Room size for natural verb-

Paul Cavins · Post by **Paul Cavins** » Wed Jun 25, 2003 2:50 pm

Hey-

Another one from new-guy. I would like to record classic pop/rock in a room in which I could get natural reverberation suitable (loaded word, I know) for the drums without using artificial verb.

This would also be a room in which my band would practice and hang out.

Thanks much-

Paul

Post by **John Sayers** » Wed Jun 25, 2003 3:38 pm

are you talking about a treated room or just a live garage?/

cheers
john

Paul Cavins · Post by **Paul Cavins** » Wed Jun 25, 2003 3:44 pm

Hmmmm.....I would like it to be a rather live treated room--How's that for a cop-out!

Thanks so much for the replies-

Paul

p.s. To elaborate, It would be my major living space, and pretty open. I'm thinking about a space roughly 20 x 42'. I have an architect friend who is interested in the use of budget materials in building homes. Cinder block, creative use of plywood, corrugated steel- etc.

Paul Cavins · Post by **Paul Cavins** » Wed Jun 25, 2003 3:51 pm

OK--sorry-- to elaborate again, the 20 x 42' is for the performance area, control room, iso booth would be beside that---

Paul

knightfly · Post by **knightfly** » Sat Jul 12, 2003 9:28 pm

Paul, looks like this one fell through the cracks - if you're still around, what's the ceiling height of your room? It's amazing how few people think of all three dimensions when mentioning rooms in an acoustic connotation... Steve

Paul Cavins · Post by **Paul Cavins** » Tue Jul 22, 2003 1:53 am

Thanks for the reply. I've been on vacation for a week. Back to reality.

This building still exists only in my imagination. I'm plotting to combine an inexpensive steel frame building with much of my own hard work to build my home/studio. I'm thinking of a two story place where the 1st floor music room is open up to the roof, so I guess the ceiling would be about 22-25' or so. Other rooms for living would be more typical in their dimensions. Pushing the building height upwards is my desire for a control room on the 1st floor that has a suitably high ceiling itself, keeping in mind the ratios (H, L, W). So far this project is very cost effective, because it is still just an idea!

Thanks again-

Paul

knightfly · Post by **knightfly** » Tue Jul 22, 2003 3:12 am

Paul, of the materials you mentioned only the cinder block will give you much in the way of sound isolation, and even that will need some extra design help - what are your sound isolation needs in the location you're contemplating?

Also, large rooms with high ceilings can get a natural reverb that's acceptable for recording, but how live do you want it? Are you talking about drumsounds for "Arena Rock" type bands, or something a little less grandiose? Also, are you willing to live with that particular acoustic for everything? If not, you might consider adjustable acoustics such as designs put forth by F. Alton Everest, and the similar ones shown by John here -

http://www.saecollege.de/reference_mate ... encies.htm

(scroll down to Variable Panel Absorber)

In Everest's version, there is no appreciable absorption with the box closed, because all the absorbent is on the inside. According to him, you open the box for "dead" and close it for "live", idea being that the protrusion into the room helps with diffusion.

John's version seems more useful to me, because of the extra low absorption - few rooms don't need that.

Another thing; doing a room for natural reverb is a lot more tricky than just changing a few panels - you need to keep the reverb times at all frequencies fairly close to each other, or the room takes on a "color" all its own. I'm not sure how one would accomplish that other than with massive amounts of calculation/experimentation/note taking (so you could repeat it) or, even if it would be worth the effort.

A room the size you're considering could support a decent reverb field, but you'd need to stay away from bad room ratios (LWH) even if you splay the walls (and ceiling) to stop flutter echo. From what I've read so far, even non-parallel walls sound better when proper LWH ratios are observed, you just use average dimensions for calculation.

BTW, the modal response for a 42 x 20 x 22 room really suck - One of Sepmeyer's preferred ratios would return values of 41.9 x 28.8 x 18', sticking with your length. Sticking with your width #, that same ratio would work out to 30.3 x 20.8 x 13' (those are both for the ratios of 1:1.6:2.33)

Ignoring room ratios generally will make it much harder to treat the room for good acoustics - it soon becomes obvious that standard sizes for building materials were NOT decided by acousticians... Steve

Paul Cavins · Post by **Paul Cavins** » Tue Jul 22, 2003 3:26 am

Great info- Lots to chew on--

Thanks! The H W L ratio issue is sure nice to know!! Good thing I'm thinking about this at an early stage. My dimensions and such are starting points/ideas.

I'm assuming the walls would end up being drywall, and then I could vary it with some wood etc. I would guess I'd end up with either concrete or wood floors.

I think I'm going overboard with the reverb stuff. Knowing a bit more, I think I should just go for a nice room sound for a drum kit that I could vary somewhat.

I'll check out your links and such after work----

Thanks again-

Paul

Paul Cavins · Post by **Paul Cavins** » Wed Jul 23, 2003 2:42 pm

Hey there-

I went to the link for the panel absorber. Looks really cool.

My modally crappy dimensions (20 x 40--obvious no-no) generally fit into the overall building concept I have at this time.

This big room would also serve as my living/dining room, the living and music areas being at either end. The architect I'm working with has the idea to separate the two areas with storage closets on wheels of sorts. This is to accomplish the feeling of different spaces. They could be absorptive on one side and reflective on the other and could be moved around for some cool experimenting.

If my ceiling was 22-25' or so and these storage things were 10' high, what real effect if any would they have on the modal characteristics of the room, assuming they could be made to stretch from side to side in the room?

I am open to changing my concept, but I want a big overall room and to keep the length would mean adding some serious square footage ($$$) to build a desirable width.

Thanks for all of your advice--

Paul

barefoot · Post by **barefoot** » Thu Jul 24, 2003 8:39 am

Paul,

The space you have in mind is certainly large enough to create a nice nature reverb. As I see it the issue is "complexity". Simple shaped spaces tend to have sharp resonances and a harsh sound. Complex shapes with lots of different material types tend to break up ordered resonances and create a smooth reverberant field.

How you build it also depends on your intentions. Do you want a sort of nondescript reverberant room, or do you want something that has it's own character? Building a live room with character and a specific sense of place and space is certainly an option. For example, Pierre Sprey has gained an excellent reputation recording Jazz and Blues players in his Maryland mansion. http://www.mapleshaderecords.com/main/d ... paper.html He does things like adjust the decay time by opening or closing doors to adjoining rooms. He also happens to have some peculiar superstitions about audio gear , but his recording skills are undeniable despite some minor irrationality. All his recording have a very distinct flavor of the house they were recorded in. You might consider going down this sort of path as well.

Thomas