Intrigued by JBL M2 speaker system .... Opinions please ...

[bromide]

It was from a Synthesis rep that came out to the house. It may have been specific to me. I have a 7000cuft room and expressed concern about the S1S-EX output @ 20hz, so he might have felt 4 corner loaded subs were essential to get what I wanted.

Thanks for the link & info on the subs.

 

[Robh3606]

Hello Dallas Justice

There is a protection capacitor and attenuator resistors in the internal passive network. The tuning looks to be about 22hz and there is a 6db Q2 bump in the DSP at that frequency. Typical JBL legacy tuning with assist as used in the B360/380 with the BX-63 network except 26hz there.

Rob

 

[Nyal Mellor]

Amir,
What is the port tuning frequency? I ask because my room gets smoother bass with a pair of mono frontwall subs, one quarter width, than just running a pair of full range speakers. I wouldn't want to try to integrate subs below the tuning frequency without crossing them over well above the tuning frequency.(port phase reversal)

Do folks ever use their own 3rd party DSP off the server to handle room correction and crossovers for subs with the m2? It seems possible.
Michael.

Michael.

It might be possible but the M2 has some unusual filters, including variable slope shelving filters on both the tweeter (11dB) and woofer (5.5dB) and 36dB low pass on the woofer. At the minimum if you were to use another DSP solution you'd want to first measure with the JBL DSP and then adjust the replacement DSP to do the same thing. I would not assume a 12dB crossover in one DSP is the same as in another. I've found many different implementations of parametric EQ "Q" for example.

 

[Nyal Mellor]

It was from a Synthesis rep that came out to the house. It may have been specific to me. I have a 7000cuft room and expressed concern about the S1S-EX output @ 20hz, so he might have felt 4 corner loaded subs were essential to get what I wanted.

Thanks for the link & info on the subs.

Got to love JBL, they are all over the place on their "requirements"

 

[dallasjustice]

Right. But if I used the standard JBL filters and then just add my own filters on my server out to a MCH DAC for the room bass and high pass to integrate a pair of subs (around 80hz), that seems feasible? I guess the only downside to that kind of setup is that I am adding a second layer of dither. But that's prolly not audible.

It might be possible but the M2 has some unusual filters, including variable slope shelving filters on both the tweeter (11dB) and woofer (5.5dB) and 36dB low pass on the woofer. At the minimum if you were to use another DSP solution you'd want to first measure with the JBL DSP and then adjust the replacement DSP to do the same thing. I would not assume a 12dB crossover in one DSP is the same as in another. I've found many different implementations of parametric EQ "Q" for example.

 

[dallasjustice]

How does the jbl software work when the user doesn't use the crown amps? If I used a BLU-160, would the software reside on the BLU-160 or inside a computer connected to the BLU-160?

 

[amirm]

Nothing lives in a computer. The PC is used for measurements and programming of the DSPs (independent or inside crown amps). Once you have done the programming, the PC is disconnected and plays no role.

 

[bromide]

Does anyone know if it's possible to equip the SDEC-4500P with an AES output card? It appears to be an option on the BSS processor the SDEC is based on. Or possibly on the companion SDEC-4500X? On the JBL Synthesis site, they mention the processor can be customized to fill different needs, but don't go into detail what customization are possible.

The iTech amps bundled with the M2 in the Pro path don't support Blu-link, but they do have 24/96 AES inputs.

 

[dallasjustice]

Thanks Amir for answering so many questions. I also noticed that the Itech amps only take 48khz and 96khz on the AES3. Is that also true for the BSS? Can the BSS be ordered with a word clock input to make sure it's synced with other hardware?

 

[amirm]

Does anyone know if it's possible to equip the SDEC-4500P with an AES output card? It appears to be an option on the BSS processor the SDEC is based on. Or possibly on the companion SDEC-4500X? On the JBL Synthesis site, they mention the processor can be customized to fill different needs, but don't go into detail what customization are possible.

The iTech amps bundled with the M2 in the Pro path don't support Blu-link, but they do have 24/96 AES inputs.

I have asked this question in the context of the same processor in other JBL Synthesis packages and the answer is yes, but with special arrangement through your dealer and Harman. It required a special firmware and they want to make sure your dealer knows how to manage such situation.

Now, it is possible they were only going to make an exception for me . So please don't tell your dealer that I said this. But simply ask and insist that if you are going to get it, you would need this configuration.

 

[amirm]

Thanks Amir for answering so many questions. I also noticed that the Itech amps only take 48khz and 96khz on the AES3. Is that also true for the BSS? Can the BSS be ordered with a word clock input to make sure it's synced with other hardware?

The second answer is yes, it has word clock input. See http://rdn.harmanpro.com/product_do...566/BSS-Dig-In-Out-CardDataSheet_original.pdf

But it does seem like it only supports 48 Khz and 96 with an onboard resampler to convert other rates to this.

 

[joeinid]

Hi Amir,

i've thought about the M2's, could other amps be substituted for the Crowns like two McIntosh MC452's and still be run properly? I'm not sure Crown would be to my liking but would prefer a softer/sweeter amp. How difficult would that be to configure or is it even allowed?

 

[amirm]

The technology doesn't care which amp is used. But they are always concerned about other amplifiers being damaged when pushed in EQ department due to lack of headroom and having to deal with that liability. To the extent your dealer can vouch for suitability of you using your own amp and Harman trusting their capabilities in this regard, it may be possible. So as with my last answer, go ahead and ask but don't mention my name .

 

[joeinid]

Hi Amir,

Thank you so much. I wish you were my local dealer I've asked around and don't get the feeling anyone wants to do the dirty work. I really think the M2's could be ton of fun with the right amps.

Thanks again.

 

[bromide]

Amir, understood.

I did have one last question, if you don't mind. How important do you think the JBL subs are to SFM with the M2's? I wasn't crazy about the specs on S1S-EX to start with. 4 of them are coming in at just over $32k list with amps. I'm sold on the M2's but it seems like there are better options/value out there for subs. Will I be undermining Arco / SFM calibration if I use someone else's subs?

 

[Phelonious Ponk]

Hi Amir,

i've thought about the M2's, could other amps be substituted for the Crowns like two McIntosh MC452's and still be run properly? I'm not sure Crown would be to my liking but would prefer a softer/sweeter amp. How difficult would that be to configure or is it even allowed?

Have you heard the Crowns?

Tim

 

[joeinid]

Have you heard the Crowns?

Tim

Hi Tim,

Honestly, not those exact amps, but I've owned a Crown many years ago and friends own current Crown amps. I personally prefer warmer, less neutral amps. Another friend owns the M2's, knows my taste, and feels another "sweeter" amp would be better for our taste, although he does love the system for movies. I have not heard his system, yet. I do need to listen the the M2 system, properly set up for myself.

 

[amirm]

Amir, understood.

I did have one last question, if you don't mind. How important do you think the JBL subs are to SFM with the M2's? I wasn't crazy about the specs on S1S-EX to start with. 4 of them are coming in at just over $32k list with amps. I'm sold on the M2's but it seems like there are better options/value out there for subs. Will I be undermining Arco / SFM calibration if I use someone else's subs?

I am with you on that. In my own theater I am using other brand subs. SFM works across all subs. The only issue is potential for damage again per my earlier note. JBL subs may not be the latest or greatest designs but they sure can take punishment. So if you are using other brand subs, listen to some high SPL material and quickly turn down the volume and then gain of the subs if they start to clip as ours did initially. It is pretty easily done.

 

[amirm]

Hi Amir,

Thank you so much. I wish you were my local dealer I've asked around and don't get the feeling anyone wants to do the dirty work. I really think the M2's could be ton of fun with the right amps.

Thanks again.

Thanks for the kind words . My designer has had a relationship with Harman and their key designers for decades so they trust us to do unusual things whereas for other dealers, they won't easily make exceptions. If they are going to be at RMAF, my suggestion is to come to that show and have a talk with them. Last time I chatted with them they were willing to make exceptions if the end customer signed a simple waiver that said if other equipment was used and got damaged in the process, it was not their responsibility. I don't know if they still do this but it is worth an ask.

I have not firmed up my plans for RMAF but if I go and they are there, I am happy to make special arrangements for those of you interested to have such a chat with them and proper demo.

 

[gandy]

Just installed the M2/Crown system in my living room. Had to upgrade the electrical circuit to true 20 amp to feed the Crowns, and had to remotely install the amps due to the fan noise. This effort was well worth it since the sound is sublime. Competitive with the most expensive Wilsons, Magicos, Rockports, MBLs, Focals, etc., in my opinion, and at a fraction of the cost. Just good science (Dr. Floyd Toole), years of experience (JBL), and deep pockets (Harman) geared toward industry professionals rather than wealthy audiophiles. Will keep using the Crowns since not sure the extra 30 to 40 thousand dollars for processor/Mark Levinson would result in significantly better sound.