I received Oblique Micro Perforated panel information last year, and finally decided to tried it in my theater room.
The benefit is simplicity of broad band absorption with deep enough cavity.

Compare with isolation material, it is more expensive, but it is almost permanent when install indoor without health hazardous concern.

The absorption coefficient reference as attached.

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the only perforated acoustic panels I've seen on the market are these: https://kineticsnoise.com/interiors/sereno.html
They are mounted in front of other absorption materials.

As for a panels designed to absorb sound at certain oblique angles, I haven't seen a product. Did a quick search and could only find theoretical papers

Jeff,
I actually bought few customized size OMP panel from manufacturer, CKM.
The product name is SoundMicro.

Micro perforated means each hole is 0.04mmx0.44mm, perforated rate around 0.7%.
It is a new material for long lasting, low maintenance absorption for in/out door applications.

From the example case shown on CKM's website, a recording studio used the panel for acoustic treatment.

Therefore, this material is new to US members.

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Interesting, I looked at some of the CKM website material. The two rooms next to each other video was very interesting. But I couldn't find any reference to the oblique principle that you mentioned in the first post.

Is this available to purchase without going to Taiwan City lol, link please

Jeff,
The thesis papers are in Chinese. you can search "The study on sound-absorbing properties of oblique micro-perforated panel" by Chung-Chiech Chiang
In the original post, a report of new sound absorption material was written by National Taiwan Ocean University


It is quite interesting.
For Home theater application, it is not cost effective compare to other porous absorbent. However, it will be a good choice for ceiling and front corners.

Currently I made some wood boxes and test the low frequency absorption capability.

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I bought OMP panel directly from CKM sales in Taiwan.
I am not sure if CKM would ship it overseas.
quote from wiki :"The main reason why Micro Perforates have become so popular among acousticians is that they have a good absorption performance but without the disadvantages of a porous material. Furthermore, an MPP is also preferable from an aesthetic point of view"

There are equivalent products in Germany and China
decustik.com

According to the first graph you posted from the research, Your micro perf with .04 x.44 mm holes would be minimally effective at low frequencies. Bottom left corner less than 5% and dropping below 100hz.

[quote=BIGmouthinDC;58911996]According to the first graph you posted from the research, Your micro perf with .04 x.44 mm holes would be minimally effective at low frequencies. Bottom left corner less than 5% and dropping below 100hz.


the graph shows the absorption rate versus cavity depth.
micro perforated panel sound absorbing principle is similar to helmholtz resonator but in a very small scale. the neck of the helmholtz resonator on the panel is the size of a hole (0.04mm x0.44mm) with 1mm thickness.

at 400mm depth cavity, absorption rate at 100Hz is 0.68.

Currently no experiment was done for 500mm or deeper cavity. I would expect that it could reach 0.5 for 63Hz.

I asked a sales today, and his information is that CKM sells this OMP in the US, Japan and India. I guess there is no US website yet.

There are microperforated lexan panels available in the US if you need some combination of sound absorption and transparency. Interesting products, and the measurements look solid.

Hi Bigus,
Do you have any spec of the Lexan microperforated panel? what's the hole size, and perforated rate? thickness and purchase information?
Thank you

RPG offers the clearsorber panel, they have some data on their site. http://www.rpgeurope.com/products/product/csheet.html

There is also a company out of Norway called deamp that looks to offer some sort of slit perforated transparent product.

Thanks to Bigus

I found more information on RPG group website.
http://cms.esi.info/Media/documents/...berShee_ML.pdf

The spec is 0.5mm hole, 1.0mm thickness and 5mm spacing. It is quite interesting

Main benefit of the microperf panels is aesthetics...it doesn't look like an acoustic panel.

I can't see the benefit of application in most home theaters. Downsides are cost and better performance of other types of panels.

I can think of only one possible obscure use for home HT, which is why I ran across them: if you wanted the equipment visible through a window in side or rear of room but that fell at a location you wanted to absorb a specular reflection. My layout has morphed during house design and construction and I don't have that dilemma anymore.