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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 => SR Forum Archives => Product Reviews: Sound Reinforcement FUD Forum Archive => Topic started by: Joseph White on January 01, 2011, 06:53:31 pm

Title: JBL ASB6125
Post by: Joseph White on January 01, 2011, 06:53:31 pm
I have an application for some low profile, high output subs. I need to try to keep my sub array below 17" so they don't rise above stage level. I need to hit about 400 people with 110db or so. The venue is a long story that I don't want to get into.

Has anyone used or installed the JBL ASB6125 dual 15" subs? They fit my application perfectly on paper and the specs look very good. Since they are so new I will have a hard time getting a demo so I might have to buy them without hearing them. Any surprises I need to know about? Are they as punchy and powerful as they look?

I am open to other suggestions for high output subs the fit under 17".

Thanks in advance for you input.

Joseph White
Title: Re: JBL ASB6125
Post by: Grant Conklin on January 02, 2011, 02:17:34 am
Hello Joseph -

I don't have any experience with this particular JBL, but another possibility is the Fulcrum-Acoustic US212.  Similar specs in a much smaller cabinet:   https://docs.google.com/viewer?url=http://www.fulcrum-acoust ic.com/wordpress/wp-content/uploads/2010/05/Prod-Spec-US212- rev-3.pdf

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

Thanks,
Grant
Title: Re: Mini
Post by: Caleb Dick on January 02, 2011, 09:04:29 am
Demo the Danley TH-Mini as well. One of the best tiny subs on the market in my opinion.
Title: Re: JBL ASB6125
Post by: Adam Kane on January 02, 2011, 10:01:16 am
Grund Audio has the LPB series subs that are all 17" or smaller and sound very good. Single 18", double 18", or double 12" options are available.

I've use the 2x12 and the single 18 and they both sound very good. If the 2x18 is anything like the single 18, they should rock as the single 18 I used had far more output than I thought possible from a box that size.

http://www.grundorf.com/index.php?Type=SOUN&Application= GTS
Title: Re: JBL ASB6125
Post by: Duane Massey on January 02, 2011, 09:51:48 pm
Why does any manufacturer not include meaningful specs with their products? It's impossible to evaluate a speaker without real numbers unless you can actually demo one in a real-world environment.
Title: Re: JBL ASB6125
Post by: Grant Conklin on January 02, 2011, 10:09:57 pm
Duane Massey wrote on Sun, 02 January 2011 20:51

Why does any manufacturer not include meaningful specs with their products? It's impossible to evaluate a speaker without real numbers unless you can actually demo one in a real-world environment.



I agree.  Fulcrum is making an honest effort by including "Nominal Sensitivity" (presumably the number you compare to less scrupulous manufacturers) and "Equalized Sensitivity" charts and graphs.  They also base their calculated max output on the AES rating of their speakers.

If Systune and Smaart files were available for download, one would be able to compare between manufacturers in much more meaningful ways.  

Grant
Title: Re: JBL ASB6125
Post by: Duane Massey on January 02, 2011, 10:34:35 pm
Grant, the most useful item on their specs is the graph showing response in a half-space environment. What I don't see is how they claim 102db nominal sensitivity, unless this number refers to the highest level within the stated operating range.

Response graphs are much more informative to me than all the various sensitivity mumbo-jumbo that seems to be the norm. Power handling is useful, but no one talks about the actual effects of power compression, so you rarely see max output as a measured spec, but nearly always a calculated spec.

I know, bitch, bitch, bitch. Fulcrum is certainly better than most.
Title: Re: JBL ASB6125
Post by: Ivan Beaver on January 03, 2011, 07:46:08 am
Grant Conklin wrote on Sun, 02 January 2011 22:09

If Systune and Smaart files were available for download, one would be able to compare between manufacturers in much more meaningful ways.  

Grant


Even then, there would be other "issues" at play in "the game".  Such as drive signal-was it a voltage or referenced to a wattage-based on a rated impedance?

How far was the measurement taked from the box?

Clearly stated half or whole space.

What is the 0dB reference? The rated sensitivity or something else?

Single box of a group of boxes and back calculated and presented as single box?

It is only when the manufacturer is trying to be honest (and not getting caught up in the "numbers" game) that you can start to really compare with a degree of accuracy.

Are they trying to show what the box REALLY does or what they "wish" it would do?
Title: Re: JBL ASB6125
Post by: Ivan Beaver on January 03, 2011, 07:47:49 am
Duane Massey wrote on Sun, 02 January 2011 21:51

Why does any manufacturer not include meaningful specs with their products? It's impossible to evaluate a speaker without real numbers unless you can actually demo one in a real-world environment.

What would be your list of meaningful specs that you would like to see?
Title: Re: JBL ASB6125
Post by: Caleb Dick on January 03, 2011, 08:18:06 am
Frequency response and output at the level where 3dB of deviation from the norm occurs. It's the torture test Pat Brown does.

Also a frequency vs. time domain impulse taken at 4x the drive level of the above test.
Looking for max real long-term output, freq at that level, and how accurately it handles transients.

Title: Re: JBL ASB6125
Post by: Duane Massey 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.



Title: Re: JBL ASB6125
Post by: Silas Pradetto 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.
Title: Re: JBL ASB6125
Post by: Joseph White 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?
Title: Re: JBL ASB6125
Post by: Pat Latimer 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


Title: Re: JBL ASB6125
Post by: Josh Ricci 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
Title: Re: JBL ASB6125
Post by: Grant Conklin 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
Title: Re: JBL ASB6125-Max output
Post by: Ivan Beaver 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/
Title: Re: JBL ASB6125
Post by: Adam Kane 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.
Title: Re: JBL ASB6125
Post by: Duane Massey 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.
Title: Re: JBL ASB6125
Post by: Jeff Wheeler 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.
Title: Re: JBL ASB6125-Which "standard"?
Post by: Ivan Beaver on January 04, 2011, 08:05:14 am
Jeff Wheeler wrote on Tue, 04 January 2011 01:57

[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 hate to highjack this thread-as this is a totally different subject and has nothing in common with the origional post.

The problem with that "test" is what to use for the source waveform.  Some say pink noise-OK what crest factor? 6dB-12dB.  That makes a lot of difference.

Or should you use a specific "curve"? Which one?  There are all sorts of standards that the developers each think theirs best describes a music source.  What kind of music.  Metal and classical have very different  freq content.  Most of the standard curves roll off the low freq, yet it is the low freq that is actually putting the strain on the cabinets. Rolling Eyes

Have you ever looked at the typical time vs freq content of a song? I am thinking of starting a thread on that one. but since it is time that produces heating, I would think that it should be considered-but I have not seen any of the "standard" curves that have what looks like it agrees.  Then again-musical styles vary.

If one manufacturer uses one curve and somebody else uses a different one-how do the two compare?

How much distortion is "to much".  

Speaking from a manufacturer perspective, we have been asked to provide certain specific data.  Yet no other manufacturer provides this data.  So somehow the cutomer who requested it is going to use it to "evaluate" the product and then attempt to compare it to a product that does not have that data. Rolling Eyes   How is that possible?  Let's say they see something they don't like.  What about the other product under consideration?  They don't provide the data, so they get a "free pass"? How does the customer know that their data is better or worse-if they don't have it?

There are some things that can be kinda compared.  And then other things are very dependant on the measurement conditions.

I do agree, I would LOVE to have a standard that all manufacturers would have to adhear to.  But I don't think that is gonna happen in our life time.  It is hard enough to get manufacturers to get the spec numbers and their own measured data/graphs to agree.

Even something as simple as the -3dB point in freq response.  It SHOULD be the freq at which the response is 3dB down from the rated sensitivity.  The two HAVE to be tied together-but very rarely  are.  Take a look at the graphs yourself.

Let's say a loudspeaker has a sensitivity of 100dB.  Then the -3dB point would be the freq that is at 97dB on the curve.  SImple as that.  Now if the manufacturer wants a lower cutoff number, then they need to state a lower sensitivity.  Or if they want a higher sensitivity, then they need to be willing to settle for a higher cutoff freq.

You can't have both.

I better stop now before I get in trouble.  I can get very "emotional" when it comes to specs and honesty Laughing  Very Happy
Title: Re: JBL ASB6125-Which "standard"?
Post by: Duane Massey on January 04, 2011, 09:52:02 am
I'm afraid I started the "hijack". Sometimes my pet peeves get the best of me.
Title: Re: JBL ASB6125
Post by: Tim McCulloch on January 04, 2011, 09:56:34 am
Duane Massey wrote on Mon, 03 January 2011 18:25

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.

This is why Flat View sucks.  Duane posted his reply at the bottom of the page, but it is replying to a post by Adam Kane, but as you can see he's responding to posts by Ivan and Silas.
Title: Re: JBL ASB6125
Post by: Gene Hardage on January 04, 2011, 10:46:08 am
http://www.ramsdellproaudio.com/products/subs/680r.htm
http://www.ramsdellproaudio.com/images/products/largehiq/subs/680R_lrg.jpg

2x18 low profile - made here in good ol' FLA just across the state from you.
Title: Re: JBL ASB6125-Which "standard"?
Post by: Jeff Wheeler on January 04, 2011, 09:33:35 pm
Ivan Beaver wrote on Tue, 04 January 2011 07:05

Speaking from a manufacturer perspective, we have been asked to provide certain specific data.  Yet no other manufacturer provides this data.  So somehow the cutomer who requested it is going to use it to "evaluate" the product and then attempt to compare it to a product that does not have that data. Rolling Eyes   How is that possible?

This is why I put forth my opinion that any additional data DSL provided beyond their current spec sheets would probably not change the fraction of customers who want an in-person demo before making a decision.  When you are already providing equal or better comprehensive specifications (and underlying methods) than the competition, there is no advantage to doing more.
Title: Re: JBL ASB6125
Post by: Phil Ouellette on January 30, 2011, 01:17:58 pm
A church I ran sound for (where I got my start in audio) used a pair of GT-1800 subs for a decade (at least) with no reliability problems.  They were used with pole mounted SOS for half that period and ended being installed in a sub stage pocket after the church moved into their own home.

They are not the most musical sub down low that I have ever heard, but the build quality is decent.  When I first saw them they were powered by an ancient CS800 which was pretty inadequate.  They sounded a lot better after upgrading to a PLX2402 amp.  We got a big sound quality improvement after I reconfigured the system for aux fed subs, we could have gotten a lot better performance with a properly configured DSP crossover, all we had was an analog crossover.

Bottom line, they met the needs and the budget without failures.  I wouldn't hesitate to use them again if they fit the application. That 17" high double 18 sub looks like it would be great for stage pocket installs.