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Bozak 302 Mid Century Speakers

Hi Ron,
Isn't that something. I told Dan I was going to contact you about these. They were on CL locally for about 2 weeks I think, and the guy let me have them for $120. I thought that was a pretty smoking deal. Apparently nobody really called on them. I was the only one inquiring. He initially wanted $150. I put them in my living room and I compared them to everything else I have and I think these beat the others hands down. Do yours have the midrange with them? I thought they did. These might have the same exact drivers as yours in different cabinets. I've been having pretty good luck for a newcomer this year. BTW, your 890 is fantastic. I have it as my main receiver. Liking it a lot. I was talking to Dan today about it, and I commented that this was one piece I'll never sell.
 
richartistic said:
I'm pretty certain that the idea of 'resonance' off of a solid wood piece is an urban legend or myth. The idea that the density of the wood would cause resonance doesn't strike me as very plausible.
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Biggles is 100% correct.

Wood has been known for many hundreds of years to posses resonance which varies by the species. This is why certain woods make lovely violins, violas, cellos, and double bass, while others make horrible stringed instruments. Stradivari's legendary tonal quality resulted (in part) from specific resonance characteristics of the wood. Those properties, in turn, result form the tree's genetics and growing conditions, including fungus infections. I have read many articles about the type of wood and its resonance, the ideal growing season and cutting time, and the particularly varnishes used and how those interact with the wood's microstructure. Much of this is hypothesis being tested, but the research is obtaining very interesting results.

Speaker builders have avoided solid wood for many decades, and the Olde Ones warned us to use plywood, MDF, or materials like concrete or Corian.

Rigidity of the cabinet is an issue. Furniture is an easier problem, because one is not constructing an air-tight box which must flex as little as possible, be dimensionally stable no matter the moisture content of the air (varies by time of year), and must not resonate (see above).

For those of you tuning in who are not woodworkers or cabinet makers, solid wood is not dimensionally stable; it expands and contracts in different ways for width vs. height. Trying to force wood to not expand, or using wood which has one moisture content in an environment with a different moisture content, can result in warping and cracking.

The change in dimension of the baffle (differs for W vs H) will put force on the drivers which normally must be tightly fixed to the baffle to prevent resonance and air leakage. This is not insurmountable; it could be solve using some sort of flexible gasket and slots in the baffle to avoid stressing the basket. Otherwise the expansion/contraction may put unequal tension on the driver.

Forcing the box to be stable (dovetail maybe?) will stress the joints. The moisture content must be at equilibrium when it is assembled, and I can't believe it will not warp over time.

A very thick and heavy plywood box with a veneer is going to yield better sonic results then the equivalent thickness of wood.

Solid-wood cabinets are rare for a reason.

As far as the Tobin mod, I've elsewhere explained how they work and the benefits, and how a minor tweak (L-Pad) provides an adjustable tweeter balance far more superior than the fixed resistor, and why a flowerpot makes the best midrange cover.

As Biggles noted, when you are done with the cabinets someone in the area will want them to build a Bozak.

Edit: corrected typo pointed out to me.
 
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richartistic said:
I found a nice pair of Bozaks locally today. I'm pretty sure they are the 302 Models. They have grill cloth all the way around. Top, sides and bottoms are all plywood with the top and the bottom veneered in Birch or Maple. Pretty decent condition overall. These are solid and fairly heavy.
These have a very deep bass response. I'm thinking they sound better than good. Very clear as well on the instruments and vocals.
Although the cabinets aren't bad looking, I'm partial to a bit fancier cabinets. I plan to build new ones, Solid African Mahogany tops with veneered bottoms as well as more visible base supports. I want these to be a focal point since I'll be keeping them. My thoughts are to keep the size about the same but curve the front of the top and bottom for a nice effect.
Should be a fun project. View attachment 1036963 View attachment 1036965
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I am picking up a set tomorrow, I think they are 302, but i have not seen them in the cabinets i am looking at. Ill post some pics shortly. Just relized that this thread started in 11/1/2017. Kinda cool!
 
jobrewer1983 said:
I am picking up a set tomorrow, I think they are 302, but i have not seen them in the cabinets i am looking at. Ill post some pics shortly. Just relized that this thread started in 11/1/2017. Kinda cool!
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Try to get a pair with the mids, 6”. Them can get pricey to add later.

Biggles
 
I had the pleasure of owning two pair of Bozak 302 speakers. A pair of Urbans and a pair of Centuries

Here is all the info I collected about the Tobin mods so you too can experience folks with different opinions

Bozak 302a Tobin Mods 2015

I perform the Tobin crossover modifications to my 1968 Bozak 302a Centurys Here is what I base my changes on From Pat Tobin: Regarding Tony's mods to my mods: for the lower xover freq., Bozak used 800 for the (single woofer) 302A systems and 400 Hz for the larger Symphony (two woofs per box)...
audiokarma.org

Added taper legs to my Bozaks

These B302A speakers sat on the ground with no stands. I thought about building a pedestal but decided to try these taper legs and mount plates first Before: A little Howards treatment later I think they look great and they get the speakers off the floor The speakers do not have veneer on...
audiokarma.org

Good luck, you'll love them
 
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