JBL M2 Reference Master Monitor Review

[Zvu]

... Only problem is you need to know someone to get the waveguide if I'm not wrong.

https://reconingspeakers.com/product/jbl-m2-horn-lens-5025594/

 

[King_Pin]

https://reconingspeakers.com/product/jbl-m2-horn-lens-5025594/

Cool! Last time I looked a few years ago it was very difficult to get some parts. I'm not too sure which one it was but I thought it was the Waveguide. If I didn't have $12k in parts in my closets I would be very tempted.

 

[srm51555]

Thoughts:
Harman's testing showed a preference for the Salon 2 over the M2.

Awesome thread, Thanks to Erin for the measurement work performed and starting the discussion.

I suspect this this is due to a couple of things. First I'd say M2 is more of a studio tool vs something one would have in their living room. Second is the D2430K and its use in the M2. Greg Timbers notes the distortion between 750 Hz -1500 Hz vs the 4" offerings at JBL here at LHF. My guess this is where the Salon bested the M2. The D2430K does provide the necessary dB needed for mixing and is a fraction of the cost, plus it looks cool.

When I built mine with the D2430K's, it did sound nice, but I ended up using the 2451's with standard JBL Diaphragms after some unsuccessful listening trials with the Truextent Diaphragms. If interested amps used were/are the Crown DCI 4300N.

Thanks,
Scott

 

[Zvu]

Cool! Last time I looked a few years ago it was very difficult to get some parts. I'm not too sure which one it was but I thought it was the Waveguide. If I didn't have $12k in parts in my closets I would be very tempted.

If you have 12K in your closets already, what is 500$ more ?

 

[Speaker-Inquisitor]

@srm51555
What‘s wrong with the Truextent Dias?
My next Speaker Project will include my M2 Waveguides with my second pair of 2450SL drivers, (Stock Aquaplas coated Titan) but the Beryllium Dias from Truextent are a long time on my List.

Currently the plan is a large three way with 14“ Midrange (1400Pro) and 18“ Low (2268H). The drivers are all waiting to be used, but unfortunately i‘m out of space for another pair of speakers.

 

[King_Pin]

@srm51555
What‘s wrong with the Truextent Dias?
My next Speaker Project will include my M2 Waveguides with my second pair of 2450SL drivers, (Stock Aquaplas coated Titan) but the Beryllium Dias from Truextent are a long time on my List.
View attachment 150469
View attachment 150468Currently the plan is a large three way with 14“ Midrange (1400Pro) and 18“ Low (2268H). The drivers are all waiting to be used, but unfortunately i‘m out of space for another pair of speakers.

I have 3 of these waiting to be used when I have room.

 

[srm51555]

@srm51555
What‘s wrong with the Truextent Dias?
…. .

Unfortunately they drop like a rock at around 13-14kHz If I remember correctly. I was never quite able to EQ enough to balance it out with the 2216’s and trust me I wanted it to.

A member more wise than me ran many many different driver combinations on the M2 and ended up settling on the 2450 SL diaphragms so that’s what I went with.

When you do start your build please post if you can, we always like a good project thread.

Thanks,
Scott

 

[King_Pin]

 

[srm51555]

Here are some raw measurements of the D2430K vs 2450SL-be. The post also has a bonus 476be plot as well.

Side note - The 2446's have 2" exit vs the D2430K and 2450SL 1.5".

 

[jtwrace]

Well, won't you be surprised then

https://www.thingiverse.com/thing:2446845

You got me curious so I’ll get to see it tomorrow and compare to the real thing.

 

[hardisj]

The 2446

That's what I have in my home theater, paired with the 2380A horns.

 

[stevenswall]

its an active 2 way, that is actually a 3 way and has no internal amplifiers, or crossovers, aside from the passive on the tweeter? so its not so much an active speaker, but an incomplete speaker?

Yeah, it does seem incomplete. Better described as a passive two way speaker with Bi-Amp capabilities and missing crossover components.

The three way confusion is because it has 2 similarly sized diaphragms in the compression driver to increase SPL. There is no crossover between the two diaphragms, and they are nearly identical in size, so it's still a two way... Think of it more as cramming more tweeters on something to make it louder.

Need to experience one in person at normal volume levels to see what the praise is about.

 

[Bartl007]

How is the M2 different from something like the active genelec s360 which has the option of rack mounting the included amplifier?

https://www.genelec.com/s360a

 

[synthetic]

I actually much prefer the seperate active solution. In traditional active systems I usually worry about the durability of the electronics. If something fails on a seperate system you can just replace that part.

I do get that it's more complicated for consumers though.

 

[Absolute]

I don't understand how it's more complicated for customers. It's a stereo-dac to a power-amp and from there's wires to the speaker.
If that is complicated I guess there's no hope.

With Kii Three there's a power cord to each speaker, a Cat5 cable from a digital pre-amp to one speaker and then another cat5 cable from that speaker to the next one. Not much simpler.
Now, having to take care of the speaker boxes for ages in case something dies inside and then organize shipment back to Netherlands for repairs with the right documents filled out to avoid having to pay taxes on the speakers all over again, that's complicated.
Out of warranty probably expensive as well.

Separated electronics for me all day.

 

[aac]

How is the M2 different from something like the active genelec s360 which has the option of rack mounting the included amplifier?

https://www.genelec.com/s360a

You can use a wider selection of amplifiers or sound processors with m2. You can even measure it pretty easily if you can find a bss unit for rent (i want to do it for so long for my 708i, but always end up being to lazy to look for bss) or just a cheap used unit and recreate filters yourself with any dsp.

 

[Zvu]

You got me curious so I’ll get to see it tomorrow and compare to the real thing.

View attachment 150819View attachment 150820

If you're gonna compare it by measuring, it is of utmost importance that you make inner surface of the port really smooth. Depending on the nozzle diameter and the material you're using it can be more or less easy to do that (acetone or sanding).

Mine look like this

 

[Skeptischism]

Perhaps the confusion stems from the fact that the D2 driver for the HF is a dual-diaphragm annular ring device? However unlike the BMS or other pro audio dual diaphragm annular compression drivers that split the driver into two separately driven HF and VHF sections, the D2 uses opposing pairs of identical diaphragms to improve compression with lower distortion.

Here’s one of the key patents from the illustrious Alexander Voishvillo (with cool diagrams):
https://patents.google.com/patent/EP0051454A2/en

Yes, For some reason in my head I was thinking of it as a 3 way. I havent read the thread, just the OP and video. I guess I was looking at the driver in a similar way to how dual BA drivers in IEMs are used. sometimes there is a crossover, sometimes not, but each excelling in a band, or sometimes a true dual driver, or quad driver composed of identical units bundled together to lower distortion. I didnt realize they were used push-pull in the M2, is that what you are saying?, intriguing. I wonder if the same could be done with IEMs to lower distortion (not that they are high distortion) I had never looked far into the design, just loved the waveguide. it had just came out last time I had any time to think about audio, before the last relationship ... lol

 

[Skeptischism]

As for seperate electronics. I diy, so it depends what I want. It should be possible to just have an embedded RPI compute module running CamillaDSP, a dac, and then an amp in each case, somehow automatically synced over the air, using a setup routine at each power on cycle (I would expect the delay to be different each time the 2 units started up, so you couldnt just assume the same delay, unless there was some kind of master and even then.

For sheer performance, having the shortest direct connection to the drivers is best, but ... at the same time, syncing DAC channels is easier if they use the same clock. I dont really have an issue with building the amps in and it keeps the chunky cables to a minimum (8 core 14->12AWG is a lot bigger than 8 core 26AWG), but sync issues and just keeping radiated noise out of the speaker and amp seems prudent, or at least no disadvantage. one power cord to each speaker and a central DSP/DAC and multicore line level balanced interconnects isnt a big deal as far as cabling mess. I'm likely to fiddle with, or replace the amplifiers long before the speaker dies; as is my way.

If only PoE was capable of powering an amplifier. a circuit to power and connect to a dac/node over PoE is doable, but not a power amp ... or 4. currently my dacs and amps are built together as separate, but I would like to integrate the amps into my next build I think.

 

[Absolute]

Just for fun, here's my a nearfield of my left speaker with an EQ profile I built based on Erin's data.View attachment 149799

Had to check after putting some more stuffing in my clones. Here's your after Klippel EQ vs my clones original Crown cdi M2;

How did you measure the ports? Inside or at some distance? Between them?