Constrained layer speaker cabinets

beat · « **on:** 16 Jan 2005, 07:05 pm »

Hey guys,
anyone have any info or know where I can find some guidelines for constrained layer boxes? I want to play around with easy to build concrete tube based boxes..possibly some line arrays eventually. I remember someone turned me on to someone elses project once but I can't find it now.
thanks.
beat

JLM · « **Reply #1 on:** 17 Jan 2005, 02:37 am »

Easiest to build would be sections of concrete pipe, but I sure wouldn't try it. Some poor guy a couple of years ago tried to build the Decware RL-1s out of concrete pipe and reportedly it sounded horrible. Search the Decware forums if you like.

Cylinderical forms for concrete is another story. The geometry of a circle is inherently strong to uniform pressures. And if they can hold up to the pressures of wet concrete they'll surely work for as speaker cabinets.

JoshK · « **Reply #2 on:** 17 Jan 2005, 04:15 am »

Lest us not forget simple geometry! We have all heard it said that a box resonance, and boxes in general, can wreak havoc on the sound reproduced by drivers because the reinforcement of tones of a wavelength matching the inner dimension of the box.

This reinforcement happens for the entire length of one side of the cabinet in a square since the distance between the two sides is the length of reinforcement. Now, in a cylinder the diameter is now that length, which by a little deduction is going to be much longer than side of a rectangular volume of the same volume. Now unless I have misunderstood something about how these standing waves occur, I would think that cylinders would be the mathematical worst of all shapes. A tube with an oval cross section seems to be a much better bet....think B&W Nautilus series.

beat · « **Reply #3 on:** 17 Jan 2005, 05:54 am »

Thanks guys,
Maybe I'm not too far off track then. When I said concrete tube, I was referring to the form, and as for the shape, I was thinking of splitting it down the length and attatching it to the flat baffle. I would probably end up with a little over half of the tube from the plan view..a C shape basically. My idea for using the tube was to try and eliminate standing waves in the first place...I dont know what's going to happen with this but we'll find out.
thanks again.
beat

Christof · « **Reply #4 on:** 20 Jan 2005, 06:42 pm »

Beat

Search DIYaudio.com You will find lots of information there. I had a nice thread going about 6 mos ago on various methods/materials. You might also search for CLD.

beat · « **Reply #5 on:** 22 Jan 2005, 04:43 am »

Thanks C,
I found a ton of information over there..cool site, cant believe I havent been there before. Seems like alot of knowledge is shared over there. I have a mockup going and will spend the weekend dialing it in. Tomorrow I'm going to play with the port as so far they sound good but bass is lacking..I know I can get more out of these 8" woofers. On that note, I'm liking these little silverflute tweeters!