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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB: The Classic Live Audio Board => Topic started by: Nitin Sidhu on December 08, 2012, 01:19:06 PM
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Now in the Vintage section of the JBL website.
This should get a sale going!
STX.
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You are late to the funeral my friend.
Sent from my iPhone using Tapatalk
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insert man on the moon joke..
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Gahh! Why?! It's such a good series...! Oh well... :'(
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They dont have a moron smiley now ??
;D
I really have been under a rock! Swear!
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Now in the Vintage section of the JBL website.
This should get a sale going!
STX.
I think this had part to do with the price of neodymium going through the roof here recently.
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RE: JBL STX 835
How do you take 2 JBL 2226's each with a 97db sensitivity, place them in a bandpass cabinet, and come out with a 96db sensitivity?
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RE: JBL STX 835
How do you take 2 JBL 2226's each with a 97db sensitivity, place them in a bandpass cabinet, and come out with a 96db sensitivity?
Wire them incorrectly ?
:-)
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RE: JBL STX 835
How do you take 2 JBL 2226's each with a 97db sensitivity, place them in a bandpass cabinet, and come out with a 96db sensitivity?
Probably by rating the sensitivity at a frequency below 100 Hz instead of above.
Without seeing frequency response charts, (and knowing the drive voltage, test condition, and actual impedance) comparing sensitivity of two different enclosures is next to useless.
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Probably by rating the sensitivity at a frequency below 100 Hz instead of above.
Without seeing frequency response charts, (and knowing the drive voltage, test condition, and actual impedance) comparing sensitivity of two different enclosures is next to useless.
Put that in the same catagory as "this cabinet get's to 139db, and this one get's to 142db. Which cabinet is better."
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Put that in the same catagory as "this cabinet get's to 139db, and this one get's to 142db. Which cabinet is better."
Or even worse-"Why does the one that only goes to 139 seem louder".
DUH-Maybe the way it is rated-and at what freq.
Simple single numbers usually don't mean much. you HAVE to look at bit closer to get the REAL story.
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1m/1m across a near-identical passband.
I realize there are lots of cabinet, LS & T/S parameters that do not make any spec sheet, but this in particular seems odd.
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1m/1m across a near-identical passband.
I realize there are lots of cabinet, LS & T/S parameters that do not make any spec sheet, but this in particular seems odd.
Jim,
A picture is worth a thousand words, post up the charts of each "near-identical passband" and cabinet dimensions so we can see what you find odd.
Art
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www.jblpro.com/pages/pub/components/2226.pdf
www.jblpro.com/backoffice/productattachments/jbl_stx835.v1.pdf
1w/1m passband on the standalone cone is 100-500 hz.
Cannot find test LF starting point on the 2 x enclosure, but it tops out at 250hz.
I was kind of hoping someone from the factory would weigh in.
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www.jblpro.com/pages/pub/components/2226.pdf
www.jblpro.com/backoffice/productattachments/jbl_stx835.v1.pdf
1w/1m passband on the standalone cone is 100-500 hz.
Cannot find test LF starting point on the 2 x enclosure, but it tops out at 250hz.
I was kind of hoping someone from the factory would weigh in.
The problem with simply having a "0" point on a graph is that you don't know what SPL that 0 is referring to..
It could be anything, and maybe all they are trying to show is the deviation in amplitude response-not an absolute reference.
How you perceive the graph and other associated numbers in the spec sheet may not how they intended.
Unless you have graphs that are measured in close to the same way (distance-input level etc) it can be hard to say they are "the same".
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The problem with simply having a "0" point on a graph is that you don't know what SPL that 0 is referring to..
It could be anything, and maybe all they are trying to show is the deviation in amplitude response-not an absolute reference.
How you perceive the graph and other associated numbers in the spec sheet may not how they intended.
Unless you have graphs that are measured in close to the same way (distance-input level etc) it can be hard to say they are "the same".
Thought this was relevant here. "On paper" the new STX subs are a disappointment - heavier, higher operating frequency range, etc. Digging in a little farther into the charts, it appears the STX subs aren't a step backwards, and if the graphs are to be believed, have more LF extension than SRX did.
My methodology for these (excluding the Fulcrum subs) was to take the 1/2 space peak number, find the highest point of the published curve, and subtract from there at each of the data points I was interested in. For the Fulcrum subs, I used the "Equalized Maximum" and equalized curves.
Usual disclaimers apply - spec sheets lie, different measurement techniques, probably errors either on the spec sheets or in my copying, etc. Please feel to correct this if you have better info than what I've found/calculated.
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We've moved from bassrange 15's to subs.
"First watt" (1w/1m) subwoofer measurements can paint as an inaccurate sonic picture as "calculated maximum SPL" ratings w/o charting where the device runs out of xmax gas or the onset of power compression.
Returning to my original posit (and hopefully someone within JBL can reply) it seems prima facie odd that a doubling of the the components results in a reduced a sensitivity rating, OR, what are the in-house sensitivity rating protocol differences that produce this result?
Loudspeakers are quite a stew, aren't they?
Interesting to me is that JBL has seen fit to employ the 20+ year old 2226's in current & competitive designs. I've long been a fan, and there are dozens of boxes I built in the 1990's still performing respectably and earning $ for their owners, but 2 decades is quite a stretch.
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Returning to my original posit (and hopefully someone within JBL can reply) it seems prima facie odd that a doubling of the the components results in a reduced a sensitivity rating, OR, what are the in-house sensitivity rating protocol differences that produce this result?
Jim,
There seems to be a discrepancy of about 1.5 dB from the STX 835 spec sheet's 96 dB "passive mode" sensitivity compared to the FR chart, which looks to be more like 97.5 dB in free field.
Since the cabinet is designed to be flown, it shows measurement in both free field and half space.
The half space measurement shows 100 dB sensitivity at 50 Hz, rising to 104 dB at 70 Hz.
Using the 2226 spec sheet, we can interpolate from the 60 watt chart that the "0" line on the frequency response curve of a 5 cubic foot vented cabinet is 97 dB 1 watt one meter half space, about 96 dB at 50 Hz.
The STX 835 (probably about 4 cubic foot net per driver) is as much as 8 dB more sensitive than the 5 foot vented cabinet, but rolls off at about 12 dB per octave from 70 Hz, at 40 Hz the two boxes are about the same sensitivity.
Classic illustration of Hoffmann's Iron Law, low, loud, or small-pick two.
Also an illustration that using a single sensitivity figure is useless, you need to look at the FR graph to determine where the sensitivity is derived.
Anyway, thanks for the links, this is the first time I ever saw JBL underate (even if only by 1.5 dB) sensitivity on one of their cabinets.
Art