Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums > LAB Subwoofer Forum

Box plans ASB6128V JBL

<< < (2/3) > >>

Art Welter:

--- Quote from: Paul G. OBrien on February 19, 2021, 06:41:00 PM ---Thanks Art some good points there, although all that doesn't seem to result in much of a sensitivity advantage going by the published response graph... the box is still only about 98dB@1w below 80hz. Like you say a single driver tapped horn would probably spank it pretty bad.

--- End quote ---
98 dB 1w1m at 30Hz is pretty sensitive.
By comparison, 1w1m 30Hz :
90dB JBLSRX728 (2x18" bass reflex)
91dB EAWSB1001 (2x18""V" load bass reflex)
92dB DSL TH118 (1x18" tapped horn)
99dB DSL DBH-218 (2x18" folded horn of similar size to the JBL ASB6128V)

The DBH-218 FLH is far more sensitive above 30 Hz, more "spank" ;^).

Art

Paul G. OBrien:

--- Quote from: Art Welter on February 20, 2021, 05:14:33 PM ---98 dB 1w1m at 30Hz is pretty sensitive. 
--- End quote ---

That is now that you mention it, but can that really be attributed to V loading? I see it as just a low tuned box targeted at install applications.
I found an interesting document about these Differential Drive units that includes some data on the 2258H used in this box..
http://www.cieri.net/Documenti/JBL/Technical%20Notes/JBL%20Technical%20Note%20-%20Vol.1,%20No.34.pdf

Art Welter:

--- Quote from: Paul G. OBrien on February 20, 2021, 06:15:15 PM ---That is now that you mention it, but can that really be attributed to V loading? I see it as just a low tuned box targeted at install applications.

--- End quote ---
The high sensitivity at 30 Hz mostly comes down to box size, Hoffman's Iron Law: loud, low or small, pick two.

That said, with pro drivers available now with double the Xmax of the 2258H (8mm) the Iron Law can be bent a bit, if you use more power. Doubling Xmax can provide 6 dB more clean output, but uses six dB more power too..

Art

todd kroeker:
Great info guys. I would like to see what folded cabinets these  (2258 3"vc ) will work good in. I am trying to stay small without under doing it at the same time. I have a bigger system that has 4 18" hog scoops and this system is supposed to size in about half  of it.
This system is
2-18's Total and,
-each side is:
1 - 15 front horn loaded   
2 - 12's front horn loaded
1 - 2445 with flat front 2380

Riley Casey:
Blast from th past PA. Your system sounds like what I was using back in the late 70s and early 80s.If you want maximum level without maximum under 40hz output there is always the the Don Keele W 18 horns. Another popular solution was to make oversized versions of the JBL 4520 folded horns as single or dual 18s rather than the original dual 15s.

http://www.audioheritage.org/vbulletin/showthread.php?35664-Early-80-s-Don-Keele-amp-Mark-Gander-JBL-horn-plans


--- Quote from: todd kroeker on February 26, 2021, 11:18:35 PM ---Great info guys. I would like to see what folded cabinets these  (2258 3"vc ) will work good in. I am trying to stay small without under doing it at the same time. I have a bigger system that has 4 18" hog scoops and this system is supposed to size in about half  of it.
This system is
2-18's Total and,
-each side is:
1 - 15 front horn loaded   
2 - 12's front horn loaded
1 - 2445 with flat front 2380

--- End quote ---

Navigation

[0] Message Index

[#] Next page

[*] Previous page

Go to full version