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Author Topic: Line Array HF Throats  (Read 16322 times)

Rory Buszka

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Re: Line Array HF Throats
« Reply #10 on: June 21, 2011, 08:23:48 pm »

One thing that I think is very often overlooked in designing line array horns is reflection from the upper surfaces of the waveguide or wave-shaper to the lower surfaces. The solutions I've seen from Heil/L'Acoustics, Danley, and Adamson don't do anything to mitigate internal reflection, which can only be achieved either by using a lossy material lining the walls or by forcing plane wave tube behavior for a short length of horn. At higher frequencies, the wedge-shaped portion of the Heil waveguide begins to focus its output at the center of the axe-head, taking on behavior that is closer to that of a point source originating from the middle of the slot's exit. Devices like the EV Hydra and Meyer Sound REM force plane wave behavior along the length of their internal waveguides, which does not permit internal reflections and point-source formation to occur. Danley's Paraline has the shortcoming that it requires waves to perform 90-degree bends inside its structure, causing some of the wave to be reflected rather than bent. It's a very elegant-looking solution, but I'd like to see its impulse response.

I have several patentable ideas that I believe incorporate the desirable aspects of the leading line array waveguides on the market while minimizing their flaws. Obviously, I'm keeping them under my hat for now.
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Jim McKeveny

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Re: Line Array HF Throats
« Reply #11 on: June 22, 2011, 10:27:25 am »

As I conjectured, specified bandwith starts at @2Khz on the Alcons devices....
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Niels Janssen

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Re: Line Array HF Throats
« Reply #12 on: June 22, 2011, 03:32:56 pm »

As I conjectured, specified bandwith starts at @2Khz on the Alcons devices....

The RBN pro-ribbon drivers starts @1kHz. Crossover is @1kHz.
You can compare the RBN401 (which is 4" high) to a 1,5" compression driver with waveguid. But with up to 14dB more headroom. This is information from a independent (THD) measurement which compared the LR14 (2x6,5"+1xRBN401) to a comparable loudspeaker from a French manufacturer.

If you are interested: come see Alcons Audio somewhere in Europe or USA exhibition show. Where you also can hear a nearfield setup with the RBN401 pro ribbon driver. Or if you are interested in more technical details they can show and/or expain you the measurement data (which are independent!).

The other factor which isn't discussed is the transient respons (decay) time. Which is with ribbon drivers a huge difference. Because ribbon drivers and especially the ProRibbon drivers have faster transient respons.
And second is the dynamic. Because of the non-compression part: ribbons drive direct air, they have a dynamic respons (rms to peak) of 1:15 compared to compression drivers of 1:2

More on this technology:
http://www.alconsaudio.com/site/line-array/index.html



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Iain.Macdonald

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Re: Line Array HF Throats
« Reply #13 on: June 23, 2011, 09:48:13 am »


The other factor which isn't discussed is the transient respons (decay) time. Which is with ribbon drivers a huge difference. Because ribbon drivers and especially the ProRibbon drivers have faster transient respons.
And second is the dynamic. Because of the non-compression part: ribbons drive direct air, they have a dynamic respons (rms to peak) of 1:15 compared to compression drivers of 1:2

More on this technology:
http://www.alconsaudio.com/site/line-array/index.html

Graphic to illustrate the point being made by Niels. Decay /transient is really important, whether it's a subwoofer or a HF device. A is the alcons 6" ribbon measured on the waveguide. B is a large format line array, with state of the art compression drivers, with a xover point at 1.1Khz approx. You can see that the decay point on the ribbon is 2.7ms and the compression driver is 12.7ms. Please note that the compression driver is not designed to operate below 900Hz. So that big ridge should be ignored. These measurements were done independently, by Production Partner, an entertainment technology magazine from Germany.

Iain.

« Last Edit: June 23, 2011, 10:20:41 am by Iain Macdonald »
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Jim McKeveny

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Re: Line Array HF Throats
« Reply #14 on: June 23, 2011, 10:02:00 am »

Very appealing waterfalls. The proof of the pudding is in the eating. I look forward to hearing these devices in use...
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Matt Errend

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Re: Line Array HF Throats
« Reply #15 on: June 24, 2011, 04:31:08 pm »

Very appealing waterfalls. The proof of the pudding is in the eating. I look forward to hearing these devices in use...

The man behind the Alcons ribbons was also responsible for the ribbon drivers used in Stage Accompany products, and they have always been fantastic to listen to. We've got several of the Entertainer series boxes from SA and we've pushed them pretty hard and never damaged a driver as a result. The only time I've had to replace a driver was after some numbskull dropped a screw into the driver while removing the grill.

The big fault of the SA drivers was the neo bar magnets that they were using was so strong, the binding compound used to make the magnets doesn't hold up over time and will actually disintegrate if you try and take the rear cover off to get at the diaphragm.

« Last Edit: June 24, 2011, 04:42:26 pm by Matt Errend »
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Niels Janssen

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Re: Line Array HF Throats
« Reply #16 on: June 25, 2011, 05:28:40 am »

Very appealing waterfalls. The proof of the pudding is in the eating. I look forward to hearing these devices in use...

The man behind the Alcons ribbons was also responsible for the ribbon drivers used in Stage Accompany products, and they have always been fantastic to listen to. We've got several of the Entertainer series boxes from SA and we've pushed them pretty hard and never damaged a driver as a result. The only time I've had to replace a driver was after some numbskull dropped a screw into the driver while removing the grill.

The big fault of the SA drivers was the neo bar magnets that they were using was so strong, the binding compound used to make the magnets doesn't hold up over time and will actually disintegrate if you try and take the rear cover off to get at the diaphragm.


This is not an issue anymore with the Alcons RBN. Its magnet radation is complete inside. The other two big difference between the SA compact driver and the RBN (in favor of the RBN off course) is the lighter weight and the patented true 90 degrees horizontal dispersion (from 1 kHz to up to 20kHz). Where other brands ribbon drivers are only 90 degrees (horizontal) at 1 kHz and get smaller (30 degrees) at >16kHz.
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Jim McKeveny

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Re: Stage Accompany
« Reply #17 on: June 25, 2011, 02:36:06 pm »

I had the opportunity for an extended tinker with Stage Accompany components over a decade ago, here in the NYC area. I loved the concept and sound, but the sensitivity was down a whole bunch vs. other pro sound gear. Watts cost more then, and they made their way to a low/medium spl install in a church basement. I would like to know what design changes have produced the 7-9db sensitivity increase. (?)
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Frank Bothe

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Re: Line Array HF Throats
« Reply #18 on: June 26, 2011, 04:55:00 pm »


The other factor which isn't discussed is the transient respons (decay) time. Which is with ribbon drivers a huge difference. Because ribbon drivers and especially the ProRibbon drivers have faster transient respons.
And second is the dynamic. Because of the non-compression part: ribbons drive direct air, they have a dynamic respons (rms to peak) of 1:15 compared to compression drivers of 1:2

More on this technology:
http://www.alconsaudio.com/site/line-array/index.html

Graphic to illustrate the point being made by Niels. Decay /transient is really important, whether it's a subwoofer or a HF device. A is the alcons 6" ribbon measured on the waveguide. B is a large format line array, with state of the art compression drivers, with a xover point at 1.1Khz approx. You can see that the decay point on the ribbon is 2.7ms and the compression driver is 12.7ms. Please note that the compression driver is not designed to operate below 900Hz. So that big ridge should be ignored. These measurements were done independently, by Production Partner, an entertainment technology magazine from Germany.

Iain.

Hi,
funny graphs this. The decay point of the compression driver is 10ms later. Well, the origin of its time axis is also 10ms later. Does not look very scientific to me...
Frank
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Matt Errend

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Re: Stage Accompany
« Reply #19 on: June 26, 2011, 05:25:29 pm »

I had the opportunity for an extended tinker with Stage Accompany components over a decade ago, here in the NYC area. I loved the concept and sound, but the sensitivity was down a whole bunch vs. other pro sound gear. Watts cost more then, and they made their way to a low/medium spl install in a church basement. I would like to know what design changes have produced the 7-9db sensitivity increase. (?)

Just off the top of my head, the efficiency of the 13ohm SA 8535 was well over 100dB @1w/1m, with waveguide I believe it is 107dB 1w/1m.

That's pretty efficient in my book.

It's also not surprising that Alcons has been able to improve the technology considering the 8535 was designed 15 years ago.
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ProSoundWeb Community

Re: Stage Accompany
« Reply #19 on: June 26, 2011, 05:25:29 pm »


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