Hello!

I wonder if a plastic / vinyl drapery could be used to break up a bare plasterboard wall without absorbing the highs? I mean the type of heavy curved drapery that can be seen in industrial enviroments, factorys etc., that is a couple of mm thick. Here's a picture:

http://www.bullerbekamparen.se/bilder/drap/j2.jpg

My idea is to have rigid fibreglass wrapped in fabric behind it to make it absorb lows a bit and also stop any vibrations that can be heard in the room.
I don't suggest that it would be like a purpose-built diffusor, but rather more like curved plywood areas and such. What do you think?

Daniel, Sweden

What type of Music application is this for?A Live sound room,Mix room,Home theatre,Music listening Room?

For a combined mix / recording room. 8x5m (24 by 15). But I'm just curious generally if this type of material has ever been used to make a large bare wall a bit mor usable without installing anything permanently. I have seen soft textile draperys in live rooms, but never reflective ones.

That plastic stuff might be a little better than a bare wall, but not much. If you're not up for making or buying real diffusors, you'll do better with absorption but less than full coverage. 2x2 squares or 2x4 panels in a striped pattern works well to solve these problems without making the room too dead.

--Ethan

One thing we will sometimes recommend to the person who can't afford diffusion is custom size panels that are 6"x24", 4 inches thick and space them apart from each other 4". This will put a "well" between each panel that will "kind of" diffuse. Not the perfect diffusor by any means, but a nice way to make a wall/room less dead. We have done this in a few drum rooms and must admit it does sound pretty nice.

Thanks!

Ethan: Do you mean soft fiberglass panels here or will paper-faced rigid fiberglass work as well?

Glenn: Do you mean panels made of wood ? Is 4 inches enough or should I make some wells deeper? Is it better to have 4'' between every panel or a variation of sizes and placements?

I would like to avoid installing any fiberglass with fabric on the walls, and instead use large movable screens both for mixing and more "intimate" tracking. I know I don't have a very large room but it would be nice to try and record drums without any damping at all and see how it sounds. All walls are thick painted concrete now but the front wall have windows all the way.

No the panels are made of rigid fiber glass or mineral wool.



You could make them deeper but keep in mind that this is not any kind of "real diffusor" as to speak.



See my statement above.



That is going to be hard to do if not impossible. If nothing else I would put bass traps in the corners and maybe think about building something like our Screen Panel (2 panels 16"(W)x6'(H)x4"(Thick)hinged together) that can be moved around the room to help control things. Absorption is not all about deadening the room but helping to control the room moods ( What are Room Modes SPOTLIGHT:Bob Katz ) that are out of control.

It needs to be plain rigid fiberglass, not faced with paper. Paper facing is suitable only for corner bass traps.

--Ethan

Thank you very much! Very good explanation! I understand now that I can have thinner portable screens if I want to deaden HF around a singer or instrument, but that doesn't take away the need for mid freq absorption and/or really good diffusion installed on the walls, to control the room response in general.

The Bob Katz interview you posted leads me to a very important question that gives me no sleep..

If you can pick anything you want, is it better to have solid concrete walls and ceiling in a control room, or something like plasterboard or wood panel walls?

Bob says a good mastering room should have solid walls, floor and ceiling. Why is it so? Do you want the really low end to stay inside the room? I thought that it was impossible to have too much bass trapping from 0 to 300Hz. Wouldn't it better if the interior walls of a mix room were really thin? (With solid soundproof walls outside of course, to stop leakage)

I grew up in a typical Scandinavian 60's-70's house which had inner walls made of thin board on wood beams with insulation in between, and I remember having a wonderful and even bass response there! You could listen on big 10'' speakers in a small bed room and still hear the bass notes pretty clearly.

I understand that wall material is not to be confused with professional bass trapping, but since plasterboard or fibreboard is relatively cheap.. Should I or should I not do any construction to solid concrete walls in a basement room??

(The room is 25 / 15 / 8 feet, to be used as mixing/recording space)

/Daniel

My own philosophy is that walls should be as flimsy as possible. Better to let the bass out than reflect back toward your ears. Of course, this isn't always possible for many reasons. But IMO the ideal walls would be made out of brown box cardboard.

--Ethan

It is more about letting sound in then anything else.

I agree about the isolation factor, though I have seen arguments that containing the bass "pressurizes the room" more. I can't see what "pressure" has to do with anything, and I think that explanation comes mostly from audiophile types.

--Ethan

I understand that the room must be quiet, that goes without saying in mastering. But I guess for someone like Mr Katz it wouldn't be too expensive to build a thin wall a couple of inches, or even a couple of feet , from the existing solid wall. Or line the entire rear wall with bass traps.. But he chooses to have double layer plasterboard walls with only a few traps on precise locations, and only a 23' long room.. That confuses me.. It must mean that you're mixing/mastering for a "room" and not just listening to the content from the speakers, even in the low range.. Whatever. I can't rebuild my room, but I thought the ideal in mixing/mastering was to not even have a rear wall, only open air for say..100 miles Thanks for the opinions!

I have worked with Katz on his B room and I can tell you that he is VERY anal about the room not being totally dead but as even as possible.

would a thin plastic covering work the same as paper for the corner traps??

Yes, or at least similar to paper.

--Ethan