Working on acoustic treatment. Need advice!! Ethan Winer where are youuuu?? :D

[2FLY]

Hi guys,

 

All weekend I've been working on the acoustics of my room.

 

PICTURES OF OLD SITUATION:

 

FLY's studio 1

 

FLY's studio 2

 

So far I've done this:

 

1. There's a curtain in front of the window-wall

2. The table + mixer are both exactly in the middle (of the window wall)

 

Tonight I'm building monitor stands + putting acoustic foam on the side walls.

 

Now I have the mixer facing the window with a curtain in front of that wall... Maybe this is a WAY better option:

 

1) Mixer on the opposite side of the room against the even wall (see pic 2).

2) Put 2 layers of isolationmaterial + acoustic foam over the entire wall (in front of monitors).

3) Hang ANOTHER curtain in front of the already present curtain opposite the monitors (some form of bass trap)

 

Questions:

 

1. is covering the entire wall with material even necessary?? Wouldn't a strip behind the monitors be enough?

 

2. Could the double curtain trick work?

[Ethan Winer]

Fly,

 

 

The biggest problem I see is you have too much gear and no acoustic treatment.

 

 

No, you don't need or want to cover everything. And certainly not with thin foam.

 

 

That's one of the last places to treat because your speakers are not facing that way! What you really need is as much broadband bass trapping in the corners as you can manage, plus mid/high frequency absorption at the first reflection points on the side walls and ceiling.

 

--Ethan

[2FLY]

Hey Ethan,

 

Ur right.

 

A lot has changed tho. Last night me and a buddy worked til' 4 am on the speaker stands. And... it worked PERFECTLY. Pics'll be up tonight.

 

The plan is this:

 

The mixer is symetrical in front of the wall with the curtain and the speakerstands+monitors are placed in a way that they are also symetrical (translation: I've created the triangle)

 

Tonight I'm planning to do this:

 

I've bought 8 x 100 cm long - 50 cm high - 3cm thick acoustic foam. I'll buy some more tonight.

 

I'm going to (or plan to) attach 6 foams on each sidewall. 2 above eachother, 3 in a row in length of 3 meters. I'll do this in a way that the middle of the monitor is also the middle of the 2 foams hung in length. (Get this: so that there'll be an equal amount of foam above and below my ear when listening. This will be from behind the curtain 300 cm into the room.

 

Question:

 

Is the acoustic foam enough for the mid/high frequency absorption.

 

I've put my couch in the middle of the wall opposite the wall with the curtains.

 

The goal is to create bass traps or diffusors or something to handle the low frequencies.... this is where forums and Ethan Winer come in..

 

My plan was to cover the entire wall (except couch ofcourse) with:

 

Isolationmaterial (not the yellow soft stuff, the stuff with several colors mashed together)

 

+

 

Acoustic foam

 

Question:

 

Would that be of any effect?

 

 

Thanx for all your help!!

[Mind Riot]

I'm not Ethan, but I'm somewhat of a student of his.

 

3 cm thick foam won't do anything except tame the highs just a tad. That thickness probably won't even go too far into the mids. If you can hang them out from the wall a few inches, it can help extend their effective range a bit lower.

 

For bass traps, you need to treat your room corners with decently thick absorptive material over an air space. Rigid fiberglass is ideal at 3 to 8 pounds per cubic foot density. It should be four inches thick if possible. You may be able to find it from local HVAC suppliers or you can order it from www.mcmaster.com. I can provide you with an item number if you decide to go that route.

 

You want to treat as many corners of your room as you can in this way, smaller rooms need lots of bass trapping. As many corners as you can fit and afford, starting with trihedral corners (corners where three surfaces meet, like two walls and the ceiling, two walls and the floor). Corners are where bass frequencies tend to build up.

 

You'll want to span the corner, creating an airspace behind the panel. This will help extend the traps' range and make it more effective.

 

Here's a couple pics of my home studio. The traps are all simple wood frames filled with rigid fiberglass like I described covered in acoustically transparent fabric. Even though mine is a small room (8' x11'), using these methods I was able to get enough of a flat response to use it for mixing.

 

 

 

Here's one of Ethan's articles on acoustic treatment that will give you some more information to orient yourself with all this. In a small room like yours, your chief concerns should be bass trapping and dealing with first reflections at the listening position, followed by general flutter echo treatment.

 

http://www.realtraps.com/rfz.htm

[Ethan Winer]

> Is the acoustic foam enough for the mid/high frequency absorption.

 

I'll add to MR's excellent answers by pointing out that all foam is not equal. Good acoustic foam will do a fine job at mid and high frequencies if it's thick enough. But some foam is very poor, even if it's sold as acoustic foam. Packing foam and bed foam etc are never good. Except for packing and sleeping on, of course.

 

--Ethan

[MrKnobs]

There are lots of very complex treatment options and lots of complicated ways to measure their success.

 

But it mostly comes down to this:

 

If you allow low frequencies to reflect off your back wall and both side walls you're going to have severe bass modes in a small room. These are areas where the bass cannot be heard correctly. If you mix while sitting or standing in these areas your mix will reflect that in a negative (and inverse) way.

 

If you have limited funds or enthusiasm, focus your treatment on the back wall and possibly one side wall. Thin foam is worse than useless as it will absorb high frequencies and make your room sound dead while doing nothing to the real problem, which is the low frequency reflection.

 

Thick foam works, spaced fiberglass panels work, tuned resonators work. Everything else is useless, unless you want to knock out the back wall entirely. Missing walls don't reflect bass energy, but they do attract cops, thieves, and insects.

 

Let me just interject one important statement here, then I'll finish my simplified acoustic rant:

 

IF YOU CAN'T HEAR RIGHT YOU CAN'T MIX RIGHT

 

Sorry for shouting, but that's the second most important thing to know about recording. The first is, "If something sounds terrible, recording it with expensive equipment isn't going to make it sound great."

 

Back to acoustic treatment. The sound of your room is often more important than your choice of monitors. After a certain price point, all studio monitors are fairly flat. Rooms can have dips and humps in their response of 20 dB or more!!! And you're looking critically at a speaker response chart with 1-3dB dips.

 

I understand, fixing up your room doesn't feel as satisfying as putting a new Avalon 737sp in your rack. But it's much, much more important.

 

Me, I use a combination of a few of Ethan's RealTraps, plus some Auralex MegaLENRDs. Because I do acoustics research at a major university, I just had to build myself a Helmholtz resonator and a tube trap and measure the room with a bunch of high $$$ gear.

 

Bur really all I needed to do was use a bunch of broadband absorption in the back of the room and on the back of one sidewall and I'd be maybe 95% where I am now, which is having a pretty good listening room for the size it is.

 

Last piece of advice to y'all:

 

If you're interested in acoustics, by all means get into a complex do-it-yourself sound treatment project or two. Very educational! But if you can afford it, buy proven products from people who know what they're doing like Ethan's company or Auralex so you can get back to recording or playing or whatever your real focus was supposed to be.

 

Just be sure and buy products based on what you need, not on what's cheap. Wishful thinking has a pretty low coefficient of absorption, and the transmission loss is even lower. Buying the right thing the first time, even though it's more expensive than the wrong thing, works out much cheaper in the end.

 

Enjoy!

 

Terry D.

[Phil O'Keefe]

Excellent points all the way around folks.

 

A few random thoughts...

 

I agree with the importance of symmetry. IOW, if you were to divide the room in half, right down the middle, the left and right sides should ideally be mirror images of each other.

 

Carpet, or carpet pad, when placed on the walls is pretty much worthless for anything but very high frequency absorption. Acoustic foam can be useful, but like any acoustic treatment, needs to be used in the correct way, and to address / treat the correct problems.

 

Usually, the biggest problem in small rooms isn't the highs and mids, but the low frequencies. After addressing the low frequencies (more on that in a minute), you still may have some flutter echo issues, or spot reflections off of the walls or ceilings that foam or fiberglass may be suitable to help deal with, but if you apply foam to the entire room, I GUARANTEE you'll have a unbalanced sounding room - very dead and dry in the mids and highs, but with runaway bass. You won't want to mix in a room like that...

 

Isolationmaterial (not the yellow soft stuff, the stuff with several colors mashed together)

 

Link please? It sounds like you're talking about carpet pad, but if you mean something else, we need to see exactly what you're talking about.

 

When it comes to isolation, that's another difficult issue for most small rooms. Soundproofing, or "isolation", requires mass and / or trapped airspace to deal with, and the louder the levels, and the lower the frequencies, the more mass you need to "isolate". The cheapest material for that is usually a few additional layers of sheetrock / drywall. Products like Auralex Sheetblok can be helpful when used between two layers of drywall or applied over the top of the existing drywall, but any untreated "openings" (windows, dorrs, etc.) in the wall will reduce / eliminate the benefits. Walls have to be solid and air-tight in order to be efficient at blocking sound and preventing sounds inside the room from escaping, or to keep outside sounds from traveling into your room and getting picked up by your mics during a take.

 

Another principle which can come into play when it comes to isolation is mechanical coupling. Try this - stand a couple of feet from your wall and reach out and knock on it with your fist. Now stick your ear directly aganst the wall and knock on it again. Notice the difference? In the second situation, you've coupled your ear to the wall, and the knock is much louder. When you're trying to isolate, that's a big concern. Sound will travel between rooms very well due to this mechanical coupling. In "big" studios, the way that is addressed is either by using extremely heavy / massive walls (less likely to start vibrating at reasonable / sane levels) and by mechanical decoupling. That can be accomplished via the double wall / "room within a room" approach, where there is an inner wall / floor / ceiling structure that isn't in contact with the room's outer walls / floor / ceiling. Not usually something that most homeowners want to try... and if you're a renter, that's almost always completely out of the question.

 

IOW, isolation is a big issue for small home studios, and not one that can usually be addressed easily if you have loud sources in or out of the room, or if you have cranky neighbours who have their finger forever hovering over the speed dial button to the local police department. The best things you can do there is to get on good terms with your neighbours, schedule your sessions when noise from outside is at its lowest and when you're less likely to disturb your neighbours and / or family / room mates.

 

As far as low frequencies, Ethan's done some great articles and how-to's on the subject. Check out his DIY bass traps article for info on making some membrane traps, as well as the plans for the semi-rigid fiberglass corner bass traps. Let me know if you need a link.

 

IIRC (and Ethan, please correct me if I'm wrong), his Real Traps use both a compresed fiberglass AND a membrane to address LF absorption, and should be even more effective than the DIY fiberglass traps. I still have not heard them in action myself, but I can say that I trust Ethan's knowledge and expertise on the subject, and would expect them to be a very good product.

 

Diffusion is another useful acoustic tool for some problems, but IMO, for a smaller room, it's not something that will be all that beneficial. Better to deal with things via broadband absorption than to try to bounce things around more... especially if you have less than 10' from your ears to the diffusers.

 

One more comment about compressed fiberglass and acoustical foam - if you offset it from the walls a couple of inches, you can increase or extend the effective frequency range of absorption. IOW, if you want to spot treat a couple of areas (usually side walls directly to either side of you, as well as directly above and behind you, when you're seated at the mix position), using some "stand offs" to get it a couple of inches off of / away from the walls may be a good idea vs just gluing it directly to the walls.

 

How do you know where to mount all this stuff? Well, the corners are the best place for the compressed fiberglass bass traps. Not just the wall / wall corners, but also the wall / ceiling corners too if possible. Check out Mind Riot's excellent photos.

 

As far as where to mount the wall / ceiling foam or fiberglass, get someone to help you. Find a small, handheld mirror, and while you're seated at the mix position, have your assistant hold the mirror flat aganst the walls / ceilings at various locations. If you can see your speakers reflected in the mirror, sound will bounce from that exact point on the surface and reflect directly to your ears. Not good. So those places are where you want to apply the spot treatments.

 

Fly, I appreciate the photos. If you can give us a few more, that show the rest of the room as well as your curtains, that would be great. Also, if yuo can get us some accurate measurements of the room dimensions, that would also be helpful.

 

 

[Brittanylips]

 

Originally posted by Phil O'Keefe I agree with the importance of symmetry. IOW, if you were to divide the room in half, right down the middle, the left and right sides should ideally be mirror images of each other.

 

I'd add one caveat -

 

Symmetry can breed standing waves that cancel each other out at certain frequencies.

 

For example, if you had parallel reflective walls, at a certain frequency the up sine wave is going to equal the down sine wave and they'll cancel each other out, and you'll notch out that freq.

 

Some acoustic treatments are particularly good at disrupting parallel walls (in a good way) and redirecting standing waves so they won't hurt themselves. Some treatments, for example RPG's, are particularly good at this.

 

one other thing I'd keep in mind that people often don't keep in mind:

 

You want this to be an inspiring space conducive to creating music. You don't want to have the ambiance of a wet toilet seat. I don't think queer eye for the straight guy is doing studios, but you really want to think like them, at least for a day.

 

A friend of mine put together a studio in NYC, a nice one, actually, and had some speakers that were not very accurate but sounded flattering and generally pleasing. I'm a speaker accuracy freak, and knowing that, he explained that it was important for him to enjoy listening to his material while he was working, even if it wasn't a super duper studio speaker, which was a great point. It sounded good, which made him happy to work and productive.

 

I think the same is true with the vibe of a studio. Sometimes it's more important to sacrifice sound quality for beauty, if it helps create a place that makes you feel happy about being in there and doing your thing. And acoustic treatments can sometimes look so ugly, medicinal, and claustrophobic. So yeah, acoustic treatments are helpful, but I'd be careful not to accoustic treatment yourself into a habitrail.

 

-Peace, Love, and Brittanylips

[Phil O'Keefe]

Well, I don't have parallel side walls, so my symmetry comment makes a bit more sense when you consider that.

 

But you do make a good point about standing waves and reflections off those parallel side walls. But that's not something that can always be easily and completely addressed in most bedroom studio situations. Good broadband absorption at the reflection points would be my second recommendation, with angled side walls being the first. The bass modal issues are still going to be a concern with foam or fiberglass at the side wall reflection points, but at least you can fairly easily address the mid to high frequency bounce with some judicious application of the right materials. It's not going to be as good as if you could angle those walls and had some serious bass traps going on, but it beats a hard slap coming back at you and screwing up the imaging. And since bass frequency waveforms are so long, and so omnidirectional, and tend to be reinforced in corners, anything you can do to help tame them - especially in the corners and in the back of the room will help the sound of the room overall IMO.

 

There's all sorts of things that can be done... the questions are, how much can you modify the room, how much space are you willing to give up (deep bass trapping can require some serious space), and how picky and / or adaptable are you? Oh, and how much money do you have?

 

As far as decor, I'm no designer. But then again, I'm the guy who - by far - spends the most time in my studio, and so I went with what works for me. I didn't go into all that "colors and psychology and mood enhancement" stuff, or study it in any great depth - I just went with things I liked. Not a lot of people have green walls, but I've always loved the mountains, and green and wood just remind me of that environment - very soothing and peaceful... at least to me. I went with lighting that was variable, with several lighting areas all on seperate switches, so I could vary it if the mood strikes me. Lighting is a "biggie" IMO. Too little and you struggle to see, and too much and you / the talent can really feel like you're under a microscope - which is already an issue with studios for a lot of musicians. So IMO, some attention to lighting and the ability to vary it (avoid el-cheapo variable resistance light switches though folks - they can cause noise issues) can be a good thing, and that alone can go a long way towards making some people more comfortable.

 

Oh, and you've got a studio, you've gotta have a Lava Lamp. It's the law, and it's a good one. I've got three. But Laval Lamps alone do not "vibe" make.

 

But as long as that subject is on the table, I think we might want to do a seperate thread on it - I think that would be a great topic for discussion, but I don't want to take this one too far OT from 2FLY's acoustical considerations and issues - even though the way the treatment is applied and designed into the room can have an obvious impact on the aesthetics.

 

Blips, would you care to get it started and give us some suggestions / opinions?

[2FLY]

And people ask me why I love Harmony-Central..

 

You guys absolutely rock. I appreciate it a lot guys - seriously.

 

I have to say (maybe I'm nuts) but after creating the plan to build my own speaker stands, buying all the equipment and then 3,5 intense hours of drilling, glueing, bashing, getting p*ssed off , filling, screwing, unscrewing and measuring.. and then to finally see 2 identical massive speakerstands only 0,5 cm higher than planned.. feels ABSOLUTELY great. And way more satisfying than buying X (expensive) product for my studio.. which quality is basically useless in an acoustically 'challenged' room . I look @ the monitors on my speakerstands.. and think 'yes!'. Me and my buddy were working at it for hours but it's done and it feels SUPERB. I told him 'This construction stuff could get addictive..' haha.

 

I've read your replies and have a few new questions. I'm taking a whole bunch of pictures of the room tonight. All walls, behind the curtains and I'll give you guys the exact measurements

 

It's obvious low-frequency absorbation is #1 on the 'treat-list'. I think it's smartest to 'attack' each of the 5 walls (front, back, 2 x sidewalls, ceiling).

 

My questions:

 

SIDEWALLS

 

1) I'm planning to put up the acoustic foam on my sidewalls tonight. It's 1 inch (3,5 cm) in thickness. I understand that that's not thick enough and that it will be more effective in absorbing if it's not directly attached to the sidewall. I've been thinking about something 1 inch thick the exact same size as the acoustic foam. What material should I put between the wall and the foam?

 

2) My plan is to hang 300 cm width x 100 cm height on both sidewalls. My table + mixer + monitors are 100% symmetrical. The centerpoint of the width will be at the exact same height as the centerpoint of my monitor/listening position. Is this a good idea

 

FRONTWALL]

 

1) The curtains are hanging 10cm from the frontwall. The monitors are 10cm from the curtain (20cm from the frontwall). Is this enough space. If not.. how much space is sufficient?

 

BACKWALL

 

1) I put a couch in the middle of the backwall exactly opposite my table/mixer/monitors. A stand with a synthesizer is standing symetrically in front of it (+/- 15cm - 4 inches) Is the couch usefull in the absorption of low frequencies?

 

2) Is the synthesizer a problem?

 

3) Is someone sitting on the couch a problem?

 

4) Do I remove the synth-stand when I mix a song

 

A lot of questions.. we'll get to the ceiling and the entire bass-traps/corner-traps thing later

 

THANX GUYS!!! This is kind of becoming an OUR project. My younger brother, my girl, 2 buddies and ofcourse the Harmony-Central think-tank have all stepped in and helped!!! Cool yo!

[Brittanylips]

 

Originally posted by Phil O'Keefe Well,...IMO.

 

[nodding in agreement]

 

Originally posted by Phil O'Keefe ... the way the treatment is applied and designed into the room can have an obvious impact on the aesthetics. Blips, would you care to get it started and give us some suggestions / opinions?

 

Well, as you know, I'm a little shy at posting... so I may save the topic until I get my druthers up or someone else is so moved.

 

My own .02 is to have a space that's conducive to working. I don't go for a lot of distracting design elements, but prefer a space that's clean, ergonomic, open, well lit, flexible, and inspiring.

 

I also find that sometimes acoustic problems just kind of work themselves out. For example, I have a relatively new space that was a little too live at first, but was tamed by the simple addition of furniture.

 

I think as the project studio evolves, and more functions are subsumed by the computer, studios will progressively look (and sound) less and less like traditional console-oriented studios, and more and more like places in which you would naturally listen to music.

 

.02

 

-Peace, Love, and Brittanylips

[Kendrix]

FWIW- here are some pics of my very small space.

 

http://adobe.kodakgallery.com/Slideshow.jsp?mode=fromshare&Uc=l1mhnqr.4oex4sqj&Uy=tek06o&Ux=0

 

(Note that there are two photo alums to open at this site per the link near the bottom.)

 

I have some auralex foam btweeen the monitors and double thick panels of 703 fiberglass hung above my desk and iinserted into the far corners.

 

The auralex and one 703 panel on the window opposite it removed some flutter echoes that were a huge problem.

 

For some reason the "cloud" panels above the desk made a HUGE improvement. It really helped me mix.

However, despite what everyone says, the corner treatments seem not to have made such a big impact. Perhaps its cause Im lazy and havent built the airtight encasements for the fiberglass to ensure the lows get trapped.

 

At this point Im not sure its worth pursuing that. - The room is so much better than pre-treament im satisfied (at least for now)

 

Also i managed to get the 2'X4' 703 fiberglass panels for about $2.50 a piece from a local building materials supplier..