JBL 'M2' Master Reference Monitor - Page 5 - AVS Forum | Home Theater Discussions And Reviews
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post #121 of 138 Old 06-28-2015, 01:46 PM
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Active crossovers do use electronic EQ, it's one of the main advantages active speakers have. That's why it's +/-1db while most speakers fall way short of that.
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post #122 of 138 Old 06-28-2015, 01:57 PM
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It has active digital EQ in the necessary processors, it seems. For instance, in the manual (I only just found), page 9 or so, it mentions that it can correct for the HF loss typical with speaker placement behind a acoustically transparent, perforated cinema screen:

"Digital equalizers
in Crown power amplifiers and BSS
Soundweb London processors used in
the M2 System compensate for screen
loss, and restore neutral frequency
response in the listening space."

http://www.jblpro.com/ProductAttachm...anual_RevA.pdf

Presets specific to this M2 speaker are downloaded from Crown's site:

http://www.crownaudio.com/en-US/products/i-tech-5000hd

In A/V reproduction accuracy, there is no concept of "accounting for taste". We don't "pick" the level of bass, etc., any more than we pick the ending of a play. High fidelity means an unmodified, neutral, exact copy (or "reproduction") of the original artist's tonal balance, timing, dynamics, etc..

Last edited by m. zillch; 06-28-2015 at 08:10 PM.
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post #123 of 138 Old 06-28-2015, 03:18 PM
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They use high quality Crown Itech 5000 amps, one per speaker. The amps are $5000 each. A pair of JBl m2 uses two of them. There's a lot of DSP functionality in those amps so the m2 has all that.
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post #124 of 138 Old 06-28-2015, 09:54 PM
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Quote:
Originally Posted by prm1138 View Post
We have an LCR spread of M2's in for evaluation. Lots of very positive comments, and the imaging from just a stereo pair is astonishing.
Haha! Yeah the imaging is crazy good.

Are these in a studio environment?
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post #125 of 138 Old 06-29-2015, 04:50 PM
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Quote:
Originally Posted by Mfusick View Post
They use high quality Crown Itech 5000 amps, one per speaker. The amps are $5000 each. A pair of JBl m2 uses two of them. There's a lot of DSP functionality in those amps so the m2 has all that.
I don't see why I need a kilowatt of power for a tweeter. The iTech amps are made for touring. They're designed to have enough power to fill a a stadium. It seems ridiculous to require that much amplification as a condition for the sale of the speaker. The SDEC-4500 / BSS can provide cross over functionality, EQ, etc. But can you pair a 92dB sensitivity speaker with reasonable 200w or 300w amps? No. It has to be 3 x 5,000w amps on the Pro side or 6 Mark Levinson mono-block amps (@ $39,000) on consumer side. 300w HF / 300w LF is fine if you want to use the ML amps, but when it comes to the SDA-8300 (or DCi 8|300N), well then 300w isn't up to their standards anymore.

 

 

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post #126 of 138 Old 06-29-2015, 05:20 PM
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The M2 is targeted at recording studios, which often spend that much for playback systems. Crown is an accepted brand in that world.

The Consumer side of JBL wanted in on the action, so Pro let them sell it as a bundle with the Levinson units and BSS DSP. Kind of clunky that way, instead of the clean integrated Pro Crown setup.

The high-end press has not been kind to JBL over the years, for the most part treating their products as glorified PA speakers with those -- ick -- "horns." IMO the dearth of advertising placements in the high-end mags by JBL is a factor here.

Now that JBL has a product that has piqued the curiosity of the high-enders, JBL is kind of hoisting them on their own petard by leveraging the M2 with the Levinson products that they love, or at least used to before Harman acquired them. It seems that so far, at least, JBL is ignoring the high-end publications' entreaties for review samples. Good for JBL -- those guys had it coming.. Let them read all about it in Mix Magazine.
John Schuermann likes this.

Last edited by PrimeTime; 06-29-2015 at 05:44 PM.
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post #127 of 138 Old 06-30-2015, 06:55 AM
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Quote:
Originally Posted by rabident View Post
I don't see why I need a kilowatt of power for a tweeter. The iTech amps are made for touring. They're designed to have enough power to fill a a stadium. It seems ridiculous to require that much amplification as a condition for the sale of the speaker. The SDEC-4500 / BSS can provide cross over functionality, EQ, etc. But can you pair a 92dB sensitivity speaker with reasonable 200w or 300w amps? No. It has to be 3 x 5,000w amps on the Pro side or 6 Mark Levinson mono-block amps (@ $39,000) on consumer side. 300w HF / 300w LF is fine if you want to use the ML amps, but when it comes to the SDA-8300 (or DCi 8|300N), well then 300w isn't up to their standards anymore.
The tweeter is a revolutionary design with many patents, it's ultra clean far up past the audible range and very smooth with extremely low distortion. It's a push/pull design.

You might not need all 2500 watts for the tweeter, but it's there in case you need it. These are a pinnacle of engineering. No whimpy amps allowed.
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post #128 of 138 Old 06-30-2015, 11:08 AM
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Quote:
Originally Posted by rabident View Post
I don't see why I need a kilowatt of power for a tweeter.... But can you pair a 92dB sensitivity speaker with reasonable 200w or 300w amps? No. It has to be 3 x 5,000w amps on the Pro side or 6 Mark Levinson mono-block amps (@ $39,000) on consumer side. 300w HF / 300w LF is fine if you want to use the ML amps, but when it comes to the SDA-8300 (or DCi 8|300N), well then 300w isn't up to their standards anymore.

Excellent point.

In A/V reproduction accuracy, there is no concept of "accounting for taste". We don't "pick" the level of bass, etc., any more than we pick the ending of a play. High fidelity means an unmodified, neutral, exact copy (or "reproduction") of the original artist's tonal balance, timing, dynamics, etc..
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post #129 of 138 Old 06-30-2015, 12:56 PM
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It is worth noting that the D2 HF driver in the M2 has a 9 dB pad on it. Which might not be necessary if the signal processing had remained in the linear domain, as the DSP is adding noise to the source. This may be possible, given that the digital delay correction (270 uSec) is not applied to the HF section.

As it is, of the 300 watts available to the 32-ohm D2 load, 270 of them would be allocated to the resistive attenuation.
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post #130 of 138 Old 06-30-2015, 05:58 PM
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Quote:
Originally Posted by Mfusick View Post
You might not need all 2500 watts for the tweeter, but it's there in case you need it.
Either I need it or I don't. Anything extra is a waste.

Quote:
Originally Posted by Mfusick View Post
These are a pinnacle of engineering. No whimpy amps allowed.
The whole "M2 were designed to be used with power output of the iTech 5000" might have credibility if JBL didn't pair 300w amps with the M2's in their $117,000 Synthesis M2 system.

How do you figure a Crown DriveCore amp @ 300 watt is wimpy, but ML @ 300 watts is not? Why do I need 8x more power from a Crown amp to have the equivalent performance from ML? I don't think the answer has anything to do with engineering.

 

 

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post #131 of 138 Old Yesterday, 11:15 AM
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Jbl m2

Quote:
Originally Posted by Gooddoc View Post
Haha! Yeah the imaging is crazy good.

Are these in a studio environment?
We have a mixed music studio and film post environment, along with 9 small screening rooms. These speakers are very enlightening.

Pair them with a Meridian Audio digital front end and they are crazy.

Last edited by prm1138; Yesterday at 11:17 AM. Reason: additional comment
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post #132 of 138 Old Yesterday, 12:21 PM
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To the best of my knowledge this thread has never had posted the on-axis response of the M2 [not to be confused with the listening window which is an average of many curves], with or without its requisite processor which includes EQ. Here it is, I assume with EQ:

source: http://www.audioheritage.org/vbullet...Monitor/page46

In A/V reproduction accuracy, there is no concept of "accounting for taste". We don't "pick" the level of bass, etc., any more than we pick the ending of a play. High fidelity means an unmodified, neutral, exact copy (or "reproduction") of the original artist's tonal balance, timing, dynamics, etc..
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post #133 of 138 Old Yesterday, 03:16 PM
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If you cannot use another M2 as a center channel speaker because you have a TV instead of a projector, what do you recommend using as a (horizontal) center speaker?
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post #134 of 138 Old Yesterday, 03:37 PM
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If you cannot use another M2 as a center channel speaker because you have a TV instead of a projector, what do you recommend using as a (horizontal) center speaker?
Nothing. Go phantom. The M2's imaging is without peer.
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post #135 of 138 Old Yesterday, 03:37 PM
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Use a phantom center channel. All Dolby licensed products allow for that mode. Or all three speakers in a line below the display.


Horizontal center speakers came out in the days of CRT and were designed to fit on their top edge. Somehow the public came to think that's the shape a center channel should be, but it is not so. Look at what Dolby Laboritories uses themselves in their $50K system, for instance:

edit: Gooddoc beat me to posting by under a minute!

In A/V reproduction accuracy, there is no concept of "accounting for taste". We don't "pick" the level of bass, etc., any more than we pick the ending of a play. High fidelity means an unmodified, neutral, exact copy (or "reproduction") of the original artist's tonal balance, timing, dynamics, etc..

Last edited by m. zillch; Yesterday at 03:43 PM.
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post #136 of 138 Old Yesterday, 06:59 PM
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Intersting data, thanks.

I'm puzzled that the sound power is more rolled off than both the on-axis and listening window, as it's a combination of both.

Quote:
Originally Posted by m. zillch View Post
To the best of my knowledge this thread has never had posted the on-axis response of the M2 [not to be confused with the listening window which is an average of many curves], with or without its requisite processor which includes EQ. Here it is, I assume with EQ:

source: http://www.audioheritage.org/vbullet...Monitor/page46

Noah
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post #137 of 138 Old Yesterday, 08:17 PM
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Intersting data, thanks.

I'm puzzled that the sound power is more rolled off than both the on-axis and listening window, as it's a combination of both.
No, its not. It's the sum of all sounds radiated by the loudspeaker in all directions.
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post #138 of 138 Unread Today, 09:16 AM
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Quote:
Originally Posted by prm1138 View Post
We have a mixed music studio and film post environment, along with 9 small screening rooms. These speakers are very enlightening.

Pair them with a Meridian Audio digital front end and they are crazy.
Nice. I am working towards an all digital path to the M2's. I really haven't convinced myself it's worth the effort and money, but your comments certainly give me a bit more motivation .

What monitors did the M2's replace?
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