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Title: Meyer JM-1
Post by: Jim McKeveny on February 12, 2014, 07:55:47 AM
Does anyone have experience with this model?

I originally viewed it as a grownup L'Acoustics ARCS, but then I looked closer: The HF is crossed over at 520hz? That is a lot of spectrum for a diaphragm to cover, especially at high power levels. Breakup modes and IM distortion are pretty big beasts to slay across that many octaves..

Any thoughts?



Title: Re: Meyer JM-1
Post by: Art Welter on February 12, 2014, 04:22:07 PM
Any thoughts?
I have not heard the JM-1, but have heard the 50x40 CQ-2 which also uses a 4" diaphragm 1.5" exit, but crossed at 900 Hz above a 3" voice coil 15.
It certainly had plenty of high end, but sounded pretty hashy when driven at all hard.
Light jazz sounded OK, but with a full band with plenty of mid/high content reminded me of why we started using low mid drivers to reduce bandwidth on mid/HF many decades ago.

The JM-1 uses a narrower, deeper 20x60 horn which should load lower, and is above a presumably less sensitive 4" coil 15" woofer, which would make excursion demands on the HF somewhat comparable, though in a 4 or 5 wide array where the woofers tend to sum while the HF remains discreet, I'd think they would start to sound even more (dis)stressed than what I have heard of the CQ-2.

The breakup modes sound worse the louder they are driven, so for quiet, short throw shows they could be perfectly acceptable, but they would not be on my short list if loud and clean was the goal.

Title: Re: Meyer JM-1
Post by: Thomas Dameron on February 12, 2014, 04:57:46 PM
M2D are the same idea.  It makes for a nice sounding speaker but not a very loud one.

thomas d.
Title: Re: Meyer JM-1
Post by: DavidTurner on February 12, 2014, 10:48:32 PM
I have heard them sound really good....

I have not heard the JM-1, but have heard the 50x40 CQ-2 which also uses a 4" diaphragm 1.5" exit, but crossed at 900 Hz above a 3" voice coil 15.
It certainly had plenty of high end, but sounded pretty hashy when driven at all hard.
Light jazz sounded OK, but with a full band with plenty of mid/high content reminded me of why we started using low mid drivers to reduce bandwidth on mid/HF many decades ago.

The JM-1 uses a narrower, deeper 20x60 horn which should load lower, and is above a presumably less sensitive 4" coil 15" woofer, which would make excursion demands on the HF somewhat comparable, though in a 4 or 5 wide array where the woofers tend to sum while the HF remains discreet, I'd think they would start to sound even more (dis)stressed than what I have heard of the CQ-2.

The breakup modes sound worse the louder they are driven, so for quiet, short throw shows they could be perfectly acceptable, but they would not be on my short list if loud and clean was the goal.
Title: Re: Meyer JM-1
Post by: Art Welter on February 13, 2014, 03:37:19 PM
I have heard them sound really good....
David,

At what distance, SPL and relative humidity percentage?

Art
Title: Re: Meyer JM-1
Post by: Jon Arneson on February 13, 2014, 04:19:04 PM
I have not heard the JM-1, but have heard the 50x40 CQ-2 which also uses a 4" diaphragm 1.5" exit, but crossed at 900 Hz above a 3" voice coil 15.
It certainly had plenty of high end, but sounded pretty hashy when driven at all hard.
Light jazz sounded OK, but with a full band with plenty of mid/high content reminded me of why we started using low mid drivers to reduce bandwidth on mid/HF many decades ago.


One of the advantages of the JM-1P's two-way design with relatively low crossover frequency (besides saving on cost and weight, although neither are terribly low!) is that it maintains its 60deg vertical coverage pattern to within +/-10deg down to 450Hz. The deep horn, a well-matched amp, and some clever signal processing tricks keep the compression driver happy by controlling excursion and distortion.


Quote
The JM-1 uses a narrower, deeper 20x60 horn which should load lower, and is above a presumably less sensitive 4" coil 15" woofer, which would make excursion demands on the HF somewhat comparable, though in a 4 or 5 wide array where the woofers tend to sum while the HF remains discreet, I'd think they would start to sound even more (dis)stressed than what I have heard of the CQ-2.


How so? LF summation in an array increases LF headroom. It doesn't add to the demands on the HF section, which is naturally more efficient than the cone as you mention. Maybe I'm missing something here.


Quote
The breakup modes sound worse the louder they are driven, so for quiet, short throw shows they could be perfectly acceptable, but they would not be on my short list if loud and clean was the goal.


Breakup modes of the HF diaphragm are related to several factors, but I don't think crossover frequency is one of them. If and when they occur in certain designs it's well above 520Hz, 900Hz, 3.24kHz, or whatever your "ideal" x-over freq is. More like >7kHz where wavelength < dome diameter.

To imply that the JM-1P may suffer from HF breakup modes specifically because it's a two-way design (or because you heard "hash" come out of a CQ) is a bit of a stretch IMO.






Jon Arneson


MSLI
Title: Re: Meyer JM-1
Post by: Art Welter on February 13, 2014, 05:03:17 PM
LF summation in an array increases LF headroom. It doesn't add to the demands on the HF section, which is naturally more efficient than the cone as you mention. Maybe I'm missing something here.

Breakup modes of the HF diaphragm are related to several factors, but I don't think crossover frequency is one of them. If and when they occur in certain designs it's well above 520Hz, 900Hz, 3.24kHz, or whatever your "ideal" x-over freq is. More like >7kHz where wavelength < dome diameter.

To imply that the JM-1P may suffer from HF breakup modes specifically because it's a two-way design (or because you heard "hash" come out of a CQ) is a bit of a stretch IMO.
Jon,

You are correct, HF breakup "hash" will occur related to diaphragm size, and is independent of the crossover point, which simply requires more excursion for a given SPL from the diaphragm when used lower. One can limit excursion (and SPL) to keep diaphragm excursion related distortion to an acceptable level, which in general in our industry seems any amount less than heard when the diaphragm is not hammering the phase plug.

Since the HF section dispersion is well defined, it does not benefit from the LF summation in an array, which as you say, increases LF headroom.
Since the natural inclination for many operators is to run systems at the limits of headroom, and the HF does not gain any headroom, the breakup modes are pushed harder (and sound worse) when trying to "keep up".

Does the JM-1 use clever signal processing tricks controlling distortion absent in the CQ2?

What signal processing algorithms are capable of eliminating breakup mode and excursion related distortion?

Could you share the THD distortion  charts of the JM-1 HF section at full rated power and it's rated 138 dB?

Art
Title: Re: Meyer JM-1
Post by: Ivan Beaver on February 13, 2014, 06:49:46 PM

One of the advantages of the JM-1P's two-way design with relatively low crossover frequency (besides saving on cost and weight, although neither are terribly low!) is that it maintains its 60deg vertical coverage pattern to within +/-10deg down to 450Hz. The deep horn, a well-matched amp, and some clever signal processing tricks keep the compression driver happy by controlling excursion and distortion.


Jon Arneson


MSLI
Just doing the "simple math" and allowing the horn to be 70° (60+10) then it will lose pattern control slightly above 1000Hz.  For 450hz it would have to be twice as large.

Of course the 20° horizontal would lose its pattern control an octave higher.
Title: Re: Meyer JM-1
Post by: Jon Arneson on February 13, 2014, 07:31:18 PM
Jon,

You are correct, HF breakup "hash" will occur related to diaphragm size, and is independent of the crossover point, which simply requires more excursion for a given SPL from the diaphragm when used lower. One can limit excursion (and SPL) to keep diaphragm excursion related distortion to an acceptable level, which in general in our industry seems any amount less than heard when the diaphragm is not hammering the phase plug.


I keep re-typing a few sentences about horn design / compression driver excursion / distortion but worry I'm veering into trade secret territory... Agreed the diaphragm hammering the phase plug is a universally-accepted threshold of unacceptable distortion!

Quote
Since the HF section dispersion is well defined, it does not benefit from the LF summation in an array, which as you say, increases LF headroom.
Since the natural inclination for many operators is to run systems at the limits of headroom, and the HF does not gain any headroom, the breakup modes are pushed harder (and sound worse) when trying to "keep up".


Sounds like more of an "enough rig for the gig" problem than a loudspeaker headroom problem. Or operators looking to get a particular "sound" from the speakers by pushing them to the limit.

Quote
Does the JM-1 use clever signal processing tricks controlling distortion absent in the CQ2?


Both products share some dynamic limiting techniques but the JM-1P incorporates some new ones we've developed in the years since the CQ's first release.

Quote
What signal processing algorithms are capable of eliminating breakup mode and excursion related distortion?


None that I am aware of since these are non-linear effects. But they can be minimized or prevented when the acoustics, amp, and signal processing are all designed together.







Jon


Title: Re: Meyer JM-1
Post by: Jon Arneson on February 13, 2014, 07:53:22 PM
Just doing the "simple math" and allowing the horn to be 70° (60+10) then it will lose pattern control slightly above 1000Hz.  For 450hz it would have to be twice as large.

Of course the 20° horizontal would lose its pattern control an octave higher.


Maybe there's more to the design than you're aware of, Ivan.

There are methods - some well-known, others we've patented - that allow one to extend the vertical directivity of a two-way system well below the horn's natural cutoff frequency.

Why don't you look at the JM-1P in MAPP or Ease if you don't believe the spec I quoted.




Jon

Title: Re: Meyer JM-1
Post by: Frederik Rosenkjær on February 14, 2014, 01:33:00 AM

Maybe there's more to the design than you're aware of, Ivan.

There are methods - some well-known, others we've patented

"We"!?
Title: Re: Meyer JM-1
Post by: Jon Arneson on February 14, 2014, 02:29:59 AM
"We"!?

"I - the royal we, you know, the editorial."

"Me... and (four) other guys..."

http://www.imdb.com/title/tt0118715/quotes




Jon

Title: Re: Meyer JM-1
Post by: Frederik Rosenkjær on February 14, 2014, 03:37:40 AM
"I - the royal we, you know, the editorial."

"Me... and (four) other guys..."

http://www.imdb.com/title/tt0118715/quotes



Jon

What I mean is: Are you affiliated with Meyer? In that case it would be considered good netiquette to have your signature reflect this.
Title: Re: Meyer JM-1
Post by: Andrew Hastings on February 14, 2014, 07:42:19 AM
What I mean is: Are you affiliated with Meyer? In that case it would be considered good netiquette to have your signature reflect this.

Hi frederik

I recognised his name
You may have over looked this from one of Jon's earlier posts below his signature he typedMSLI
ie Meyer Sound Laboratories ?
He may also know something about high frequency transducers
http://www.linkedin.com/pub/jon-arneson/4/75b/227

Hope this helps

Glenn

]
Title: Re: Meyer JM-1
Post by: Jim McKeveny on February 14, 2014, 08:40:48 AM
The deep horn, a well-matched amp, and some clever signal processing tricks keep the compression driver happy by controlling excursion and distortio



Breakup modes of the HF diaphragm are related to several factors, but I don't think crossover frequency is one of them. If and when they occur in certain designs it's well above 520Hz, 900Hz, 3.24kHz, or whatever..



As the OP I was curious about IM distortions across such an unusually broad swath of audio frequency spectrum in the JM1.

Prior art suggests that HF diaphragms do not remain anywhere near pistonic when so tasked at high power.

If there are unique, Meyer-patented solutions, they are publicly available and protected, so please share! The prosound community is all-ears...(all puns intended).
Title: Re: Meyer JM-1
Post by: Jon Arneson on February 14, 2014, 02:20:20 PM

As the OP I was curious about IM distortions across such an unusually broad swath of audio frequency spectrum in the JM1.

Prior art suggests that HF diaphragms do not remain anywhere near pistonic when so tasked at high power.

If there are unique, Meyer-patented solutions, they are publicly available and protected, so please share! The prosound community is all-ears...(all puns intended).



Hi Jim,

IMD, THD, and diaphragm breakup are all separate issues but all can be either reduced or prevented electronically (upstream of drivers), electro-acoustically (in the driver/horn design), and/or acoustically (downstream of the drivers), depending on the issue. IMD and breakup effects cannot be "canceled out" once they start, as far as I'm aware. THD can however.

Our patents are easily searchable but some of our methods are kept as trade secrets and John Meyer often prefers to do this over patenting some ideas and techniques.

I can't say if the JM-1P horn's wide bandwidth (5 octaves) is directly related to a greater amount of IMD than if it were a three- or four-way design since I haven't tested that exact relationship. We've found the pros of two-way self-powered systems tend to stack up pretty heavily against the cons, and IMD hasn't been an issue for JM-1P users as far as I'm aware.


I hope this info is useful.








Jon

MSLI

Title: Re: Meyer JM-1
Post by: Art Welter on February 14, 2014, 04:09:31 PM
IMD and breakup effects cannot be "canceled out" once they start, as far as I'm aware. THD can however.

I can't say if the JM-1P horn's wide bandwidth (5 octaves) is directly related to a greater amount of IMD than if it were a three- or four-way design since I haven't tested that exact relationship.

I hope this info is useful.

Jon

MSLI
Jon,

In reply to the question of what signal processing is capable of eliminating breakup mode and excursion related distortion, in Post #8 you replied:
"None that I am aware of since these are non-linear effects."

Now you seem to suggest that though IMD and breakup effects can not be "canceled out", THD can be, though I see no reference to any "distortion cancelling" processing utilized in the JM-1P, or any other MSL product, with the possible exception of the Pressure Sensing Active Control used on the LF portion of the X-10 control room monitor.

Typical 4" diaphragm horn/driver combinations exceed 10% distortion above 9 kHz at around 108 dB one meter, similar to the level the JM-1P HF should do (midband) at one watt, working back from a rated output of 138 dB at a presumed 550 watt peak. At an output level nearly four orders of magnitude higher, HF distortion must exceed 100%.

To insure having "enough rig for the gig", what SPL should users expect from the JM-1P above 8000 Hz without exceeding 10% THD?

Art
Title: Re: Meyer JM-1
Post by: Jon Arneson on February 14, 2014, 04:38:42 PM
Jon,

In reply to the question of what signal processing is capable of eliminating breakup mode and excursion related distortion, in Post #8 you replied:
"None that I am aware of since these are non-linear effects."

Now you seem to suggest that though IMD and breakup effects can not be "canceled out", THD can be, though I see no reference to any "distortion cancelling" processing utilized in the JM-1P, or any other MSL product, with the possible exception of the Pressure Sensing Active Control used on the LF portion of the X-10 control room monitor.



That's right! Thanks for reminding me about the X-10's PSAC. I need to check with the guys who designed that - they are way, way smarter than I am and will know if the technology cancels IMD as well as THD.

(I was only thinking of upstream, open-loop distortion cancellation in that quote.)


Quote
Typical 4" diaphragm horn/driver combinations exceed 10% distortion above 9 kHz at around 108 dB one meter, similar to the level the JM-1P HF should do (midband) at one watt, working back from a rated output of 138 dB at a presumed 550 watt peak. At an output level nearly four orders of magnitude higher, HF distortion must exceed 100%.


Assuming you're right, I can't hear the 2nd harmonic of 9kHz or anything above that so what's the problem?  :)


Quote
To insure having "enough rig for the gig", what SPL should users expect from the JM-1P above 8000 Hz without exceeding 10% THD?


Sorry Art, but I'm not going down this rabbit hole with you. Prospective and existing users can consult with our Design Services department for these kinds of questions. If they need more specific info (like THD percentages) then R&D will get involved.






Jon


Edit: poor choice of words
Title: Re: Meyer JM-1
Post by: Jim McKeveny on February 14, 2014, 05:58:49 PM

 Actual users

Jon

Well, this prospective user has crossed MSLI from my PAC's short list!
Title: Re: Meyer JM-1
Post by: Art Welter on February 14, 2014, 06:29:05 PM
Assuming you're right, I can't hear the 2nd harmonic of 9kHz or anything above that so what's the problem?  :)

Sorry Art, but I'm not going down this rabbit hole with you. Actual users can consult with our Design Services department for these kinds of questions. If they need more specific info (like THD percentages) then R&D will get involved.
Jon
Jon,

The second harmonic of 9kHz would not be a problem for me either, but the harmonic distortion stacking up from crossing at 520 Hz at 520 Hz intervals to 14560 are still a bother to me  ;).

But in the long list of harmonics, really the odd order ones are the bother, the rest are just "rock and roll".

Breakup modes- well, like the output of an air compressor hose, they can measure flat but just don't sound very good.
Ask John M. why he stopped using piezos decades ago  ;).

In humid San Francisco, HF distortion is not such a big deal as it is here in the high dry desert, where HF air attenuation can require 10-20 dB more VHF SPL than in the wetlands.

One can see the HF air attenuation problem here:
http://www.meyersound.com/sites/default/files/leo_application_profile_marysville.pdf

The Leo array at 12.5 kHz drops from about 82 dB at 30 meters to 60 dB at 120m, a 22 dB drop.
We see the HF basically dropping in to the noise floor at 120 meters, although the rest of the audio range has only dropped about 6 dB in the same distance.

Obviously, 22 dB boost ain't going to work when driver distortion is already fairly high, and the additional 12 or more dB HF gain needed in the desert, well, as you said, you aren't going down that rabbit hole  :).

Since no other manufacturers publish HF distortion figures above a few watts, I really did not expect you would reveal that Meyer also has not made much progress in that regard either.

I still find it a hoot that we scoff at amps with 1% THD, but regularly listen to systems at levels that produce 10 to 20 times that distortion.

Thanks for the "info"!

Art

Title: Re: Meyer JM-1
Post by: Jim McKeveny on February 15, 2014, 07:57:26 AM
This helps explain the low nominal crossover frequency:

www.US8406445.pdf.

Some well placed response bumps and grinds between drive units, coupled with critical spacing and horn wall design, permits extended pattern control. This probably comes at the expense of ultimate output.

Thanks Jon. I answered my own question.
Title: Re: Meyer JM-1
Post by: Jon Arneson on February 15, 2014, 04:10:12 PM
This helps explain the low nominal crossover frequency:

www.US8406445.pdf.

Some well placed response bumps and grinds between drive units, coupled with critical spacing and horn wall design, permits extended pattern control. This probably comes at the expense of ultimate output.

Thanks Jon. I answered my own question.


Jim, sorry about that - I thought you were asking if we had specific patents on IM distortion. I should have linked to this one.

http://www.google.com/patents/US8406445 (http://www.google.com/patents/US8406445)


Jon
Title: Re: Meyer JM-1
Post by: DavidTurner on February 16, 2014, 02:37:36 AM
Hi Art:

In room A at Soundcheck in Nashville (which is their largest rehearsal hall) - at Meyer's introduction of the JM1 to the Nashville touring community. It was a local cover band being mixed by one of Meyer's engineers. I don't know the relative humidity, but since it was in the South, probably pretty high. I'm guessing an SPL of about 106 db at FOH - which was about 50' from stage. I walked the room and the coverage was really good throughout. Haven't heard them in a big room or at great distance.

The act I tour with just rehearsed in that same room with the same rig. I do monitors and I didn't get out front to listen, but our FOH engineer was happy with the rig.

David,

At what distance, SPL and relative humidity percentage?

Art
Title: Re: Meyer JM-1
Post by: Ivan Beaver on February 16, 2014, 08:24:59 AM
I'm guessing an SPL of about 106 db at FOH - which was about 50' from stage.
Stating a SPL "number" without any other metric is almost worthless.

A-C-Fast-Slow-Peak etc makes all the difference.

I have MEASURED a difference of 30dB using different weightings/time of the same sound at the same position.

YES IT MATTERS!!!!!!!!!!

Yes you may "know" what you think you are saying-but it doesn't mean anything to somebody else if their "standard" is using a different metric.

Just sayin'
Title: Re: Meyer JM-1
Post by: DavidTurner on February 17, 2014, 11:47:33 AM
OK, Mr. Beaver:

Based on my 30 years experience of mixing FOH at a comfortable level for me that usually works out to be about 106 dba measured with a Radio Shack meter set to slow response time, I would guess that it was about 106 dbA  JEEEZ. HE asked and I said I'm GUESSING....

BTW It really did sound good, but I suppose that, since I did not take a measurement rig in and document all the parameters, my opinion of how it sounded is meaningless to loudspeaker designers....BUT, I made no claim other than it "sounded really good to me."



Stating a SPL "number" without any other metric is almost worthless.

A-C-Fast-Slow-Peak etc makes all the difference.

I have MEASURED a difference of 30dB using different weightings/time of the same sound at the same position.

YES IT MATTERS!!!!!!!!!!

Yes you may "know" what you think you are saying-but it doesn't mean anything to somebody else if their "standard" is using a different metric.

Just sayin'
Title: Re: Meyer JM-1
Post by: Ivan Beaver on February 17, 2014, 12:07:47 PM
OK, Mr. Beaver:

Based on my 30 years experience of mixing FOH at a comfortable level for me that usually works out to be about 106 dba measured with a Radio Shack meter set to slow response time, I would guess that it was about 106 dbA  JEEEZ. HE asked and I said I'm GUESSING....
Not to be picky but the A scale was never intended to be used above around 80dB-but that never stopped anybody-using something the way it was intended to be used.

I know MANY MANY people that use C weighted fast and their "guesses" are based on that "base knowledge" they have in THEIR heads and THEIR reference.

Often the difference between A slow and C fast can be 20dB-not exactly a 'little bit".

Since you did not use a weighting or state what "your" reference-how is anybody to know?

Again-maybe YOU know-but others have no idea-if they use a different reference.

I would argue that many different situations could be setup and fool even experienced sound guys with regards to SPL level.  Just change the distortion a little bit and it sounds louder than it actually is.

I bet it would be easy to fool guys by at least 10dB if you were to "pull them off the street cold" and ask them what the SPL was-----------

And JUST TO get picky- 106dB mean ONLY ONE thing.  That is the difference between 2 levels.  Without knowing what the other level is-there is no way to know what 106dB  actually refers to.

The dB is a RATIO-NOT a absolute value-like a volt or a foot or a gallon.
Title: Re: Meyer JM-1
Post by: DavidTurner on February 17, 2014, 12:12:04 PM
Now that we have all had our physics lesson for the day:

Someone asked for an opinion and I gave it. Sorry it did not meet your criteria. GOODBYE!

Not to be picky but the A scale was never intended to be used above around 80dB-but that never stopped anybody-using something the way it was intended to be used.

I know MANY MANY people that use C weighted fast and their "guesses" are based on that "base knowledge" they have in THEIR heads and THEIR reference.

Often the difference between A slow and C fast can be 20dB-not exactly a 'little bit".

Since you did not use a weighting or state what "your" reference-how is anybody to know?

Again-maybe YOU know-but others have no idea-if they use a different reference.

I would argue that many different situations could be setup and fool even experienced sound guys with regards to SPL level.  Just change the distortion a little bit and it sounds louder than it actually is.

I bet it would be easy to fool guys by at least 10dB if you were to "pull them off the street cold" and ask them what the SPL was-----------

And JUST TO get picky- 106dB mean ONLY ONE thing.  That is the difference between 2 levels.  Without knowing what the other level is-there is no way to know what 106dB  actually refers to.

The dB is a RATIO-NOT a absolute value-like a volt or a foot or a gallon.
Title: Re: Meyer JM-1
Post by: Ivan Beaver on February 17, 2014, 12:27:27 PM
Someone asked for an opinion and I gave it. Sorry it did not meat your criteria. GOODBYE!
It is not my "criteria".  Just pointing out that what appears to one person can be something completely different to another person-depending on what their reference is.

And just trying to accurate.

In this business all kinds of statements get "thrown around" usually with nothing to back them up or have little meaning (and often wrong) on their own.

It is important to have details-YES IT DOES MATTER.  At least to some people.

To others who don't understand or care if it it correct or not-then "anything goes"----

Maybe if you paycheck had the same numbers on it-but the sign was changed to pesos instead of dollars it would make a difference to  you.  You still got paid X amount o funits-they are just a different value.
Title: Re: Meyer JM-1
Post by: DavidTurner on February 17, 2014, 02:29:04 PM

It is important to have details-YES IT DOES MATTER.  At least to some people.


What part of the phrase "I'm guessing" do you not understand? Since it was, admittedly, a guess, there was no accuracy implied and none should be inferred.  Again, I made no claim other than "I've heard them sound really good." Then, when asked, I tried my best to describe the conditions under which I made that assessment. Would I have been more accurate to say "at a moderately loud yet not uncomfortable level?" What would have been the reference for that? An uncomfortable level for me might not be loud enough for you or vice versa.

Title: Re: Meyer JM-1
Post by: Jim McKeveny on February 17, 2014, 03:01:18 PM
Well. This has been a fun trip.

Thank you to all contributors, esp. JA from Meyer.

I thought my initial query was reasonably innocent, but apparently it caused some unforeseen friction downstream. I think we should blame it all on Winter 2014 weather..

Regards to all!!

JMK
Title: Re: Meyer JM-1
Post by: Art Welter on February 17, 2014, 07:12:04 PM
Based on my 30 years experience of mixing FOH at a comfortable level for me that usually works out to be about 106 dba measured with a Radio Shack meter set to slow response time, I would guess that it was about 106 dbA  JEEEZ. HE asked and I said I'm GUESSING....
....BUT, I made no claim other than it "sounded really good to me."
David,

You answered my question to the best of your abilities based on your observation of 6 Meyer JM-1 and two 700Hp subs at approximately 50 feet indoors producing around 106 dBA slow under humid conditions (about 10 dB louder than I find comfortable, but that is neither "hear" nor there).

Based on Meyer's claimed output level, a 106 dBA level at that distance with that array could be from 18 dB (or quite a bit more) under it's maximum level, the JM-1s would be loafing along at around 10 watts or less apiece.

I found the Meyers cabinets I commented about sounded fine at that level too.

Their HF just did not sound very good when driven anywhere near the rated SPL.
I'd chalk the reason they did not sound very good to HF diaphragm breakup and distortion, which are far more problematic in the low humidity conditions here, due to the added demands placed on HF drivers.

Thanks,

Art
Title: Re: Meyer JM-1
Post by: DavidTurner on February 17, 2014, 08:47:00 PM
 :) comment removed by author
Title: Re: Meyer JM-1
Post by: Merlijn van Veen on February 18, 2014, 04:17:12 AM
Some well placed response bumps and grinds between drive units, coupled with critical spacing and horn wall design, permits extended pattern control.

After careful reading the patent, I came to the conclusion IMHO that it's a little bit more sophisticated. Basically the 2 drivers operate in concert from 400 Hz to 1,2 kHz, approx. 1,18 octaves, in combination with clever filtering to optimize the overlapping range in terms of relative magnitude and phase, extending vertical coverage towards lower frequencies. The majority of EQ is applied to optimize frequency response. The all-pass filters aren't novel, these have been used in many products in order to restore transient response and flatten phase response.

Sincerly,

Merlijn
Title: Re: Meyer JM-1
Post by: Dan Mortensen on February 19, 2014, 05:18:05 PM
Part of this interview with John Meyer talks about the process of designing a speaker and amplifier, which may be relevant to this thread:

http://mixonline.com/john_meyer_a_lifetime_of_sound_science/
Title: Re: Meyer JM-1
Post by: Art Welter on February 19, 2014, 06:31:30 PM
Part of this interview with John Meyer talks about the process of designing a speaker and amplifier, which may be relevant to this thread:

Yes, he describes one of the problems associated with drivers covering very wide bandwidths:
"ON LINEARITY
But in loudspeakers, the minute the cone starts to move it starts to shift some of the frequencies, so you have frequency modulation. We can’t really build something perfectly linear because the nature of the motion itself would change it."