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Author Topic: JBL ASB6125  (Read 13878 times)

Duane Massey

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Re: JBL ASB6125
« Reply #10 on: January 03, 2011, 10:04:23 am »

Ivan, what would make sense to me (and most semi-tech guys) would be the basics, some of which are already common:

Operating range, +/- 3db
Graph showing response in full or half-space, actual measurements of 1 box, not modeled or calculated
Rated power handling, basic stuff, no "dog watts" or other BS
Physical dims and weight
Max output as actually measured, not calculated

Things I would find useful that others might not would include measurements off-axis in a real-world environment.

Some manufacturers do include some or all of this stuff, but marketing seems to creep in even then, such as the apparent practice of using the highest number measured as the 1w/1m spec, even if this number is outside the normal application.



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Duane Massey
Houston, Texas, USA

Silas Pradetto

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Re: JBL ASB6125
« Reply #11 on: January 03, 2011, 10:59:02 am »

Duane Massey wrote on Mon, 03 January 2011 10:04

Ivan, what would make sense to me (and most semi-tech guys) would be the basics, some of which are already common:

Operating range, +/- 3db
Graph showing response in full or half-space, actual measurements of 1 box, not modeled or calculated
Rated power handling, basic stuff, no "dog watts" or other BS
Physical dims and weight
Max output as actually measured, not calculated

Things I would find useful that others might not would include measurements off-axis in a real-world environment.

Some manufacturers do include some or all of this stuff, but marketing seems to creep in even then, such as the apparent practice of using the highest number measured as the 1w/1m spec, even if this number is outside the normal application.






Pretty much everything you just mentioned except dimensions can be interpreted differently by different manufacturers, making the numbers meaningless.


Operating range, +-3dB from what?

Graphs can be smoothed and otherwise misrepresented. Measurement conditions can't be quantified easily.

Power handling could be the thermal capacity of the coil, but that really means nothing when music is playing.

Max output can be measured, but where? 1k? 50Hz? At an impedance maximum or minimum? After two hours of operating for full power? Or with no power compression?

I'm sure Ivan is going to chime in, but what you're asking for is impossible.
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Joseph White

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Re: JBL ASB6125
« Reply #12 on: January 03, 2011, 12:32:51 pm »

Grant Conklin wrote on Sun, 02 January 2011 07:17

What is the distance from the subwoofer to the farthest row that you want to hit with 110db?


The room is shallow and wide in a fan shape, so the farthest row is only about 40 feet from the stage, maybe 45 since I want to put the subs at the center of the stage.

I had never heard of Grund Audio, but their flat mounted dual 18 may be perfect for my application and I see nothing but good reviews.

What is the price point of the Fulcrum? I really need to keep it under $2000 each to get it financed. Honestly, the low cost of the Grund ($1400) almost makes me nervous.

Does anyone else want to chime in on the Grund subs?
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Joseph White
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Pat Latimer

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Re: JBL ASB6125
« Reply #13 on: January 03, 2011, 12:41:05 pm »

Joseph White wrote on Mon, 03 January 2011 12:32

Grant Conklin wrote on Sun, 02 January 2011 07:17

What is the distance from the subwoofer to the farthest row that you want to hit with 110db?


The room is shallow and wide in a fan shape, so the farthest row is only about 40 feet from the stage, maybe 45 since I want to put the subs at the center of the stage.

I had never heard of Grund Audio, but their flat mounted dual 18 may be perfect for my application and I see nothing but good reviews.

What is the price point of the Fulcrum? I really need to keep it under $2000 each to get it financed. Honestly, the low cost of the Grund ($1400) almost makes me nervous.

Does anyone else want to chime in on the Grund subs?



If you're gonna go that far, check out some of the offerings from Bag End. http://www.bagend.com/pro.htm You may find something that could work for you there.

Pat


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Josh Ricci

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Re: JBL ASB6125
« Reply #14 on: January 03, 2011, 12:51:52 pm »

It really is hard to quantify but what I would like to see is an impedance measurement unsmoothed covering at least 20-200hz for subwoofers and a half space, 1 m frequency response measurement that is unsmoothed or at least 1/24 smoothing or less. Id like to see the drive level be a voltage that provides no more than approximately 1w into the minimum impedance of the system within the manufacturer's specified frequency bandwidth of intended use. A 10m halfspace response measurement also with minimal smoothing and 10x the voltage from the 1m one would be nice. A specification for the voltage input that results in driver excursion limits being met within the manufacturers  intended passband I would also like to see. Maybe a long term high power pink noise compression test to determine long term max output? 3db of total compression cutoff? Not sure how you'd specify bandwidth or crest or...?

Yeah I see all that happening soon. Rolling Eyes
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Grant Conklin

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Re: JBL ASB6125
« Reply #15 on: January 03, 2011, 12:56:16 pm »

Hello Joseph -
The US212 Lists for $2085.  

You probably know this, but hitting 110db at 45 feet would require a source of 133db, plus headroom.  

Thanks,
Grant
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Ivan Beaver

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Re: JBL ASB6125-Max output
« Reply #16 on: January 03, 2011, 01:12:24 pm »

Here is a simple example of how "Max output" can say one thing and mean quite another.

Below is a max output GRAPH of a particular loudspeaker (who shall remain nameless-so don't ask).  This is THEIR data.

They claim 143dB max output on the spec sheet.  If you look at the measured max output, you will see that it can only produce that max output at around 1.3Khz.  At the other freq (sometimes we want more than 1.3Khz in the mix Rolling Eyes ) it is a good bit lower-by 10dB or more.

So the "usable" max output is no where near the speced max output-even though they are not lying and the box will produce some freq that loud.

Once you EQ the peaks down, the max SPL is a good bit lower, but the numbers don't look as good on a spec sheet.

A good example of what happens when you try to use a simple number to describe a complex situation or when trying to describe what is usable.
index.php/fa/34542/0/
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Adam Kane

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Re: JBL ASB6125
« Reply #17 on: January 03, 2011, 02:29:22 pm »

Joseph White wrote on Mon, 03 January 2011 12:32

Grant Conklin wrote on Sun, 02 January 2011 07:17

What is the distance from the subwoofer to the farthest row that you want to hit with 110db?


The room is shallow and wide in a fan shape, so the farthest row is only about 40 feet from the stage, maybe 45 since I want to put the subs at the center of the stage.

I had never heard of Grund Audio, but their flat mounted dual 18 may be perfect for my application and I see nothing but good reviews.

What is the price point of the Fulcrum? I really need to keep it under $2000 each to get it financed. Honestly, the low cost of the Grund ($1400) almost makes me nervous.

Does anyone else want to chime in on the Grund subs?


Grund isn't as well known as many other companies. They also build racks/cases and I think many people assume that because of that, their audio gear is not worth looking at. After working with much of their gear in the past, I no longer have reservations using their stuff (GT Series). The other boxes are entry level DJ type stuff that has its place...wouldn't use that for installations. All of the GT stuff is baltic birch, very nice cabinet construction, loaded with drivers from B&C, Celestion, Selenium, real crossovers (for the full range stuff).

Call them and ask for a demo...they'll be happy to set something up.
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Duane Massey

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Re: JBL ASB6125
« Reply #18 on: January 03, 2011, 07:25:39 pm »

Ivan, that is my point. I can look at a graph and at least see the actual response IF the graph is accurate and legible. Even if it is the standard 1w/1m info it is useful if you have several other boxes with the same info.

You are correct, +/- 3db is only useful if you know what it is referenced to. I'd rather have the graph.

Silas, you are correct. It is not possible unless everyone uses the same standards, and that will never happen.
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Duane Massey
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Jeff Wheeler

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Re: JBL ASB6125
« Reply #19 on: January 04, 2011, 01:57:54 am »

Josh Ricci wrote on Mon, 03 January 2011 11:51

Not sure how you'd specify bandwidth or crest or...?

I'd like to see the specified useful frequency response range actually used for specified peak power testing, without driver damage or outrageous distortion from cone flap.  I know my MRX525s can't go to 60Hz (or whatever the JBL spec is) at anything close to the specified 3200w peak drive level without flapping or likely self-destructing.  Yet JBL chooses to rate the speaker with those performance figures, as if they are separate.

I'd also like to see honest power compression information, both how long it takes to heat up, and how much output is lost, at given drive voltages.

Josh Ricci wrote on Mon, 03 January 2011 11:51

Yeah I see all that happening soon. Rolling Eyes

Danley has pretty comprehensive spec sheets compared to virtually every other manufacturer.  I bet any additional information they added would not significantly change the fraction of customers who want to hear a demo box in action before they decide to purchase the box.

If it were, say, Bill Fitzmaurice DYI designs adding a bunch more informative, honest specifications with detailed explanations of measurement methods, I imagine it would discourage some purchasers.

JBL is certainly somewhere in-between, and does not respond to questions like, why don't they correct large, obvious errors in the spec sheets.  So, I guess JBL figures spec sheets aren't a big contributor to loudspeaker sales?

Interestingly enough, the ASB6125 cut sheet indicates it is loaded with the same woofers as the SRX725.  Obviously the box is not the same.
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