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.
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.
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.
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.
It doesn't seem to be the case with Qt 1.25 and Fs 41 Hz. There must be resonant peak above Fs.
Alpha 15 has indeed been found to be a great performer in OB's; See MJK's highly ambitious work:
OB Theory
http://www.diyaudio.com/forums/full-range/108751-new-mjk-baffle-article.html
"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: http://www.diyaudio.com/forums/full-range/108751-new-mjk-baffle-article-3.html#post1310027
(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.)
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I believe the SPL curve was generated with the Alpha 15A in an enclosure, I seem to remember reading this in the fine print of an Alpha 15A spec sheet. The curve is totally inconsistent with the manufacturer's specs, mine and other's measured specs, simulation results using the measured specs, and listening impressions in real systems. On the right baffle it extends flat to 40 Hz or in an H frame to about 30 Hz. The manufacturer's SPL curve has caused a lot of confusion and is really not accurate for the driver.
Martin
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