OB bass bin for Altec 511B/902-8B combo...

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panomaniac said:
I have a buddy in California how has build a lot of OB stuff. He has a pair of OBs with 2 Eminence 18s (going opposite directions) a Beta 12LTA for the mid and a big dome tweeter. That's a lot of speaker!

You could skip the 12" and dome and use your 511 horn instead. I'll see if I can dig up a photo of his dipoles.

Cool. Sounds good!

I'd be interested in see a pic of that. ;)
 
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Here is a photo.
Very bad photo, but it's all I have. You get the idea, anyway.
 

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Those 18"ers would be about perfect for a ripole (might even give you an Fs as low as say 18Hz in that config). Of course since you want them to run up so high, ripole won't work for you (even small drivers in ripole really won't sound good or even respond audibly above say 200Hz). In OB, yeah, they'll need EQ, or possibly you could use some resistance in series with them to raise their Qts a bit to help out.

Kensai
 
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That 2x18 - 1x12 + tweeter shown above is all passive filtered.
EQ is part of the crossover. Basically the hi/mid of the 18s is attenuated to bring it into line with the resulting low end.

I have not heard them - I'm 4000Km away and they aren't that loud! But they've been around to a number of DIY meets and the bass is said to be "heart rending." Driven off about a 100 watt, amp I think.
 
Cal Weldon said:


Do you do this? I found that all you have to do is to damp one of the two "lips" to deaden the horn. No need to coat it, there's no ringing other than at the lips.

Ahh, stop givin' me lip! LOL :clown:

No, I never did anything to the horns except give them a really good bath after I got them...

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The music has to be pretty loud to get any audible ringing out of the horn, and at that point, the music is a heck of a lot louder than any ringing coming from the horn. IOW, I'm not too concerned about it. ;)
 
Hey no lip from you either ;)

If you want to do a little testing use a stick of wood to tap on the horn at different locations. You'll find that only the lips ring and that putting your finger on it will damp it very quickly. If you want to be silly like me, just put some water in the upper lip when listening and see if you can get it to dance with a little volume. :D

OMG, I spend too much time in the garage. I have to go out more often.

And yes, the horns need a pressure washing about once a year. Helps to remove the dirt and what's left of the paint.
 
Just wanted to show everyone what my plans are. I may just get started on this little project within a week or so, maybe sooner.

BTW, this is my first time ever using AutoCAD. The last CAD program I ever used was Generic CAD when I was about 13. I'm now 31!

Anyway, let me know what you guys think...

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