[new guy]

Hello to all you out there. I just wanted to ask a quick and easy question for you all here. I have done a couple open baffles and would like some input on my next project. This one has to count. I love the sound of fullrange drivers. I would love to make any open baffle with a fostex Fe 206e drivers and then a lower woofer on the side of the baffle. If it needs to be up front fine. I have $500.00 to spend on everything. I have the amp and  and binding post and hook up wires. I am looking at the wood, glue, screws, stain or oil and drivers and caps and coils. I have a solder gun and solder. So if you know of a good pair that will really rock my world with a few watts let me know. I will be using theses speakers for t.v. watching movies and music duty's and sports events as well. I want to hear every detail I can. I do have a hearing problem and was born with it. The fullrange driver just really mated well with my ears. So any who. If you can help me out please do. Thanks new guy

[zipidachimp]

try this,  or a variation:      http://www.quarter-wave.com/OBs/OB_Design.pdf

a 'best bet' for a newbie.

then google images : open baffle,  or the gallery search on this forum for 'open baffle'

good luck!

[dobias]

New Guy,
"and then a lower woofer on the side of the baffle. If it needs to be up front fine."
I built some baffles & tried the woofer 90 degrees to the side. I wound up hearing weird phase changes, when walking around the room,  that were only corrected by facing the woofer to the front (preferred by the experts) or facing the back on it's own baffle (preferred by me to keep the baffle(s) narrow & short, but deeper). Just don't aim them out the sides & keep the baffles away from the side & back walls.
dobias

[Dmason]

New Guy,

For $500 you could actually build a KILLER OB system, as long as you didnt deviate from that which has been proven to work well. For that, and your budget I would absolutely follow Martin's wisdom, starting from the bottom up:

Eminence Alpha 15 bass drivers, all drivers mounted on the same plane, you can use ONE, $60 Eminence Alpha, per side, very successfully. Martin demonstrates the Fostex Fe127. I would, for a few extra dollars, make the enormous upgrade to the Fostex FE108E-Sigma, which is a drop-in upgrade option. Mids to highs, these are pretty hard to beat no matter what. Build quality is outstanding, and they look REALLY cool in person, little sand dollars inside tires. No need to change the XO circuitry either. An .01uF cap of high quality high passes to the driver @ ~100Hz, and protects the driver from being blown from over-excursion. Use Soniccraft caps for success here. This would be the one really essential high quality doodad.

Laminate 2X 3/4" or even 1" void-free plywood for rigidity.

use 3/4- 1" roundovers on vertical baffle edges is a must. Use plunge router bit to flush-mount bass drivers, makes a big difference in presentation, both sonically, and visually. Not necessary with the FE108 due to its purpose built concentric flange with this in mind. Also, if laminating baffles, this adds the opportunity to either make roundover or bullnose routing to the back plane of the baffle, for the mains driver, as a sort of waveguide. what we have seen is that this helps enormously with imaging, pushing the image backward, allowing the backwall to "melt" away, more effectively. If you use a single blank, you might think about using a 3" depth Sono Tube as a short cylindrical waveguide, short enuff to avoid cavity resonances. If you were to eventually veneer these baffles, this would be a very acceptable looking unit.

Do this, applying Martin's recipe, [thanks as usual, Martin,] and you will have a KILLER, amazing OB set up, which should come in for well under $500... Links to the goodies:

www.usspeaker.com   Eminence
www.madisound.com   Fostex and caps, coils, etc.
www.soniccraft.com   Speaker capacitors

[rca9449]

Dmason,

If I use low drivers other than Eminence Alpha 15, do I still use the same crossover per Martin's recipe or that schematics only apply to the Alpha 15.  I plan to use Fostex 126 for the high as it is more efficient than the other Fostex drivers

[doorman]

rca: The 126's are indeed more efficient than the 108Ez's. I have both, and have driven the 108's quite acceptably w/a low powered SET, the mids being very impressive! What amp(s) are you using?
                                                                          Don

[rca9449]

Hello Dan,

I plan to use a .75watt single ended darling amp.  i also have an eico hf-81 that i can use in case the darling amp does not have enough juice...

[dmr]

The 126 is a very nice driver but the greater efficiency is of no advantage on the MJK open baffle design.  The overall efficiency is limited by the woofer and you will have to pad down the 126 to sound right.  The crossover design is based on the Alpha woofer and if you use something else, all bets are off for the values.  The Alpha is very cheap (<$60 each at PE) and is well suited for open baffle.  I highly recommend the Alpha.

I used the Fostex 108 sigma which has a rated efficiency of 92 and found that I had to pad down that driver to blend well with the Alpha.

The MJK open baffle is a great design for the $$$.

[rca9449]

I got it now DMR.  Thanks.

[D OB G]

Hi new guy,

Do you have the FE206Es?

David

[Wind Chaser]

Hey dmr,

Have you got a picture of your OB's you can share with us? 

[dmr]

You can see my open baffles on MJK's gallery page, about three projects down...

http://www.quarter-wave.com/Gallery/Gallery.html

They are straight from the MJK design but using the old model FE108 Sigma fullrange driver.  I've been listening to them for about 3 months now and I'm still as thrilled with them as when they were new.  It's my first time with open baffles and I love the sense of a 3D sound stage I get with these.  You get the wonderful midrange from the Fostex drivers and very effective bass too.

[SteveRB]

i've just been catching up on this post. this looks like an awesome project. Stay tuned, i'm working out a design and budget to pull off this recipe.

[anibal1966]

an aspiring newbie's questions

wouldn't it be even easier as a first project to use hawthorne's 10" driver-plus-crossover?

would it be posible to fold the baffle in King's project? 50 cm/20" width is just too much to place in a room 1,92 m. / 78" wide