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Very small control room remodel... less absorption ETC Studio Monitors
Old 17th February 2010
  #61
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DanDan's Avatar
Cool

I am very glad that the misconception got teased out of hiding.
I reckon soffit mounting is quite common in small pro spaces, e.g. OB trucks. I cannot confidently say that our pseudo-soffits would perform better than superb corner traps though. No comparison experience.
I say pseudo because of that gap all round the edges. A true soffit is sealed to the walls /floor/ ceiling. My guess is that a small gap will not diminish the performance much. 2 inches is very small compared to Bass wavelengths and compared to the very large panel. However again, no real comparison experience.
BUT. I was once asked to treat a room but allowed no structural alteration or even fixings. A listed building. The speakers were at either side of a fireplace, with consequent alcoves. I placed the speakers very close to and flush with the fireplace. I leaned 8x4 sheets of plywood into the alcoves to create sort of soffits, just behind the speakers.
Rolls of attic insulation in bags behind the panels.
This had quite a dramatic effect. More bass, 6dB off peaks and nulls.
I wouldn't drop the soffit idea yet. You have considerable construction skills and inventiveness, so if anyone can make this work......
Some speakers are designed to be heard off axis. PMC IB1s have installation guides which recommend that the tweeters be higher than ear and focussed on a point behind the listener. If you end up soffitless, I would consider wall mounting the speakers. Good AV type wallmounts with a Recoil Stabiliser or other resilient mount can work well with small speakers. Very close to the wall is IMHO very close to soffit mount, although this is a controversial view. My own tests have shown such close to wall mountings exhibiting much better performance than further out on stands.
+1 to Lupo comments on angles , but I would include heights. If you end up with speaker stands make them adjustable at least until you are happy.
These days, with affordable large flat TV's some with DVI connection, one could lose the traditional computer monitor scenario.
Lastly, looking at the last few sketches, I am tempted to suggest facing the east wall, with the two superchunks.
DD
Old 17th February 2010
  #62
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Dan, you're just egging me on aren't you? heh

Here's what happens with full soffits:

My listening position is dead center in the room's dimensions. Lupo said earlier "add volume for the closet and subtract for the truncated corner". I may have to disagree with subtracting for the truncated corner... as I plan to build a replacement breathable door, should I not be able to add volume for the door as well? Instead of subtract?

Anywho... here are a few shots. I eliminated the back wall completely so we can better see what's going on here.

The detail of the soffit:

I imagine a triangular 2x4" frame stuffed with pink fluffy. I could reasonably build these in two vertical sections, just so I can get them in the room, and couple them in place. Between the wall and the frame (grey) is 2" thick rockwool. This may or may not be necessary. On the face of the frame is two wood layers, ugly and pretty. These could reasonably be scribed to the walls. The entire face of the soffit measures just over 4'. The seam for the ugly wood would be staggered from the seam for the pretty wood.


I worry about the very slim sliver of front wall between the soffits.
Attached Thumbnails
Very small control room remodel... less absorption ETC-backview.jpg   Very small control room remodel... less absorption ETC-topview.jpg   Very small control room remodel... less absorption ETC-soffitdetail.jpg  
Old 17th February 2010
  #63
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Quote:
Originally Posted by DanDan View Post
Lastly, looking at the last few sketches, I am tempted to suggest facing the east wall, with the two superchunks.
DD
I was orientated that way originally. Imaging was a nightmare with that open closet volume on my right.

I suspect you suggest this for more back wall treatment places? I have some ideas for the current back wall to follow soon
Old 17th February 2010
  #64
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Quote:
Originally Posted by dykstraster@gmai View Post
I worry about the very slim sliver of front wall between the soffits.
So stick a vertical band of absorption there.

Paul P
Old 17th February 2010
  #65
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Kinda what I was thinking, thanks Paul.

In the above proposal, the speakers are closer to the inner edges of the soffits. What if I were to only extend the baffle outwards as far as it is inwards... thus exposing a foot or two of the back of the soffit for bass trapping? Does this negate the effect?

[edit]

second shot with Paul's center absorber, and more side open to bass traps... again to center speaker in the baffle.
Attached Thumbnails
Very small control room remodel... less absorption ETC-soffitcentered.jpg   Very small control room remodel... less absorption ETC-center-absorb.jpg  
Old 18th February 2010
  #66
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I fear those nice hard surfaces are going to be reflecting things coming from
elsewhere in the room right back in your face. They're pretty close.

Paul P
Old 18th February 2010
  #67
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I just realized that you've backed yourself into a corner, so to speak. You're
now facing into a corner, with no absorption at that. There's bound to be
some weird interaction between the sound crawling along the walls/baffles
from both speakers.

So I prefer the original setup :

with absorption in front of you between the two.

Paul P
Old 18th February 2010
  #68
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Quote:
Originally Posted by PaulP View Post
There's bound to be
some weird interaction between the sound crawling along the walls/baffles
from both speakers.


Paul P
Yeah, that's the concern. Don't know that the absorption will cut it.
Old 18th February 2010
  #69
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Hey guys,

I've been obsessing over soffits, lately.

Here's a couple of quick (sort of random) things:

To really make it worth the effort, you should have at least 3x the woofer size on all sides of the speaker. 4 feet would be better.

Your plan with the chunk/soffit above, wouldn't really cut it in this sense. However, it would accomplish making good use of what little space that you have.

I don't know if you have already been through this, but a 90 degree angle has been used with success. This would get you out of the middle of the room, and also minimize the corner effect that seems to be appearing.

The plans over at Sayer's: The bottom portion is used as a bass trap, and yes there is absorption on the face of it, BUT if you notice, the baffle is still extending downward behind the thin absorption.

The most important thing is that the speakers are flush with the baffle, but not touching.
The baffle needs to be massive.
Concrete being great, but 3/4" - 1" of MDF or HDF works, too.
It does not need to be a sealed structure.
It would be nice if the baffle structure and whatever structure that supports the speakers were decoupled from one another.

Oh, and soffit mounted speakers excite longitudinal room modes more that free standers.
You'll need some serious bass trapping in the back.

Sorry if this is random pieces of useless information.
I just saw that you posted over at Sayers, and I thought I might try to give you a hand.

Seamus
Old 18th February 2010
  #70
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Oh, and if you end up having to angle your speakers down, you must angle the entire baffle.

Here's a quick picture of a 90 degree set up.

Using a 90 degree set up would either require you to increase the angle of your side walls, or make sure that you have some serious absorption at all your reflection points.

Oh, and I'm sure you know about the bass boost caused by flush mounting.
It may be necessary to build a passive filter, ie T. Barefoot's model from Sayers' forum.
Attached Thumbnails
Very small control room remodel... less absorption ETC-90-degree.jpg  
Old 18th February 2010
  #71
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Old 18th February 2010
  #72
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Thanks for the links Mumbles,

Gives me some hope in this, though I do worried about extended bass modes.

Sort of a trial by fire first post over at Sayers huh? DIfferent world over there, I felt like a kid's first day at a new school. Such is life.

When I FINALLY get some time over at the space, I'm going to get some waterfall plots from the current mix position, as well as a few at other distances... in an attempt to find where the room mode actually is given the weirdness of both closet and open volume outside the room. I'm thinking this is critical, as it will really determine what can be done space wise at the front of the room.

Thanks again,

John
Old 18th February 2010
  #73
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Happy to try and help.

Have Fun,
Seamus
Old 18th February 2010
  #74
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DanDan's Avatar
Tease

I think we are teasing out some ideas here. The final result may or not be a plan, but I am sure we will all learn something along the way.

Some points.
The full size 60 degree soffits look too big.
I reckon that angles are an open subject. I would guess that say 30 degree soffits with the speakers angled another 30 would work just fine. Similarly vertical angles. Remember we have a highly skilled wood worker here. Heck I bet he could have the speaker mount section remain angle adjustable! Egging on, you bet!

I have just looked at the orientation again, referring to original pictures. I now agree on the current orientation. I see the closet now. That closet looks like it could be persuaded to be an enormous bass trap. Maybe it is already. Maybe this room is already working well? Also if this closet, angles and generally broken up stuff is behind, it probably removes some of those bounce back problems.


DD
Old 18th February 2010
  #75
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Thread Starter
Quote:
Originally Posted by DanDan View Post
The full size 60 degree soffits look too big.
I reckon that angles are an open subject. I would guess that say 30 degree soffits with the speakers angled another 30 would work just fine.
DD
totally confused. the soffits are 30 degrees. the 60 degree reference is the combined angle to both monitors. 60 degree listening position.
Old 18th February 2010
  #76
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Based on my readings at Sayers, soffits need not be sealed, nor extend to the boundaries. I'm not able to do sketches today, but given that development, I am picturing not only the breathable section along the outer edges I have depicted above, but also breathable strips horizontially at the ceiling and floor. Again, for added bass trap response.

I'm pondering something in the area of a 38-40 degree soffit. This should allow me to lessen the center corner effect... it's likely I will also narrow the soffit face a touch, so I can build a wider center false wall.

Again, based on guidelines at Sayers, the soffit face should be 48" wide, with the speaker centered. What I have at the 30 degree soffit, even with the absorption band at the edge is just under that. I think I can get away with narrowing it a touch. Ideal....no. But let's face it, this room is far from ideal to begin with so sacrifices are going to need to be made.
Old 18th February 2010
  #77
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Too quick

Sorry I was editing. The edited version should make more sense, but just in case.
I agree with the northern orientation, now that I do see the closet. Perhaps that closet can be enhanced in it's bass trapping.
60 is a typo or whatever. Rewrite that as 15 plus 15 degrees. That should save a lot of space and should still prevent flutter. My real point is that all angles are open to discussion. Many soffit installations, e.g. OB trucks and other small spaces have no angle. I have also seen the speakers loosely positioned in mounting boxes, i.e. little box shelves, they are then easily removeable for service and are easily angled to ones own taste.
The full seal and all other dictats are an aspiration, but in the real world, with vast bass wavelengths, a gap here and there is hardly a deal breaker.
DD
Old 19th February 2010
  #78
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Quote:
Originally Posted by Mumblesound View Post
Check out the sketch up on this page:
John Sayers' Recording Studio Design Forum • View topic - Small studio in 3D

It's about the same width as your room.
You would have to change some things to suit your length.

Check out any of the "container studio" builds on Sayers' site, for that matter.
Hey Seamus,

I suspect I'm missing another fundamental point. I was looking at that thread, and the sketch-up. I traced what would be an equal lateral triangle on the floor, and it extends way far back in the room. On top of that, they are really high on the wall.

If you follow the link in thread, third post or so, you can see photos of the actual space. His desk is nearly as close to the front wall as mine. I suppose these could be intended for listening further back in the room, as he does have Ns-10 nearfields on the desk... though I suspect no one mixes exclusively on those things.
Old 19th February 2010
  #79
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Weird.
I thought I posted this one:
John Sayers' Recording Studio Design Forum • View topic - 3D of a Basement Studio in Sketchup

This one has about a 9' width.

There are things on that forum that you really have to dig for.
It took me quite a while to discover that the MDF box in Sayers' soffit design is intended to be lined with a decoupling agent (ie mlv, etc). There are other things about the diagram that either assumes a certain amount of knowledge or keeps a secret.

I guess what I'm saying is that I know it's odd, but you can't take pictures at face value.

I fully encourage you to absolutely scour the sub forums there.
You will not be disappointed.
Old 19th February 2010
  #80
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Hey guys.

I talked with my guitarist/co-engineer yesterday about the plans, and he told me he's been thinking of getting new monitors.

After some discussion, we came to the conclusion we should look into some 6"ers. Shallower mounting depth, less cabinet width and height... in addition to bass boosts accompanied by soffits all point in this direction.

I'm currently researching options in the $1500 a pair range, ala ADAM A7, Focal CMS 50, and Quested S6r. May also look into some passive options to eliminate cooling headaches.

Those PROAC Studio 100's look pretty awesome

If anyone has any suggestions I'd be grateful.
Old 21st February 2010
  #81
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If I was in the market for new monitors, I would love to check out ATC SCM11.

You want to stick with passive, right?
Just for the easier mounting..

You can find a used Bryston 4b for $600, I think.
Old 21st February 2010
  #82
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Quote:
Originally Posted by Mumblesound View Post
If I was in the market for new monitors, I would love to check out ATC SCM11.

You want to stick with passive, right?
Just for the easier mounting..

You can find a used Bryston 4b for $600, I think.
Sheesh, 5 reviews later and I finally find someone to tell me they're sealed. Those look nice, though it seems no one likes them quiet. It also worries me a touch that all of the ATC's review links were in audiophile rags. Good new is Vintage King carries them both, perhaps they'd allow a shoot out.

Thanks for the heads up Seamus
Old 21st February 2010
  #83
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Ahem....

Quote:
some sealed box designs e.g. by ATC.
cough cough...... ATC's, particularly the smaller ones appear to be designed for soffit mounting. I have heard them without. Stunning but no bass. Should be good in place.

I wonder if we have focussed/obsessed on the current plan. There is an elephant in the room here, or several. A soffit design will eliminate SBIR, but provides no absorption or modal control. Some measurements, particularly a Waterfall would be very useful in helping to choose between soffit and corner absorbers.
DD
Old 21st February 2010
  #84
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Quote:
Originally Posted by DanDan View Post
cough cough...... ATC's, particularly the smaller ones appear to be designed for soffit mounting. I have heard them without. Stunning but no bass. Should be good in place.

I wonder if we have focussed/obsessed on the current plan. There is an elephant in the room here, or several. A soffit design will eliminate SBIR, but provides no absorption or modal control. Some measurements, particularly a Waterfall would be very useful in helping to choose between soffit and corner absorbers.
DD
Dan I agree measurements need to be done. Hopefully this afternoon.

But I don't see why we have to choose between corner traps and soffits.
Attached Thumbnails
Very small control room remodel... less absorption ETC-sofit-6-.jpg  
Old 21st February 2010
  #85
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Well, this REW is frustrating.

Do I NEED an SPL meter?

I've been trying to fudge around the calibration, but I keep getting level too low messages, and when I crank the mic pre, not only do I get level too low, but also clip messages.
Old 21st February 2010
  #86
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Tweaky

Maybe try ignoring the clip warning and take a look at the graphs instead. FM has no clip light so I just adjust the level to get pretty close to the top graph-wise. Pretty much like recording in the old days! Watch out for clipping at HF in your speakers or amp or output card or device. You may have to resort to longer and repeated sweeps to get a good S/N ratio.
IMHO these softwares are best used relatively. So, I don't think you NEED an SPL meter. However I find an SLM really useful to set repeatable levels, both in measurement and in monitoring, particularly when Mastering. So I certainly recommend getting one and suggest there are better choices than the RS ones these days. I haven't used REW that much but from what I have picked up the actual level is important to get decent decay readings. There is a way to read the ETC I believe which will help optimise the level for decay purposes. It also seems to me that REW does decay readings (Topt) better than most other attempts, so I would persist with it. Might be worth asking the author John, for input on this.
DD
Old 21st February 2010
  #87
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Sigh

Well, I got the error messages to quit, however, there doesn't seem to be any usable data. I'd love to post what's there, but the studio computer isn't online, so I'll have to save and move to this machine.

The "waterfall" shots are nothing but flat lines.

We are practicing soon, so I'm done for the day.

Keep on keeping on I guess.
Old 22nd February 2010
  #88
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Quote:
Originally Posted by dykstraster@gmai View Post
Sigh
Courage. There's a lot of back and forth fiddling to get REW running smoothly
but it's well worth the hassle. We're dying to see your room's response.

I was also under the impression that you didn't need an SPL meter, this is
stated in some places, but it looks like it's necessary to calibrate things
properly. So I'm going to have to get one myself. Is there anything better
than the Radio Shack one for a similar price (ie cheap) ? As DanDan says it'll
certainly come in handy for other things.

I've had to set my levels very high as well.

Paul P
Old 22nd February 2010
  #89
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My day job is as a hearing instrument specialist, so I have access to one (spl meter) for when I go to factories to test hearing and what not. I'll try to get it home from work this week, and hopefully next Sunday I can get it (rew) functioning.

I suppose reading the rew manual wouldn't be a bad idea either.

Just brought home a mix of the hip hop group we are doing. I'm gonna edit down a sample and try to get it up here soon. The rest of the boys are starting to doubt if anything is necessary, I kinda disagree.
Old 22nd February 2010
  #90
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Quote:
Originally Posted by dykstraster@gmai View Post
I suppose reading the rew manual wouldn't be a bad idea either.
I refrained from saying RTFM in case you had, but now that you mention it...

The help page is quite complete and there's a lot of info inside the program itself.

Paul P
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