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R/E/P => R/E/P Archives => Acoustics in Motion => Topic started by: Adam The Truck Driver on January 25, 2009, 07:13:00 PM

Title: Reverb Chamber
Post by: Adam The Truck Driver on January 25, 2009, 07:13:00 PM
Do reverb chambers have specific measurements that they should be? Do they have to be under ground? What can they be constructed of, other than concrete, if anything else?
How do they actually work as far as signal into and out of them? Does one record the source from within the chamber itself?

I think that covers it for now.

Thanks
AB
Title: Re: Reverb Chamber to add
Post by: Adam The Truck Driver on January 25, 2009, 07:35:58 PM
I had read a post somewhere recently where someone said they went to go move the microphone in the chamber and then noticed the chamber was flooded. That's not good. But I still don't know
what is the microphone for...is it source direct, or is it picking up signal from a speaker box?

I'm wondering would I get better results from an EMT Plate, or a Lexicon or Eventide box rather than an actual chamber?

Thanks
AB
Title: Re: Reverb Chamber
Post by: Mike O on January 25, 2009, 09:23:05 PM
Hi Adam -

From the speaker. You might find this thread http://recforums.prosoundweb.com/index.php/t/26668/743/interesting if you havn't read it already. Especially page two where Tery has posted pictures as well as dimensions of one of CP's chambers.

A good/great chamber will be mucho more expensive to create, unless you already own what just happens to be a good space. Worth it for some people for sure. The acoustics experts here can give you a lot more info what is involved in creating a good space.

If you like the sound of a plate vs. a chamber a 140 is about as painless as it gets in terms of one particular kind of GREAT sound.

Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on January 25, 2009, 11:15:02 PM
Thanks Mike

All I see with that link is the EMT thread of late.

I use the search on here frequently...usually come up
with ziltch. reverb chamber, and compass point reverb chamber draws a blank.

My studio isn't yet built, so before I even start to pour
foundations I want to gather all info I can on what gets
the or makes the best sound; in this case for reverb. If it is within reason on price, and it will be something I'll use all the time then I'm willing to lay out the cash...eventually.

I'm planning however to have a fairly large live room, roughly 25'x35', and acousticly treated accordingly as nessessary, with 13' ceiling on the carpeted end, and a hipped ceiling, about 17' a the peak on the other end. None of this is positively set. This is just the design I have in mind. I steal all my ideas from things I've seen elsewhere...So...I might not even need much in additional reverberation.

I have thought of asking a pro about designing my space. Just haven't asked one yet. I know there are one or two here. This will be a private studio though, and I think I have good ideas to start with, but time will tell.

Gratsy
AB
Title: Re: Reverb Chamber
Post by: Dominick on January 26, 2009, 07:26:13 AM
Adam The Truck Driver wrote on Sun, 25 January 2009 19:13


Do reverb chambers have specific measurements that they should be?

Not really. I've seen lot's of different sizes & shapes.

Adam The Truck Driver wrote on Sun, 25 January 2009 19:13


Do they have to be under ground?

No but the chamber should be sound isolated unless you want the sound of traffic and planes flying overhead in your echo return.

Adam The Truck Driver wrote on Sun, 25 January 2009 19:13


What can they be constructed of, other than concrete, if anything else?

Plaster, tile, sealed drywall, etc.

Adam The Truck Driver wrote on Sun, 25 January 2009 19:13


How do they actually work as far as signal into and out of them?

Reverb send feeds an amp that feeds a speaker in the chamber.
Microphone(s) in the chamber pick up sound.
Mic(s) out to mic preamps that feed reverb returns.
Play with different speakers and mic(s)
Move speaker & mic(s) around until you get what you're looking for.

Adam The Truck Driver wrote on Sun, 25 January 2009 19:13


Does one record the source from within the chamber itself?

Not normally, but it's been done.
Roy Halee put Hal Blaine in a freight elevator and recorded the shaft for Bridge Over Troubled Water


Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on January 26, 2009, 09:05:27 AM
Thanks Dominick.

The mic and speaker in a room is kind of what I figured would be the scenario in a reverb chamber...just wanted to make sure.

I didn't like this idea at first, thinking I wouldn't want to put an expensive speaker and microphone in a room that might get flooded, but then I could use a cheap speaker and microphone, but then that would probably cause bad distortion, but then it doesn't have to be under ground, and it doesn't have to be concrete, and now I see the possibilities are many.

Along with the live room space, which will have various acoustic properties, I will also have an insulated shop building with concrete floor. Maybe I can use that as a reverb chamber? It will be within a short distance of my live room conected by a hall seperated by 2 doors.

I will have so much insulation and such thick walls, double wall in the main parts of the studio, that outside sounds shouldn't be much of a problem.

Most that I do know, or have some understanding of related to studio acoustics I have learned from this web site.

I'm out of breath.

Thanks everyone for sharing your wisdom...with people like me.
AB
Title: Re: Reverb Chamber
Post by: Dominick on January 26, 2009, 09:18:30 AM
I can't count the number of studios / sessions where I've seen a bathroom used as a chamber.
I wouldn't tie up my best mic / speaker for a chamber
I've gotten good results with an old PA speaker being picked up by a EV 635
A basement space that floods doesn't have to be counted out as long as there isn't a constant dripping sound.
Standing water is a good reflector of sound.
Just hang all your cables and place the speaker & mic on expendable stands that keep them above the high water line.
Of course the sound will be inconsistent between dry and wet and between 1 inch and 1 foot of water.

Title: Re: Reverb Chamber
Post by: Mike O on January 26, 2009, 11:50:38 AM
Adam The Truck Driver wrote on Mon, 26 January 2009 04:15

Thanks Mike

All I see with that link is the EMT thread of late.

AB



Adam - My apologies; wrong link. Try this  http://recforums.prosoundweb.com/index.php/m/295601/6490/?sr ch=EMT#msg_295601. The last several pages....all the rest is EMT but some comments in passing may have some relevance re: your questions of chamber vs. plate; especially as the discussion transforms is the later pages to chambers.
Title: Re: Reverb Chamber
Post by: compasspnt on January 27, 2009, 12:51:16 AM
index.php/fa/7815/0/


index.php/fa/7888/0/

The Compass Point Chamber #1.
Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on January 27, 2009, 10:45:02 AM
Well...okay then. Just some minor off angles...nothing appearing too complicated. I should probably try to build one. Is that all
drywall walls on a concrete floor?

EDIT: and where are mics...in the boxes on the walls?

Thanks
AB
Title: Re: Reverb Chamber
Post by: 0dbfs on January 27, 2009, 11:43:56 AM
Try mounting those square 70's mirrors (the ones with the gold veins) on the walls.

Those are pretty reflective.

Cheers,
j
Title: Re: Reverb Chamber
Post by: franman on January 27, 2009, 12:44:11 PM
Adam The Truck Driver wrote on Tue, 27 January 2009 10:45

Well...okay then. Just some minor off angles...nothing appearing too complicated. I should probably try to build one. Is that all
drywall walls on a concrete floor?

EDIT: and where are mics...in the boxes on the walls?

Thanks
AB


It's fairly typical to move the speaker and microphones around the find the "best" (smoothest) room response. Then, they usually stay put. There's no magic in designing these chambers... You need a quiet room, with all highly reflective surfaces, thus the plaster/cement finishes. There is definitely some magic in building a 'good one' (take it from experience). We are working on a project in VT right now that includes a dedicated chamber above some of the recording spaces. There's some tuning involved for sure, but we haven't had a chance to hear it via the transducers yet.. only by standing in the room. It's a fun project, but it's a space killer.. you need to have the space to dedicate to it. I agree with earlier comments about the 'bathroom as a chamber' in almost every studio I've been in that records live instruments. Let us know what you decide to do and how it works out please... (DIY topic???)
Title: Re: Reverb Chamber
Post by: compasspnt on January 27, 2009, 03:35:31 PM
Yes, plaster walls and ceiling, not drywall.

My speakers ended up just about on the "than" just south of centre, and my mics are just north of the 12" H.

Note that ALL dimensions are unequal, ceiling height, all walls, etc.

The boxes are probably placed for some ventilation, and to help break up standing waves.

In the old Abbey Road Two chamber (on most Beatles records), there were various concrete-like half-conduit pieces spaced about by experimentation to get the "returning waves" to sound the best.  (Those are mostly gone now, for some reason.)
Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on January 27, 2009, 05:35:33 PM
compasspnt wrote on Tue, 27 January 2009 14:35

Yes, plaster walls and ceiling, not drywall.

My speakers ended up just about on the "than" just south of centre, and my mics are just north of the 12" H.

Note that ALL dimensions are unequal, ceiling height, all walls, etc.

The boxes are probably placed for some ventilation, and to help break up standing waves.

In the old Abbey Road Two chamber (on most Beatles records), there were various concrete-like half-conduit pieces spaced about by experimentation to get the "returning waves" to sound the best.  (Those are mostly gone now, for some reason.)



Another question: Would using metal work inside a reverb chamber? Because if I do a reverb chamber it will be in part, or in the entirety of my shop, now planned as a 25'x50' structure with an open ceiling and barn roof. which will be concrete floored with metal walls, and fully insulated inside. For that I'm making the house smaller and the main studio just a bit smaller. It would be reflective that is for sure, and sort of having built in minimalist diffusion as the metal surface isn't completly flat. So? My truck could make a big sound wave breaker upper too...lol.
Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on February 22, 2009, 11:20:00 PM
Plans changed. Studio will be entirely self contained.
Back on this a minute. Can a reverb chamber be to big to be effectively useful? This is going to happen or I'll die trying. I'm planning room to fit in basic floor shapes of 4'x16', 6'x24', and 8'x32' for my halls/chambers within the facility all yet to be built. Not sure on a ceiling height or type just yet for those halls/chambers. I have drawn in non parrallel nooks at each end of the 2 largest ones, and walls can be slanted or angled inward or outward. All will be on a 4" thick steel re-enforced concrete slab and above ground. I'm contemplating the use of any one or combination of stone or brick, hardwood, plaster, and or possibly metal as the reflective surfaces within these spaces, and certainly each room could not only be a different size but have different tonal charactoristics per the surfaces within them....right?
I wish I had a program to draw something that looked decent but I don't. I'm just using a .25"x.25" gridded paper to draw on. I'm old school.

Should I nix or change anything in the basic layout? Any more insight is greatly appreciated.

TYVM
AB
Title: Re: Reverb Chamber
Post by: compasspnt on February 23, 2009, 01:09:05 AM
Theoretically, the larger the room, the loner the delay time.


Download GIMP, a great and free "photoshop" programme.
Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on February 23, 2009, 08:23:17 PM
Thanks Terry

So if it is a big dense sounding reverb I want a bigger room like the 8'x32' space with let's say a 16' high ceiling would be the way for me to go...what I am concerned of is the thing(s) sounding muddled due to being either too big or small. If that isn't an issue to worry over then I'll proceed onto other details in the planning process.

Terry, do you use your chambers on a lot of stuff regularly, or do you use the plates or digital ones most?

TYVM
AB
Title: Re: Reverb Chamber
Post by: Dominick on February 24, 2009, 07:12:04 AM
Since all dimensions are multiples of 8, an 8' x 32' x 16' room would have some serious resonance issues.
Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on February 24, 2009, 08:23:58 AM
Alright Dominick

That is the kind of info I am wanting and needing to know. I can make it 8'x31' with a 15' ceiling. Would that settle bad resonance issues? I don't know why I was thinking all I had to do was avoid multiples of 10. I think I understand now though. I need to avoid any multiples in width depth and height? My spaces dimensions aren't too big. They're just wrong...lol...how typical...luckily it's just a plan and can be adjusted.

thanks again
AB
Title: Re: Reverb Chamber
Post by: Thomas Jouanjean on February 24, 2009, 09:09:24 AM
For a reverb room I'd go straight for a "golden" ratio, no question - so the reverb is not too colored by modal response of the room. Of course it matters less what the orientation of the ratios are, look at it like a rectangle and place it on which ever side you prefer so you don't loose too much space.

Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on February 24, 2009, 09:36:32 AM
Thanks Thomas

That sounds cool. Now let me find out what the "golden ratio" is and I'm set. I am aware of the rectangles are best scenario, but is this "golden" rule something special within or of said rectangle?

TYVM
AB
Title: Re: Reverb Chamber
Post by: Thomas Jouanjean on February 24, 2009, 10:00:59 AM
Good pages about it:

http://www.acoustics.salford.ac.uk/acoustics_info/room_sizin g/
http://www.acoustics.salford.ac.uk/acoustics_info/room_sizin g/?content=methods

And what you are looking for to solve your size problem:

http://www.acoustics.salford.ac.uk/acoustics_info/room_sizin g/?content=best

Pick any that fits you the best Smile
Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on February 24, 2009, 11:27:38 AM
Without a doubt, this is over my head. Ratios? Does 1:1.4:1.9 mean...well...I need things to be in feet and inches, or even meters, cm, and mm...that I can figure out...maybe.

1'x1.4'x1.9'=12"x15"x18.4" and if I can stay within increments of 1/16th of an inch I won't need a special tape measures that uses 10ths.

So I have an 8' wide space. It should be 10' long and 10.13' high? I would wager that I am very wrong.

I foresee much confusion on my part if I want to follow certain standards which aren't in feet and inches.

Title: Re: Reverb Chamber
Post by: Thomas Jouanjean on February 24, 2009, 11:55:32 AM
If we work in the meter scale, if your room is 8' so roughly 2.43m the rest of the room dimensions need to be: 2.43m x 1.4=3.40m and 2.43x1.9=4.56m

So roughly 8' / 11.15' / 14.96'

For a reverb room, this box can sit on any of it's sides, doesn't matter. Just make it practical for it to work right.
Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on February 25, 2009, 10:06:55 AM
Thanks again Thomas

Which measurement would be the height if 8' is the width? 11.15' or 14.96'?

Also I can only guess the reverb tail in this room would be very dependent on the surfaces within to a degree, and if I wanted a bigger/longer reverb I would need to quadruple it first?
Title: Re: Reverb Chamber
Post by: Thomas Jouanjean on February 25, 2009, 10:36:24 AM
Yup, the materials matter a lot.

Be very careful with size or you may end up with slap echo like phenomenon... You don't want that.

Have a look at the Haas theory.
Title: Re: Reverb Chamber
Post by: franman on March 01, 2009, 11:07:52 PM
Guys,

I want to point out that the finish material(s) for ALL surfaces is very important for chambers. We are working on one for one project under construction right now and it makes a big difference once you cover the surfaces with smooth hard plaster..... really brightens things up. We have also done some experimenting with baffles (deflectors is probably a better description) inside the room. These helped as well.

I will try to make a post with some more specifics when I have a minute (at work) as all the details are there... it's been interesting.
Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on March 02, 2009, 05:16:18 PM
That would be great.

TYVM
AB
Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on April 27, 2009, 11:16:45 PM
franman wrote on Sun, 01 March 2009 22:07

Guys,

I want to point out that the finish material(s) for ALL surfaces is very important for chambers. We are working on one for one project under construction right now and it makes a big difference once you cover the surfaces with smooth hard plaster..... really brightens things up. We have also done some experimenting with baffles (deflectors is probably a better description) inside the room. These helped as well.

I will try to make a post with some more specifics when I have a minute (at work) as all the details are there... it's been interesting.


Ahem
Title: Re: Reverb Chamber
Post by: rankus on April 28, 2009, 12:41:47 AM


Adam,  I think that when you want longer reverb you simply feed back some of the returned reverb back into the chamber.  No need to increase the size of the room to get longer tails. (this used to be known as "foldback" ... or on some older reverb units it is labeled "feedback")

If your returning the verb into a channel strip on your console then you can do this by increasing the (reverb) aux send on that channel which will send some of the wet signal back to the chamber.

Would love to see some of those photos Fran was mentioning too.

Title: Re: Reverb Chamber
Post by: Adam The Truck Driver on May 20, 2009, 05:07:46 PM
That is so obvious...now. It never occured to me to do that Embarassed . Saves space too. Thanks a bunch.