Best "bang for the buck 15" driver?

[J.D.B.]

Hi all, the new "lightweight" 215 cabinet project is moving along with Mr. Bellair. He asked me to post the question of "what, in their collective opinion, is the best 15" driver for the money?"
Here's the design, so far. He's doing experimental panels at the moment. Could be very cool if he can, indeed, meet the assignment. The whole thing should weigh about fifteen lbs. more than the drivers and hardware, yet be stiff enough to sound like 3/4 ply. The extra enclosed spaces are for dialable mids.

Josh

 

[rpsands]

Kappalite 3015's at beachaudio demolish everything else imho. It's tough to say without your porting and volume characteristics though. Looks like around 3cf per box but tough to know for sure.

Are you planning on putting midranges in those boxes?

 

[J.D.B.]

The cabinet volume and porting "basic idea" is optimized for Peavy Scorpions. It can easily change per driver specs. Bob wants mids in those extra enclosures as mentioned, I would like them to be "dialable"(off is my own preference)(!)

Josh

 

[rpsands]

If you're going with mids, I would suggest modifying the baffle layout and going with 3015LF's and B&C 6md38s. Just this man's opinion though, the 6nd410 from 18 sound will get a lot of votes.

The baffle layout in greenboy's 151566 makes a lot more sense as it gets the mids closer together, and near the top of the cabinet.

 

[BassmanPaul]

You seem to be going about this in reverse. Usually the driver is the first thing to be selected and the cabinet designed around its specifications. IIRC good mid-range drivers are sealed back and as such don't need an enclosure.

Paul

 

[rpsands]

Definitely incorrect, Paul. Sealed mids are convenient but none of the ones I have ever heard compare to the 6nd410 or 6md38. The sealed mids seem to be given to peakey response - lots of peaks and valleys, not terribly even sounding.

 

[billfitzmaurice]

You seem to be going about this in reverse. Usually the driver is the first thing to be selected and the cabinet designed around its specifications.

Paul

Depends. When I get a new prototype driver I build the cabinet around it, but when I get a spec for a cab capable of delivering a specified output and bandwidth I try a variety of drivers and boxes until I find the best result.
OP, assuming this is for bass, bag the Scorpions, they have horrible specs for electric bass. And bag those curved reflectors at the duct entrance, they're not doing anything beneficial and eat up cabinet volume.

 

[will33]

Any particular reason the vent is in the middle? Moving it to one side or across the bottom would put the drivers up closer to ear level.

How much bang for how much buck? The 3015LF is a great driver but I can't think of a need for two of them unless you're playing some huge place with no PA. Could get away with a little less buck and still have a fine cab seeing as you're using 2 woofs and 2 mids.

 

[billfitzmaurice]

Any particular reason the vent is in the middle? Moving it to one side or across the bottom would put the drivers up closer to ear level.

That location is beneficial in stiffening the cab walls and the baffle. Having the woofers higher up doesn't make much difference, but having both mids in the upper section as high as possible would be much better.
Oh, and bang for the buck goes to the Eminence Delta Pro 15, though it's a bit heavy.

 

[edbass]

Seems very similar to some Reeves single 12" driver Port City licensed designs I've demo'ed in the last year.

 

[billfitzmaurice]

Seems very similar to some Reeves single 12" driver Port City licensed designs I've demo'ed in the last year.

If you mean the internal angled reflectors, they don't do anything. The intent would be to guide sound waves through the port. However, to do so the reflector has to be a full wavelength wide. The shortest wavelengths that pass through the port are at least ten feet long, so the reflectors are just excess baggage.

 

[zac2944]

Hi all, the new "lightweight" 215 cabinet project is moving along with Mr. Bellair...

He's doing experimental panels at the moment. Could be very cool if he can, indeed, meet the assignment. The whole thing should weigh about fifteen lbs. more than the drivers and hardware, yet be stiff enough to sound like 3/4 ply.

"experimental panels"? Might I ask what materials? Plywood?

 

[J.D.B.]

Carbon fiber. Structured like a race car body. (honeycomb sandwich). Looking for stiffness AND light weight.

Josh

 

[billfitzmaurice]

Carbon fiber. Structured like a race car body. (honeycomb sandwich). Looking for stiffness AND light weight.

Josh

It will work, no one will be able to afford it. A few manufacturers use it, in the +$5,000 per cab range.

 

[J.D.B.]

Thank you for those encouraging words, Bill!
Looks like we're going with the Kappalites, and likely a tweeter of some type, (as the Kappas reach into the midrange decently, at least on paper). It's also been decided that the project will be in two cabs, for more versatility(ala Zac2944). Thanks a bunch, guys!

Josh

 

[zac2944]

IMHO, using a good mid driver rather than a tweeter will give you a lot more mid/high end detail and a more even tone on stage in a loud mix. I'm loving the 3012LF/Alpha-6A combo and I would guess you'll have similar results with the 3015LF/mid combo.

 

[Bellair Audio]

I wanted to use a midrange but opted for a 15" with good midrange and Piezo tweeters for sparkle with almost no additional weight. One Kappalite 3015 in a 3.3 cu ft cab with two 4" dia. ports and two tweeters should be good for the typical bar and then you could stack on another cab or more for bigger venues. I am shooting for under 30 lbs and I think I am going to use just one handle. The top, bottom and sides will be Carbon fiber, alum honeycomb, Kevlar sandwich and the front and back will be 1/8" plywood, fiberglass, Styrofoam, fiberglass sandwich that can be cut into without the danger of carbon fibers in your lungs and no need to seal off the honeycomb area after the holes are cut. more to come......

 

[billfitzmaurice]

I wanted to use a midrange but opted for a 15" with good midrange and Piezo tweeters for sparkle with almost no additional weight. ..

The problem is that no fifteen has wide enough dispersion to be useful much above 1.5kHz, and that leaves an octave wide hole before a piezo kicks in. True, the 3015 axial response looks fine to nearly 3kHz, but axial response only benefits a small percentage of the audience. Unfortunately the all important off-axis response is not published by most driver manufacturers, and the only way to determine it is to measure it yourself.

 

[greenboy]

The problem is that no fifteen has wide enough dispersion to be useful much above 1.5kHz, and that leaves an octave wide hole before a piezo kicks in. True, the 3015 axial response looks fine to nearly 3kHz, but axial response only benefits a small percentage of the audience.

Partly because the off-axis stuff is what is reflecting off walls and around. And if most of the reflected and off-axis sound is shy of mids and treble, guess what things sound like in most of the room? Let alone around the stage. Amazing how few MI speaker designers have thought about any of this.

 

[zac2944]

Bill is spot on about the piezos not making up for the lack of off axis midrange. I'm sure you'll still end up with something that works, but having that missing mid range in your tone can really help with clarity on a noisy stage.

Also, I've spent some time testing (very basic SPL/Hz) many differrent piezos (CTS/Motorola to cheap Dayton) and a couple piezo arrays, and the lower midrange is my least favorite part of their output. Not only is it usually peaky, but the ear is very sensitive to this area. Running piezos too low has always sounded harsh to me. That said, I do like using them for high end only (>5kHz). They are still a little peaky in this range, but IMO it still sounds pretty good. I'm guessing that this is because there isn't much output from a bass up this high, and the ear isn't as sensitive to uneven output in this area.

I'm very interested in hearing more about your construction method. I've had great success with XPS foam, fiberglass and epoxy. The three cab I built all came in around 7-8 pounds empty and around 20 pounds finished. I did use some carbon on my last two, but only for looks. XPS and fiberglass do a great job and really help to keep the cost down.