Ethans Real Traps vs traditional room treatments.

[kevinc]

Merry Christmas all.

I`m about to embark on a good sized studio build and I`m trying to work out the rest of the kinks.


I was wondering what some of you who have worked in some nice control rooms think about blowing off all the math and additional physical effort required for a decent DIY room treatment and just chucking up a bunch of realtraps ???


On the one hand I have most of the materials I`d need from previous homemade intalls (lots of 703 etc...) so it would be a minimal investment. I like the looks of the rooms I`ve seen with the slat absorbers like you see on John Sayers site. (which is an incredible resource b.t.w.) The other thing is if I could get it right I could really nail down EXACTLY what the room needed to make it sound good.

The disadvantage is I have a hard time wrapping my head around the math required for properly treating a room (especially when accounting for angles) so I`d probably need to hire someone to come up with a basic plan for me. I suppose I could just post a plan on the site and pray for some help but I`m to lazy to learn the drawing programs they work with there and the forum moves kinda slow overall.


On the other hand the Ethans traps seem like a logical idea because they`re all premade and you just need to figure out a good setup for the room and throw them up there. Done deal with less math involved and less blisters. (which I`ll have plenty of after putting up all the walls themselves) On Ethan`s site he seems to throw out some main principles for installing them that are the same for any room imaginable. From than it`s just adding more depending on room size and taste.

Sounds good but to be honest I`m a bit skeptical just because it`s simply too easy ! Theres so much less thinking involved with it and I find it hard to believe you can match the sound of some of these rooms out there with custum tailored treatments thought up by guys that are being paid $500 an hour (or whatever) to come up with a plan. I would love it if that were the case though.


I suppose I could just try it out in the control room and if it just didn`t seem to be doing the trick in there I could throw them in the live room instead. (which will be big enough to need a whole lot of stuff in there anyways.)


What do you all think ???

[Ethan Winer]

Kev,

I won't comment on the cost / benefit of using my company's traps, but I will address this:

> I have a hard time wrapping my head around the math required for properly treating a room <

I don't see math as necessary for treating a room. The old-school approach was to design a room with "correct" dimensions and a good shape, then measure the room, and finally design custom bass traps to target the known problem frequencies. But most people these days are treating an existing room, so that removes the first issue. The second issue is also mostly irrelevant because as we now know, broadband absorption is a better solution than tuned trapping.

Some people in the business of measuring and treating rooms object to my simplistic approach. I guess they have a vested interest in making it appear complicated, as a way to keep themselves in business. But for the vast majority of us with home studios and other small rooms, a math-based approach is not really needed.

--Ethan

[kevinc]

Originally Posted by Ethan Winer

The second issue is also mostly irrelevant because as we now know, broadband absorption is a better solution than tuned trapping.

I agree with that personally though I`m far from an expert on either of the two methods.

The thing that seems a little strange about hemholtz or slat resonators is that though they suck up whatever frequency they`re tuned to it doesn`t really adress the rest of the rooms problems. So you`d have to have multiple boxes made each sucking up different freq`s for it to really even things out I`d think and that doesn`t seem particularly economical.

I was kind of brought up acoustically by trying different ideas from F. Alton Everests books which mostly seem to deal with broadband absorbers. That method just seems to make a lot more sense to me.

Some people in the business of measuring and treating rooms object to my simplistic approach. I guess they have a vested interest in making it appear complicated, as a way to keep themselves in business. But for the vast majority of us with home studios and other small rooms, a math-based approach is not really needed

Some of the studios out there crack me up with some of the treatments they have.
A lot of them look really cool and space age looking (different diffusers in particular) but I can`t imagine they`re all necessary. Again I agree that a lot of this kind of thing is put together with designers with unlimited budgets. The same kind of specs can most likely be achieved much more economically without the funny shapes.

I`m mostly just looking for a reasonably neutral sounding room in which I can achieve mixes that will translate to the outside world. (my mixing skills excluded from the equation obviously. ) Why does the room need to look like the inside of an alien spaceship to achieve this ?


Ethan have you ever measured some of these rooms and than tried to get the same kind of specs from a room done in your traps ?

[cajonezzz]

FWIW Kev- we have a pretty odd shaped control room- about 22-20 but with some really weird angles. We bought 16 mini traps and put up 12 in the CR ( left 4 to be moved around on stands) and the change in the the room tone was nothing short of amazing.


We also have 703 panels floated off the ceiling ( 16 ft sloping ) they are 4x6 ft .

We've always planned on putting up another 6 mini traps, jjust haven't got around to it.

It think a combo of DIY treatment as you build and the Real Traps will get you in the ball park really quick.
I'm planning on another 8 minitraps for my home garage mix room that I'm starting this month. ( I'll be posting a build out thread as well!! )

Merry Christmas!

cz

[kevinc]

Thanks Ballzzzz and Merry Christmas to you as well. It`s the first day off I`ve had in ages so I`m using it as internet catchup day and ignoring my family.

Sounds encouraging on the Realtraps. I`m starting to really think they`re the way to go and even if I add some other treatments here and there it`s not like I`m wasting my money. Theres allways a place your going to need some more absorption.

The funny thing is they even have resale value unlike used cut up pieces of insulation.


I`ve been dying to start one of the construction with pics threads since you started yours years ago. Rich`s is pretty cool too.

[Glenn Kuras]

>Ethan have you ever measured some of these rooms and than tried to get the same kind of specs from a room done in your traps ?<

mmmmm, sounds like ANOTHER fun challenge Ethan..
I myself have been in these crazy rooms and can tell you first hand that a lot of the hemholtz or slat resonators are just wooden boxes doing nothing at all.. Not that they do not work, but people build them wrong all the time..

Glenn Kuras

Glenn

[mltamisin]

I agree with Ethan that the math is just not essential. It's nice but not required. I've been building stuff and moving things around for a year now and I finally have a phenomenal sounding room with a bunch of DIY stuff mixed with materials designed for acoustical treatment. I've never used Ethan's traps but would die at the opportunity to have them. I've heard they're much better than 703. Unfortunately, I'm still tracking with a 002 and an NTK as my best mic and simply cannot afford it. It's all about placement of materials and broadband absorption. Diffusion is something that gets overlooked and should be seriously considered when designing a room. If you can afford it get Ethan's stuff and some good RPG stuff and mix it with the DIY stuff. You won't be disapppointed. If you're skeptical get a little of each and see what it does to your room. Buy 2 boxes of RPG hemiffusors, 2 realtraps, and 2 panels of 4" thick 703. You can always add more of what you like. Most rooms need treament in similar areas. If you're in a rectangular room chances are you need it in the same spots....corners, the ceiling, the middle of the walls and the 1st reflection points. Just walk around your room and listen. It's that simple. You hear comb filtering - put up a diffuser. Bass buildup - put up some absorption.

[jayfrigo]

Though I agree that the general person with a project studio is going to be fine just using a lot of broadband bass trapping in an existing room, I think people are often too dismissive of the math. Acoustics can be art, but it is definitely science, and the math is there to help you.

First off, the math really isn't that difficult. You do need to learn it, and how to apply it, and situations can become quite complex, but the math itself isn't terribly oppressive.

Secondly, those "math" rooms with targeted absorption actually use a majority of broadband absorption. Nobody treats a room with all narrow helmholtz resonators. Everest's book certainly doesn't recommend it. I've been in countless "math" rooms, and been involved in the building of my fair share, and never have I seen or recommended a bunch of narrow absorbers used as the primary trapping. Those big traps in the back of rooms that operate on the quarter wavelength principle are actually broadband traps in the way they are traditionally constructed. Even traps that operate on the Helmholtz principle come in various configurations and are usually partially filled with frictional absorbers to widen the Q and make them closer to broadband traps.

Ethan's traps are advertised to operate as broadband bass absorbers with less mid and high frequency absorption to allow more of them to be in a room without deadening it too much. This is a good idea. I don't know how he accomplishes it, but there are a few ways it's often done. You can do it in some constructions by using fiberglass with backing and have the backing face out. You can also do it with a perforated panel trap based on Helmholtz with only a little math (Russian acoustician Mankovsky did excellent research in this area).

A piece of plywood with a certain density of holes over a cavity filled partially with insulation will accomplish this as well. Some simple calculations and a little research will let you figure out how wide the Q will be and at what frequency the maximum absorption takes place. Knowing where your problem areas are lets you target the center of the Q to your worst problem, but still be very effective over a wide bandwidth. The lower density of perforation, the lower the effective frequency. The deeper the cavity (but nothing like depth of 1/4 wave traps), the easier it is to broaden the Q. With an 8" cavity filled with 4" of insulation and a 1/4" piece of plywood with 3/16" holes on 6-7" inch centers, if memory serves, I think you get peak effectiveness somewhere around 80 or 100, but it's effective for a couple octaves in either direction.

A lot of other examples come to mind where a little math can help you, and the rooms don't have to be very expensive to build. Depending on what you want to accomplish and how effective you want to be, you can use as much or as little math as suits you. However, It's just as expensive to put a wall in the wrong place as it is to put it in the right place. You can easily spend as much building traps that won't help you as you can building ones that are well-suited for the room. Math does not equal expensive, nor does it equal impossibly difficult. Acoustics does require some study to know where to begin, however. If you don't want to spend the time on the learning curve, there are professionals that can help you. Hiring a consultant does not automatically mean expensive solutions.

All this said, Putting up a bunch of Ethan's traps certainly isn't a bad way to go if you need a fast, no-brainer fix; but the more you learn, the more you have an appreciation for more "geeky" fixes as well.

[Ethan Winer]

Kev,

> have you ever measured some of these rooms and than tried to get the same kind of specs from a room done in your traps ? <

There's no reasonable way to compare two different rooms using different trap types. But what I have done - many times - is measure the same room before and after adding my company's traps. The main problem with trying to compare a pro designed and treated control room with one of my customer's rooms is the rooms are usually very different sizes. So that right there makes any direct comparison impossible. However, we recently treated Tony Maserati's pro designed room because he and his engineer were still not happy with the low end. They just installed all the traps this week (a lot of traps), so I don't yet have any before / after data. But I expect to soon.

--Ethan

[Ethan Winer]

Jay,

> Acoustics can be art, but it is definitely science ... the math really isn't that difficult <

I agree completely, and maybe I oversimplified my oversimplified approach a bit. While I need to know a little math, most of my customers probably do not.

> Nobody treats a room with all narrow helmholtz resonators <

I don't have stats on how many rooms are done this way or that, but I do know of one popular home theater designer who relies on tuned absorption exactly as I described. That said, I agree with you that a lot of pro studios use a lot of broadband absorption.

--Ethan

[warhead]

That's it, I'm moving my control room to an open field.

War

[matt_tricks]

Cz,

Originally Posted by cajonezzz

We also have 703 panels floated off the ceiling ( 16 ft sloping ) they are 4x6 ft .

What thickness of 703 did you use on the ceilings? What are your ceilings made of?

My ceilings are a little over 8' and made from that thin-ish gyprock (dunno what you guys call it in the US, it's about 1/2" thick and basically just plasterboard). I'm fairly sure that alot of sound waves under about 140hz would go straight through it but I want to stop pretty much anything coming off the roof.

I was thinking of something alot like what you've done although based on some advice from Ethan it's not really worth sloping? I've done 4" of #704 spaced 4" from my brick walls but for the roof I was thinking I might get away with 2" thickness on the roof just because I don't think much of the bass resonance is coming from the ceiling. What do you guys think?

Matt

[Ethan Winer]

Jay,

> Nobody treats a room with all narrow helmholtz resonators. Everest's book certainly doesn't recommend it. <

One more thought on this: It's interesting to note that nowhere in Everest's book (4th edition) does he show your basic rigid fiberglass panels straddling a corner.

--Ethan

[Glenn Kuras]

<I was thinking of something alot like what you've done although based on some advice from Ethan it's not really worth sloping? I've done 4" of #704 spaced 4" from my brick walls but for the roof I was thinking I might get away with 2" thickness on the roof just because I don't think much of the bass resonance is coming from the ceiling. What do you guys think?>

Putting 2 inch panels on the ceiling spaced 2" works fine....

Glenn

[Snatchman]

Ok....what results would one expect, using 3" 703 spaced 2" from the wall ( back wall)..? Thanks....

[jayfrigo]

Originally Posted by Ethan Winer

Jay,
One more thought on this: It's interesting to note that nowhere in Everest's book (4th edition) does he show your basic rigid fiberglass panels straddling a corner.

I went and pulled the book off the shelf and took a look... In my 3rd edition copy he has illustrated something similar on page 176. It's the membrane corner trap. He shows the plywood on the outermost surface, then airspace, and then the fiberglass. True, it's not just glass in the corner, but certainly similar in principle, and taken a step further.

I'm not sure how this related to the Helmholtz stuff, or was it just an aside? The comment is true enough, but I think I missed the point... Help please...

[jayfrigo]

Originally Posted by Ethan Winer

Jay,

> Acoustics can be art, but it is definitely science ... the math really isn't that difficult <

I agree completely, and maybe I oversimplified my oversimplified approach a bit. While I need to know a little math, most of my customers probably do not.

No, you made sense. The typical project studio guy indeed does not need to worry about the math; and you have more than a passing interest in this, so I'm sure you appreciate the "geeky" side that I also enjoy.

My point was just to say to those DIY studio guys that the basic math really isn't that big an obstacle. If a person wanted to dive in and take things a step further, they shouldn't worry about the math. Give it a go. Mixing the common sense approach with a little of the math will help the DIY projects really get to the next level.

> Nobody treats a room with all narrow helmholtz resonators <

I don't have stats on how many rooms are done this way or that, but I do know of one popular home theater designer who relies on tuned absorption exactly as I described. That said, I agree with you that a lot of pro studios use a lot of broadband absorption.

I'm sure all kinds of strange things are done, so "nobody" isn't technically accurate. Perhaps I should have said, "nobody worth using," but I wouldn't want to dismiss anybody specifically without knowing the full picture.

I'd have to say I'm with you on the point that using only narrow band resonators is not a great way to go. I certainly would stop short of saying that all tuned absorption is unnecessary, though I again will agree with the point that the average project studio is going to be just fine with an assortment of broadband traps.

However, I don't want people to get the idea that anything more complex can't be useful, or to have the erroneous impression that guys like Russ Berger are just doing it for show. There are complex acoustical situations, and not only in studios, where the math, science, and experience of the designer are all essential. This is not news to you, of course, but I add it just for some balance for the thread lurkers.

[jayfrigo]

Originally Posted by warhead

That's it, I'm moving my control room to an open field.

Ah, but the ground, the awful ground! You still have a boundary to worry about! How can we create a magnetic field to levitate listener and speakers into free space?

[jayfrigo]

Originally Posted by matt_tricks

?My ceilings are a little over 8' and made from that thin-ish gyprock (dunno what you guys call it in the US, it's about 1/2" thick and basically just plasterboard). I'm fairly sure that alot of sound waves under about 140hz would go straight through it but I want to stop pretty much anything coming off the roof.

As for "going right through," 1/2" GWB on wood studs with insulation in the cavities will have an expected TL (transmission loss) of about 22-23 dB at 140 Hz, And if you wanted to do a rough guess, the mass law predicts about 6dB lower TL with each halving of frequency, so around 16-17 dB at 70 Hz etc., but this is a different subject. The absorption coefficient of the same construction at the same frequency (140 Hz) is about 0.3. This means you'll actually get some bass absorption just by having a gypsum board wall or ceiling. Walls act as flexural absorbers. That's why an especially rigid room construction (concrete or cinderblock for example) will typically need more bass trapping.

I was thinking of something alot like what you've done although based on some advice from Ethan it's not really worth sloping? I've done 4" of #704 spaced 4" from my brick walls but for the roof I was thinking I might get away with 2" thickness on the roof just because I don't think much of the bass resonance is coming from the ceiling. What do you guys think?

Sloping can be useful. It depends on what you are trying to accomplish and so many factors in the room and construction of the treatments in question. In your case of a pretty low ceiling (from a studio acoustics point of view at least) if you are going to slope, it should be a pretty shallow one. Without knowing more about the specifics, I'd say that the slope issue isn't a big deal. Separate from the bass trapping discussion, you do want something soft in position to absorb first reflections from the ceiling just as you would from the side walls. A simple panel of compressed fiberglass spaced several inches from the surface won't get you very deep bass absorption, but will get some low mids. The stuff you mention at 140 Hz and below won't be impacted very greatly by such a panel. If you use membrane absorbers or perforated panel absorbers you can get much better performance at lower frequencies from the same depth traps. You can also face them with 1" 703 in places that you want mid and high frequency absorption as well. You don't want the 703 to actually touch the plywood in a membrane trap as it will damp the membrane and change the effective frequency in a way that will be hard to predict. You'll need a small airspace to let the membrane flex freely.

[natpub]

Originally Posted by jayfrigo

...However, I don't want people to get the idea that anything more complex can't be useful, or to have the erroneous impression that guys like Russ Berger are just doing it for show. ..

Right on! Not only that, but Russ and his like offer something not discussed as much, and that is design of live rooms with beautiful, rich, organic and desirable sonics, graceful natural reverb tails, etc. That kind of science meets creativity is definately at a whole different level. I think it's great that the rooms we mix in are free of problem acoustics, but the rooms we are recording are part of the music, as if they were players themselves.

[shapemod]

If you have real problems in the lowend(roommodes) like in the 60Hz range or even lower, I don't think that you can solve this problems with broadband absorbers. I got several helmholz resonators build, now the lowend is much more even, definetly not perfect but much better. And of course I have lots of broadband absorbers as well.

[Glenn Kuras]

>If you have real problems in the lowend(roommodes) like in the 60Hz range or even lower, I don't think that you can solve this problems with broadband absorbers.<

Not so sure about that.. I have treated enough rooms and seen before and after graphs that broadband absorbers did very well at 60hz.. But you do have to straddle corners to hit that low..

>Ok....what results would one expect, using 3" 703 spaced 2" from the wall ( back wall)..? Thanks<

It should work pretty well, but you may want to space it 4" and use 4" 703.. There is a lot of low end coming back at you so it is best to absorb as much of it as possible..

>My point was just to say to those DIY studio guys that the basic math really isn't that big an obstacle. If a person wanted to dive in and take things a step further, they shouldn't worry about the math. Give it a go. Mixing the common sense approach with a little of the math will help the DIY projects really get to the next level.<


Very well said sir....


Glenn

[the-oger]

Originally Posted by warhead
That's it, I'm moving my control room to an open field.

Originally Posted by jayfrigo

Ah, but the ground, the awful ground! You still have a boundary to worry about! How can we create a magnetic field to levitate listener and speakers into free space?

Naaahh... just make sure the field you setup in has a good mixture of timothy grass and clover. Together they will act as a very effective broadband diffuser. You might want to erect a huge pop-filter around the mix area however (a pair of Roseanne Barr’s nylons oughta do it), in order to filter out any wind… if that grass gets-a-swayin’ you might end up with uncontrollable comb-filtering!

Oger

[Ethan Winer]

Jay,

> He shows the plywood on the outermost surface, then airspace, and then the fiberglass. True, it's not just glass in the corner, but certainly similar in principle, and taken a step further. <

Ah, this is the key. A wood panel membrane trap is a tuned absorber, not broadband. With two or three different thicknesses you can get absorption similar to broadband, and my Bass Traps article from Electronic Musician shows an approach using two thicknesses. But that type of membrane trap is not as effective as *newer designs, especially in the small rooms many people use these days.

--Ethan

* as related to this thread's title

[kevinc]

Originally Posted by jayfrigo

However, I don't want people to get the idea that anything more complex can't be useful, or to have the erroneous impression that guys like Russ Berger are just doing it for show. There are complex acoustical situations, and not only in studios, where the math, science, and experience of the designer are all essential. This is not news to you, of course, but I add it just for some balance for the thread lurkers.

Yeah I totally agree with that Jay as well as your first post.


My own backgorund in acoustics is from going through Everests book for about 10 years on a couple rooms I`ve built + more recently spending loads of time on the John Sayers site.


I`ve got a bit of an understanding of this stuff now but when it comes to spending money and time building it I`d want to make sure I was really nailing down what the room NEEDS and not just haphazrdly throwing up DIY solutions that aren`t helping me. This is where hiring somebody to design it comes in and though I`ll probably do that in the future it makes more sense to me to just quickly get it up to 90% or so with Ethans traps and get to work ! These room aren`t going to pay for themselves !

[DannyDay]

Originally Posted by natpub

Right on! Not only that, but Russ and his like offer something not discussed as much, and that is design of live rooms with beautiful, rich, organic and desirable sonics, graceful natural reverb tails, etc. That kind of science meets creativity is definately at a whole different level. I think it's great that the rooms we mix in are free of problem acoustics, but the rooms we are recording are part of the music, as if they were players themselves.

Yes, yes! I live and die by the live room (or hall much of the time).

DD.