Compression driver with horn, help!

[diyiggy]

Thanks for the answer.


Question for Twin Spark I assume 🙂

 

[Pano]

Yes - Those Beyma 12 would be better as horn loaded mid-bass than as woofers.

 

[diyiggy]

... sort of VOT A7 DESIGN...

 

[Pano]

Maybe. But probably best suited for a smaller front horn loaded box for mid bass.

 

[GM]

That does look like a mighty small horn for an 800Hz xover point.

That's just because folks like us are use to horns that control directivity over a wider BW 😉; its 1/2 WL axial length is > 833 Hz and mouth perimeter is ~332 Hz, so plenty large enough, though with a 2" throat it will need a $$driver$$ with a long internal HF horn to get to 10 kHz.

GM

 

[diyiggy]

you mean the length is ok till 416.5 hz and the mouth (round) is as big as 332 hz so around 1.3 meters circa 4 feet ! Coooool 😎... the car is outside the basement I assume 😀

 

[GM]

More like 1.035 m, i.e. 2*[7.875"+12.5"] = 40.75" WL or a little < half the size of my Altec 511/500 Hz XO horns, so not all that big and what? Maybe a 5th the size of Pano's [late?] Altec multi-cell horns, which did require taking up a lot of his garage IIRC. 😉

GM

 

[Pano]

My 803 multicell horns survive and are doing PA duty in an outdoor theater. Sounding great.
The 1005s are long gone. Gone to Korea, I think.

 

[e6zion]

Norman (and anyone else)
1. Were there any challenges adaptung a 1.4" compression drive to the 2384?
2. There seem to be a shortage of good 1.4" horns. The 18sound XT1464 and Ciare PR614 look to be the most modern designs, but both only have 60 degree horizontal coverage. Any other suggestions for 1.4" compression drivers?

I am looking to cross it to a 12in midwoofer.

 

[norman bates]

Couldn't say.
I had the jbl 2435hpl.

The ev hr90 horn wasn't too bad.

Those 18sound xt146 looks like they can sound clean.
Remember, the 50 x 60 dispersion can be a deal breaker for some.

 

[diyiggy]

...rotated jbl horns 😕

for the lovers of 3 Watts Set amps : JBL AM7200/95 High Power Mid-High Frequency Loudspeaker not Full range but 350 hz to 18 K hz in a compact format and good drivers (the mid is an AUdax copy when Audax used to provide few drivers to JBLs)

I'd like if I was living alone to have also the big EV horn some have with Jubillee bass cabinet 🙂

Is it ok for normalised 13/15 feet listening distance... I just don't know...for me horns world is like General relativity of Einstein... I don't understand when the space and time is bonding related to the observer ?!😀

 

[norman bates]

that is really neat.

If you want bass far away, I recommend more cone area.

 

[Twin Spark]

Yes
If you run the formulas, you see that you will not go flat to 30hz with those.

Will you run a subwoofer ?

The 12" BEYMA loaded by 70 liters bass-reflex, F(-3dB) = 40 Hz
Port is 10cm diameter, 10cm lenght.


Here are the tweeters :

 

[norman bates]

Fs = 42

And

Qts = .27

Ported 4th
Best case scnario.

You will be 10db down at fs or 42hz.

Here is 4th ported
Speaker Box Enclosure Designer / Calculator

22L or .8ft3
F3 = 75hz
Tune at 63hz

That is a bullet tweet, basically a super tweet.
No way I'd cross it below 5khz, let alone 2kh or under.

Sorry for pooping in you corn flakes.

 

[Twin Spark]

BEYMA 12 LW30/N

Fs = 42Hz
Qts = 0,27
Vas = 84 Litres

The tweeter will work on the 7kHz - 20kHz range.

 

[norman bates]

Ah yes, my bad, a 3-way.

I thought you were trying to cross the 12 beyma to those bullet tweets.

 

[Twin Spark]

Right, I need a 2" midrange compression driver for 800 Hz to 7000 Hz range.


If the compression driver have a flat impedance curve that' s perfect.

 

[GM]

Hmm, based on a mean acoustic power distribution:

~[800*7000]^0.5 = ~2366.43 Hz

~13543/pi/2366.43 = ~1.8217" dia.

Based on HF corner: 7000/3 = ~2333.33 Hz

~13543/pi/2333.33 = ~1.847" dia.

~[1.8217*1.847]^0.5 = ~1.834" dia.

A 2" horn throat works OK, though with your earlier 10 kHz limit, it was a 1.5" horn throat [if such exists], otherwise 1.4" which is known to work fine down to 500 Hz with a ~9237.58 Hz upper limit plus whatever HF extension is built into the driver.

GM

 

[Rick PA Stadel]

If the compression driver have a flat impedance curve ..

Uhh .. it probably won't as it approaches 800 Hz (if that's the horn/waveguide cutoff) -- even if it does when tested on the factory's *infinity* tube. Another sensible reason to consider bumping the crossover frequency up a little -- 1000, 1200, even 1600 Hz would not be beyond consideration, according to the FR you showed earlier for the Beymas. 1600 Hz wouldn't be as good of a match on dispersal, though, since it'll be starting to beam.

 

[Twin Spark]

I think that 1,4" size compression driver exist, and it' s better for my Visa card.


If I want a flat impedance curve I must add in parallel with the driver a RLC circuit? Do you have a link to caculate the values for components, I made a search but I didn' t find.