My Harman (JBL M2) Trip

TomS · « **Reply #380 on:** 15 Jan 2018, 08:13 pm »

I described the M2's to Jason as a scalpel, where perhaps a butter knife could suffice at times. They give it all up, no excuses. There is little, if anything they can't do, so you just have to prepare yourself. They must really be da bomb in the music production business.

I have them set up with a BSS London outboard DSP XO so will try some different amps. The challenge is you need 4 identical channels of sufficient power for ease of set up. The Crown DCI definitely does that job well, but the fans are just too obtrusive for my home environment.

jtwrace · « **Reply #381 on:** 17 Jan 2018, 03:59 pm »

Great to have you Rich! Just think if my cables were up to your standards.

I think another AC member is coming over to listen at some point too.

I got news today that one of my speakers is pregnant and the babies arrive tomorrow.

richidoo · « **Reply #382 on:** 17 Jan 2018, 05:58 pm »

Quote from: jtwrace on 17 Jan 2018, 03:59 pm

I got news today that one of my speakers is pregnant and the babies arrive tomorrow.

YAY! Congrats proud grandpa!

Better get those M2s neutered before this happens again.

richidoo · « **Reply #383 on:** 17 Jan 2018, 11:18 pm »

Quote from: TomS on 15 Jan 2018, 08:13 pm

I have them set up with a BSS London outboard DSP XO so will try some different amps. The challenge is you need 4 identical channels of sufficient power for ease of set up. The Crown DCI definitely does that job well, but the fans are just too obtrusive for my home environment.

But what is sufficient power, really? The 1200W power requirement is to meet the M2's 123dB SPL and distortion specs with Crown amps. 1200W@ 123dB means ~5W @100dB. And that makes sense because the M2 woofer's sensitivity (2216Nd) is 95dB@1W/8R, typical of most 15" professional drivers. Audiophiles use drivers with high sensitivity like that for their 2W SET amps. The M2's 1200W@123dB spec leaves good headroom, and at 100dB the 2216Nd actually burns only 3.5W. The D2 has a passive attenuation network and even higher sensitivity than 2216Nd. At 105dB, as loud as I would ever play at home, M2 needs <10wpc x2.

Modulus 286 is 2x40wpc @8R. That should make >113dB, w/ two M2s playing in-room at clipping. But mod86 distortion stays low to full power so >107dB is realistically usable SPL. Mod86 SQ is generally well regarded, I think you'd be pleasantly surprised if you haven't heard this little amp yet. Electrical damping is comparable to DCI, as both use abundant negative feedback. Mod86 is at least as resolving as DCI, imo. It's shocking the resolution the first time you hear it.

I use single channel Mod86 on my 92dB sensitvity, 4ohm (2.9ohm dips,) passive xo, 4 way Legacys in a very large room. It plays very loud and sounds excellent. Mod86's 65w@4R is not quite enough for the full performance envelope of the Legacys, so I occasionally get a trace of thermal protection when I really push it hard. But that is a far bigger load than a single active 15" 8ohm 95dB woofer which would voltage clip before thermal protect.

I have 4ch of Mod86 (ver1) that I can put into a box for you guys to try with the M2s: Jason, Tom, Joel, if anyone's interested. I have Par86 I plan to build for the Legacys anyway, and extra chassis and tranny, etc. Eventually I'll make 2 3way mod86 amps for future speaker projects, but not planning to use them anytime soon. I personally would love to hear Mod86 on M2. But you need external crossover - Mod86 don't do no math.

poseidonsvoice · « **Reply #384 on:** 17 Jan 2018, 11:34 pm »

Rich,

Unless the M2’s have some crazy amounts of EQ in the low end (ie <50Hz), I agree with you. The power requirements for a 2ch enthusiast in a typical “small” room are going to be miniscule compared to an M2 in an auditorium, commercial theater or large studio. JBL had certain goals for certain venues as such they have larger powered amplifiers for a rather efficient speaker. I had a similar discussion with goskers.

I’ll be sending my rear panels for both my 4ch modulus 286 and parallel 86 on Friday to FPE

Best,
Anand.

richidoo · « **Reply #385 on:** 18 Jan 2018, 12:44 am »

Yes, for big EQ adjustments like room correction and mastering jobs you might need more power. But the ported bass reduces the boost requirements compared to OB or sealed. Anyway, the M2's high sensitivity opens up many possibilities.

One thing that I'm interested in understanding better was Tom's comment that they need high power for setup.

Can you email me a pic of your panels? Are they doing your back connector panels too?

jtwrace · « **Reply #386 on:** 18 Jan 2018, 02:06 am »

Quote from: TomS on 15 Jan 2018, 08:13 pm

I have them set up with a BSS London outboard DSP XO so will try some different amps. The challenge is you need 4 identical channels of sufficient power for ease of set up. The Crown DCI definitely does that job well, but the fans are just too obtrusive for my home environment.

I have the same BSS BLU 50 coming so I'll be able to try some too.

goskers · « **Reply #387 on:** 18 Jan 2018, 04:09 pm »

I currently have a four channel Modulus286. Am planning on getting a BSS unit as a stand alone so I can try those out. We shall see if a noticeable improvement is heard or not.

jtwrace · « **Reply #388 on:** 22 Jan 2018, 04:07 pm »

They have arrived!

goskers · « **Reply #389 on:** 22 Jan 2018, 04:14 pm »

Cute little bastards.

poseidonsvoice · « **Reply #390 on:** 22 Jan 2018, 04:28 pm »

Very nice!

Best,
Anand.

cloudbaseracer · « **Reply #391 on:** 22 Jan 2018, 06:05 pm »

Jason,

Are you using the 705P for rear and side home theater? If not, why the addition?

Cheers,
James

jtwrace · « **Reply #392 on:** 22 Jan 2018, 06:42 pm »

Quote from: cloudbaseracer on 22 Jan 2018, 06:05 pm

Jason,

Are you using the 705P for rear and side home theater? If not, why the addition?

Cheers,
James

Those are the 708P actually and not for theater at all. Why not!?!?!

cloudbaseracer · « **Reply #393 on:** 22 Jan 2018, 06:56 pm »

I meant 708P - will edit to correct.

So these are in your main system? You will switch between the M2 and 708P for 2 channel listening?

Cheers,
James

jtwrace · « **Reply #394 on:** 22 Jan 2018, 07:55 pm »

Quote from: cloudbaseracer on 22 Jan 2018, 06:56 pm

I meant 708P - will edit to correct.

So these are in your main system? You will switch between the M2 and 708P for 2 channel listening?

Cheers,
James

These are currently next to my M2's. I was blown away with them when I was in Northridge and knew I wanted a pair for a few reasons.

jtwrace · « **Reply #395 on:** 6 Mar 2018, 02:32 am »

Just a quick update on the M2's. I finally have the BSS BLU-50 in the house loaded with the tuning file. Next step is to get the output wiring done and get some amps!

pis99 · « **Reply #396 on:** 6 Mar 2018, 03:50 am »

Nice, I also got my BLU-800 connected to M2 couple days ago. It is clear to my ear that the CobraNet route sounds best when pairing with Crown I-techHD amp. It is also a good choice for none JBL/Crown set up. I am really surprised how good the M2 can sound with the combo of BLU-800 and ML532.

Quote from: jtwrace on 6 Mar 2018, 02:32 am

Just a quick update on the M2's. I finally have the BSS BLU-50 in the house loaded with the tuning file. Next step is to get the output wiring done and get some amps!

jtwrace · « **Reply #397 on:** 6 Mar 2018, 11:48 am »

Quote from: pis99 on 6 Mar 2018, 03:50 am

Nice, I also got my BLU-800 connected to M2 couple days ago. It is clear to my ear that the CobraNet route sounds best when pairing with Crown I-techHD amp. It is also a good choice for none JBL/Crown set up. I am really surprised how good the M2 can sound with the combo of BLU-800 and ML532.

Very nice! The BLU 50 doesn’t have CobraNet so I won’t be able to try that which is fine.

poseidonsvoice · « **Reply #398 on:** 6 Mar 2018, 12:36 pm »

Quote from: pis99 on 6 Mar 2018, 03:50 am

Nice, I also got my BLU-800 connected to M2 couple days ago. It is clear to my ear that the CobraNet route sounds best when pairing with Crown I-techHD amp. It is also a good choice for none JBL/Crown set up. I am really surprised how good the M2 can sound with the combo of BLU-800 and ML532.

ML532 being Mark Levinson 532 amplifier?

Thanks,
Anand.

TomS · « **Reply #399 on:** 6 Mar 2018, 01:02 pm »

Quote from: jtwrace on 6 Mar 2018, 11:48 am

Very nice! The BLU 50 doesn’t have CobraNet so I won’t be able to try that which is fine.

But you COULD connect via BLU-Net to the Crown DCI4 running pass through