betsy plus 15's idea..........
 

http://i959.photobucket.com/albums/a...QuasarMKII.jpg

The quasar open baffle.

melon head got this response but I'm not sure how he crossed in the 15's using an10 with dual an15's (qts=.5, probably more). The an10 is listed qts=.286 but a german review had them at .411

The 300hz hump was said to be crossover issues, and the climbing response past 1khz is the an10's natural response.

http://i959.photobucket.com/albums/a...rdualan15s.jpg
http://i959.photobucket.com/albums/a...0overan15s.jpg

The easiest woofer would be the inexpensive eminence alpha15, but some want a less floppy sound (requiring more eq due to lower qts).

Norman

FWIW, my AN10s give measured qts of .343, my BetsyK's give .479

Now there is an idea for a new project. Norman, I have seen Berts BD Design website but details are lacking (or very hard to find) around how to construct something like this. Do you have any suggestions/thoughts? Thanks

Well...............

I'd use an active crossover, and probably a lot of boosting.

200hz crossover point (24db) is yuck.
So maybe 100hz, but need at least 6db of boost to get down there with a 18" wide baffle, maybe more.

So with the mini-dsp, it should be possible. But the 15's used in similar b200 plus alphas, usually have a 12db low pas filter at 40hz to counteract the roll-off.

See the visaton NoBox.
The VISATON NoBox BB Loudspeaker Kit Review By Dick Olsher

There is a youtube video, it has some thump with headphone listening, but missing midbass to my ears.
https://www.youtube.com/watch?v=pa2N9Ej7WnM
The room is way too live, speakers firing towards parallel walls = bad.

Norman

Hello Norman,

Coincidently, yesterday I put together a test setup similar to what you are suggesting. I tried another OB project with Betsy and the hinged baffles earlier this year, but was unimpressed with the bass department.

I am now trying another attempt with her. This time with helper woofers, a DSP acting as a crossover and equalizer and two stereo amps.

I have used the MDF from my previous OB project. Baffle size is 120 x 46 cm. The woofers are Eminence Alpha 15 A. The DSP is a 2x 4 miniDSP in a box. The Betsy's are driven by a LM3875 gainclone, the woofers by a Rowen Absolute Two.

As an initial setting I crossed over at 200 Hz with 12db Linkwitz Riley. The bass channels are boosted by +10db. I have also applied a high shelve filter of -3 db from 2 kHz.

An initial soundcheck in the garage was promising. I currently run them 24/7 to break them in. I will then measure and further equalize them as required.

Pictures (large size....) are in my blog: Open Baffle Project | Michael's Project Page

Biggest problem currently is WAF. My SO was not impressed with the looks of them...... (Quote: "They are not going into the living room!")...

I will post the final DSP settings once I am done.

Best

Michael