NEW 1.5 inch horn for 4345 / 4343

Am I grateful for those last posts. Saved me hours of digging in my computer.

Quote:

---

Originally Posted by Giskard

Yes, sorry for taking so long. There is actually a right way to integrate this horn and there is the quick and dirty way. The quick and dirty way probably works good enough with digital signal processing applied.

For those who might hesitate to cut a 2307 or H91 down to the 1.5" exit for use with 1.5" c.d.'s, don't. JBL did just that to make the 2311/H93 for 2" exit c.d.'s. Don't use the 2312 or H92 though, the flare rate isn't "right" for this application. Also, none of these horns are for use below ~ 1 kHz.

---

Is it a matter of the new tapper being wrong for the old taper? Excuse me if taper isn't the correct term, I'm not sure if it is or not. How bout when you want to put a 1.5 on a 1" horn. Can you cut it where it's large enough drill the flange and weld (or glue) it back on. Or are there special rules there. Also do you change the low cut off because you've changed the ratio of the input to the output? Sorry for the freshman questions but I've been wrestling with them and they seemed very related.

Quote:

---

Originally Posted by Thom

Is it a matter of the new tapper being wrong for the old taper? Excuse me if taper isn't the correct term, I'm not sure if it is or not. How bout when you want to put a 1.5 on a 1" horn. Can you cut it where it's large enough drill the flange and weld (or glue) it back on. Or are there special rules there. Also do you change the low cut off because you've changed the ratio of the input to the output? Sorry for the freshman questions but I've been wrestling with them and they seemed very related.

---

I'd suspect there are some heavy mathematics behind the final correct solution for this kind of mod ...

Or, as Giskard mentioned, the Quick and Dirty approach.


Sorry - all I can think of is flow testing an intake manifold - smooth is better, gentle curves and gradual tapers.

Isn't audio related to airflow over the surfaces?

Question:

What about manufacturing a conical shaped horn out hardwoods with the correct flare rate and length and ending in a 1.5" mounting flange. Seems like a lathe turning operation.

Or:

Machining the above mentioned horn out of an aluminum billet.

It seems as if it would be similar to making a birch bowl on the lathe, that so many turners do here in Alaska.

It could be turned out of Beautiful hardwoods, or laminations of different species, and end up as a real show stopping piece of art.

I could have my friend, the Admiral, turn one from a billot of al, or maybe brass.

Is this idea plausible, and has anyone else tried it?

Scott.

Designing ( horns ) is not an exact science - as G.T. said, it is a series of compromises. Even the newest computer aided manufacture PT horns are a series of different tapers and surfaces that flow into a single mouth...that is some serious math and even THEN it does not work well for some combinations!

The length, throat size, mouth size, the throat to mouth ratio, the flare rate ( x, x2, x3 ) ( conical, exponential, hyperbolic ) ALL come into play.

And then you have to blend it in between the mid and UHF components that are near opposites in design and function.

This endeavor was to use newer drivers *without* messing up the baffles on the large 4 ways and not change the flare rate of the horn. This approach was the best compromise I could come up with and with a shop full of tools, fairly straight forward.

I was never in love with the idea of having HF smash up against a series of plates ( plastic, wood, metal, etc ) and coupled to a horn with a small format diaphram ( 1" ) that is now very expensive and fragile.

However if Giskard deems it acceptable ( dirty or otherwise ), I can dig out the jig ( assuming it survived the big purge last year ) and cut up horns for others. Bondo and paint are the fun part left for the owners..:)

eeehhhaaahhhhhhhhhhhh

sub

Have you thought of acquaplasing the 2405 diaphagm's if you going to that sort of trouble and expense. That driver is totally dated and flawed in comparison to current soa compression drivers.

If run the tad full range it might be interesting.

Quote:

---

Originally Posted by Ian Mackenzie

If run the tad full range it might be interesting.

---

And I have thought about that.

However, you might have noticed on Widget's masterwork, he finally included a TAD tweet, too.

Hi

- A 2311 with an added 1.5" to 2.0" adapter ( available only from P-Audio, now that Selenium no longer makes them ) has @ 2" of extra horn length ( measured perpendicular to the phase plug ) when compared to just a 2311 or subwoofs' 2313 ( the cutdown 2307 ).
- This extra 2" is still a bit less than what the old 2441 ( with 2311 ) has in total throat depth / similarly measured inside the drivers' throat and going back to the phase plug.

- The extra 2" does make a difference in MF loading ( over the 2313 ).
- This 2-piece approach would be my preferred way to go, if I actually wanted to retrofit a 1.5" exited driver into a 434x 4-way.

- This 2-piece combo will load to 1000 hz ( though maybe needing the help of a 2-pole bump filter / FWIW: the DD66000 uses this approach of gentle MF boost, "see the OM" ) . 1000 hz to 10K is obtainable ( and IME, quite desirable if one has a quality compression driver that's worth listening to ).

- & yes, a little bit of bondo to smooth any rough joints is quite likely desirable.

:p

Here are some measurements of the 2421B/2307/2308 and the 435Be/2313/2308

The second graph is somewhat normalized.

The impedance curves are completely different and I'll post them when I have time.

I've decided to put this whole 435Be/2313/2308 variant on the far back burner for now due to the shear number of deliverables that I am in hot water for. These 2313's are headed back to subwoof next Monday.

Thank you subwoof.

The TAD TD-2002 on the 2307 option is pretty damn nice. I have no idea what the cost differential is though.

Thank you Mr. Widget.

Thanks for posting that! Reminds me I have to order my horns!

Rob:)

Just leased a 30 X 60 building for the shop(s) so after a 2 year downtime and having stuff housed in 3 locations for over 4 years, the woodshop will be cranking out cabs later this summer.

And during the move the custom bandsaw jig was found for the 2307 cutting so any forum members who are interested, send me a PM.

And I found box after box of horns ( no 2307's though ) that were squirreled away for future projects and of course I won't need them all so when the dust settles, I will post what's available on the marketplace forum.

And thanks to giskard for elbowing the other projects aside for a quick analysis on the 2313 horns. It looks like they will work OK with the stock passive crossover frequency points of the larger 4 ways.

:o)

:cheers:

Quote:

---

Originally Posted by subwoof

And thanks to giskard for elbowing the other projects aside for a quick analysis on the 2313 horns. :cheers:

---

I wonder how he finds the time to do all these things!

Ron

I was under the impression he was semi retired............? :blink:

Quote:

---

Originally Posted by spkrman57

I wonder how he finds the time to do all these things!
Ron

---

Perhaps ...?

a. He is really dedicated to this stuff and, despite the frustration, still tries to give and share info with those who he feels can really appreciate it

b. He has a gadget he got from Nikola Tesla and cloned himself ... ala The Prestige

c. Wormhole technology

d. He has an espresso coffeemaker and rarely sleeps

e. He is part of a business and "Giskard" is just the corporate image, like the Maytag repair man - many people may be playing the role of G*

f. Sidney H. pays him the big bucks to be here (might be related to e. )

g. perhaps he has a nice life offline and longs to be there more than here ...

(Said in playful support, no offense or slights intended to G)

I still think he is retired, and can't get enough. (Eats, Sleeps, and Drinks JBL) :bouncy: