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Has anyone with an SDP or Trinnov noticed that the M2 HF response seems to roll off around 13k? All my other SCL and SCS's measure to 19-21k or so... I checked with a fellow member, and he sees the same response with his Altitude and M2's

No PEQ, and tried with and without the AEQ files loaded just to compare. The below graph has a gentle large curve roll off about 3db from 1k onward, but note the steep drop around 3-4k onward. It was severe enough that Optimizer couldn't lift 10k upward as seen in the After graph.


3119371


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Does the Optimizer mic have some odd issue with the D2 driver? Since both I and a fellow member see the same thing on different systems and in different rooms, wanted to open this up to others to see that their results are, or what might be contributing this this.

Thanks
 

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I've seen the same thing in ARC and Dirac with the M2 versus the smaller CD on the 708/705

Probably doesn't matter for my ears at this age though
 

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I've seen the same thing in ARC and Dirac with the M2 versus the smaller CD on the 708/705

Probably doesn't matter for my ears at this age though
thanks - did you ever find out why that would be the case? I was going to dig out my Omnimic and try REQ to see... It's almost like X-Curv-ish look....
 

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thanks - did you ever find out why that would be the case? I was going to dig out my Omnimic and try REQ to see... It's almost like X-Curv-ish look....
I'm not a speaker designer, but I'm pretty sure it's the size of the compression driver to get more output, it sacrifices extension. They've boosted the on axis to get a nice average, but the off axis is poor. The size of that CD starts beaming up high and the waveguide isn't doing much.
 

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I'm not a speaker designer, but I'm pretty sure it's the size of the compression driver to get more output, it sacrifices extension. They've boosted the on axis to get a nice average, but the off axis is poor
Hmmm.. well, that still seems to be a significant roll off, and all drivers are pointed directly (within a few degrees anyway) toward the mic, so would be considered on-axis I would surmise....

Inquiring minds want to know!

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Has anyone with an SDP or Trinnov noticed that the M2 HF response seems to roll off around 13k? All my other SCL and SCS's measure to 19-21k or so... I checked with a fellow member, and he sees the same response with his Altitude and M2's

No PEQ, and tried with and without the AEQ files loaded just to compare. The below graph has a gentle large curve roll off about 3db from 1k onward, but note the steep drop around 3-4k onward. It was severe enough that Optimizer couldn't lift 10k upward as seen in the After graph.


View attachment 3119371

View attachment 3119373

Does the Optimizer mic have some odd issue with the D2 driver? Since both I and a fellow member see the same thing on different systems and in different rooms, wanted to open this up to others to see that their results are, or what might be contributing this this.

Thanks
I would be worried here.
As you point out, the rolloff starts at 3khz and it does not correlate with the M2 measurements I have seen elsewhere or in my own theater (I'm using the BSS for crossover).

Have you tried near field measurement? This way you seperate room and speaker. It is important that the speaker is performing as designed before starting all the auto-magic routines in the room. You have a lot of autocorrections above ~500hz which should not really be necessary with M2 if speaker tuning were correct.

Regarding the rolloff above 10khz, take a look at the M2 spinorama. It is expected to rolloff due to the reasons previously mentioned. Even though your speakers are pointed at you the microphone is still getting all the reflection and is seeing the sum. Nearfield should be flat though.
 

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I would be worried here.
As you point out, the rolloff starts at 3khz and it does not correlate with the M2 measurements I have seen elsewhere or in my own theater (I'm using the BSS for crossover).

Have you tried near field measurement? This way you seperate room and speaker. It is important that the speaker is performing as designed before starting all the auto-magic routines in the room. You have a lot of autocorrections above ~500hz which should not really be necessary with M2 if speaker tuning were correct.

Regarding the rolloff above 10khz, take a look at the M2 spinorama. It is expected to rolloff due to the reasons previously mentioned. Even though your speakers are pointed at you the microphone is still getting all the reflection and is seeing the sum. Nearfield should be flat though.
What do your M2‘s measure to in the summary tab?

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Interesting. @thrang how far were the M2s from the mic when you took the measurements? You said the drivers were already pointed directly toward the mic so the measurements should be on axis measurements, meaning directivity or "beaming" at the highest frequencies shouldn't be issue. Seems to contradict the entire point of the M2 and the specs that they touted so much. The D2 driver in the M2 is claimed to be capable of extension up to 40 kHz. I don't think the tunings allow for that kind of extension, that was just a claim to illustrate the capabilities of the driver.
 

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I am thinking about jbl m2s..But my room is smallish.. 14ft wide, 27ft long and 7.5ft heigh..
Wondering if m2s will work well in my room
 

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I am thinking about jbl m2s..But my room is smallish.. 14ft wide, 27ft long and 7.5ft high
Wondering if M2s will work well in my room
I had Dunlavy SC-V's in a room that was 17' x 23' x 9'. They were huge (75" tall, x 15" wide by 27" deep and 330 lbs each) but not too big for the room.

M2's should work very well in your room if you set up a good equilateral triangle and locate you and the speakers well.
 

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I am thinking about jbl m2s..But my room is smallish.. 14ft wide, 27ft long and 7.5ft heigh..
Wondering if m2s will work well in my room
You'll be fine. I've had them in a smaller room than that...they were good; just not like they are now.
 

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M2 hiss comments


Just wanted to report back about the reported tweeter hiss on the M2 for those of us with low noise floor (sound isolated) rooms. My room is double stud construction with double drywall/green glue everywhere, dedicated HVAC and communicating double doors/air tight seals, etc. More details in my build thread.


I am currently driving my M2 LCR with the crown DCI/N series amps (2/600N for center channel and 4/1250N for left and right). All amps are fed signal by the monoprice HTP-1 pre-pro with 2.0V output setting. Unlike thebland who reported issues with his room necessitating an amp change, my surrounds channels (4 tops, 4 side) are all driven with the non DSP crown DCI 4/300 amps. Perhaps this difference is what decreases my cumulative hiss to undetectable levels


Listening distance is 12ft 8inches to MLP. I can detect no hiss or hum at any volume level from the listening position. With my ear at the microperf screen (~10” away from tweeter) there is a very small amount of background hiss, but it's a non issue at normal seating distances.


I thought this may be useful information to others who were considering M2’s with crown amplification. No regrets here!
 

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Gents - I was looking at M2's as well as Fulcrum Acoustic RM22's (passive speaker 3" CD dual 12's Reference Monitors that Joan Biaz, Greg Allman and other use in recording - 130db) for LCR which require FIR Filter to be downloaded into the Powersoft/Linea/Crown Amp...

Out of frustration (having to deal with fan noise/heat/and added expense) on having to buy new amps I spoke to my JBL/Fulcrum dealer and asked if there was a way to use existing HT Amps instead of Pro Audio Amps...to my surprise he said "YES" He carries the Linea Research Line which has an Active Crossover ASC48 (approx $2100) )which is a 4 XLR x 8 XLR out and can allow FIR Filter for the M2's work with any Multi-channel amp (XLR-based Amp)

The upside is these HT amps typically will remain "Stone Cold" and "Silence" (no fan) to achieve the same sonic result (maybe more refined) of Pro Audio Crown when matched with the M2's. I thought it was a very justifiable cost to have access to all HT amps I thought this was an amazing find and worth sharing...(He said Linea works only thru Pro Audio dealers -IM me if u want to be put in touch with him).

The dealer also stated that many High-End studios are using M2's with Bryston, Levinson, Audio Control Amps with the Linea to eliminate building an "Amp closet" or relocating Pro Amps in another room - I hope you find this helpful info: https://linea-research.co.uk/wp-content/uploads/LR Download Assets/Datasheets and Brochures/ASC48 Brochure.pdf

For Sale: JTR Captivator 4000ULF, JVC DLA-RS2000... Lyngdorf MP-60 16-Channel Immersive Processor
 

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@Dr.Tom 2001: If you want to use an amp of your choice and stick with the engineered JBL M2, there are only two options:
1. Buy a BSS Soundweb and use as a crossover
2. Buy a SDP-75 processor and use as a crossover

Other active crossovers might work very good - or might not work very good. It is very easy to reverse-engineer the M2 files and get the presets, but will the ASC48 with filter X behave identical to a BSS/Crown DSP with the same filter?
 

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This subject has been discussed in this thread numerous times.

You can use BSS processors with M2's, they have the proper tuning files, no need to reinvent the wheel. The problem with outboard amps for M2 is you need very high power that can drive the 20 ohm compression driver and 15" woofer. Recommended amplifier power: 1200 Watts per channel into 8 ohms

The M2 contains no internal crossover network; it must be used with BSS Omnidrive HD Digital Signature processing to provide proper integration of the speaker’s low-frequency and high-frequency transducers. The following Crown power amplifiers incorporate BSS Omnidrive HD DSP and are specified for use in the M2 System:
• Crown I-Tech 5000HD two-channel amplifier (one amplifier is required for each M2 speaker)
• Crown I-Tech 4x3500HD four-channel amplifier (one amplifier is required for two M2 speakers)

From the M2 manual: If you wish to use an amplifier other than the two Crown I-Tech models specified above, you must also use the BSS Soundweb™ London BLU-800, BLU-160 or BLU-80 signal processor to provide the Omnidrive HD processing required by the M2. (A list of recommended M2 system components can be found in the downloads section at www.jblpro.com/M2.)
 

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As you can see Fulcrum Speakers FIR filters works with Crown I-Tech - BBS - Linea Amps and others Processor Configurations | Fulcrum Acoustic

Similar to, if not identical to how M2's with FIR Filters - the Linea ASC 48 "is the FIR interface" that's inside the Linea Amp except its external...I just thought it was helpful info and worth looking into...

Here is the Fulcrum speaker (RM22) not sure how it stacks up against the M2 but the suggested matching Linea Amp is 1250w x 8 output https://www.fulcrum-acoustic.com/wp-content/uploads/2019/10/Prod-Spec-RM22-v5.pdf which is the 88C10 that also accepts FIR Filters


For Sale: JTR Captivator 4000ULF, JVC DLA-RS2000...
Lyngdorf MP-60 16-Channel Immersive Processor
 

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I spotted some M2s in the wild this weekend. In the documentary Clive Davis: The Soundtrack of our Lives, Clive has them in his office. Regardless, it was a great documentary and can be seen on Netflix. I learned a lot and never really knew his contributions and genius within the music industry over the last 50 years.
 

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I spotted some M2s in the wild this weekend. In the documentary Clive Davis: The Soundtrack of our Lives, Clive has them in his office. Regardless, it was a great documentary and can be seen on Netflix. I learned a lot and never really knew his contributions and genius within the music industry over the last 50 years.
That was a great documentary. When I was in high school, the keyboard player in a band I played in got a record deal with Clive! The guy was a pop music songwriting genius and went on to found the band "Champaign" ("How 'Bout Us", "Try Again", etc). His solo album never got released because of the scandal Clive got caught up in at that time, ca. 1972.

 
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