Quote:From what I observe and understand about this design, as with just about any of the RPG products, I would highly recommend them for what they are designed to do. This makes for an excellent product to place within a ceiling grid. It is two-dimensional based upon the primitive root system. The benefit to this is the fact that divider sections are not so critical within a design such as this with the added fact that periodic lobing will not be so much of an issue. I believe that one would be hard pressed to surpass the performance ratios of this design with current designs offered for use in a ceiling grid. That is not to say that something close or even better can not be designed by alternate methods. This does indeed work beyond a shadow of doubt.
Quote:On the same site I found a bass trap with a membrane which turns the sound energy into kinetic which is easier to stop. I don't have a lot of place for bass traps because of a door, so would this one do it instead, and can I build it by myself?
http://www.rpginc.com/products/modexcorner/index.htm I absolutely am on board with this concept!! The principle behind this design is very impressive. It is not hard to understand why this type of unit provides such great acoustical coefficients across the audio spectrum.
Absorption techniques are just as important as that of diffusion techniques. This design is an example of high performance coefficients over a very large portion of the frequency spectrum where it counts the most.
I have experimented with large diaphragmatic designs in the past, which were coupled directly into the room corners from floor to ceiling. This provided a spectacular result in it’s own with a dramatic transformation within the room’s frequency balance. I have no doubt that these modules will provide that level of improvement when placed properly within the room.
If you do not remember anything else, just keep this critical rule in mind for all of this to be justified.
Know the Minima / Maxima rule! Maintain the Odd-Order Quarter-Wave principal in all of your designs, and placement within the room.
Do that and results should be optimum for you.
I am well aware of the RPG designs past and present. I maintain full respect for what they offer in a technological perspective. After all, I have put many of their designs into practice with great results.
If you had observed the large Binary Grid Diffuser units placed behind the speakers at the top of this thread, you would notice that they are patterned very closely to that of RPG's design.
These are practically clone's with a computer generated grid of binary code that is of the same principal and tactic. This type of unit built with a degree of curved proportion as shown represents a new generation of diffusion design, with vastly improved coefficients over a much greater area of the audio spectrum.
These offer significant improvement over that of the QRD designs in more than one aspect. Not only do they maintain far wider range with superior coefficients, but also they are more effective at closer range within a small room. The detrimental aspect of periodic lobing which is inherent within QRD repetitive placement, is no longer a problem with these modern designs.
Through sophisticated computing techniques, new innovative design standards are quickly placing the old QRD & primitive root based designs into obsoletion. The movers and shakers behind this technology just happen to be a major influence behind the information focused upon within the well-respected Master-Handbook-Of -Acoustics series of publications. These movers and shakers just happen to be those responsible for RPG's success.
The major drawback to actually acquiring products from RPG is that of cost. If you can afford these products then that is fine. I think that the average audio enthusiast will have a hard time justifying the total cost for these products on a large scale.
If you understand the principles and how to put those principles to work for you at the greatest benefit possible, plus have the ability to build your own versions with respectable accuracy, then it is of your best interest to build your own when budget restraints are the deciding factor.
That is what we are doing here. The best techniques are considered as the basis for design, while cost no longer presents prohibitive barriers for which a designer must place limitations. The bang for the buck ratio here is of tremendous value within a very affordable outcome.