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[Marjan Milosevic]

Yes. Much better.

[Jared Scott]

Cool.

I'll run some numbers, model it up, and post what I get back here to see if I'm making progress with this stuff.

I appreciate the help guys.

[Elliot Thompson]

Jared Borchardt wrote on Thu, 04 December 2008 23:24

Lets see if I'm heading in the right direction. Would an 18" driver with these numbers be a better fit for horn loading?: Fs: 30.8 Qts: .28 BL: 27.1 SPL: 97.3dB

That is a good starting point. You need to have various drivers so you can compare. Going closer to 0.2 than 0.3 will offer more mid-bass (80 Hertz - Up) while, closer to 0.3 while offer more bass (80 Hertz - Down)

Keep in mind horns are more finicky to drivers than a reflex bin when it comes down to performance. You may want to look more on the European market for they specialize in horn-loaded design eighteens more than American manufactures.

Best Regards,

[Marjan Milosevic]

Elliot, that is surely true if you think PD and Void.

But you have access to 18Sound, B&C, RCF, P-Audio... that also has good drivers for horns.

My bigger concern is that Jared is not entirely aware of the physical size of that box.

That is a Lab sub dimensions box.

Here is one picture that will give an idea of how that box will be.
That box will also be heavy so i will suggest to go with a neo magnet driver.

Regards
Marjan

[Jared Scott]

I'm fully aware of the LABsubs size, the guy I work for has 8 of them.

Part of the reason my design was so complex is because I intended on making the internal parts out of a fiberglass/plywood laminate that I can make and form to any shape I desire.  The idea was to save a bit of weight using the fiberglass instead of plywood inside.  My idea was to maintain truck-pack dimentions on the height and depth for transport, but it is 2.5" narrower as well.

[Casey McDonald]

The group delay plot - it has a huge dip at about 65hz.  What does that really mean, is it really that bad in practice or is it a hornresp thing?  

I play around with hornresp a fair bit and always get massive peaks and dips (esp 2pi), and have trouble getting my head around the fact hornresp says a box itself can have nearly 0.1s of delay within itself at certain frequencies.

I've done some searching around and found a rule of thumb that says 1/f is the point at which it becomes audible.  I've built horn subs based on hornresp frequency response alone (before I found out / knew about all the other graphs) and they seem to sound okay but the GD plots are horrible, so how much does it really matter?  i.e. when designing these should one pay as much attention to the GD plot as to say, frequency response?

To keep my post on track with the thread - yeah, seems the OP's selected driver is also a heavy mms...

[Marjan Milosevic]

Jared,

i think you should be looking in a folding like in the punisher. See the picture.

You dont need to complicate anything. For low frequencies it would not have any effect on the response.

[Marjan Milosevic]

You should just make it bigger in order to use 18 inch driver.

[Elliot Thompson]

Marjan Milosevic(MarjanM) wrote on Fri, 05 December 2008 12:18

Elliot, that is surely true if you think PD and Void. But you have access to 18Sound, B&C, RCF, P-Audio... that also has good drivers for horns.

I wasn't talking about availability but more on a manufacturing standpoint.

18Sound, RCF and, B&C are European drivers. P Audio is Asian. There are lots of companies not widely used like BMS and, Faital Pro that offer 18 inch horn drivers as well available in the States. The only European Manufacture that does not focus on horn-loaded designs is Beyma.

I agree on the overall size.

One of the things many assume is bigger speaker = bigger/better bass. Well, from a horn's concept you need a huge cabinet to not only compensate the driver, but the horn as well achieve the low 40 - 30's that is easier with a reflex using a smaller thumbprint.

I remember reading someone building a single 30-Hertz straight horn using an 18-inch driver and it was bigger than his house.

We can learn a lot from just looking at a compression driver versus horn ratio in terms of overall size. Especially, those that are capable in achieving 500 - 300 Hz full-space.


Best Regards,  

[Art Welter]

Elliot,

You said:

"Especially, those that are capable in achieving 500 - 300 Hz full-space"


Don't know what you were going for, but 200 Hz bandwidth was probably not it..