lower-mid horn design

Hi Ray

to do one horn to cover 100hz to 2khz (single driver)is for me an no win plan

try this HD15 from 80/100hz to 180/220hz and MT102 180hz to 16khz

and you get one kick ass quad amp system but big and heavy

or you can get some turbo aspect tops(i dot know if they are ok or not)or some flood flash to be on the safe side

my take hope it helps

yours Vitor 

Hi

If you're planning to build some horns, I recomend 100 Hz straight horn (Quarterwave of course!) with a 15 inch driver with a QTS of 0.2 - 0.26

Having around four of them fed with some good power (800+) should really get the job done.

I'm currently using EAW KF 750's. But, I used to use some old 170 Hz straight horns. (4 of them) The total mouth of the combined four was 56 inches by 62 inches (2 high, 2 wide) They housed 18 inch drivers, but, I used the old EV Proline EVM 15L (no. 7.5%) instead. The low mids were very potent to say the least.

Best Regards,  

RayVaughn
Quarterwave - so the length of the horn needs to be more than 1/4 the wavelength? So 1m long is good?

Elliot Thompson

Yes. that will be fine.

RayVaughn
Why use a 15" driver though? There are some 2.5" and 3" voice coil 10" out there with good power handling (though not 800w continuous) and I'd be very worried about cone breakup at 1kHz with a 15".

Elliot Thompson

You said "Low Midrange", so, it should be cutoff at 1khz (Least efficient). The majority the work will be coming from 500 - 150Hz, and, cutoff at 120 or 100 Hz. (Whichever sounds better)  

RayVaughn
Here's the drivers I'm thinking of:
Precision devices PD107
18 Sound 10ND610
JBL 2012H

Elliot Thompson

When I think of midrange, I think 10 inch drivers. When I think of   Low Midrange/Midbass, 15 or 12 inch drivers comes to mind.

I just don't think a 10 inch can handle frequencies under 400 Hz very well without cone breakup.

Best Regards,

RayVaughn                                                                       I'm confused. For me 'cone break-up' is where the diaphragm stops acting as a piston and exhibits resonant modes across it. This is one reason why we use smaller diaphragms at higher frequencies.

Elliot Thompson

I agree. But, 1 Khz is midrange, and, anything below that is considered low midrange. If you want to go down to 150Hz cleanly, you're better off with a larger driver.

RayVaughn
The disadvantage with using smaller diaphragms for lower frequencies is less air being moved rather than break up - no?

Elliot Thompson

From my experience, smaller drivers will distort faster than larger drivers, when used in lower mid frequencies, under high spl use.

Since we are talking low midrange here, an not bass, your not going to find 10 inch drivers with 15 inch characteristics for midrange purposes. If you are so against 15 inch for low midrange, use a 12 inch instead.

RayVaughn
Also the diameter of a 15" speaker is approaching the wavelength at 1kHz which causes beaming in a direct radiating design. It's not clear to me how this influences behaviour in a compression design but my guess is it's not good.

Elliot Thompson

All speakers beam at a given frequency. The samething applies to horns. A Parametric will solve this problem.

RayVaughn
Thanks for the advice but the jury's still out on this i reckon...

Elliot Thompson

If you noticed, when I mentioned using 15's for low midrange, I mentioned, the EVM. The EVM is a speaker, not a woofer, and, offers a more fullrange sound. Today, you may not find a 15 that offers such  a response like the EVM 15. So, you might be better off going for a 12 inch for the design. 

I know the horn determines the frequency. But, I feel that a larger speaker is more efficient at 200 Hz, than a smaller one.

Best Regards,