Phase IV complete

This post has nothing to do with ants. Twenty five years ago Graham kindly sold me at cost a pair of really nice bass drive units which I built into a pair of speakers. The only calculations I did were some fairly rough estimates of air volumes for the cabinets. I built a new design using the same drivers about 2 years later and the result was a slightly worse sounding speaker. I left them in my father's attic when I moved to France in 1990 and he, in turn, left them for the dustmen in one of his major clean-outs. So my 801 bass units are, regrettably, gone.

So when I set out to build another pair this August, I decided to use the cheapest drive units I could find. This time, however, I had some really remarkable design software thanks to Mark Zachmann, a computer, and some measuring equipment. The design was sketched in August I started cutting wood in September. The speaker (I decided to build only one prototype) saw its first activity this week.

Here it is next to one of the B&W DM6s I bought in 1979 and which has been my principle pair of speakers ever since. The crossover is sitting on the top of the DM6; I wanted to be able to adjust the component values without having to take the cabinet apart.  

I can't say for certain yet, since I'm listening to a B&W in one channel and my latest attempt on the other, but I think this time I've got something that sounds at least as good or even a tiny bit better than the B&Ws.

I've tried to do a farfield measurement and the only problem seems to be a bit (-15dB!) of a hole between 1-2k, but I'm not sure whether that's something to do with the room since the B&Ws exhibit a simialr problem when I measure their response. I've been listening to them almost continuously for three days and the sound is not in the least bit fatiguing, a good sign I think.  

So over the break I will be getting some more wood and building its companion. I know it's ugly, but I have yet to learn how to apply veneer. The drivers are Vifa D27TG45 (unfortunately no longer made but Scan-Speak makes some pretty similar ones), Scan-Speak Discovery 15M-4624G and a pair of Silver Flute W20RC38-08s. The Silver Flutes are made by a Chinese company, Vifa is a merger of a Chinese manufacturing firm and Danish designer.

I'm also thinking about building (Phase V) a two driver design using an Aurum Cantus  250F1 and an SB-Acoustics SB29RDC-C000-4 which I will probably cross over at about 700Hz.  Too much to do, too little time...