D-MAN Posted February 2, 2006 Share Posted February 2, 2006 Boy, there is certainly nothing new under the sun! (Vanity of vanities!). We've all seen (and probably even heard) the B&W Nautilus... But is the technology new? I found a patent that would say NOT. First up, here is a pic of the B&W flagship loudspeaker "Nautilus". Quote Link to comment Share on other sites More sharing options...
D-MAN Posted February 2, 2006 Author Share Posted February 2, 2006 Now here is a patent from 1959 that seemingly establishes the technology. Ok - so turn the horn around (i.e., invert it so the throat is at the opposite end as a termination) and what have you got? A B&W Nautilus, of course! Note that the horn channel itself is terminated, it does not actually vent to the atmosphere. The idea is to damp the backchamber using a reversed horn termination. In the patent, the horn is not reversed, but the idea is essentially the same. The unreversed backhorn in the patent is used to be somewhat additive to the back of the cone - the reversed horn in the B&W is used to acoustically damp the back of the cone. I found another even earlier patent (not handy right now) that also uses damping on the front of the horn driver cone using bifurcated terminated columns. Same concept, different implementation. But the concept has been around since before I was born, and that means ITS OLD! DM Quote Link to comment Share on other sites More sharing options...
seti Posted February 2, 2006 Share Posted February 2, 2006 I've heard kaiseerSetSay's B&Ws driven by BAT gear and some nice 800 B&W series driven by mac gear and I have always found them to sound really good. Quote Link to comment Share on other sites More sharing options...
boom3 Posted February 2, 2006 Share Posted February 2, 2006 I don't think the "cochlear" Nautilus is still in production. It was very expensive to build. I think the current Nautilus 800 is the top of the line. I think B&W referred to these as transmission lines, not reverse horns, although a rose is a rose... I saw an article by Solomon c. 1945 in the IEEE (or was it the IRE?) that described a large terminated bass horn. If I copied that article in 1975 when I saw it, it's long gone. May Google knows where it is. My impression based on a 30 year old memory of what was then a 30 year old design is that it was a lot of woodworking for no improvement on then-current designs. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted February 3, 2006 Author Share Posted February 3, 2006 I ran across an AES paper from B&W in the early anthology AES book from Old Colony that was concerned with reverse horn calculations, specifically for the use of the (I assume) precursory "Nautilus" type of speakers. I would disagree about it being a transmission line, but simply a reversed terminated exponential/hyperbolic horn. Theoretically, a terminated transmission line would only produce wave reflections directly back to the source, totally defeating the purpose of a dampening effect IMO. Here is a link to the book. http://www.audioxpress.com/bksprods/books/bkas1v1.htm DM Quote Link to comment Share on other sites More sharing options...
sunnysal Posted February 3, 2006 Share Posted February 3, 2006 I like mine better.... Quote Link to comment Share on other sites More sharing options...
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