So what do you believe about the new JH-90 ?
"The JH-90 is simply the most accurate powerful loudspeaker ever
created. A single cabinet can produce quality audio well beyond 1000’
from a true full range point source housing; six 18" drivers, six - 6” mid
range drivers and three 1.4” coaxial high frequency drivers."
"The JH-90 is simply the most accurate powerful loudspeaker ever
created. A single cabinet can produce quality audio well beyond 1000’
from a true full range point source housing; six 18" drivers, six - 6” mid
range drivers and three 1.4” coaxial high frequency drivers."
A monster,yes.Monsters are a long way off,of being beautiful,no?
And not so much of a full range,as far as,specs go.
B.L.
A large array can do better and is more well... "arrayable"
Hey over 700 pounds of weight per box, it is not a two persons job
Attachments
If anyone would like to know more about this product check out prosound web forum. There has been discussion about it between the pros and the manufacturer. To my understanding it was developed to be a one box solution for everything up to (but not including)? the largest staduim concerts. And as always it is still the great pursuit to acheive point source coherence in any system. It definitley would have helped their claim if its f3 was 30 hz though
It was a bit of a mental shift for me when I first started looking into Danley's Unity/Synergy designs to absorb just how huge the 'Houses of Worship' market is in the pro audio world. Not surprising at all once you think about it, but coming from a 'music' perspective it's automatic to think pro-sound == bars/concerts.
Bandwidth does seem to be a bit mismatched for 'HOW' usage though - more than necessary for vocal reproduction, but insufficient for reproducing the full spectrum of the organ music that traditionally accompanies hymns. Of course, maybe the typical hymn doesn't plumb the depths quite like Bach does....
Hi Guys, freddyi
Actually the JH-90’s have not been installed anywhere indoors yet. The purpose of the cabinet is to replace a large line array systems with a single box. In doing so, it has several audible advantages in that unlike a line array, the frequency response does not change as a function of distance or position, only the spl lowers. There is much less sound projected up, to the rear and sides, one can easily talk behind the system at high levels. Being a broad band single source without lobes and nulls in it’s pattern, they have a very simple radiation lobe one can use the lobe in the old fashioned way, flown, “pointed at the back row”. That cannot be done normally as multiple sources normally cause lobes and nulls, prevent a single strong lobe over a broad bandwidth.
That approach can greatly reduce the normal inverse square law making the spl much more constant with distance . Also unlike a line array which produces a complex interference pattern, being a single source, simple beam, it does not suffer from even strong crosswinds. Being a single source in time and space means a very much more hifi like reproduction of whatever the program. I have not tried it with the JH-90, but it should be able to reproduce a square wave over a significant bandwidth like most of our others.
I got to hear one system that was installed at BYU stadium. The operator was playing CD’s and I was walking around thinking man, they need to show movies here. That 70Kw system has 6 TH-812 subwoofers as well as 4 JH-90’s (and a couple sh-50’s for side fill).
If you go to the BYU cougars website and click the view from the south, the speakers are behind the upper part of the score board. From that point, one is about 740 feet from the speakers, at which point the contractor had measured 105dBc slow, although they don’t run it that loud normally. It sounds nothing like a stadium, nothing like the line arrays and everyone is happy.
BYUCougars.com - LaVell Edwards Stadium
While that stadium has 65,000 seats, the other installation is at a smaller venue, a 45,000 Ryan field at Northwestern university in Evanston IL. Here two jh-90s are used for music, entertainment and announcements.
There is a large installation coming up in Poland at the Spodek arena that uses a good pile of them which should be humorous. Each of the LF system in a jh-90 can produce about 3000 acoustic watts.
The key to making these work is the combiner that allows the outputs from three coax compression drivers to sum within the horn without interference and load a 90 degree wide horn.
I can't really go into that yet though.
Best,
Tom Danley
Actually the JH-90’s have not been installed anywhere indoors yet. The purpose of the cabinet is to replace a large line array systems with a single box. In doing so, it has several audible advantages in that unlike a line array, the frequency response does not change as a function of distance or position, only the spl lowers. There is much less sound projected up, to the rear and sides, one can easily talk behind the system at high levels. Being a broad band single source without lobes and nulls in it’s pattern, they have a very simple radiation lobe one can use the lobe in the old fashioned way, flown, “pointed at the back row”. That cannot be done normally as multiple sources normally cause lobes and nulls, prevent a single strong lobe over a broad bandwidth.
That approach can greatly reduce the normal inverse square law making the spl much more constant with distance . Also unlike a line array which produces a complex interference pattern, being a single source, simple beam, it does not suffer from even strong crosswinds. Being a single source in time and space means a very much more hifi like reproduction of whatever the program. I have not tried it with the JH-90, but it should be able to reproduce a square wave over a significant bandwidth like most of our others.
I got to hear one system that was installed at BYU stadium. The operator was playing CD’s and I was walking around thinking man, they need to show movies here. That 70Kw system has 6 TH-812 subwoofers as well as 4 JH-90’s (and a couple sh-50’s for side fill).
If you go to the BYU cougars website and click the view from the south, the speakers are behind the upper part of the score board. From that point, one is about 740 feet from the speakers, at which point the contractor had measured 105dBc slow, although they don’t run it that loud normally. It sounds nothing like a stadium, nothing like the line arrays and everyone is happy.
BYUCougars.com - LaVell Edwards Stadium
While that stadium has 65,000 seats, the other installation is at a smaller venue, a 45,000 Ryan field at Northwestern university in Evanston IL. Here two jh-90s are used for music, entertainment and announcements.
There is a large installation coming up in Poland at the Spodek arena that uses a good pile of them which should be humorous. Each of the LF system in a jh-90 can produce about 3000 acoustic watts.
The key to making these work is the combiner that allows the outputs from three coax compression drivers to sum within the horn without interference and load a 90 degree wide horn.
I can't really go into that yet though.
Best,
Tom Danley
Thank you for joining in Mr. Danley, much appreciated.
I hope someone will raise the question about how the three CD's are summing up acoustically. It's ok if you can't tell us yet, we are still trying to figure up in detail how the old synergy and unity designs are working so, yeah, there is time
I hope someone will raise the question about how the three CD's are summing up acoustically. It's ok if you can't tell us yet, we are still trying to figure up in detail how the old synergy and unity designs are working so, yeah, there is time
Another question.
How about the non-linearity of the air itself? I remember reading somewhere (more than once) mentioned that the ratios of volume changes of air are different under positive or negative pressure. So it's 2nd order harmonics in nature.
And the density differece of air molecules in sound wave defines SPL. The higher the SPL, the harder the air being squeezed and expanded. Is the degree of non-linearity in a certain proportion with SPL? I suppose so. (correct me if I'm wrong)
So, an SPL so high and produced within such restricted area (what a 'point source' !!), the non-linearity of air must be skyrocketing, no? (the air near the throat might also be heated up !? )
Is there anything done for dealing with this? Some methods to 'counteract' the intrinsic character of air, or... ?
How about the non-linearity of the air itself? I remember reading somewhere (more than once) mentioned that the ratios of volume changes of air are different under positive or negative pressure. So it's 2nd order harmonics in nature.
And the density differece of air molecules in sound wave defines SPL. The higher the SPL, the harder the air being squeezed and expanded. Is the degree of non-linearity in a certain proportion with SPL? I suppose so. (correct me if I'm wrong)
So, an SPL so high and produced within such restricted area (what a 'point source' !!), the non-linearity of air must be skyrocketing, no? (the air near the throat might also be heated up !? )
Is there anything done for dealing with this? Some methods to 'counteract' the intrinsic character of air, or... ?
Would you care to develop this a little bit? Maybe some links?
I believe this is related to what JLH mentioned some time ago in a thread. I think that at these huge pressure levels the air starts behaving like a laminar flow.
I am not sure if this is correct because to me the pressure generated by one of the midrange drivers in the Unity or Synergy is not entirely different by the one produced in a CD. And as far as I know phase plug design is not treated considering this kind of laminar flow but a more familiar concept of sound pressure.
edit: Maybe Mr. Danley could shed some light on this..
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Hi all
Air nonlinearity is a real effect; the cause is the fact that the high pressure side of a wave is slightly warmer than the rarified side of the wave. The speed of sound is partly coupled to temperature so in a very loud sound wave say a plane wave or one traveling down a tube, the warm side actually catches up to the cool side which produces a saw tooth waveshape and harmonic distortion.
The traditional formula relates the horn bandwidth to distortion based on an exponential horn. The wider the horn’s bandwidth, or the greater the throat pressure, the higher the 2nd harmonic distortion will be. That math was possible because the low frequency end defined how slowly the horn could expand which the high frequency end defined how short the wavelength would be relative to the slow expansion.
The longer the wave had to travel at a small area (high pressure) the more time it had to go bad. The worst case would be a single driver covering a very wide bandwidth because the expansion rate must be slow.
The synergy horns get around or minimize that problem several ways;
By having a very rapid initial expansion (property of a conical horn), the sound pressure from the hf driver decreases rapidly.
By dividing the horn this way, low frequencies are not even produced at the throat and a slow expansion is not required.
By using larger throat area for the mid frequency drivers, the average pressure at the throat is lower than if a conventional mid compression driver were used there.
Also, any of the side mounted drivers load the horn through an acoustic low pass filter so harmonics the driver produces are attenuated.
Lastly, in the JH-90, the HF internal pressure isn’t any higher than a single driver produces, the area is simply 3X larger to accommodate the output from 3 drivers, each coax driver see’s about a 30X40 degree portion of the horn, with the loudest portion of the horn in the upper third of its vertical pattern.
Hope that helps
Tom
Air nonlinearity is a real effect; the cause is the fact that the high pressure side of a wave is slightly warmer than the rarified side of the wave. The speed of sound is partly coupled to temperature so in a very loud sound wave say a plane wave or one traveling down a tube, the warm side actually catches up to the cool side which produces a saw tooth waveshape and harmonic distortion.
The traditional formula relates the horn bandwidth to distortion based on an exponential horn. The wider the horn’s bandwidth, or the greater the throat pressure, the higher the 2nd harmonic distortion will be. That math was possible because the low frequency end defined how slowly the horn could expand which the high frequency end defined how short the wavelength would be relative to the slow expansion.
The longer the wave had to travel at a small area (high pressure) the more time it had to go bad. The worst case would be a single driver covering a very wide bandwidth because the expansion rate must be slow.
The synergy horns get around or minimize that problem several ways;
By having a very rapid initial expansion (property of a conical horn), the sound pressure from the hf driver decreases rapidly.
By dividing the horn this way, low frequencies are not even produced at the throat and a slow expansion is not required.
By using larger throat area for the mid frequency drivers, the average pressure at the throat is lower than if a conventional mid compression driver were used there.
Also, any of the side mounted drivers load the horn through an acoustic low pass filter so harmonics the driver produces are attenuated.
Lastly, in the JH-90, the HF internal pressure isn’t any higher than a single driver produces, the area is simply 3X larger to accommodate the output from 3 drivers, each coax driver see’s about a 30X40 degree portion of the horn, with the loudest portion of the horn in the upper third of its vertical pattern.
Hope that helps
Tom
Hello,
Thank you for the insight on the nonliniarities of air!
There is still a question bugging me and I couldn't find an answer in the threads dedicated to your designs.
While I believe I understand the way the midrange drivers (4"-5") are loading unity and sinergy designs, I can't understand why the midbass drivers (for example the two 12" in sh-50) are having their exit ports so close to the mouth and so far from the throat of the horn. Is there any other reason excepting the one stated above?
Also, how comes that two 12" midranges are able of 100db at 50Hz as stated in the sh-50? Is the horn loading that important even if the ports are so close to the mouth? Also, how is the horn providing any loading below 300Hz when it is this small?
I would really appreciate your advice on this!
Regards,
Florin
Thank you for the insight on the nonliniarities of air!
There is still a question bugging me and I couldn't find an answer in the threads dedicated to your designs.
While I believe I understand the way the midrange drivers (4"-5") are loading unity and sinergy designs, I can't understand why the midbass drivers (for example the two 12" in sh-50) are having their exit ports so close to the mouth and so far from the throat of the horn. Is there any other reason excepting the one stated above?
Also, how comes that two 12" midranges are able of 100db at 50Hz as stated in the sh-50? Is the horn loading that important even if the ports are so close to the mouth? Also, how is the horn providing any loading below 300Hz when it is this small?
I would really appreciate your advice on this!
Regards,
Florin
The locations of the ports are determined by the xover frequencies and the phase (timing) characters at those points. I suppose you already know it. (it seems you're a big fan of them )
LP sections are relatively delayed (from the HF's POV), so they are compensated by moving towards the mouth to proper distances.
As to the high output, I guess the bandpass nature of the driver/port arrangements also contribute some, other than the horn gain. And, is this model supposed to be used in form of array?
)LP sections are relatively delayed (from the HF's POV), so they are compensated by moving towards the mouth to proper distances.
As to the high output, I guess the bandpass nature of the driver/port arrangements also contribute some, other than the horn gain. And, is this model supposed to be used in form of array?
Google suitable midrange unity horn
There's a thread on here that explains a lot of this.
In a nutshell, the main reason that the 12" woofers in a synergy horn are so close to the mouth is that we're more concerned with synergy of the wavefront than we are with gain. So, yes, you could get more gain if you put the twelves closer to the throat, but then the output from the low section would interfere with the output from the mid and the high section.
This is also the reason that the location of the low frequency drivers is not critical. At high frequencies, wavelengths are very short, and moving the midranges a single inch can screw up the integration. The opposite is true at low frequencies.
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