Please help! I'm confused on which way to go w/a new cab build.

LongHairFreak · #1 06-15-2010, 10:09 PM

Hey

I'm still looking at Don at LDS to build me a 2x15+? cab. He's given me suggestions; some of which are controversial to what I read on TB and some of which is just plain up to personal preference. I'd like to ask for opinions in both instances.

First--
Per my request of a fairly lightweight cab w/a small footprint, Don has suggested the 15"s be diagonal and a pair of mid drivers be vertical along side of the upper woofer. I like the whole vertical alignment thing and would like to stay away from diagonally placed speakers, but am unsure of which way to go at it.

With a pair of mid drivers vertical along side the vertically aligned 15"s, it'd make for a somewhat wide cab (though not terribly so). A 2x15 plus a pair of mid drivers, all stacked vertically is 40+" in speakers alone. Add the box & castors and you've likely got a cab pushing 50" tall. Is that very practical? The common answer to that of course, is to split that into two cabs. Laid on their sides so that both 15"s and mids are vertically aligned with their counterparts, the mids are again along side of the woofers. Does that work for proper dispersion? Or is it still best (relative) to have all vertical?

Second--
I've had one cab design with a single 3015LF with the Alpha 8MR and I didn't like the sound at all; could've been the cones, or it could've been the cab design. I want what may be considered a vintage tone and IMO, that didn't produce. As I've stated in other threads, my favorite 2x15 (of the relatively few I've heard) is an older MB Diesel. It had a very fat and...bouncy sound to it. Keeping that in mind, Don has suggested using Delta 15 LFs paired with Eminence's 6.5s.

I'm guessing the Deltas will do fine enough, but I'm skeptical about those mids. I was thinking more along the lines of Beyma or Eighteen Sound; though I don't really know which of either.

Any suggestions or comments? Truly, all are welcome. I really cannot decide, so I'm begging for help from some TB experts.

pearcey · #2 06-15-2010, 11:54 PM

Regarding cabs check out BFM site and forum:

http://billfitzmaurice.info
http://billfitzmaurice.info/forum/

More than a liftetimes worth of info. Cabs are really personal I think, which does make DIY more difficult. I love my BFM O15TB; used a Kappalite and an 8MR too tho.

LongHairFreak · #3 06-16-2010, 07:58 AM

Been there man. That's where I got a lot of information on speaker placement (vertical alignment). (BTW, it's the BFM O15TB that I mentioned above and didn't much like the sound of).

LongHairFreak · #4 06-20-2010, 09:47 PM

Nobody else eh? (sigh) O.K. I'll keep searching.

meRTKendrew · #5 06-20-2010, 09:55 PM

If you liked the diesel , why dont you bass the cab on a TL-606 design, maybe using the 3015 (not LF) driver.

RTK

LongHairFreak · #6 06-20-2010, 10:06 PM

I've certainly thought of that. Don says he'll put together whatever I like. But I believe (and only believe) the EV cones used in the Diesel is a good part of what it puts out. To use the 3015 will likely not produce what I expect, so I'm looking in a somewhat different direction.

rpsands · #7 06-20-2010, 10:10 PM

With mid drivers, you do not need to worry about the drivers being diagonal as long as the crossover is low enough. I'd suggest 800hz maximum if you're going to put them more than a little offset. The mids should be vertical though of course.

IMHO, the 18 sound 6n410 can sound pretty vintagey if you dial it in, but it requires some eq to achieve. So there is the possibility of a fEarful 15/6.

That said:

If you want an oldschoolish out of the box cabinet, I'd go with a pair of 3012HOs, vertical, with a switchable horn (just in case you ever want to sell it).

Have Don tune the 3012HOs up high, around 50hz, and put them in a pretty small box (say 1.5cf net per driver or less).

You will need to dial in some upper bass to get it to sing, but it will do it. You want +6db @ 125-175hz or so with a 1 octave Q. This can be achieved using all neck pickup and picking way forward to the neck too mostly.

LongHairFreak · #8 06-20-2010, 10:23 PM

Thanks for the specific response rpsands. I'm a bit confused on one thing you said though.

Are you refering to the woofers when you say... "With mid drivers, you do not need to worry about the drivers being diagonal as long as the crossover is low enough"? Or do you truly mean the mid drivers?

Also, as you said, the mids should be vertical. But what I'm wondering is should they be vertical in line with the woofers? Or does it make absolutely no difference whether they are above or beside a woofer?

Again, thanks man.

rpsands · #9 06-20-2010, 10:39 PM

The mid drivers need to be in line with each other. Above a woofer beside a woofer is fine - close to the woofer is good, IIRC, something about everything being clustered closer together acting more like a single point source.

What I meant is that it's OK for the woofers to be offset somewhat as long as they are crossed over to mid drivers.

Check out the fEarful 1515/66 baffle for a good layout of offset woofers with mid drivers.

LongHairFreak · #10 06-20-2010, 10:53 PM

Thanks for the clarification.

Of course, not everybody knows that I'm blind, so as far as checking out the fEarful design goes... Well, that's a good part of me not finding all the information that's available here on TB w/o asking questions. A lot is referenced to pics, rather than spelling it all out in text.

Not that there's anything wrong with that! By far, majority is sight oriented, so that's the way it all works. It's still something I need to work around though.

rpsands · #11 06-20-2010, 11:17 PM

Oh sorry man! I had no idea

On the fEarful 1515/66 the bottom woofer is offset 3.25" left of the top woofer. That's probably about as far as I'd go with a ~800hz crossover. Lower the xover the more offset you can do.

LongHairFreak · #12 06-20-2010, 11:21 PM

Really? That precise eh? Interesting!

rpsands · #13 06-20-2010, 11:26 PM

I don't know the math on it but that's what Greenboy recommends and he did the math

Here's a rough idea:
A single 15 starts beaming around 600hz and is totally directional by 1200hz, or in that ballpark. The wider the source, the lower it goes. Say you have a diagonal pair of woofers, the maximum distance across them is 18.25" (15" + 3.25" offset), it acts roughly as if it were an 18.25" speaker for purposes of the frequencies becoming directional.

So it starts beaming earlier and becomes totally directional sooner.

The real math is probably a lot more complex than that, but that's the basic understanding I've garnered from listening to Bill & GB go on about it.

billfitzmaurice · #14 06-21-2010, 06:20 AM

Quote:

Originally Posted by LongHairFreak

BTW, it's the BFM O15TB that I mentioned above and didn't much like the sound of.

Based on that you don't want a 1515/66. It's not quite so hi-fi as the O15, but it's close. I'd go with a standard 2x15. If you're looking for a sound close to the Diesel load it with Delta Pro 15s or Kappa Pro 15s, they come closest to the original EVMs in the mids. Heavy, but there really aren't any neo drivers with the same mid character. Make life easier and go with two 1x15 instead of one 2x15.

LongHairFreak · #15 06-21-2010, 09:06 AM

Thanks for the tips Bill. I've certainly been thinking on two 1x15/6.5(?).

So, you think the K-Pro & D-Pro would be better suited for what I'm looking for, rather than the Delta LF? I ask because, though not as sensitive, the D-LF weighs less and has better xmax than those others.