Amp upgrade for JBL M2 (would be submitted for testing)

[Bugal1998]

Subjectively? Sure. Realistically? Who knows. I did it to mitigate fan noise. No, BSS has been on 24/7 since I got it. I do keep all of my gear plugged into a Zero Surge (TSC) as well.

Very helpful @jtwrace... With my sound isolated equipment room- and absent evidence of a marked improvement for a typical listener in soundstage and imaging from a Dallasjustice style custom crossover implementation- a used or b-stock DCI 4|1250N is still likely the cheapest/easiest/best bang for the buck overall solution.

 

[Koeitje]

I have imported speakers before (active Apogee Divas) but now would prefer a local(ish) dealer and JBL treat the UK market with contempt so it would be a problem if anything went wrong. I decided against buying anything JBL after great frustration a number of years ago.
Anyway I am an old bloke and really pleased with the SQ I am getting now, so no need to ever change again!

I think JBL/Harman shafts the entirety of Europe. You can get some JBL Synthesis through some dealers, but what you mostly see is bluetooth and headphones. I would also like to see Infinity in Europe as their Reference series are pretty good bang for buck.

 

[jtwrace]

Very helpful @jtwrace... With my sound isolated equipment room- and absent evidence of a marked improvement for a typical listener in soundstage and imaging from a Dallasjustice style custom crossover implementation- a used or b-stock DCI 4|1250N is still likely the cheapest/easiest/best bang for the buck overall solution.

I never would've changed my amps if I had a separate equipment room. Well, unless I got bored and needed to tinker with something. You are correct though, it's meant to be plug-n-play which it is once you get through the odd software UI to setup the DCi.

If you haven't seen it, this might help you as I document my journey.

What Dallasjustice has done is great. I tried Audiolense and it was nothing but issues so I bailed as spending that much time trying to get the basics working isn't exciting to me. If/when the software improves maybe I'd revisit it.

 

[Absolute]

The only way to know for sure is to measure the speaker though which "pos" hasn't done.

What can you use that information for? As far as I know there's only one third-party measurement of the M2 out there and that's not enough to verify unit-to-unit consistency. When you measure the output of the BSS/Crown you measure the exact electrical signal going into the speaker. Match that and you have copied it exactly.

Do you have measurements of your M2s? Or the possibility to measure on-axis (aiming down the tweeter) from 1m/3 feet? Then I'd be interested to see how that looks compared to mine

 

[jtwrace]

Do you have measurements of your M2s? Or the possibility to measure on-axis (aiming down the tweeter) from 1m/3 feet? Then I'd be interested to see how that looks compared to mine

I have tons of measurements. Too many.

If you give me your REW settings I'll shoot mine so you can compare.

 

[Bugal1998]

I never would've changed my amps if I had a separate equipment room. Well, unless I got bored and needed to tinker with something. You are correct though, it's meant to be plug-n-play which it is once you get through the odd software UI to setup the DCi.

If you haven't seen it, this might help you as I document my journey.

What Dallasjustice has done is great. I tried Audiolense and it was nothing but issues so I bailed as spending that much time trying to get the basics working isn't exciting to me. If/when the software improves maybe I'd revisit it.

Oh yes! I followed your thread when exploring the M2... many thanks to you for documenting your journey!!!

I’m very familiar with the Crown UI and find it pretty straight forward to use. I’ve been living with the Crown UI in my current DCI 8|300N... including bridging the eight channels down to four to deliver 600 watts/driver for the M2- and back again, due to the amp defect I discovered.

I hear clear differences in speakers, speaker placement, rooms/room treatment, and EQ, so that‘s where I spend my time ‘tinkering’. DACs, Amps, sources, etc.— with very few exceptions— all sound exactly the same to me. I agree with you... the hobby for me is listening to music, not programming computers.

 

[Absolute]

I have tons of measurements. Too many.

If you give me your REW settings I'll shoot mine so you can compare.

Well, I'm adaptable! Just mounted Umik-1 and took a sweep with the settings I found from Itech in GREEN and tweaked in RED;

The crossover-dip at 800 is because the listening axis is around the JBL stamp between the drivers and the delay settings is adjusted to that in the M2. This is measured on tweeter axis. Non-gated, in-room with speaker close to wall and 1/24 smoothing.

 

[jtwrace]

Ha!
1 meter

Mic View

Raw

1/24 Smoothing

 

[Absolute]

Adjusted to be similar to your scale. This is the tweaked version, likely the difference is that I don't have the cherry-picked M2 D2340k version, but the generic ones. According to the designer, the M2 version is just hand-picked for frequency response. This looks similar enough given the limits of in-room measurements

 

[pos]

The only way to know for sure is to measure the speaker though which "pos" hasn't done.

??

 

[jtwrace]

??

What I read on miniDSP you said you didn't own M2's, did that change?

 

[RayDunzl]

I would do the same if M2s were available in the UK.

They aren't?

https://www.soundtech.co.uk/profess...ing-and-broadcast/m2-master-reference-monitor

They're sold via JBL Professional Recording and Broadcast, not JBL Synthesis, or JBL consumer toys outlets.

 

[pos]

The only way to know for sure is to measure the speaker though which "pos" hasn't done.

Measuring the speakers is adding a lot of uncertain parameters in the equation (mic, room, drivers consistency, etc.).
Measuring the output of the filter is the way to go.

Now regarding using alternative devices instead of the BSS/Crown ones, I think this is a sound move for many reasons, especially for home use.

What I read on miniDSP you said you didn't own M2's, did that change?

I do own clones: original drivers and horn, filtered with a pair of openDRC-DI, SMSL M8 DACs, and amplified with nc400 for the woofers and THX789 for the compression drivers.
There is no noise to be heard, neither from the hardware itself (no fan anywhere, nu humming either) or the drivers (high dynamic DACs with output levels matching amp sensitivity, and amps with low residual noise). Idle power consumption is also very low compared to the Crown stuff...

 

[Frank Dernie]

They aren't?

https://www.soundtech.co.uk/profess...ing-and-broadcast/m2-master-reference-monitor

They're sold via JBL Professional Recording and Broadcast, not JBL Synthesis, or JBL consumer toys outlets.

Yes, they are nominally imported but not in reality, and you get pissed about.
I would probably have them if I lived in the US, doesn't make sense here.

 

[Dialectic]

Yes, they are nominally imported but not in reality, and you get pissed about.
I would probably have them if I lived in the US, doesn't make sense here.

They are difficult to find even in the USA, unless you are buying them site unseen from a web/phone retailer such as Sweetwater Sound.

Until recently, I lived near Harman's multilevel flagship showroom on Madison Avenue (unsure if it is still open), where they had the M2s in a window display. When I went in and asked to hear them, a salesperson told me that I could not buy the speakers there and that, if I wanted a demo, I would have to go to Harman's facility in California.

 

[jtwrace]

They are difficult to find even in the USA, unless you are buying them site unseen from a web/phone retailer such as Sweetwater Sound.

Until recently, I lived near Harman's multilevel flagship showroom on Madison Avenue (unsure if it is still open), where they had the M2s in a window display. When I went in and asked to hear them, a salesperson told me that I could not buy the speakers there and that, if I wanted a demo, I would have to go to Harman's facility in California.

Dale Pro Audio in Brooklyn has them usually for demo. Ask for Dan.

I did go to Harman for the demo though.

 

[Bugal1998]

They are difficult to find even in the USA, unless you are buying them site unseen from a web/phone retailer such as Sweetwater Sound.

Until recently, I lived near Harman's multilevel flagship showroom on Madison Avenue (unsure if it is still open), where they had the M2s in a window display. When I went in and asked to hear them, a salesperson told me that I could not buy the speakers there and that, if I wanted a demo, I would have to go to Harman's facility in California.

I finally bought a pair of used M2s sight-unseen, fully expecting I may have to sell them and continue the search... Instead I was blown away. Given the lack of retail support I wasn’t surprised to hear that JBL Synthesis/Harman Luxury recently dropped them, leaving them as a JBL Professional product only.

My last visit to the Harman store was as an M2 owner, (I went to hear the SDP-75, the new Be line, and the 4367). The rep I was working with had been to the Harman factory, and when I mentioned that I owned the M2 his eyes lit up and said the M2 was his favorite speaker; the sales manager was nearby and gave a big smile, nodded an emphatic yes and gave a thumbs up for the M2 as well. There is clearly enthusiasm for the speaker, but as @Dialectic said, they can’t demo or sell them.

 

[Bugal1998]

Update: I bought a used pair of Crown I-tech 5000HD amps. Here's hoping there are no issues with them!

I paid the same for the pair of 5000HD amps as I would have for a used 4x3500HD, BUT I won't need a 30A circuit installed. They cost more than a b-stock DCi 4|1250N but I avoid the Phoenix connector non-sense, and I can repurpose the 5000HD amps to power quad JBL 5628 subs (planned) if I don't hear a material difference compared to my current DCi 8|300N on the M2s... 2500 watts/cab should be WAY more than I'll ever need.

 

[Absolute]

That'll be an interesting comparison. I'm driving my clones with the Crown cdi 4/1200 DriveCore now. Previously I used Hypex Nc400's for all channels, but since those were the low gain (13 dB) version I could only squeeze about 15 watts out of them with my current Hypex DLCP pre-amp.
I couldn't resist a local deal for the Crown and bought it without testing.

My view? The Crown provides such an oomph to the lower frequencies compared to the measly 15 watt output of the Ncores and the top end sounds similar/identical. There's a bit too much hiss/white noise coming through the tweeter for my liking at the lowest gain setting, but I'm spoiled by the non-existent noise of the 13 dB gain Ncores.

The fan noise was bloody infuriating and I've changed the two 24v fans (very simple, 5 minutes worth of screwdriving) to low-speed ones. Now I can't hear a thing, but I think I went a little overboard with 1500 rpm fans (17 dB) since the amplifier channels now run at around 68 degrees celcius during normal usage. With the standard fans (54 dB) they were running at 37-40 degrees.
I'll get some 2200 rpm ones instead and take it from there.

The Phoenix-stuff is stupid, but it's only annoying once.

 

[Bugal1998]

The fan noise was bloody infuriating and I've changed the two 24v fans (very simple, 5 minutes worth of screwdriving) to low-speed ones. Now I can't hear a thing, but I think I went a little overboard with 1500 rpm fans (17 dB) since the amplifier channels now run at around 68 degrees celcius during normal usage. With the standard fans (54 dB) they were running at 37-40 degrees.
I'll get some 2200 rpm ones instead and take it from there.

The Phoenix-stuff is stupid, but it's only annoying once.

I’m hoping the improved SNR of the I-Tech amps will make hiss a moot point at the listening position... and I don’t hear it when music is playing anyway.

After channel 8 on my DCi amp is repaired I may venture down the 2200 RPM fan route until my listening room build is complete. Thanks for the tip!

Agreed on Phoenix being a one-time only annoyance... in theory. But I had to rework them to go from XLR to RCA when I bought the amp... and then rework them again to go from RCA to XLR when I bought a new source, and then I’ll have to rework them AGAIN if my future theater source doesn’t offer XLR. With the I-tech that’s all history.