So, I felt rather adventurous today, and, having successfully made a hydrophone earlier this week, I felt fairly confident in my building skills as well. So, I decided to attempt to make one of these. The article calls for aluminum tubing, but although I felt confident, I didn't feel confident enough to drop $200 on this project. I, like Selcuk, often turn my DIY projects into RIY projects. So I decided to make a prototype out of PVC pipe (which dropped the construction price to $25 - a admission fee worth the fun even if I fail...). So, if it works, and fairly well, I may venture into making one out of aluminum. We'll see...
I bought the pipes today, as well as epoxy and such. I've gotten the main pipe system almost put together, but I ran out of epoxy around midnight, so I'll give it a rest til I can get some more tomorrow.
Here's what I have so far:

(source: colinhartonline.com)

(source: colinhartonline.com)
Once I'm done with the project, I'll post a blog about the whole process, as well as recordings (however they turn out...)
Wish me luck!