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Post by Omicron9 on Aug 30, 2019 8:31:46 GMT -6
Greetings.
Work progresses on the new studio. As such, I'm working on the acoustic treatments. My question is about GIK's (or similar company's) combination diffusor/absorbers. Have any of you tried these? If so, are you happy with them? My concern, never having used or heard them in person, is that they could be one of those all-purpose things that doesn't really work as effectively as dedicated diffusors and absorbers. As in, they're better than no treatment, but no match for separate/dedicated diffusors and absorbers.
To wit:
Just wondering.
TIA, -09
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Post by Tbone81 on Aug 30, 2019 8:41:23 GMT -6
I haven’t used their diffusion traps specifically but I did build some bass traps with wood faceplate, almost identical to GIK’s Alpha Series.
My take is this: if you need dedicated diffusion as part of your overall acoustic plan, get a diffuser. If you need primarily bass trapping or broadband absorption but want to retain some of the lively-ness of your room than those alpha series or scatter plates should work great.
In my room my bass traps sucked out too much mid and high end. Adding craft paper to the front side of the insulation and adding wood faceplates really helped balance the room.
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Post by svart on Aug 30, 2019 10:45:05 GMT -6
These are more effective for focusing on specific mid-range frequencies. The amount of reflective area determines the upper cutoff frequency, while the amount of opening area determines the lower cutoff frequency.
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Post by svart on Aug 30, 2019 10:52:10 GMT -6
Also, I wouldn't call them a diffuser at all, that would be a lie as they aren't doing diffusion at all.
I'd call them selectively reflective or selectively absorbative panels, depending on which is the greater action happening.
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Post by johneppstein on Aug 30, 2019 12:33:15 GMT -6
Also, I wouldn't call them a diffuser at all, that would be a lie as they aren't doing diffusion at all. I'd call them selectively reflective or selectively absorbative panels, depending on which is the greater action happening. Right. A diffusor scatters the reflection more or less evenly around the room. A flat plate can't do that. I generally prefer 2-D ("hemispheric" or "skyline") type diffusors. |
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Post by svart on Aug 30, 2019 12:55:07 GMT -6
Also, I wouldn't call them a diffuser at all, that would be a lie as they aren't doing diffusion at all. I'd call them selectively reflective or selectively absorbative panels, depending on which is the greater action happening. Right. A diffusor scatters the reflection more or less evenly around the room. A flat plate can't do that. I generally prefer 2-D ("hemispheric" or "skyline") type diffusors. Exactly. Diffusion doesn't absorb any frequencies, it attempts to redirect all frequencies equally in random directions with the ideal goal of the acoustic properties of the room being identical anywhere in the room. In practice, it's impossible to do but they also take some of the power away from the reflected waves and allows distance to dampen them further by decoupling and scattering the frequencies, but also in practice they have upper and lower frequency limits due to the size of the diffracting elements (unless you look at a place like Blackbird with their crazy diffusion and the room is 75% diffusion).. I guess you could also call these GIK things notch absorbers. |
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Post by gouge on Aug 30, 2019 14:10:19 GMT -6
Also, I wouldn't call them a diffuser at all, that would be a lie as they aren't doing diffusion at all. I'd call them selectively reflective or selectively absorbative panels, depending on which is the greater action happening. the link from the op shows diffusers. its not right to say theyre lying by using the word diffuser as thats what the panels are. |
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Post by svart on Aug 30, 2019 14:25:46 GMT -6
Also, I wouldn't call them a diffuser at all, that would be a lie as they aren't doing diffusion at all. I'd call them selectively reflective or selectively absorbative panels, depending on which is the greater action happening. the link from the op shows diffusers. its not right to say theyre lying by using the word diffuser as thats what the panels are. I clicked on the OP's link.. again.. And no, those are just called diffusors, but they don't actually work by diffusion. Maybe the link is not what OP thinks it is, but where it goes are not diffusion. |
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Post by Ward on Aug 30, 2019 14:49:09 GMT -6
Same basic principal as an absorbing fractal diffusor as I have in my control room. I guess I'll have to post a picture. It's very easy to build!!
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Post by mulmany on Aug 30, 2019 15:26:26 GMT -6
They technically should be calling it scattering instead of diffusion. The BAD panel is not marketed as a diffuser and that is was this is designed off of.
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Post by johneppstein on Aug 30, 2019 15:48:09 GMT -6
Also, I wouldn't call them a diffuser at all, that would be a lie as they aren't doing diffusion at all. I'd call them selectively reflective or selectively absorbative panels, depending on which is the greater action happening. the link from the op shows diffusers. its not right to say theyre lying by using the word diffuser as thats what the panels are. The link shows ONE true diffusor, the "Evolution Polyfusor", which is a very simplistic one-dimensional diffusor design that uses a multi-radius curve as the diffusion element. The other devices on that page are not true diffusors except maybe at one specific frequency, as they lack the necessary variable depth required to provide diffusion over a range of frequencies.
I really don't think much of the type of diffusor that uses a single multi-radius curve and I really don't think much of one dimensional diffusors in general - the main thing that they have going for them is that they're cheap and easy to construct.
Auralex sells a "skyline" style two dimensional diffusor, but I don't know how effective it is since it's made of thin molded plastic.
Generally I prefer the "skyline" type diffusor made out of WOOD. Designs are readily available online and they're not particularly difficult to make for somebody with basic woodworking skills and tools. Their main drawback is that they're on the heavy side - but a diffusor that lacks mass probably isn't going to be effective, as lightweight materials tend to be more or less transparent to audio at many frequencies.
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Post by johneppstein on Aug 30, 2019 15:49:52 GMT -6
Incidentally, the word is properly spelled DIFFUSOR, not "diffuser".
It's a technical term.
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Post by gouge on Aug 30, 2019 16:00:22 GMT -6
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Post by johneppstein on Aug 30, 2019 16:21:15 GMT -6
Most of the stuff on the GIK page superficially resembles the "MLS diffusor" (which is a really crappy design for a diffusor anyway) but they're not that. The MLS uses adjacent strips of two different depths and varying width. Those GIK devices don't - they use a reflective plate but there's nothing behind it besides absorption - nothing to reflect. Therefore it's NOT a true diffusor, not even an MLS. And most of what I saw there doesn't really vary the width of the non-cutout areas of the plate which is vital to diffusion at multiple frequencies in that design.
Again, the ONLY real diffusor on that page is the "Evolution Polyfusor", which uses the variable radius of the curve to provide quasi-randomized scatter and the varying depth of the curved surface to make it work across a range of frequencies. The problem with that design is that it only provides scatter in the horizontal plane.
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Post by gouge on Aug 30, 2019 16:32:26 GMT -6
i dont agree with your post john
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Post by svart on Aug 30, 2019 19:15:41 GMT -6
Most of the stuff on the GIK page superficially resembles the "MLS diffusor" (which is a really crappy design for a diffusor anyway) but they're not that. The MLS uses adjacent strips of two different depths and varying width. Those GIK devices don't - they use a reflective plate but there's nothing behind it besides absorption - nothing to reflect. Therefore it's NOT a true diffusor, not even an MLS. And most of what I saw there doesn't really vary the width of the non-cutout areas of the plate which is vital to diffusion at multiple frequencies in that design.
Again, the ONLY real diffusor on that page is the "Evolution Polyfusor", which uses the variable radius of the curve to provide quasi-randomized scatter and the varying depth of the curved surface to make it work across a range of frequencies. The problem with that design is that it only provides scatter in the horizontal plane.
Correct. It's not using the principle of diffusion for their effect, they're using frequency selective absorption or reflection, which are not the same as diffusion in any real regard. I don't understand why gouge has an issue with this. Companies call their products things that they aren't all the time. I'm sure these products work just fine for what they're being sold for, but they're not true diffusers. |
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Post by gouge on Aug 30, 2019 20:43:35 GMT -6
for starters all acoustic treatments are frequency selective and mix from scatter to diffusion. non frequency selective don't exist.
so no diffuser is perfect. they all have notches, lobes, frequencies of scatter, and absorption. it depends on room, placement etc.
in johns example a polyfusor does not scatter only in the horizontal plane. that depends on how it is installed. it can do vertical and any angle in between.
if you read the data and speil on the webpage you will see that they use the word scatter and diffuser depending on product.
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Post by gouge on Aug 30, 2019 20:48:19 GMT -6
Right. A diffusor scatters the reflection more or less evenly around the room. A flat plate can't do that. I generally prefer 2-D ("hemispheric" or "skyline") type diffusors. Exactly. Diffusion doesn't absorb any frequencies, it attempts to redirect all frequencies equally in random directions with the ideal goal of the acoustic properties of the room being identical anywhere in the room. it's impossible to build a diffuser that doesn't absorb. just placing a diffuser on a surface leads to absorbing not even taking into account what the diffuser is made of and varying the distance behind the diffuser. |
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Post by svart on Aug 30, 2019 22:01:13 GMT -6
Exactly. Diffusion doesn't absorb any frequencies, it attempts to redirect all frequencies equally in random directions with the ideal goal of the acoustic properties of the room being identical anywhere in the room. it's impossible to build a diffuser that doesn't absorb. just placing a diffuser on a surface leads to absorbing not even taking into account what the diffuser is made of and varying the distance behind the diffuser. By definition, a diffuser doesn't absorb. It redirects the sound pressure in equal but random directions. It has zero to do with absorption. A flat plate with holes is not a diffuser, and placing it on front of absorption doesn't make it a diffuser either. Maybe you're thinking of the term "resonator"? I'm not sure how to explain it any better, but I think you have your terminology mixed up or something because what you're saying is unfortunately not correct. |
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Post by gouge on Aug 31, 2019 1:00:17 GMT -6
a flat plat with holes is very much a diffuser.
what do you think a binary amplitude diffuser is.
putting a diffuser over an absorber doesnt stop the diffuser from being a diffuser and can actually enhance the absorber behind to absorb certain frequencies better.
win win situation.
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Post by Omicron9 on Aug 31, 2019 7:32:40 GMT -6
Most of the stuff on the GIK page superficially resembles the "MLS diffusor" (which is a really crappy design for a diffusor anyway) but they're not that. The MLS uses adjacent strips of two different depths and varying width. Those GIK devices don't - they use a reflective plate but there's nothing behind it besides absorption - nothing to reflect. Therefore it's NOT a true diffusor, not even an MLS. And most of what I saw there doesn't really vary the width of the non-cutout areas of the plate which is vital to diffusion at multiple frequencies in that design.
Again, the ONLY real diffusor on that page is the "Evolution Polyfusor", which uses the variable radius of the curve to provide quasi-randomized scatter and the varying depth of the curved surface to make it work across a range of frequencies. The problem with that design is that it only provides scatter in the horizontal plane.
The Evolution model was the one in which I was interested. I suppose you could get scatter on both the horizontal and vertical planes, based on how you mount it, yes? IOW, mount one (or more) vertically; one (or more) horizontally. At a 90-degree angle to each other. Very interesting points of view and information; please keep it coming! TIA, -09 |
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Post by Tbone81 on Aug 31, 2019 8:28:36 GMT -6
Most of the stuff on the GIK page superficially resembles the "MLS diffusor" (which is a really crappy design for a diffusor anyway) but they're not that. The MLS uses adjacent strips of two different depths and varying width. Those GIK devices don't - they use a reflective plate but there's nothing behind it besides absorption - nothing to reflect. Therefore it's NOT a true diffusor, not even an MLS. And most of what I saw there doesn't really vary the width of the non-cutout areas of the plate which is vital to diffusion at multiple frequencies in that design.
Again, the ONLY real diffusor on that page is the "Evolution Polyfusor", which uses the variable radius of the curve to provide quasi-randomized scatter and the varying depth of the curved surface to make it work across a range of frequencies. The problem with that design is that it only provides scatter in the horizontal plane.
The Evolution model was the one in which I was interested. I suppose you could get scatter on both the horizontal and vertical planes, based on how you mount it, yes? IOW, mount one (or more) vertically; one (or more) horizontally. At a 90-degree angle to each other. Very interesting points of view and information; please keep it coming! TIA, -09 Yes, staggering them at 90 degree angles will give you diffusion in both planes. But be careful how you mount them. They need to be spaced somewhat apart as two adjacent polyfusers, if too close together, will create a concave surface that focuses sound at a certain point/direction. Polyfusers are easy to build. If you go that route check out this company They no longer sell the pre-made kit but if you call or email them they'll give you the parts list and you can order them off their website. |
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Post by lando on Aug 31, 2019 10:43:34 GMT -6
All i know is that I trust GIK very much, to my knowledge they are one of the few companies in the treatment business who are both knowledgable, extremely transparent and measure all their products in a scientific way which they post on their website. Write them an email, their support is second to none!
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Post by johneppstein on Aug 31, 2019 12:16:13 GMT -6
i dont agree with your post john That's Ok. You haven't been studying the subject for about 30 or 40 years, either. I've been fascinated by diffusors ever since the first time I set foot in The Automatt a long time ago. They were one of those studios that had custom designed diffusors that looked like modern wall art. |
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Post by johneppstein on Aug 31, 2019 12:18:08 GMT -6
a flat plat with holes is very much a diffuser. what do you think a binary amplitude diffuser is. putting a diffuser over an absorber doesnt stop the diffuser from being a diffuser and can actually enhance the absorber behind to absorb certain frequencies better. win win situation. No. A flat plate with holes in a frame is a Helmholtz Resonator. |
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