I got a 2-way Bozak B300 at auction cheap. Listened to it for a month or so mono. Enjoyed it so much I bought a B302A crossover and aluminum mid from eBay to convert the 300 to a 302. This is the normal upgrade path Bozak expected. They designed their loudspeakers to facilitate such customer upgrades. Liked it even better as a 3-way. So I bought a second B302a from eBay missing some trim which I have replaced. The price was reasonable.
The 2 speakers sounded great but their imaging was a little off. It turns out the one I bought complete had the newer style woofer with no cap on the magnet. The 300 I upgraded has the original woofer with the cap and labels. Looked the same otherwise in terms of paper, basket, and so on. But the sound was just a hair off so the imaging was way off. Anyway, as it happens I had another original woofer/tweeter set.
So I just got done replacing the newer style woofer with an original. In the process I did quite a bit of research which is where I found out that the insulation was not fiberglass, but a kind of layered crepe paper and asbestos. That's right, asbestos. So be careful ripping into these speakers because the insulation falls apart and floats up into the air like crazy! It has an interesting history. Look it up: "Kimberly Clarke Kimsul" forms the crepe paper sound baffle and hanging internal blanket. Very fragile and, to stress it again, contains asbestos with its attendant cancer risks.
https://inspectapedia.com/insulation/Crepe-Kraft-Kimsul-Insulation.phpNow, there seems to be some contention about whether the asbestos was a direct ingredient to add bulk or fire-resistance in the paper or may have been accidentally introduced through manufacturing cross-contamination.
https://forums.jlconline.com/forums/forum/jlc-online-expert-forums/building-science/1136-kimsul-insulationSpeaking of exotic materials, the woofer cones in both the original and newer versions both look, feel, and sound like wool felt. No joke. I know Master Bozak was famous for paper-making. But we are not talking a bit of wool here. My haberdashery friend said I'd better watch out for moths after feeling of them.
I really like the Bozak B302a loudspeakers. I suppose the only I like better now are my 1970 Klipsch Cornwalls. But the Bozak have a very solid, confident sound with precise almost sculptural details now that the imaging is better with matching drivers.
I spent some listening time comparing them to period ARs, KLHs, Polks and Mirages from a little later, Bose 901 VI, and Design Acoustics D-12s. All in all, the Cornwalls and B302s are just more satisfying, larger sounding, confident, with more stable, solid imaging, and they both provide music in actual scale. Not just loud, but effortlessly non-fatiguing, and musically convincing.
