researching diy speaker shapes?

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I am in an Acoustics class and for a final project I would like to research the different shapes of speaker cabinets on frequency response and other factors that effect the overall speaker performance. I would eventually like to build the design I find as optimal from this research, and I would gladly post my findings when I am finished researching. However, I do not know where to start researching at. I have seen some posts on here before with exotic shapes, but I have not been able to find articles explaining the effectiveness of these exotic shapes. Could you please point me in the right direction. Thanks,

Austin
 
Hi Austin,

I found three magazine articles that might help you. Two are the two parts of Jim Moriyasu's articles in Speaker Builder 7&8/2000 entitled, 'A Study of Midrange Enclosures'. He tries lots of different shape enclosures and analyses them both with FR and CSD (waterfall) measurements.

The same author chimes in again with a related article in AX February 2002 entitled 'Panel Damping Studies: Reducing Loudspeaker Enclosure Vibrations'. I only have SB an AX from the start of 2000, so I'm sure there are other articles of interest in these mags too. I don't have a scanner to send them to you unfortunately.

My personal view is, as much as practicable, don't use a box. Open baffles, labyrinths, transmission lines all removed the rear wave as much as possible from the driver so less of it is able to re-enter the listening space delayed and distorted through the cone (the exception being reactance anulling in horns).

There are others here who have far more experience than me and hopefully they'll put in more helpful info for you. If I find anything more amongst my files I'll post it.

Good luck, and please post your work when it's completed.
Cheers
 
Hello Austin,

Sonus Faber has a patent on the Amati enclosure shape. Try this link to read the review of Amati:

http://www.stereophile.com/showarchives.cgi?139

The article mention the lutelike shape.... but it doesn't mention the patent number of it. But probably, it could help you to the right direction for you research.

PS: If you do find the patent for this lutelike shape of amati, tell us, okay? :)

Regards,
 
thanks

Thanks guys,

I am off and running with the project, which is looking alot better than I initially imagined. I wish I had access to more books, but since I am studying in France this summer, they are a little hard to come by. After reading quite a bit, unfortunately it is looking like the most effective way to eliminate standing waves and reverberations is to use dampening material. Each shape has its own cons, but there appears to be much to gain over the typical rectangle by using more exotic shapes which may minimize the amount of dampening material one should use on the inside of the enclosure. However, the shape of the outside of the enclosure seems to be have a greater effect on the response, causing unwanted diffractions. I will see if I can find any studies about baffle treatments which may minimize these effects. I won't give any clues as to the best shapes yet. You'll have to wait till the research is complete. I will post the report in about 2 weeks.

Austin
 
I've done a similar study that took over a year of research and several different prototypes and listening tests. When all was said and done the shape that I found to be the overall best was a tapered octagon, with a dual wall construction and a tar slurry between the 2 walls and a final coat of rubberized tar on the inside.

SST8 DIY Speakers
http://64.33.91.28/kingdaddysst8/index.html


Also try this link for some seriously wierd speaker shapes, my sst8's are featured on page 29 as well.
http://exoticaudio.org/

Good luck with your study.
 
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