Midbass horn disappointment

[pooge]

Bruces recommended EVM15B driver has a Qes of .3 and a Qt of .297

[djn]

Well, there you go

[djn]

OK Pooge, you got me thinking. I have two 12" drivers I got some time ago and the fs is 18.84hz, the Qes is .4642 so using your formula of 2*fs/Qes I get 81.17 What does that represent? Is it 81hz or I don't know. Here is a screen shot of the woofers from WT3. Would these work well in a horn?

[pooge]

They wouldn't be good mid-bass horn drivers.
That formula is basically a figure of merit formula to get an idea how high in frequency it is usable.

So low fs is not that desirable. You want a highish fs, up to but under the lower crossover frequency, a low Qes, e.g., <.3, and a high BL factor above 20 or preferably higher, i.e., 23-30, which together indicate a whopping magnet and light cone able to work against the high acoustic load of the horn, i.e., against pressure.

Those drivers specs would indicate a sealed box use.

[Corvus corax]

Originally Posted by djn

What crossover are you using? The MiniDSP might be a very good choice.

I am not currently using any kind of crossover, save the very simple passive one I have on the midrange horn, which is just a single capacitor, and a couple resistors to provide the small amount of attenuation needed. I have really top notch electronics, and I have no real desire to run everything through a processor, so I'm purely old school.

My sub (when I build it) will run on a separate amplifier, with an electronic tubed crossover- passive filters. I'm going horn loaded there, too- probably a straight exponential monster of some sort with these little Faital 15 inchers I've been using in my TLs.

I want to go all horn with this system, because one of my speaker building engineer friends calls the idea of horns ridiculous. He refers to them as "acoustic amplifiers", which in itself shows his complete lack of understanding as to how they actually work. He also owned and modded a pair of VOTs in the 70s, so he's "been there, done that" with horns- since they all sound like the VOT, of course…

So I'm doing this because I love horns, and because it'll **** that guy off righteously.

-And my system can play things that would bring his lil' sealed box babies to their KNEES.

[norman bates]

Run an active crossover.

which stereolab horn do you have ?

[djn]

Sorry Corvus, Didn't mean to interrupt your thread.

[Speedysteve7]

Having just battled a Hyperbolic profile mid bass horn over the weekend - I wondered what happened to this project?

I have a ~30lt - diver rear chamber, this is with a Kappa 15A. 30lt is very close to 1.1 cuft
I have to fiddle with the volume I think. Easy to extend the chamber if needed.

Originally Posted by Corvus corax

I am not currently using any kind of crossover, save the very simple passive one I have on the midrange horn, which is just a single capacitor, and a couple resistors to provide the small amount of attenuation needed. I have really top notch electronics, and I have no real desire to run everything through a processor, so I'm purely old school.

My sub (when I build it) will run on a separate amplifier, with an electronic tubed crossover- passive filters. I'm going horn loaded there, too- probably a straight exponential monster of some sort with these little Faital 15 inchers I've been using in my TLs.

I want to go all horn with this system, because one of my speaker building engineer friends calls the idea of horns ridiculous. He refers to them as "acoustic amplifiers", which in itself shows his complete lack of understanding as to how they actually work. He also owned and modded a pair of VOTs in the 70s, so he's "been there, done that" with horns- since they all sound like the VOT, of course…

So I'm doing this because I love horns, and because it'll **** that guy off righteously.

-And my system can play things that would bring his lil' sealed box babies to their KNEES.