Concrete Pipe Speaker

[TEXAS TOMM]

Some years ago, - possibly in the 70`s - there was a project in a magazine (Wireless World?) that employed an upright concrete sewer pipe.
I have tried to find details on the net - without success. Can anyone point me in the right direction?

[rjb]

HiFi news between 59 and 62 published a number of designs by Ralph West and Rex Baldock, one of which was the Tricolumn, based on a pipe with a second internal pipe which formed effectively a tapered expanding column. A number of designs covering different pipe materials (including concrete) and driver sizes were given, with the derivative calcs. and listening notes.

Another possibility was a design by Briggs, prior to that, based on a concrete pipe with a restrictive membrane part way down to suppression resonances

Note these were all before T$S parameters were defined, so very much trial and error designs. I have more info if needed.

[Nanook]

there have been some "tubular" enclosures that work.

Linkwitz Pluto

Also look at Decware RL1.5

and of course...t-linespeakers

there are more out there, it depends on how much time you have to do a search.

stew

[fpara]

There is this also:

http://www.speakerbuilding.com/content/1019/

[speakerdoctor]

Here's a very nice looking concrete design.

http://www.speakerbuilding.com/content/1106/
click on the fig. links near the bottom to see pics.

I once saw one build out of a simple concrete block - the type used to make walls of buildings. Small openings limit ths size of the woofer though. Hey, but if you are willing to live with a small, two-way.....

IMO, some builders get too hung up on cabinet resonances. There are much bigger problems to solve when building and designing a speaker to work correctly in the biggest mystery of them all - your room!

[jamikl]

Texas Tomm, you are quite correct. Like you I can't remember if it was wireless world the article appeared in. I think the speaker used was one of the 12" Phillips around at that time with an Fs of about 19 - 21 Hz. It apparently could move the pipe when operating at volume. I think the speaker was mounted in the bell or coupling end of the pipe and faced downwards, a few inches above the floor.
jamikl