Francesca, a new dipole project

I’ve started a new dipole project, using the BG Neo3 PDR, Mark Audio CHR-70 (version I), and a pair of Exodus Audio DPL-10s (no longer in production, sadly). I’ve dubbed it “Francesca” for no particularly good reason. This project is an exercise for me to learn more about speaker measurement. Also, I want to see what can be done to make a dipole speaker for use in small rooms – or more specifically my study, which is 2.7m wide by 4.3m deep. I also wanted to experiment with getting dipole radiation from 30/40 Hz up to 20,0000 Hz. High output is not one of the primary goals.

Here is the prototype baffle. As you can see, it’s made quickly and cheaply. The baffle is a 12×36″ piece of 1/2″ chipboard. Nuff said – it’s a prototype to be thrown away when a better one is built.

The initial version of the prototype is running with a very simple passive crossover.┬áThe bass and mid/tweet are bi-amped so I can have gain control over the two sections. The woofers are low-passed with 5.5mH, and there is a first-order crossover at around 1700 Hz between the mid and the tweeter. A high-pass on the mid is done at line-level at the input to the amp. Yes, it’s a bit quick-and-dirty.

Here is the positioning of the prototype in the room. Initially there were pulled further out from the rear wall, but I was getting a big null at 100 Hz, this positioning gives a smoother response.

A miniDSP is on the way.

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