Archive for the ‘Studio build’ Category

Improving your acoustics, Part 2

March 5, 2010

Here is the second in a series on improving your listening and recording environment with Bryan Pape (see the first part here).

Bryan is lead acoustical designer for GIK Acoustics, a respected sound treatment manufacturer and dealer, as well as owner of Sensible Sound Solutions, through which Bryan sells sound treatment services and materials.  Bryan also lends his advice to thousands of audio enthusiasts and recording engineers in several online forums, including the popular Gearslutz’ studio construction and acoustics forum.

Q: Most people who record or listen to music need something to absorb some of that sound that bounces around a typical room. They can hire a consultant or purchase pre-made sound treatment, of course, from companies like yours or GIK. But if they want to try to do it themselves, what materials can they use?

A: This depends somewhat on the type of treatment you’re trying to make and how thick it’s going to be. Thicker panels, intended more for bass duties, can use less dense materials once you get to approximately 8″ of thickness. Standard wall insulation will work OK in this application.

For more standard 2″ type panels for reflections, 3lb/cu ft density rigid fiberglass board is my first choice. Many know this as OC 703. OC 703 is actually a model number for an Owens Corning product. There are other equivalent products such as JM814 (Johns Manville).

Acoustic foam is very well known. Most of it isn’t terribly good. The few that are are relatively expensive and don’t perform nearly as well

Similar density mineral wool can also be used. It’s slightly less expensive in some places but is not nearly as easy to work with if you have to cut it. Lastly, there is also 3lb density acoustical cotton. This is LEED certified green material and performs slightly better than the 703, albeit at a higher price. The advantage is that it comes in a variety of colors and does not have sharp fibers like fiberglass and mineral wool so it can be hung uncovered if desired.

Q: Where do you purchase those materials?

A: LOL. Good luck. It’s very difficult to find as a consumer. Most places that have it will only sell to you if you’re a business. There are always exceptions. I do offer 703 and the cotton for sale.

Q: Where can people find directions on how to build such a sound-absorbing panel or bass trap?

A: Again, it really depends on what you’re looking to do. For simple reflection panels, you really don’t need a plan. Build a frame that has an inner set of measurements that are maybe 1/16th” smaller than the 2×4 sheet of material you’re using. Make the frame from 1×3. Friction fit the fiberglass up at the front, flush with the front edge. Wrap with cloth and staple it to the back. Pretty simple.

Q: How thick should absorbers be? What is the difference between a bass trap and a broadband absorbing panel?

A: For standard absorber duties, a 2″ thick panel is fine. For broadband absorbers that will reach lower, use at least 4″ or 6″ of thickness. If you want a broadband bass-ONLY absorber, then you have to bond a facing to the fiberglass to provide a damped membrane and reflect the upper mids and highs. There are also tuned absorbers that only function over a couple of octaves or some even less. These are either rigid undamped membranes made from wood usually, or Helmholz resonators which work similarly to a speaker port or blowing across a bottle. The difference is that these are damped at the tuning frequency vs reinforcing it.

Q: How can people determine where they should install sound treatment like bass traps and broadband absorbers?

A: Every room is different. Corners are generally a good place to use bass absorbers or broadband absorbers. They’re efficient since they are at the end of 2 room dimensions. Remember that you have 12 corners in a room, not just 4. The wall/ceiling and wall/floor are also corners.

After that, it really depends on what particular issues you’re having in the room. Other generally good places for bass absorbers are centered on the rear wall behind the listening position, over your head to help with height related issues, behind your main speakers if they’re close to a wall to deal with boundary reinforcement, etc.

For more standard reflection absorbers, we are trying to deal with any point in the room which reflects directly back at you, arrives within a specific time period, and is a reflection that comes from far off axis where most speakers mid and high frequency response is VERY different than the direct radiated sound. The most common of these are the side wall reflection points and the ceiling between you and the speakers. These reflections, if left untreated, allow a 2nd impulse to reach you at a different time (smearing imaging, dynamics, etc.) and also are of a different frequency distribution which will change the overall tonal balance of what you hear.

Thanks Bryan! And remember, if you have any other acoustic questions Bryan might be able to answer, post them here.

Professional bass traps at a bargain price

November 13, 2009


If you’ve done much reading about treating your recording room for sound absorption, you know the importance of bass traps. In short, they capture some of the low- and medium-frequency reflections from speakers, instruments and voices, so you can hear and record accurately. While I have been building my own bass traps, I have heard from many people that the traps built by musician and audio expert Ethan Winer’s RealTraps company are second to none.

Now, RealTraps has announced a new, inexpensive line of bass traps that you can read about here. Though I haven’t used them, I am convinced by many online interactions with Ethan that these will do exactly what he says they will do.

Studio construction update!

August 3, 2009

It’s been a while since I last posted about my studio build, so it’s past time for an update.

As you may or may not recall, I’m building a small recording studio in the basement of my St. Louis area house. As we live on a quiet street and I won’t have to record much when my children are up, “sound-proofing” – or isolation – isn’t a primary concern. But I really want a good-sounding room, which is a challenge given that it’s a smallish space at about 12 feet by 10.5 feet, with ceilings not quite eight feet tall.

Because the space was in a completely unfinished part of our basement, I hired someone to frame walls and run electrical wiring. (I know my limitations!). Here’s a look at the studio space after framing and wiring.

studio 004studio 005

I said that sound isolation wasn’t my primary concern. However, I’d like to dampen as much sound as I can, within reason. Insulating the space within the walls is an excellent way to cut down on sound transmission. So I put the pink stuff between the joists on the ceiling above and between the studs of the walls.

insulationThen it was time for drywalling, something I’ve never attempted. I chose standard 1/2-inch drywall. Note that I had to drywall around a support beam, too.

A couple things I learned during my many hours of measuring, cutting and hanging drywall:

1. Measure twice, then measure again. Especially if you haven’t done this sort of thing before.

2. The strength of this stuff isn’t the gypsum, it’s really the paper on the outside. So if you drive your screw all the way through the paper, you need another screw.

3. It’s really not smart to hang drywall on a ceiling yourself. I tried, and pretty much failed. Luckily my strapping 14-year-old son, Jackson, was able to help. Thanks Jack!

Here’s a couple drywall pics:


You can see I’m no pro! But I’m going to hire some to do the mudding and taping, activites that actually require skill.

Now remember I mentioned how I want the room to sound good first and foremost? A key to preparing a room for recording and mixing is cutting down on the nasty echoes that soundwaves make. This results in muddy sound, with some notes being too loud and, oddly, some notes disappearing almost completely!

There are a raft of products claiming they will make your room sound like Abbey Road. (I mentioned some of them here). Some of them are quite good. But for the biggest bang for your buck, I think it’s best to make your own sound treatments. The key here, I’ve learned, is using either rigid fiberglass or rock wool, both of which absorb a wide range of sound.

I chose a combination of Owens-Corning rigid fiberglass — OC 703 and 705, to be precise – and some fairly dense rock wool. Note that the fluffy fiberglass — so good for insulating your home — really doesn’t do the job here, unless you can pack in three or four feet of the stuff in each corner of your room. So you need the “rigid” kind of fiberglass, which isn’t carried by your local Home Depot or Lowes. Here in the St. Louis area an excellent source for this do-it-yourself material is Bryan Pape of Sensible Sound Solutions. You can also mail order the stuff from several sources, including AST Acoustics, which I’ve used in the past.

So how do you get this stuff in your recording space? The easiest way is to simply wrap a couple panels in fabric. They generally come in four-foot-by-two-foot sections of two or four inches in thickness. But many people prefer to frame them in wood, which is the approach I’m taking for some of my treatment, as you can see:


I chose to use one-inch-thick-by-four-inches-wide pieces of wood –making a rectangle of four feet by six feet — to make four-inch-thick panels of OC 703 fiberglass. I will use them to dampen my “first reflections” from my monitors — a concept we will explore in a future post on treating your recording and listening room.

A warning: This stuff, much like the fluffy fiberglass, is rather nasty to handle. Rubber gloves, long-sleeved shirts and perhaps even a dust mask are good precautions.

Here’s the final panel, which I will cover with fabric before installation:

backup july 2009

Tips on building a small studio

May 14, 2009

IMG_0556As I’ve previously written, I’ve starting building a small tracking/mixing room for my studio, Getting Better Recording. Even when it’s finished, it will be quite humble by pro studio standards – it’s just a room I’m finishing out in my basement, after all. But I thought it would be fun to share a few things I’ve learned about creating a recording and mixing space from some very smart people.

I’ll expound on my plan and my choices soon. For now, here are my tips to creating the recording space of your dreams.

1. Know exactly what you want to do there. This is crucial. Will you be recording full rock bands or just one or two acoustic tracks at a time? Will you track live drums? Doing a lot of mixing or mastering?

The answers to these questions will guide much of your plan in terms of space.

2. Know the difference between soundproofing and sound treatment. This also is a hugely important point.  Lots of people start out assuming they want to “soundproof” their recording space. But true sound-proofing can be extremely difficult and expensive. Why? Simply put, sound is hard to contain. It takes mass – thick, heavy walls. True sound-proofing also can require decoupling floors and even the ceiling from surrounding structures, a tricky proposition at best.

Now there are a host of products and construction techniques that can help get you there: resilient channel, Green Glue, floating floors, room-within-a-room construction. If you have the time and money, these are all worthy areas of exploration.

Regardless of what you choose in this area, every recording and mixing room needs sound treatment. Which brings us to…..

3. Know the basic principles of treating a room for sound. When it comes to recording or even just listening, walls, floors and ceilings can be your enemy. Why? Because soundwaves tend to bounce off those hard surfaces, creating all kinds of problems for you. In short, the sound bouncing off all those surfaces competes with the sound coming out of your speakers — or your instrument.

So, you need to absorb some of that sound. Now lots of folks swear by the eggshell foam method – just get a bunch of that stuff and attach it to your walls and you’re set.


As has been pointed out in numerous places, thin foam — even that stuff sold by reputable companies like Auralex –– only absorbs high and middle frequencies. It leaves those big bass notes bouncing around, muddying up your sound and wreaking havoc with your recording.

One solution: homemade bass traps and sound absorbers. There are plenty of places to look to see how these things are built; when I build some more I will post the details on how I do it.

4. Set a budget. Then prepare to break it.

Sure, money can’t buy you love. But it takes money to create a good-sounding room. And if your experience is anything like mine, money will be a huge part of the equation. So set reasonable expectations and build a budget around it.

Ok, enough for now. I’ll be back soon with an explanation of some of the choices I’m making.

New studio construction has begun!

May 5, 2009

One very fun thing about being a recording geek is all the stuff you get to learn. Well  it’s finally time to build a new recording and mixing space for Getting Better Recording, my humble home-based studio. And since the last time I successfully built something with my hands was in junior high shop class, I have been learning about such alien concepts as drywall, concrete filler and insulation.

To be sure,  I’m just adding a room in my basement, not building a standalone structure. And I’m using experts for crucial parts of the job, such as framing the walls and ceiling and installing the electrical components. But I don’t have the money to have the thing completely built by professionals. So there I was this past weekend, stuffing insulation between the joists supporting the subfloor above, and in between the wall studs.

I’ll expound on my design goals in the next post, for for now, here are a few pics:

This will be the front wall.

This will be the front wall.

I'm also putting insulation between the wall studs.

I'm putting insulation between the wall studs...

Plenty of ceiling insulation…

Plenty of ceiling insulation...