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I am just learning about room treatments and would like to do it architecturally

righthookmike

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I would prefer not to put panels all over my ceiling corners, I was thinking of putting false beams across my ceiling to stop reflection, It would be cheaper for me since I'm a carpenter and would stop my game/listening room from looking like a recording studio. can anybody help with proper placement to be most effective and I could also run posts on the wall to the beams to break up the straight shot down the wall. Would this work? It is an outdoor covered area with walls on 3 sides. I could give dimensions and sketch a quick floorplan
Mike
 

FeddyLost

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It is an outdoor covered area with walls on 3 sides.
Typically this will at least greatly help if not fully prevent LF problems as all long waves will exit very fast.
If you will find something annoying in mids-highs, you can always add some wooden diffusion panels. But without one wall you can just slightly angle other walls and slope ceiling, so all reflections will fly out in few milliseconds.
 
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righthookmike

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It is the mid highs. thank you for your response, how can I calculate where to put the first beam? I think I read the best place to break it up is at the quarter wave? Please remember I only understand the basic concept. It's nothing I've ever done and I just began looking into it as a real consideration the past few days
 

DonH56

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Mid-highs you usually damp first reflection points. Draw a triangle with equal sides and base wide enough to touch the speaker and the ceiling. Center an OC-703 or whatever panel at the top point. If you are relying just on a bare beam, that is not likely to work well, but you'd want it just a little before or behind to block the sound wave reflecting off the ceiling so it intersects the sides of the triangle.

1615405813107.png
 

MRC01

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Can you adjust the relative dimensions of the length, width, height? Golden mean or 1.62:1 is a good ratio. It helps spread out the modal frequencies of the wall-to-wall distances (floor-ceiling, L-R, F-B).
PS: you mentioned doing this architecturally, so ...
 
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FeddyLost

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how can I calculate where to put the first beam?
I don't really understand what do you have now and why do you want to diffuse some ceiling reflections.
Can you just add picture or plan with description?

PS If you don't have one wall, you can relocate speakers and listening point so all the "backfire" will fly outside, for example.
 
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righthookmike

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pic of whole area . pic as2 is standind in front of speaker. the back wall is the problem area and i was thinking beams on ceiling and along left wall im going to build cement stepped shelving to make it a part of the wall and break up smooth walls. thoughts?
 

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righthookmike

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SWEET! I have a need to be outside(but I believe I could hang out there for a good amount of time) so I have to balance between what I really want and what I'm willing to let slowly deteriorate from the elements
 
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righthookmike

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Mid-highs you usually damp first reflection points. Draw a triangle with equal sides and base wide enough to touch the speaker and the ceiling. Center an OC-703 or whatever panel at the top point. If you are relying just on a bare beam, that is not likely to work well, but you'd want it just a little before or behind to block the sound wave reflecting off the ceiling so it intersects the sides of the triangle.

View attachment 117449
OK, I think Ill manufacture "beams" made of OC-703. this definitely helps. Question. based on your drawing, If i picked any point as "listener" would equal lateral triangles continue on from that point? and if so can I base my dampening on an equation to block higher frequencies? what is a good reference for sound wave legth? I can play with positioning but it would be nice to use math instead of guessing
 
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pozz

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Can you adjust the relative dimensions of the length, width, height? Golden mean or 1.62:1 is a good ratio. It helps spread out the modal frequencies of the wall-to-wall distances (floor-ceiling, L-R, F-B).
Not necessarily. Please don't repeat acoustical folklore. This depends on anything leaky like doors, windows, vents and includes the walls themselves, which will pass, reflect and absorb sound in uneven proportions and end up affecting the distribution of modes.
pic of whole area . pic as2 is standind in front of speaker. the back wall is the problem area and i was thinking beams on ceiling and along left wall im going to build cement stepped shelving to make it a part of the wall and break up smooth walls. thoughts?
This is really interesting. The reverb times will be really long, so I expect clarity to be a problem. I really have no idea what to recommend, though, as a practical solution. If I were you I would look up case studies of commercial swimming pools and the solutions used there.

Big swimming pools use floating baffles or variations of that.
1615482414184.png


I don't know how resistant the usual fibreglass is to sunlight, humidity and chlorine. Whatever solution you go with, some research into the absorbing materials is necessary.
 

MRC01

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Not necessarily. Please don't repeat acoustical folklore. This depends on anything leaky like doors, windows, vents and includes the walls themselves, which will pass, reflect and absorb sound in uneven proportions and end up affecting the distribution of modes.
...
The notion of avoiding length, width, height to be integer multiples of each other is not folklore, it's based on physics.
If the room is a cube, the modes will be stronger as the length, width & height will all support (and null) the same wavelengths. To different degrees, sure, due to factors you mention. Yet the principle still holds.
If the length is twice the width, some modes will overlap, which makes them stronger.
 

DonH56

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OK, I think Ill manufacture "beams" made of OC-703. this definitely helps. Question. based on your drawing, If i picked any point as "listener" would equal lateral triangles continue on from that point? and if so can I base my dampening on an equation to block higher frequencies? what is a good reference for sound wave legth? I can play with positioning but it would be nice to use math instead of guessing

They are not in general equilateral; the sides must be equal (so angles of incidence and reflection are the same) but their length and that of the base depends upon the distance from speaker to listener and ceiling (or panel -- mine are suspended from the ceiling a few inches) height. But yes, that is the idea. For my media room I ended up with a series of triangles (used a basic drawing program to make it easier) for different speakers and listening positions. That resulted in a range of places I needed to treat but I was able to get away with a single panel that covered the range in most cases.

How well they absorb depends upon their size (depth, thickness), wavelength, and position from the wall (or ceiling), but in general placement with respect to first reflections does not depend upon wavelength (these are considered broadband absorbers). That is, line up the triangles as you would for "line of sight", and place panels accordingly. This also works for walls, just turn the "ceiling" into a "wall" (rotate the triangles).

I keep forgetting this is outside, which makes for some interesting issues. If they are exposed to rain, you'll need to waterproof them, and that will change their sound absorption. It may be better to use a less-absorbent material and treat this as an exercise in diffusing the sounds waves rather than absorbing them. For outdoors, hanging baffles as @pozz showed are often used, or you can make a sort of lattice/trellis and attach to the ceiling, something like this:

1615490115739.png
 

pozz

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The notion of avoiding length, width, height to be integer multiples of each other is not folklore, it's based on physics.
If the room is a cube, the modes will be stronger as the length, width & height will all support (and null) the same wavelengths. To different degrees, sure, due to factors you mention. Yet the principle still holds.
If the length is twice the width, some modes will overlap, which makes them stronger.
Yes, avoiding coincident dimensions makes sense, but what you suggest assumes completely stiff, nonpermeable boundaries, not lossy boundaries capable of flexing and introducing phase shift. In the end apparent physical dimensions are not the same as acoustical ones. In acoustical literature that's about all that's accepted.
 

FeddyLost

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the back wall is the problem area and i was thinking beams on ceiling and along left wall im going to build cement stepped shelving
I'd say cheapest way that will 100% work is a sandwitch from wooden irregular (quasi-random in both dimensions) lattice and a big thick pack of fluffy rockwool in polymer film (to prevent moisturising and rockwool particles escape) behind lattice. If you can, fix it with airgap from real wall. Thickness of lattice beams will define frequiencies that will be scattered and not absorbed.
For mid-highs any masonry is overkill, even painted MDF reflects those frequencies completely.
Laquered woodwork will be also completely OK.
Mid-highs propagate like laser beam, so you can use simple "mirror check" with placement planning. If you see speaker from listening point through the mirror on the wall/ceiling - put your absorfusor there.
Regarding reflections from pool side to listener point I really don't know ... maybe you can add few layers of wooden beaded curtains to scatter some of echoes from right side, but it will be not cheap, I think, as big wooden beads are expensive. Big rolling (movable) panel from twin lattices and rockwool pack in between will be also OK.
 
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righthookmike

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OK, I think Ill manufacture "beams" made of OC-703. this definitely helps[/
Not necessarily. Please don't repeat acoustical folklore. This depends on anything leaky like doors, windows, vents and includes the walls themselves, which will pass, reflect and absorb sound in uneven proportions and end up affecting the distribution of modes.

This is really interesting. The reverb times will be really long, so I expect clarity to be a problem. I really have no idea what to recommend, though, as a practical solution. If I were you I would look up case studies of commercial swimming pools and the solutions used there.

Big swimming pools use floating baffles or variations of that.
View attachment 117624

I don't know how resistant the usual fibreglass is to sunlight, humidity and chlorine. Whatever solution you go with, some research into the absorbing materials is necessary.
No problem with the sunlight. It's only the area between pool table and dartboard(when playing darts) and I believe I have enough info now to at least start. I'll post after I try some things
I'd say cheapest way that will 100% work is a sandwitch from wooden irregular (quasi-random in both dimensions) lattice and a big thick pack of fluffy rockwool in polymer film (to prevent moisturising and rockwool particles escape) behind lattice. If you can, fix it with airgap from real wall. Thickness of lattice beams will define frequiencies that will be scattered and not absorbed.
For mid-highs any masonry is overkill, even painted MDF reflects those frequencies completely.
Laquered woodwork will be also completely OK.
Mid-highs propagate like laser beam, so you can use simple "mirror check" with placement planning. If you see speaker from listening point through the mirror on the wall/ceiling - put your absorfusor there.
Regarding reflections from pool side to listener point I really don't know ... maybe you can add few layers of wooden beaded curtains to scatter some of echoes from right side, but it will be not cheap, I think, as big wooden beads are expensive. Big rolling (movable) panel from twin lattices and rockwool pack in between will be also OK.
I'm not worried about the pool. It isn't an issue it's photobombing... I already have a pretty good idea how Im building the beams and I was already going to build the shelves because I think they will look good. I'll take pics of the build process. What I'm doing will be fairly straight forward, I just need to see what 703 is really like. It'll be my next project after the speakers I'm restoring
 
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