions
Post by: gullfo on April 07, 2008, 05:02:24 PM
i think a lot of the confusion is caused by people assuming the angled CR surfaces are boundaries... in most cases you wouldn't design the control room with angled boundary surfaces unless you had to. most designs tend to put in angled treatments so you have enough space behind them for trapping and you use panels, slats, absorption, etc on the angled surfaces to shape the space to get a proper response from baffle mounted speakers, RFZ, etc. in a live room, you can more easily get away with the angled boundary walls because asymmetry in a live room can be a good thing.

as far as angles top-to-bottom and in-out, it all depends on the amount of space and what you're trying to do... for a small room, tipping the walls out at the floor can help preserve floor space, and since you're likely making the walls pretty absorptive anyways, you're not likely to deal with strong reflections because it. if you have enough floor space, tipping them out at the top can be useful to get things moving up and into overhead traps. all in all, the amounts of different angles you incorporate into the surfaces can move the sound into more oblique angles and potentially increasing the effectiveness of absorption in the room - at the expense of increasing the complexity of the construction...
Title: Re: Darn kids and their questions
Post by: Brent Handy on April 10, 2008, 06:28:48 PM
I don't think that I agree with "no angles unless necessary".  There are many papers by the BBC where they intentionally splayed walls.  It was not to hide absorption, but to create a RFZ.  I have been in and have seen mucho rooms with splayed double walls with no absorption.

If you build a large enough room, bass is not as big of an issue like it is in a small room.  Concentrate on the aspect of sound.  Don't bring ergonomics, space restraints and all of that into it.  Would it be sonically benefical to also tilt in or tilt out a wall that is splayed already and has anyone seen/heard it?
Title: Re: Darn kids and their questions
Post by: jimmyjazz on April 10, 2008, 11:07:41 PM
OK, I think I understand the question, and I know I don't have the answer.  I've never been in such a room.

I'm sorry that I read more into your initial question than you intended.  I think the answer is going to be "it depends", but I'm interested in hearing others' thoughts.
Title: Re: Darn kids and their questions
Post by: brett on April 11, 2008, 03:38:31 PM
glen you posted this on a another thread. index.php/fa/8488/0/
Title: Re: Darn kids and their questions
Post by: Brent Handy on April 11, 2008, 10:40:12 PM
Now, what about taking the tops of those splayed walls and tipping them in?  THAT is the question.
Title: Re: Darn kids and their questions
Post by: johnR on April 12, 2008, 07:16:59 AM
Brent Handy wrote on Sat, 12 April 2008 03:40

Now, what about taking the tops of those splayed walls and tipping them in?  THAT is the question.

If the listening position is already in the reflection free zone, why go to the extra trouble? If tilting the walls is the only way of getting the listening position into the RFZ it might then be worth it.
Title: Re: Darn kids and their questions
Post by: brett on April 12, 2008, 07:38:11 PM
Brent Handy wrote on Sat, 12 April 2008 03:40

Now, what about taking the tops of those splayed walls and tipping them in?  THAT is the question.



in a room like above the only tilt necessary might be the plexi glass window in front. I would probably tilt it.
Title: Re: Darn kids and their questions
Post by: Brent Handy on April 12, 2008, 11:19:34 PM
The quest for the extreme solution screeches to hault because of simple logic.
Title: Re: Darn kids and their questions
Post by: gullfo on April 14, 2008, 11:05:35 PM
you could tip them in or out - as said - if it helps with the RFZ, or addresses some space constraints. its also a matter of skill in construction - sometimes simpler is better...

as far as splayed boundary walls - i use them all the time in designs - when they work... in a small room, where i need more side absorption because the ceiling is low, i'll try to avoid using them (i.e. use a rectangular room) so i can increase the absorption space on each side to preserve symmetry. it all depends on the situation (which is something akin to the quick and dirty diamond example brett noted).
Title: Re: Darn kids and their questions
Post by: franman on April 27, 2008, 04:26:47 PM
I have to agree with almost all the points made here as being valid. IMHO, we use rectangular hard shells for most small rooms for the reasons Glenn has listed... We use angled RFZ style shells in many larger rooms, which complicates modal calculations significantly but sometimes, makes for a better ergonomic design including site lines and room arrangements. I have seldomly used walls splayed top to bottom for various design reasons... I don't see any 'reason' or 'need' to splay walls in two planes, but there would be nothing wrong with it.... just my late two cents.

fm