[krips]

1. Eminence Alpha 15 vs  Beta 15 - using an active crossover, the Beta 15 appears to me to be the better woofer on paper. Is this the case?
2. Which would you prefer - Wide range + helper woofer(s) or super tweeter + wide range + helper woofer(s)? I was thinking of something like the audio nirvana super 10 cast + two beta 15s
3. What would your wide ranger of choice be? I'm looking for decent/high sensativity... Audio Nirvana? Fostex? Hemp? Preferably <$100/driver. Up in the mid $100s would be acceptable if necessary.
Thanks

[mightym]

Martin King has done a direct comparison of those two drivers in 3 different OB configurations, I would refer you to his paper about that comparison: www.quarter-wave.com/OBs/U_and_H_Frames.pdf

As to the other questions, it might help you to look at a couple of his other well documented projects, he's done a passive OB using the  Alpha, and a Fostex wide ranger that people seem to like, though I haven't personally heard them.  He also has an active project on his site: www.quarter-wave.com/


These should give you answers to your questions, hope it helps.

John

[mcgsxr]

Question 1 - I would say is covered with the suggestion above.

Question 2 - very personal, I would suggest.  I use a wide ranger, with active helper woofer.  The wide ranger is modded with a phase plug that in my experience helps with beaming.  I am aware that I am giving up some of the top end, and have explored ways to address with with a tweeter, but have not pulled the trigger.

Question 3 - I use the Visaton b200, but there are tons of choices out there, and lots of ways to implement.

Lots to learn, keep asking, and keep in mind that much of the data out there is subjective- though there are examples of measured curves etc.

[THWO]

While I do not enjoy own experience with Fostex, I feel very comfortable with both the Omnes Audio L8 (http://oaudio.de/Lautsprecher-Chassis/OmnesAudio/Breitband:::127_36_27.html) and the Ciare CH 250 (http://oaudio.de/Lautsprecher-Chassis/CIARE/Breitbaender:::127_28_29.html). Support in the lows by Eminence Alpha 15A (two per side in OB as well, active) and as a small super-tweeter the IMG Stage Line MHD-220 N/RD (http://www.monacor.de/typo3/index.php?id=58&L=0&act=8&act_sub=24&artid=6429&spr=DE&typ=u).

Regards,
Till

[krips]

When I model smaller driver, like the FF125K for example, and enter an OB box size of say 2000cf, my output drops by approximatly 17+db across the board. Is this correct? How do I accuratly model OB in winisd?

[longdrive55]

The paper by Martin does not compare those two drivers. It only looks at the Alpha 15A in different configurations (OB, U and H baffle). I can't offer much help on the Beta as I have no experience with it. I can say the Alpha is a no brainer in OB down to 40hz and up to around 1000-1200, lower if you use a U or H baffle. It sounds phenomenal.