OB (with proaudio drivers) + active Xovers (via pc) (!newb content!)

[rvrazvan]

I plan on building a pair of open baffle speakers using a pc as an active x over. I'm a noob regarding most aspects so i will relay on information gathered from other projects and also feedback.

I want to use proaudio drivers for the LF (12" eminence, paudio) and i also want to incorporate an SHF driver in the design. I don't have any clue about the mids. Is it possible to use a compression driver for that?
Also i need a few sugestions regarding the shape of the baffle (to H or not).

Right now i'm chopping some old speakers and MDF boars so i can get a better feel of OB sound.

anyway...I welcome any type of feedback and sugestions.

[ra7]

Here are a few suggestions:
Go for the largest LF driver you can find/afford. Cone area matters most on an OB. Eminence 15Alpha and beta are popular here. They are cheap and do the job nicely.

A compression driver (with a horn) would certainly work for the mids, but it would not be a dipole speaker anymore. Probably a good idea to go with a high efficiency cone mid. Something like the Eminence 8A (i think).

For the HF, front and rear firing tweeters are the all the rage right now... to maintain the dipole pattern.

If you're into full range drivers, something like a fostex 206 or Audio Nirvana 8" would work too.. and then you won't need a HF driver.

[frperdurabo]

+1 on Eminence Alpha and Beta.

As a huge fan of Quad ESL 57 and certain Gradient speakers, I think there's a lot to be said for dipole bass plus controlled directivity in the midrange/treble.

[rvrazvan]

alpha 15" won't be a good driver for the bass. it's goes down like a rock after 100 hz. so a beta maybe. any ideeas about the shape oh the baffle?

[MethMan]

Originally Posted by rvrazvan

alpha 15" won't be a good driver for the bass. it's goes down like a rock after 100 hz. ....

It doesn't seem to be the case with Qt 1.25 and Fs 41 Hz. There must be resonant peak above Fs.

[rvrazvan]

[kristleifur]

Originally Posted by rvrazvan

alpha 15" won't be a good driver for the bass. it's goes down like a rock after 100 hz. so a beta maybe. any ideeas about the shape oh the baffle?

Alpha 15 has indeed been found to be a great performer in OB's; See MJK's highly ambitious work:
OB Theory
New MJK Baffle Article

"Glad it worked out. The Eminence Alpha 15A is really a great driver for an OB speaker. Well built and good deep bass in a "small" baffle without any need for biamping. I cannot recommend it highly enough." – MJK; Quote: New MJK Baffle Article

(And in general, MJK's articles in the first link above are GREAT background material for any OB project. Touches on the difference between different baffle shape etc.)

[MethMan]

I am familiar with FR graph in Alpha's DS. Yet I maintain the statement.

[Kjeldsen]

Some inspiration using 15" Eminence DeltaLite II 2515

OBL11

[boudy]

Goldwood has inexpensive high-Q woofers in various sizes and they are currently on sale at Parts Express. They are adequate for experimentation and initial development. I'm still using the 8028's in my desktop OB's.