Empty Bozak B-4000 Cabinet Suggestions

[deadringer]

Hello all. First time poster, long time lurker here.
I have come into some Bozak B-4000 Symphony cabinets. They look very cool, but are missing all drivers and crossovers. They still have the black mid domes included, and all the stuffing intact inside.

I know the common consensus would be to track down original drivers and crossovers(give or take a Tobin mod here or there), and I’ve waded deep enough here to compile a shopping list with the right speaker models and impedances (16ohm woofers, Y tweeters instead of X). A couple question marks remain as far as the correct size mid ranges (6” or 8”?) or crossovers.

Now, I’m hardly an audiophile. My current setup is pretty modest. Technics SL1200->Marantz 2245->Epicure. With that, I’ve been able to appreciate the shoddy production values of early punk classics alongside “Solo Monk” or “Maggot Brain.” My tastes are more Tom Waits or Tom Verlaine, than “Tom Sawyer”.

Seeing as these came to me without any original components, I have come to ask whether I am still bound to be a gatekeeper of Rudy’s original design and intentions... or whether anyone may be brave enough to suggest some modern, readily available drivers and crossovers.

Let it be noted that I am not opposed to the former... I come from the vintage guitar world, where there is a high intrinsic value placed on primitive technology. But that is lo-fi, where distortion and lack of efficiency is deemed favorable by many. But for these, seeing as I’ll be at the mercy of availability of OEM materials and the prices they demand... in the meantime, I’d like these to serve as more than just keeping my apartment from flying away. Thank you all.

 

[drbiggles]

Hmmm, for me, I would not go original. Too expensive, too fiddly. And if yours have the 8” mid, too difficult to find. Could be years to find a decent pair of B800a’s. I’d remove the front baffle, make my own with a custom build. Probably a kickass e wave. The baffle surface area is large, make sure you have the room for them. Gonna need spaaaaaaace to let frequencies to merge.

Biggles

 

[deadringer]

Hmmm, for me, I would not go original. Too expensive, too fiddly. And if yours have the 8” mid, too difficult to find. Could be years to find a decent pair of B800a’s. I’d remove the front baffle, make my own with a custom build. Probably a kickass e wave. The baffle surface area is large, make sure you have the room for them. Gonna need spaaaaaaace to let frequencies to merge.

Biggles

I

Hmmm, for me, I would not go original. Too expensive, too fiddly. And if yours have the 8” mid, too difficult to find. Could be years to find a decent pair of B800a’s. I’d remove the front baffle, make my own with a custom build. Probably a kickass e wave. The baffle surface area is large, make sure you have the room for them. Gonna need spaaaaaaace to let frequencies to merge.

Biggles

Biggles,

What if I want to keep the cabinet as is? Would you be able to recommend any readily available driver configurations that would sit well in this enclosure? I’m not thrilled at the idea of storing two giant baffles in my apartment. Seeing as I’ve never seen or heard an original Bozak before, I’m more attached to the cabinet itself than I am to the idea of an original vintage configuration requiring extensive searching for scarce OEM drivers and crossovers that would still require additional tweaking.

 

[Ohighway]

Not sure if Parts Express or Madisound or others offer any design assistance. But I'd certainly think you could assemble something very respectable with modern 12" woofers, a 6" or 8" mid driver, and an array of tweeters that are currently available. Cabinet volume could easily be calculated so....... that's a start.

 

[drbiggles]

Measure the size of your two woofer holes. Depending on age, they will probably be 13” to 15”. Find a suitable woofer or full range driver. If you’re going to keep front baffle as is, make a cover for the bottom 12” hole. You want your drivers as close together as you can. Your new crossover should be a first order, 6db crossover. A higher order crossover will want more precise driver placement. Otherwise all your drivers and frequencies won’t converge properly. Trust me, no matter which path you choose, it’s going to be some effort.

Biggles

 

[drbiggles]

Your cabinets should be approximately 6.9 cubic feet.

Biggles

 

[deadringer]

Wow thanks for all that. You sorted all that out while I was still calculating my cabinet volume! Do you think I shouldn’t bother with having dual woofers at all?

 

[drbiggles]

Wow thanks for all that. You sorted all that out while I was still calculating my cabinet volume! Do you think I shouldn’t bother with having dual woofers at all?

no dual woofers, not even Bozak dual woofers. It’s not easy creating dual woofers that sound proper. I A/B a proper Bozak symphony and a 1 woofer symphony. The 1 woofer configuration was an easy win. More coherent, less confused, clean. Plus it saves you about $400 in 16ohm Bozak woofers.

Biggles

 

[Steve Smiley]

I agree a whole lot with what the good dr. b offers up, and I too love the Symphony cabinet. You could make a cool Ewave out of them, for sure, but... It is a pretty straight forward bit of work to build out something more original.

I totally agree with Biggles that the one woofer (8 ohm) Bozak sounds significantly better than the two woofer system. It is the most musical bass I've ever heard, in a Symphony (read big enough) cabinet.

So here's what you're gonna do:

-Single Bozak woofer, cover the lower hole per Biggles instruction
- Bozak mid range (that is the cut out for the 8 inch mid, hard to find for sure but you could use the 6 inch and an adapter plate, front mount the driver on the adapter, rear mount the adapter to the baffle., round-over or bevel the 8 inch cut out.
- 2 B-200y tweeters, wired in parallel, might be a few mounting options.

With this set up you've got good Bozak sound and you save some coin by cutting out the more expensive woofer cost ($300 savings, est.) and 12 tweeters ($150-200 savings). Now use the savings to make a great 4-way crossover, pick a good super-tweeter and mount it on the other side of the mid range (as close as you can get it) and you have much less coherence worries for a smaller listening room.

Check that, mount the super tweeter(s) and the Bozak tweeters in the same space as the original array so as to avoid interference from the paddles (speaker grill classic!)

Of course, do whatever you want but I LOVE my similar set-up!





Please pardon my assertive communication. I'm just really excited for your project. The cabinets you have are really sweet and you can do great stuff with it!

Regards,

Smiley

P.S. @drbiggles and @Retrovert helped me down this path and although, as Biggles might correctly suggest, there are easier builds, this one for me was super-satisfying.

 

[deadringer]

Mr Smiley,

No need for pardon. I appreciate your assertive communication. Though we’ve never met, I’ve read countless threads from you guys. It was really cool seeing the different phases and processes you guys went through over the years when you were in my shoes... and I hope to benefit from all that experience, while avoiding the usual pitfalls along the way!

 

[rider33]

Symphonies are big boxes with a lot of wholes to fill, that could get to be expensive. A simple solution might be to patch some of the holes (sheet of plywood from behind) and fit a single 12" coaxial driver in there. Altec duplex drivers cost a fortune but are very nice but many of the majors made quality coax drivers back in the day. 'Might try Craigslist or even Ebay & see what turns up. It would be A LOT easier tho somewhat unorthodox, then again many 50/60's home brew speakers were.

 

[deadringer]

Some great ideas and a lot of food for thought here. Dumb question: Should the tweeter array be inwards or outwards of center??

 

[nerdorama]

If a single 12" woofer would work, a Speakerlab W1208R would like a cabinet that size. Would give a nice low Q sealed alignment and they are around 92dB 1w sensitivity. Don't get the older alnico version. The magnets get weak, I've measured it.
John

 

[Audio Fan]

I have a couple of Bozak sets. I have been debating to restore both or perhaps restore one and put something new in the other set. I have not done any research, but if I get around to it, was planning to look at some Lii drivers if they have a model that will work for the volume.

 

[Nyjblbob]

The magnets get weak, I've measured it.

How do you measure it?

 

[nerdorama]

Thiel Small parameters. If the magnets lose strength the Qe goes up (loss of electrical damping) if everything else is still ok.

 

[Nyjblbob]

How do you measure the small parameters?

 

[Steve Smiley]

Some great ideas and a lot of food for thought here. Dumb question: Should the tweeter array be inwards or outwards of center??

That depends on your speaker placement in relation to your listening position. In general I tend to go tweeter inward. In your apartment photo I’d guess I would start with inward.
Smiley

 

[nerdorama]

How do you measure the small parameters?

Now days, a laptop, high res usb sound card, some free software and an amp along with a wiring interface with a measured resistor. I use Arta software.

 

[deadringer]

Hmmm, for me, I would not go original. Too expensive, too fiddly. And if yours have the 8” mid, too difficult to find. Could be years to find a decent pair of B800a’s.

Biggles

A quick update: I bought a pair of B800a’s that were in a coaxial setup, each with a single B-200Y in each. I think they were probably from a set of Bozak Bard outdoor speakers, but they look in pretty good shape. I figured I would be able to separate them from the coaxial frame, and reuse them in the Symphony configuration?

I am going to do the single woofer as almost unanimously recommended by everyone here so far. I saw a couple leads on a pair B-199A’s, also in coaxial form with a pair of tweeters on each driver. I am also still open to using modern woofers, and would love to hear tried and true recommendations.

Tweeters: any known modern drop-ins to the slot array? I intended to use four 8 ohms, but I kind of like the look of filling in the slots. I have overcompensation issues, what can I say?
Could I use a pair of 4 ohms wired in series for an 8ohm load, instead of parallel’d 16s?