Fast, fun, Inexpensive OB project

[ra7]

that pic just leaves me drooolin !! Too much fun!

[Variac]

Didn't see any discussion of maybe using Jordan JX 53 drivers for the wide range tweeter?
they have a new version now , The JXR6

http://documents.jordan-usa.com/JXR6HD.pdf
JXR6 HD

A bit pricey at $120 ea. but they should be able to handle the range and are less than some of the options mentioned I think..They are also inefficient, but as has been discussed, so are these open baffles!

[D OB G]

I'm using the "classic" Jordan 4 driver line array with the Jxr6hds, open-baffle above 400 Hz.
Works very well, but hardly fits the thread idea of "inexpensive"!

David

[Variac]

yeah, I was thinking more of just one per side crossed higher..good to hear they work fine..
especially since I have two old ones...

[Godzilla]

>>> Shhh..... don't tell.

lol... neat stuff. I bet they all sound wonderful in the right setup.

[Pano]

Vifa and Fountek are both good places to look for a small FR in this application.

[vaughn]

my timing is off, as usual

I guess I should have waited a few more days before ordering the parts for the original version, although I suppose it still stands as a good sounding solution. I would still like to see the details on the new versions, apparently a Vifa full range with the Peerless woofer?

[anibal1966]

also waiting for the details of the new versions

[John Bsuch]

Hello All

OK, some additional information on three of the four Manzanita versions. The floor standing dual 15" BFTB is still a work in progress, so more on that configuration at a later date.

After casting about for a replacement low cost tweeter to replace the original Seas TDFC tweeter and / or the upgraded (and very expensive) Scan Speak D3800 mid-tweeter, I settled on the Vifa T-FD series of 3.5" full range drivers. There are several variants in this group, but the two I like the best are the TC9FD18-08 (paper cone) and TG9FD10-04 Fiber glass cone. I tried several other potential drivers including Tang Band, SB Acoustics and Fountek. I wanted to keep the cost below $ 40 each, in line with my usual low cost, value for the money goal. I also wanted to use something that will likely be available for quite a while (fairly recent design and still in production).

Each driver of course has it's own strengths and weaknesses. As usual, it comes down to finding the best compromise. And this is where the Vifa drivers won out for use in the Manzanita and Manzanita Gigantus designs.

The High Efficiency application, as in the Manzanita HE is a totally different design situation. Again, I wanted to keep costs to a minimum, but really have a speaker that offered a sensitivity of at least 96 DBW, stand mounted to minimize floor bounce problems and have usable bass extension to below 40 Hz. I also wanted to keep the impedance up, (8 ohms or higher) knowing this design may frequently be driven with low power tube amplification. Likely SET designs. When the Seas Seas Prestige FA22RCZ (H1597-08) 8" Full-range recently became available, I knew there was a potential for an efficient 2 way OB.

And it turns out, that for my HE goals, the FA was made to order. To realize my efficiency - bass extension goals it quickly became apparent single 15" could not be used, and 2 each 15" woofers would require too large a baffle for a stand mounted system. So a very efficient 18 with at least 6 MM of Xmax would be required. I tried several potentials 18's, high Q, Medium Q, & low Q. P-Audio, Eminence, Goldwood, MCM and others.

Counter to accepted philosophy, a very low Q woofer can work quite well with the right combination of baffle area, crossover and wing depth. Not where I thought I would end up.

In future posts I will concentrate on the design details of each of the Manzanita line, one design at a time. Keep in mind that where I end up may not be the best possible solution, it's MY personal solution.

Think of what I have done as a good starting point. I love to see where others take the base designs. I will provide basic crossover topologies, baffle - wing dimensions and general crossover component values.

More later.

[vaughn]

Hi John,

I just wanted to thank you for taking the time to work up these designs and go through the effort of posting them here, your work is appreciated!

I'm personally very interested in the new version of the original Manzanita design as well as the new high efficiency model. I'm a fairly recent OB convert and after listening to some EV 12trxb's on an open baffle I'm going to have a tough time going back to a "box" speaker! Whether this takes me in the direction of electrostatics, planar magnetics or dynamics on an OB remains to be seen. Certainly the high efficiency model would open up the amplifier choices!