Major Echo Problem, $6000 Available to Fix it

[Lloyd Ubshura]

I've just finished reading 3-4 books on acoustics and studio design, but most tended to focus on more audio (voice over) type recording.

I'm converting a large garage into a TV studio for interview-type programing. Currently it is a huge echo chamber much like the indoor swimming pools of old.

The dimensions are 35' x 60' x ~18' tall. Concrete floors, drywall walls and ceilings. The ceiling is vaulted starting at 16' peaking at 20'.

A couple questions:

1. Do the 703- or 705-type (Owens Corning) rigid insulation help with echos? (I know they are excellent with bass). The specs/testing seem to say yes, but in real life, do they work for this set up?

2. If I put up a couple hundred 24" x 48" x 2" panels with a 4" to 12" seperation from the walls, would that also help with my echo problem?

3. Would foam absorbers or other treatments still be necessary with all the rigid insulation?

The shoot area (stage) is basically in one corner. I was planning on checker boarding the panels on the other 2 walls opposite the stage (BEHIND the cameras) as the walls in front of the camera would be in the camera frame. Then I was planning on suspending panels from the ceiling with about 70% coverage.

Our programing is a kids program (by kids, for kids); mostly talking, and no music, etc. so mostly spoken word in nature. Each kid is on a wireless lav, with one overhead wide angle mic to fill in any area where the wiggly kids might bump their mics.

We have a budget of about $6000 to treat everything as good as possible for that kind of money, and it does not have to be overly pretty since it won't be on camera. We are looking at this as maybe a first step to treat the sound until more funds come in to do it right.

Any other suggestions?

[Steve Kalle]

Several years back, I worked with a guy who was an audio fanatic and he had a $75k recording studio in his basement (he was studying audio engineering). We worked at Home Depot and a customer came in asking a question similar to yours and my coworker recommended the pink foam insulation and said to use the 1" pieces and double them up. He said the 2nd layer helps to deaden the sound more than just a single 2" piece.

From my own experience, I just converted a 25'x15' room with concrete floors into a studio. The first thing we did was lay down carpet, which definitely helped.

[Andrew Dean]

We built a concrete "bunker" at my old job and tried out a few different measures to reduce the 8-second reverb and make it a suitable recording environment.

For the hard-wall echo, literally *anything* that isnt hard will reduce that. Carpet helped immensely. We only threw down spot "office carpets" and the change was dramatic.

We bought a few gross of "moving blankets" (thick cotton batting quilted kind... big, cheap and dense). Then, we bought some of the semi-hard yellow insulation panels (with the foil on one side), wrapped a moving blanket around each and screwed it to the wall. They were remarkably effective and in the end looked a bit like art. The bunched up blanket on the back held the panel a little bit off the wall and left an air gap too.

We just kept adding these until the echo was gone... and it took far fewer of the panels than we would have imagined.

When I was an intern at sugar hill studios, i kept bugging the engineer about what kinda foam i should buy for my home studio and whether camping pads were "dead enough". He grew kinda impatient with my abstract "what makes acoustic foam so expensive" questions, so he stood up, pulled a square of acoustic foam off the wall and picked up a cushion off the couch. He held one on either side of my head.

"Can you hear a difference?" Of course the couch cushion just sounded like someone holding a couch cushion and the acoustic foam had that eerie "my head is near a black hole" feeling that you get when putting your head up near acoustic foam. He said "if you hold something up to your head and it sounds like that, then its dead and probably isnt a bad idea for your wall."

I applied the same logic when shopping for the insulation panels. The ones we bought had that "sucking your brain out" property so we bought them. I reckon a similar materials test at home depot would lead you to the ideal material as well.

Obviously a *real* studio has acoustic designs not only to deaden, but also to keep the outside world away as well. I hold real acoustic designers in very high regard. But on a ghetto budget? If its cheap and dead and you can screw it to the wall, i think you'll be very pleased.

[Paul R Johnson]

The acoustics problems of this type of building seem to relate to absorption, reflection, refraction and insulation.

I've designed and built quite a few rooms on budgets and as people have said, it's not that difficult to make a room sound ok for voice. The various home recording sites are great for ideas on horrible and pleasant ways of doing it. It becomes much more difficult when you start to have instruments - especially lower frequency ones. My originals were purely theoretical for my first design, and I wasn't totally sure that I could make the room sound good, so I cheated. I designed all the wall panels to be freestanding in mainly 8 x 8ft sections. We then assembled them to enclose the space, leaving room outside them where we could expand into. With them in a rectangular shape with parallel faces, the book's warning of standing waves and multi-path reflections was spot on. Pulling out the room into a slight coffin shape, really tightened up the sound, and the 'boxy-ness' vanished. Roof wise, we had the same thing - flat panels, and we guessed the remaining problem was probably going to be floor to ceiling parallel faces again. I cut Plywood into 4 x 4 squares, and then attached these to the ceiling at slight angles - again the improvement in sound was pretty evident. So once the shape was established, we simple joined the panels structurally.

Over the times I've now done this, I'm pretty aware of how small things can spoil it. Once you get some mass into the walls, and insulation - you have pretty solid and insulated panels. Stopping noise getting in and your sound, out. However, it's very easy to have things resonate in nasty ways - things like cosmetic panels covering voids - that kind of thing.

As for sound treatment, the DIY systems do actually work quite well. I bought proper acoustic foam tiles and they were VERY expensive - however, the thinner and cheaper ones work nearly as well for voice - but home made ones are much cheaper and easy to make with only basic woodwork skills. For mid to high frequencies - the old fashioned, often mocked fibre egg boxes to work. Trouble is they are ineffective from the lower male voice downwards. Heavy drapes work, as do big lumps of upholstery foam.

If you have a decent space - then just covering reflective hard surfaces is really worth it.

[Dan Brockett]

Lloyd:

You might find some good answers to your questions here:
Welcome to Auralex University
Acoustics 101...Practical guidelines for acoustic construction: building a sound studio, listening room, home theater room, and any other sound control room project.

My old audio post facility was done up with Auralex kits and it worked really well. The beauty of these links are that they really touch on the principles of acoustics and how sound works. Once you have a good understanding of how audio behaves, you will be able to anwer your own questions about what will work for your situation. It's the old, "teach a man to fish" paradigm.

Dan Brockett

[Robert Turchick]

I've used the Owens Corning and competitor's rigid insulation for years and it's fantastic. Got the idea from panels that were specified by Walters Storyk Design Group for a very nice live room in a studio I used to work for in NY. I didn't have a few hundred dollars per panel! The room was about the size of yours.

For my personal studio, I ended up with both the 1" and 2" variety of 2 foot by 4 foot panels and got the muslin and cheap fabric from a local store to cover them myself. When covering the walls with panels, it doesn't have to be every square inch...you could leave a foot or two between panels. And spacing from the walls, while working a bit better is a PITA and not totally necessary. If you alternate 1" and 2" thick panels, and space some but not all out from the walls it will help.

Flooring is up to you. Carpet with padding would be nice but again not necessary. We had hard wood floors.
The reason ours worked so well is both simple and not so simple. The ceilings were huge drop panels set at odd angles and covered with the rigid insulation or diffusors. The room itself was not a rectangle either. It was kind of a kidney bean shape.
The ceiling treatment we had is probably out of your budget but can be simulated by hanging the panels vertically at different heights throughout the room. A lot easier and safer. The pics below on the right show horizontal or angled ceiling panels.

In short, you want to "de-boxify" your room. Assuming you don't want to change the walls or build new ones, by manipulating the panels, you can create the same effect. The ceiling is VERY important. Lucky for you it's vaulted already. Personally, I'd start with that first and you will see (hear) immediate results. Once done there, start on the walls and add panels until it seems dead enough. Once again, you don't have to cover every square inch.
Hope this helps!

Below are some examples. The top left pic is the room I used to call home!

[Mike Calla]

First, carpet on the floor is no no (unless the reason is specific). The floor is the only true distance we have, leave it reflective; ceilings and walls can be different sizes, and different distances from the sound source, but the floor will always be the floor. Paint it dark grey and leave it. Egg boxes are useless unless you want comb filtering.

First contact your local building supply store give them some footage measurements and see what 6000$ can get you.

To answer your ?s
1. The Owens 703/5 IS for sound absorption…it absorbs sound. How much insulation you use, where you put it and how you install it will alter its effect.

2. It does not need to, but can be separated from the wall - Don’t do this unless you know why you are doing it. See below.

3 Rigid insulation IS an ABSORBER, you don’t need foam (Rigid insulation is more efficient too)

It’s a studio, for cameras, not for recording music - coverage is best. Making it dead is the right way to go. Again don’t suspend ceiling panels unless you know what/why you are doing it.

Because the room is large, and the sound source isn’t too powerful, simple deadening of the room will yield great results for what you want. If this was for live music recording then suspended ceilings, staggered density, placement, non flush mounting and diffusion would be necessary, but for you, NO, deaden it! Robert above is right about alternating different densities of foam. Once again it is to avoid comb filtering (peaks and valleys in the room’s frequency response)

NOTE: Chris Hurd, and mods I won’t link but I will point the OP in another direction. You can edit the post if you see fit. -- Lloyd, google “EQ Mag”, they have an acoustics forum moderated by Ethan Winer (his room is the bottom left photo in Roberts post) and some other great people. Their life is acoustics, and love questions like this.

mike

[Bill Davis]

I'm simply going to point out the cold, hard, reality that a studio designed for SOUND and a studio designed for VIDEO are two very different beasts.

Yes, we *try* to do both. But the two are generally enemies of each other.

I dare you to take Robert's GORGEOUS studio shots and figure out a way to do a proper lighting grid, or how to string cable for a three camera shoot, video village, and iso plus directors monitors for all the above and STILL maintain any integrity to that lovely room design.

In the video world, here's the reality. The floor is for MOVING camera positions, as smoothly as possible. The ceiling is generally for lighting and AC to handle the heat load of said lights and their controls. Walls, are better candidates for treatment, UNTIL you realize the storage space you're likely to need for equpment, props, scenics, etc.

Essentially - the reality in video studios is that sound treatment most often goes behind, between, and around other stuff that's equally "mission critical."

If you've got floorspace, airspace, or wall space, AND the storage space to keep stuff stored and out of the way when it's not needed - I'd recommend building yourself movable and/or hangable baffles that let you chop, block and/or screen sound reflections when possible. But if you do that it WILL impinge on camera moves, actors blocking, and/or your general ease of working around your set.

It's a CRAPPY fact of video/verses/audio life. What's great for sound is often BAD for video. And vice versa. So learn to live with compromise.

Sorry.

[Robert Turchick]

Good points and just to clarify, the pics were just to show examples of acoustic treatments in action.

Absolutely correct that you don't want your final room to look like these, just take some of the principals being applied and mod to your needs.

And glad it was reiterated, I'll do it again...don't try to "rig" ceiling panels or wall panels unless you know what you're doing. Simply attaching to walls or ceilings with proper screws into studs is fine.

On the moveable baffles idea, I think that's a great idea if they are built to be moved easily. I have two 4'(w)x8'(h) panels that are hinged together. They are about 6" deep and filled with 703/705. I used heavy duty casters which makes moving the whole thing possible when it's just me. I use it a a VO booth, divider, bass trap, and absorber. Since the fabric I chose is pretty neutral, it even works a a backdrop for interviews. I researched for months to find someone who sold something like it and ended up building it myself. All in they cost about $400 each. If you built enough of them, you could make whatever shape room you wanted.

[Lloyd Ubshura]

Thanks, everyone, for your help!

My "round one" plan is to cover most of the walls that aren't in the shots with heavy-grade (8 lb) moving blankets. I have already started putting some up with a pneumatic staple gun and making sure they aren't flat against the wall, but installed wavy. My theory (using logic, not testing) is that if the sound doesn't get totally absorbed and is reflected, at least it's going to bounce in different directions than it would if hitting parallel drywall surfaces.

I put about 20 medium-grade ones up that I happened to have around from my last move as a test, and I went from a 3 second echo down to about 1.5 with my very sophisticated "clap test." And actually, when installing them, being up close to them, they give you an eerie "Is my brain still connected" feel. So I figured it's worth a try.

I have 100 showing up this week. So I'll let you know how this works.

Also, I've got some 6 lb. rigid insulation (Owens Corning 705) that I'm ONLY going to be putting up in the corners as more of a bass trap. I plan on setting it in at a 45-degree angle to each 90-degree inside corner. That way there is some inconsistently-sized air space behind it in the middle to hopefully catch different lower frequencies that pass through and want to bounce back. I've got about 60 2x4 panels showing up to install on my 250 lineal feet worth of inside corners.

So, I say all this mostly in theory right now with fingers crossed. I will let you know how it goes after I get it all installed. If there is something glaringly wrong with this, please let me know. :)

With all the above I mentioned, I'm at just $1700 of my $6000 budget, so I figure it is worth a shot to do it this way before having to dump more money into it. :)

[Paul R Johnson]

One VERY important thing - make sure the material you're using is fire proofed/treated/resistant. If it's not, and a light sets it off - then it will spread very quickly, and I doubt you've got windows to jump out of!

[Steve Rusk]

I was just thinking how DIY soundproofing often leads to major fire hazards, like the nightclub with the Great White a few years back. Might be a time/money saver to get the local fire dept. to look at your solution before you get too far along. However it works out, I hope you document it and post it so others can learn from it. Good luck.

[Mike Calla]

the OC 703/5 should be fire resistant... should...!

And just a thought; you mentioned no music. Just kids! Bass are trap are for bass. If it was me i would be more worried about deadening the low to high mid range and the blankets will be effective for the highs to limited degree. You don't really have any bass to make use of a bass traps.

Great book by (none other than) F. Alton Everest called "Sound Studio construction on a budget" It has 8 or 9 different scenarios plus HVAC, materials, door jams etc... but a great book because it covers many different solutions that you can take from for your own problems.

Again... my advice is don't worry so much about bass traps and worry about making the frequency range of dialogue clear and articulate