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speakerdave
02-08-2005, 08:49 AM
Does anyone know:

1--Are these two the same horn?

2--Where I can find information about the 2381, if they are different.

3--Will 2380 series BRFF preemphasis work with the 2352?

4--Why JBL specifies the 2352 for its 2447 and 2451 but uses the 2381 in many of its SR series speakers?

Thanks

David

subwoof
02-11-2005, 08:11 PM
(1) no. 2380 is a 2" horn, 2352 and 2381 are 1.5"

(2) it is a assembled box only component. So is the 2332

(3) unknown - however the 2352 is bi-radial performance designed in BOTH the hor and ver axis where the 2380 is hor only. Read the detailed spec sheets.

(4) because it's the only 1.5" horn series designed for stand-alone sales. The same applies to the 2332 ( the array / venue series horn which is *also* 40 X 90 pattern and is *also* not published / sold as a component.


:)

sub

Rudy Kleimann
08-14-2005, 03:49 PM
While both models are advertised as having -6dB down coverage angle of 90Wx50H, the 2352 horn is somewhat larger than the 2381 horn. Due to the 2352's larger size, it has better pattern control, particularly in the vertical plane(up & down) in the lower frequencies, and loads the driver better to a lower frequency (cutoff) than the 2381. The mouth measures 18"H by 22"W and the horn is 10" long. Don't know the dimensions of the 2381 for sure, but they were used in all of the SR Series II and SR-X cabinets.

I recently acquired three 2447H driver/2352 horn/2509A horn&driver tilt-mounting bracket sets. I am about to put two of them to use with two of the 4508A cabinets with a pair of 2035H 15" woofers in each cab for live sound PA.. Don't know how they are going to work out for this yet, but I'm working on it...

Hope this helps-

Rudy Kleimann
08-14-2005, 04:08 PM
Correction -maybe. The 2381 is listed as a 90x40 horn in the JBL alpha-numeric model number list, but the SR-II and SR-X speakers they are used in are advertised as providing 90x50 coverage. Go figure.

The 2381's do lose vertical pattern control at a much higher frequency than the 2352, so depending on how low you want to go and how concerned you are with vertical dispersion, this may or may not be an issue for you. Go to jblpro website in vintage products and read on the 2380 horn for details. It states that 2 or three horns can be stacked to maintain full bi-radial performance [to lower frequencies], meaning better vertical pattern control. This is a function of the combined vertical mouth height of the multiple horns. However, when using several stacked horns and drivers you will experience some "coverage pattern lobing" in the vertical planedue to phase cancellation at certain angles. The cancallation angles change as you go down in frequency. This is known as the "comb filter effect" This leads to ragged frequency response as you get off-axis in these lower frequencies, vertically speaking, as in large venues where the speakers are cosiderably above ear level and you walk closer to or farther away from the stack.


FWIW, I believe the mouth dimensions for the 2380 and the 2381 are the same. Don't know about the length. the1-1/2" throat 2447 driver is shorter than the 2446 2" throat driver. The whole purpose was to get a more rapid flare rate right away from the phase plug to achieve lower throat distortion and extend high frequency response over the earlier 2" horns and drivers.

more10
04-14-2017, 03:38 AM
An old thread. But first when googling 2381. Also this link which contains some curves on 2381: https://www.jblpro.com/ProductAttachments/tn_v1n31.pdf

It says it is a 2" horn, but that is not correct.