I am considering a 20" wide OB with a 604e and one or even two Eminence Alpha 15s to augment the bass.
I was thinking of either upgrading the components on the original 1500a xover or going with a new Rick Craig design. Then using two plate amps to low pass the Alphas at 150hz or so.
That arrangement would allow the 604e to roll off based on baffle width. As an alternative, should I high pass the 604e? If so what slope and freq?
Your thoughts would be helpful.
Don't have time to delve deep into this, but at a glance you'll need four of these low efficiency 15s to match up to a 604E and even then may be marginal without EQ+higher power to line them up and yes you ideally want to high pass the 604.
If you haven't already done it, I recommend reading all the pertinent OB info on MJK's Quarter-wave site and use his MathCad WS to help you.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Well Dave - you posted the same question over on Audio Circle, got a few replies (including mine) but you never came back.
Are you really serious about this rig?
My first reaction is to wonder what the heck you are thinking?
An Alpha 15 is NOT A WOOFER!
It is a 15 inch musical instrument speaker that probably does not even go as low as the 604.
The whole thing is a bad idea.
A much better idea would be to build a single sub and put the 604 in L/R cabs.
For a cheap woofer look at Dayton Audio.
But using a musical instrument speaker is like drinking decaffeinated coffee to wake up. Ain't gonna work.
Disclaimer....some musical instrument speakers CAN be used as bass horn drivers. the Awful 15 is NOT one of them.
Your neighbors called. They like your music.
Unfortunately OG, you're out of the loop! The Alpha 15 is super popular at the moment for use as an open baffle woofer. Why? High Qts. That low end peak that the high Q woofers have helps give the Alpha 15 some actual bass on open baffle. Little or no EQ needed.
Martin J King is the champion of this approach. See this PDF. http://www.quarter-wave.com/OBs/OB_Design.pdf
That's not to say, however, that it's the best sounding woofer.
But the approach and the driver have their fans - and detractors. A lot of folks don't like the high Q woofer sound, no matter what.
The the OP asked his question over on A.C., I pointed him to the 605+18" rig I'll be showing in Dallas. But I don't think he has been back to the thread since he posted.
I sorta know the basics on that Pano, it still sounds like a horrid idea to me.
If I was going to do 604 on open baffle, i would use a regular sub.
But then the old saying about opinions.
I have to admit not being an open baffle fan. the only ones I have liked have been HUGE (caps for emphasis).
For the cost/effort I think I could do WAY better.
Yer mileage may vary and all that.
Your neighbors called. They like your music.
Well bigger is certainly better for OB. No doubt.
I like OB because it's fun and easy. But you do need to trade box for cone surface area. And power.
I don't know if you can see photos on Audio Circle without joining, but you may want to look at my thread there. Sure wish you could come to Dallas to hear the rigs. WOuls love to meet you and know what you think.
Big OB rig in Dallas LSAF (mid May)
Yes, they sound "as good" but different. I will let you know more after the show. And try to get some listener comments, too.
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