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

[chops]

I know this isn't really a "Full Range" setup as in single driver, but it's the only place where OB talk seems appropriate, so...


I'm pretty sure I want to go with an OB (dipole) setup again, but this time as the main channels. The reason I say "again" is because I have done this before, but it was a pair of dual 15" dipole subs... Some of you will remember me!



That entire system is long gone now since those subs took up way too much room and I couldn't get any decent placement for my Maggies.

Now I am back to a "monopole" sub using dual 15" Dayton DVC drivers in a push/pull configuration which has decent output down to 10Hz. It's crossed over at 50Hz.

Here's a more current view of my system...







So what I'm wanting to do now is build an OB using dual 15" again, but they need to reach up to 600Hz to meet the Altecs. I want to go OB because of the near perfect bass speed and attack, and also because of no coloration in the excellent midrange.

To get any kind of decent bass out of them (if I decide to play them fullrange from time to time) I'm going to have to build them tall and somewhat deep, not low and wide. As you can see, I'm limited in space due largely to the projection screen. And I think I would like to have both 15's up towards the top of the baffle to get them as clsoe as possible to the horn.

So what do you guys think of the design and do you think this driver would be up to the task?

http://www.partsexpress.com/pe/showd...number=264-338

Thanks a bunch in advance!

[chops]

Gee, no response yet?

[Pano]

Hey Chops(rr)

I remember you!

Cool idea. I had been planning something like it on paper, but was going to use the Eminence Alpha 15 because of the high Q and because Martin J King uses 2 in OB and really likes them. It's the "Big Butt" response of the high Q driver that looks good on paper. A little bass boost to counter the OB roll off, if you see what I mean.

But then I got to talking with friends who have done a lot of OB stuff, and was told that a more mid Q, like 0.6 usually works better, sounds better, has better control. The Eminence Beta 15 was suggested instead.

So from what I've learned, that Selenium 15 would make a very good choice. The Beta 15 has a little more x-max.

[MJK]

But then I got to talking with friends who have done a lot of OB stuff, and was told that a more mid Q, like 0.6 usually works better, sounds better, has better control. The Eminence Beta 15 was suggested instead.

I sumulated both the Beta and the Alpha and the responses were very similar in my OB design. However, the Alpha did extend a little lower and was flatter between 50 and 100 Hz. The Beta looked alot like my original Dayton response with a rounded low end but did extend a little lower then the Dayton. So I selected the Alpha and do not regret the decision. I think both driver would work really well and the differences would be very small, so it becomes a matter of personal preference.

[Pano]

Thanks Martin! That's good to know.

So Alpha, Beta or Selenium should sound a lot alike. There you go Chops.

I am torn between doing an OB with the above drivers, or a sideways BIB. I know the OB is going to have a sound I will love, but a sideways BIB (flat side to the wall) is a verified High WAF design. Takes up so little floor space, you know.

[el`Ol]

This high Qts Ciare Bass starts with cone resonances later than Eminence, but is much more expensive. But I can`t tell you whether it is worth the money.
http://www.ciare.com/pdf/catalogo/CS382S.pdf

[chops]

Originally posted by panomaniac
Thanks Martin! That's good to know.

So Alpha, Beta or Selenium should sound a lot alike. There you go Chops.

I am torn between doing an OB with the above drivers, or a sideways BIB. I know the OB is going to have a sound I will love, but a sideways BIB (flat side to the wall) is a verified High WAF design. Takes up so little floor space, you know.

Yeah, thanks Martin!

Ok, so call me stupid, but what does "BIB" stand for?!

So say I go with the Selenium drivers, how big should I go with the baffles to get decent output down to at least 40Hz. I don't need super low performance since I am crossing over to my sub at 50Hz.

And I imagine that it would be fine to run both top and bottom drivers up to 600Hz where it crosses over to the horn?

BTW, the WAF doesn't "factor" into anything with me since I have no wife... yet!

[chops]

Boy, I was expecting there to be a little more action on this thread than this. Oh well, I guess it doesn't interest too many folks.

[moray james]

also looks very good for dipole bass gets low and has enough xmax. Are those Altec horns the 500's? My very first audio "to die for" was hearing a set of Altec Valencia's with the 500 Hz sectral horn (after first falling in love with the A7 which were too big for fit into my bedroom at the time). Regards Moray James.

[chops]

Hi Moray,

Yes, the horns I have are the 511B's and 902 drivers that come stock on the A7's. They ARE great sounding horns, that's for sure.

I've been eye-balling that Delta driver as well. We'll see what happens.