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Thread: M2 residential amplifier choices???

  1. #1
    Senior Member Champster's Avatar
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    M2 residential amplifier choices???

    I'm very familiar with actively amplified systems but am disappointed that there isn't a high power amplifier choice for the M2 that would serve the 1200W minimum requirement without fans. I've talked to 3 different JBL dealers and the (different) recommended amps are the CDi 4x1200, the DCi 4x1250 or the super powerful iTech 4x3500. There is a Levinson option through Synthesis but those are far lower power (531H @ 300W) and if you study the M2 the real holly grail of this speaker is to deliver tremendous (dare I say, life-like) dynamic range so that at a normal 85dB average listening level, you can still get 20-30dB of undistorted headroom for those peaks.

    I'm hoping someone on the Forum has come up with a solution to this problem and is willing to share the idea.

    TIA

  2. #2
    Member Fitero's Avatar
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    I took a different route after trying several amplifiers with them. I even powered them briefly with a 35WPC tube amp as a test.

    I had Bob at AB Systems Amplifiers put together a 4 channel, 300WPC amp for me. No fan noise, and has more than enough grunt for domestic use. If you want, he has a 525WPC model as well. All power ratings are at 8 ohms all channels driven continuous sine wave.

    https://www.abamps.net/
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  3. #3
    Member Mitchco's Avatar
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    Another member's M2 system using Benchmark AHB2 amps: https://www.audiosciencereview.com/f...s-w-subs.2369/

    While not M2's the JBL 4722's I use have similar woofer tech and I drive them with Crown XLS 1502 DriveCore 2 Series amps: https://www.crownaudio.com/en/products/xls-1502

    There are a few models to choose from and can be bridged mono. If the fan has ever turned on, I can't hear it, even right up close to the amp. I am impressed with the sound quality, headroom and damping factor of these amps. The XLS 1502 puts out 575W into the 4 ohm load with the double 15" woofers per side. At extreme level's I can get the limiter to flash on drum transients, but adding another 1502 in bridged mode would be 1550W per channel.

    I can't speak to the high frequency sound quality of the XLS amps, as I run the JBL 4722's biamp (triamp with subs) and the amps are used to drive the bass cabs. Really impressed with the tight bass and impact. I upgraded the CD to JBL 2453H-SL and driving those with Nelson Pass flea watt ACA amps directly connected to the CD's with a protection cap and no padding. Dead silent, no hiss, lovely SQ.

    It would seem to me that a couple of bridged XLS 2502 with 1550W at 8 ohms per channel would give you plenty of headroom driving the M2 woofers. I have never heard the fan and if you check out Amazon reviews, the majority of folks are impressed with the SQ, especially at this price point

    Good luck!

  4. #4
    Senior Member baldrick's Avatar
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    If you want OEM path you will either need BSS DSP or Crown DCIN or iTech HD. With BSS DSP you could more or less buy any decent poweramps. The easy way is to buy Crown, I have DCI4/600N. Difference between 4/1250 and 4/600 is just power, you will never need more than 600, DCI4/300N would probably also work excellent.

    Otherwise you could of course use other DSP solution than Crown/BSS, but I would stick to BSS and My all in all advice would be Crown DCI4/600N

  5. #5
    Senior Member Champster's Avatar
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    Quote Originally Posted by baldrick View Post
    If you want OEM path you will either need BSS DSP or Crown DCIN or iTech HD. With BSS DSP you could more or less buy any decent poweramps. The easy way is to buy Crown, I have DCI4/600N. Difference between 4/1250 and 4/600 is just power, you will never need more than 600, DCI4/300N would probably also work excellent.

    Otherwise you could of course use other DSP solution than Crown/BSS, but I would stick to BSS and My all in all advice would be Crown DCI4/600N
    Thank you, Baldrick. I'm assuming this is your home system, do you ever hear the fans? Are the amps in the same room as the speakers?

  6. #6
    Senior Member Champster's Avatar
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    Quote Originally Posted by Mitchco View Post
    Another member's M2 system using Benchmark AHB2 amps: https://www.audiosciencereview.com/f...s-w-subs.2369/

    While not M2's the JBL 4722's I use have similar woofer tech and I drive them with Crown XLS 1502 DriveCore 2 Series amps: https://www.crownaudio.com/en/products/xls-1502

    There are a few models to choose from and can be bridged mono. If the fan has ever turned on, I can't hear it, even right up close to the amp. I am impressed with the sound quality, headroom and damping factor of these amps. The XLS 1502 puts out 575W into the 4 ohm load with the double 15" woofers per side. At extreme level's I can get the limiter to flash on drum transients, but adding another 1502 in bridged mode would be 1550W per channel.

    I can't speak to the high frequency sound quality of the XLS amps, as I run the JBL 4722's biamp (triamp with subs) and the amps are used to drive the bass cabs. Really impressed with the tight bass and impact. I upgraded the CD to JBL 2453H-SL and driving those with Nelson Pass flea watt ACA amps directly connected to the CD's with a protection cap and no padding. Dead silent, no hiss, lovely SQ.

    It would seem to me that a couple of bridged XLS 2502 with 1550W at 8 ohms per channel would give you plenty of headroom driving the M2 woofers. I have never heard the fan and if you check out Amazon reviews, the majority of folks are impressed with the SQ, especially at this price point

    Good luck!
    Thank you, Mitchco. I'll check, but do these have the built in DSP to load the software?

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    Iím really keen on the iTech 4x3500. Anybody has any experience with them? Especially the fan noise.

  8. #8
    Senior Member Ian Mackenzie's Avatar
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    Quote Originally Posted by Champster View Post
    I'm very familiar with actively amplified systems but am disappointed that there isn't a high power amplifier choice for the M2 that would serve the 1200W minimum requirement without fans. I've talked to 3 different JBL dealers and the (different) recommended amps are the CDi 4x1200, the DCi 4x1250 or the super powerful iTech 4x3500. There is a Levinson option through Synthesis but those are far lower power (531H @ 300W) and if you study the M2 the real holly grail of this speaker is to deliver tremendous (dare I say, life-like) dynamic range so that at a normal 85dB average listening level, you can still get 20-30dB of undistorted headroom for those peaks.

    I'm hoping someone on the Forum has come up with a solution to this problem and is willing to share the idea.

    TIA

    A few things come to mind.

    If you are in a domestic situation can you ever imagine running the M2'S at levels requiring 1200W headroom?
    The 1200 watt amp rating is more a safety measure so as not to clip the amp (square wave) which would probably damage the drivers.

    So if you can live wth 6 db less headroom it opens up some amp options without fans that do DSP in the Crown range.

    In any case fan noise of any kind an going to cloud the resolution of the system....

    I sticking with the crown amps with the embedded dsp for the M2 is easier on setting up the system.
    The alternative is the BSS DSP and you can buy any descent power amps but the BSS DSP is reported to also produce fan noise.
    So there is no advantage going that route.

    Therefore it might be worth looking at the feasibility of amps in a separate room.

  9. #9
    Senior Member baldrick's Avatar
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    Quote Originally Posted by Champster View Post
    Thank you, Baldrick. I'm assuming this is your home system, do you ever hear the fans? Are the amps in the same room as the speakers?
    DCI amps have fans with noise, not the worst fan noise, but absoluttely noticalbe, but iTech is louder. I know a few have sucsefully replaced DCI fans with much more silent, but it's not as easy as with i.e. CTS amps since there are sensors with the DCI. Most BSS DSPs do also have fans, only the smallest one 50 (?) are fanless.

  10. #10
    Senior Member martin_wu99's Avatar
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    I think Mcintosh/Mark/Bryston/etc. are more suitable for M2 in home HiFi system,300W/PC is enough,they will drive M2 more smooth and musical,those pro gears such as Crown are too harsh in the home system,of course you need a BSS to load M2's software.
    46 lover

  11. #11
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    What would Greg do?

    Taking a cue from Greg Timbersí set up, you could put the noisy stuff in an adjacent room if your place has an adjacent, available space.

    in his case, thereís a bedroom closet on the other side of the wall in his living room, so many of the noisy, heat producing, spaghetti-wiring-connection-forming gear is in the bedroom closet, and his front end sources are the only things in the main room. The sliding closet doors are removed, so thereís plenty of air for the gear to breathe.

    Luckily, I have a similar closet next to the room Iím using, and the JBL Synthesis SDA-4600 amps go in there. The SDAs accept the M2 files, and a pair of them handle three M2s with channels to spare. A standard outlet sized opening between the two rooms is all thatís needed.
    Out.

  12. #12
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    Back when Harman Professional had the staff at BSS, JBL and Crown, they were able to fully engineer a system like the M2. It's complicated hardware, software and acoustics. Even across inner-company division lines, those guys were able to sort through all the compromises required to make the system fulfill a demanding product definition. It started with the I-tech because that was the amp that had the necessary DSP and amplifier horsepower. Of course it's way over-powered, but you can dial the amps back in firmware. Of course the fans sound like turboprops, but users can isolate that noise. The DCi came along as a state of the art permanent installation amp. And the CDi Drivecore followed as a more cost-effective install solution. With both of these new amps it was necessary develop and validate new files used for all the speaker tunings. They all went through evaluation / optimization at JBL. So you're unlikely to hear any difference among these three amps driving the M2. Further, JBL used BSS sound processors and Mark Levinson amps to go through the Synthesis channel. Same development process. The JBL Synthesis SDA-4600 is a rebadged DCi 4x600.

    It's not just a matter of having DSP in the amplifier. It needs sufficient processing power and it needs the correct tuning files for the operating system in the amplifier. That exists only in the I-Tech, DCi and CDi.

    The I-Tech is a touring amplifier. It is the embodiment of robustness. Thermal management is critical and the sound level coming from the fan is of zero concern. Well that's what I think but marketing types kept saying the fan is too loud. At any rate the amplifier is incredibly capable and is able to work well in a studio setting if you isolate the fan noise. Anyone who says a Crown amplifier is harsh is on the other side of a great divide from me - and all the early adopters of the M2 who hailed it as a revolutionary system. So for the guy asking about I-Tech, you will love the amplifier until the end of time. But the fan is super loud.

    If you have a 4x300 watt amplifier, it's going to need a fan to keep components cool enough to last a long time. Yes, yes, of course you can design an amplifier with that power that doesn't have a fan. But there are plenty of other compromises made to make that possible. At 4x600 a fan is pretty much inevitable.

    Maybe it bears repeating that the M2 is a system that includes the amplifier. I can even imagine that the JBL guys would have preferred an amplifier integrated into the cabinet if not for weight and heat. That and the development cost. And just like we talk about driver choice, with better drivers being available in the JBL catalog, you might find better amplifiers. But I'm certainly not going to swap out the drivers in my M2. (However, I DID swap out the drivers and crossover in a pair of Klipschorns as a reference) In the same light, I have a BSS Blu-806 and can therefore connect any amp I want. But I'm super happy with a CDi 4x1200. My opinion is the CDi fan is similar to white noise and not intrusive as an ambient sound. I hear it between songs but not during quiet moments in the music. I haven't yet done anything to absorb the fan noise or install a quieter fan. Maybe I will but to my way of thinking those changes are totally benign to the M2 system compared to putting in fan-less third party DSP and amplifier components.

    And let me be clear. I don't have anything bad to say about using 3rd party DSP and amplifiers. I just don't have the capability to implement that properly.

    So my two cents is the CDi 4x1200 is very good amplifier in the M2 system. That's no different than the dealer's advice, so I haven't offered a new recommendation. But I hope my comments have added a little insight to our community.

  13. #13
    Senior Member Champster's Avatar
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    Awesome suggestions! Thank you all for your 2Ę.

    I had the opportunity to talk to a senior engineer for ATI and he confirmed that Ian offered in that these speakers need large amps, not because they are inefficient but because they are capable of such impressive amounts of dynamic range and that you don't want your amp clipping during these peaks. It is for this reason that he helped me calculate that I need a minimum of 450W to reach 110dB at my listening position. Having this or more will provide for very satisfying listening in the 80-85dB range.

    So, I'd like to stay away from the fans which drives me to the BLU-50 but then it is pretty hard to find an amp without fans that delivers >450W. So I think I'll just get an amp with fans. I'm thinking the DCi 4x600 or preferably the SDA-4600.

    Again, I don't have another room to put it in but I do have an unused fireplace or I was wondering if there are cabinets made that would enclose the amp without letting it get too hot. I'll have to do a Google search to find that out.

    Thanks for all of your input. It is super helpful!

  14. #14
    Senior Member Ian Mackenzie's Avatar
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    This is a great discussion on a solution.

    The other thing to consider is in your domestic scenario during listening what level is going to be your cruising altitude?

    For example in party mode (110db average 2 metres) I doubt you will detect fans. After about an hour of that my ears tend to compress.

    RMS power is what generates heat so if your pro sales engineer can calculated when the power amp fans will come on it might not be as big an issue as might seem.

    Depending on how the amp cooling management is programmed you might escape fan noise at say 100 db average which at 2 metres is loud.

    But if the amp fans are on at 90 db average that might not be satisfactory unless they are variable speed fans.

    I think Don who has M 2's would be one person to discuss experiences with Crown amps

    For my own part I need dead silence at normal listening levels (90 db average) so I can enjoy the resolving power of the system.That means zero mechanic noise which is not as easy as you might think.

    The trade off in my scenario is heat with the Pass Labs X250.5 which is 300 watts via massive heat sinks but I can live with that.

  15. #15
    Senior Member Champster's Avatar
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    Quote Originally Posted by Ian Mackenzie View Post
    This is a great discussion on a solution.

    The other thing to consider is in your domestic scenario during listening what level is going to be your cruising altitude?

    For example in party mode (110db average 2 metres) I doubt you will detect fans. After about an hour of that my ears tend to compress.

    RMS power is what generates heat so if your pro sales engineer can calculated when the power amp fans will come on it might not be as big an issue as might seem.

    Depending on how the amp cooling management is programmed you might escape fan noise at say 100 db average which at 2 metres is loud.

    But if the amp fans are on at 90 db average that might not be satisfactory unless they are variable speed fans.

    I think Don who has M2's would be one person to discuss experiences with Crown amps

    For my own part I need dead silence at normal listening levels (90 db average) so I can enjoy the resolving power of the system.That means zero mechanic noise which is not as easy as you might think.

    The trade off in my scenario is heat with the Pass Labs X250.5 which is 300 watts via massive heat sinks but I can live with that.

    Thank you, Ian, again for your great points. I realized I wasn't very clear about my listening habits. I typically listen at about 85db and rarely reach anything close to an average listening level of 100dB. I hate distracting noises around the house when I'm listening and in fact usually wait until everyone else is gone to sit down and listen.

    I am not familiar with Don. How could I get in touch with him? I would really appreciate hearing from wise ones that have traveled down this path before me...

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