Truextent Diaphragms in JBL four-inch compression drivers

[4313B]

These are frequency response and impedance plots. They don't convey how the various diaphragms actually sound on the various
horns. They are used to aid in the development of passive filters.

Yuichi A-290, a 290hz with a hyperbolic flare - it's a clone of the TAD TH-4001

These are some of the last measurements I took. The impedance curve of the 2445 core just looked weird. I thought it might be the felt instead of the foam in the back cap so I swapped the felt 2445 back cap with the foam 2446 back cap and ended up with pretty much the same deal above ~ 500 Hz.

The 2445 and 2446 have different phase plugs but it doesn't appear that the 2446 has any better top end response.

The plots are 1/2 octave.

[4313B]

The 2446H on the three different horns.

[4313B]

2446H and Truextent on 2311

[4313B]

2446H and Truextent on the 350hz Edgarhorn (tractrix flare).

[4313B]

2446H and Truextent on the Yuichi A-290, a 290hz with a hyperbolic flare - it's a clone of the TAD TH-4001

[4313B]

2445 core
2311 /2308 / baffled
D16R2441
D16R2445
Truextent

[Wilhelm P.]

4313B:

Thanks for sharing Greg's raw frequency response measurement of the 476Be on the Everest horn.

Could we also have the raw impedance response measurement?

[4313B]

4313B:

Thanks for sharing Greg's raw frequency response measurement of the 476Be on the Everest horn.

Could we also have the raw impedance response measurement?

Sure... but... I lied, that wasn't the Everest II horn, it was the 1400 Array Horn.

This is for the 1200FE and 1400 Array Horn with 476Be system. Call it the 1200 Array II if you want.

The Everest II data is the second two plots. Raw data and data with actual network.

I changed the scales to match the other plots in this thread. Also note that the Everest II raw data is higher resolution.

[yggdrasil]

Those 476Be curves are looking insanely good!

[4313B]

Those 476Be curves are looking insanely good!

They sound alot better than they look but you should see a waveguide/476Be curve.

JBL has stated that the only way they might be able to make the 476Be any better would be to go to a five slot phase plug but the cost/performance probably wouldn't be justifiable. The JBL curves were done in the anechoic chamber with the usual 2.83 volts input. That kind of input is deafening outside a chamber.

[Zilch]

They sound alot better than they look but you should see a waveguide/476Be curve.

Let's SEE it!

[And how a 2452H with TruExtent diaphragm performs on the same waveguide.... ]

[scott fitlin]

OK, Earl, and 4313, your request has been acknowledged, and it's done. The thread is closed.

Unless one of the administrators feels differently about this, it will remain closed. It does seem as if the original intention of measuring the be diaphragms from TrueExtent has been satisfied.