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[Helge A Bentsen]

I was looking at options for a long, narrow room and the list of line arrays with "narrow" horizontal dispersion (roughly 70 deg) is suprisingly short.

A quick search came up with four systems, K2, Flex array, KF737 and J8 (80deg).

Is there a reason for this?

[Ivan Beaver]

I was looking at options for a long, narrow room and the list of line arrays with "narrow" horizontal dispersion (roughly 70 deg) is suprisingly short.

A quick search came up with four systems, K2, Flex array, KF737 and J8 (80deg).

Is there a reason for this?

I am not aware of any line array that has large horns, or anything more than the HF with much of any waveguide for pattern control.

Of course the narrower the pattern, the larger the horn has to be to maintain the same control to the same freq.

If you are trying to keep the pattern narrow, you really need to check out how low the "rated" pattern actual has control.  It may be MUCH higher than you would like.

[Mac Kerr]

I am not aware of any line array that has large horns, or anything more than the HF with much of any waveguide for pattern control.

I would expect this is why line arrays typically have wide horizontal dispersion. In order to keep the horizontal coverage even the highs need to be what the mids are capable of.

Mac

[Tim Halligan]

"When all you have is a hammer, every problem starts to look like a nail."

I don't play in the same league as you guys, but I'm convinced that many - if not most - of the venues I see with line arrays installed would be better suited to a well thought out "point source"/trap box system.

As ever, deployment is everything.

Cheers,
Tim

[Stephen Kirby]

Many "symmetrical" LAs actually turn off the mids from one woofer so that they don't narrow the midrange from interference.  If you are willing to manage pattern though destructive interference you might be able to rework some crossover points.  Which is what I suspect some of the DSP steering systems are doing.

[Keith Broughton]

I was looking at options for a long, narrow room and the list of line arrays with "narrow" horizontal dispersion (roughly 70 deg) is suprisingly short.

A quick search came up with four systems, K2, Flex array, KF737 and J8 (80deg).

Is there a reason for this?

Once again one has to ask "at what frequency is this dispersion measured at?"

[Helge A Bentsen]

Once again one has to ask "at what frequency is this dispersion measured at?"

A quick glimpse at the datasheets reveal that they all exibit this behavior from roughly 1K and up. Give or take an octave.

Entering the numbers into a simulation program one can clearly see the difference from 1K and up, so in theory it should help to reduce room reverberation in the top 3 - 4 octaves.
Shouldn't that be an advantage worth pursuing?
Or am I missing something?

[Mac Kerr]

A quick glimpse at the datasheets reveal that they all exibit this behavior from roughly 1K and up. Give or take an octave.

Entering the numbers into a simulation program one can clearly see the difference from 1K and up, so in theory it should help to reduce room reverberation in the top 3 - 4 octaves.
Shouldn't that be an advantage worth pursuing?
Or am I missing something?

At the cost of uneven frequency response, or a big bump in low mid reverb relative to the rest of the system?

Apparently line array designers opt of smoother off axis response.

Mac

[Kent Clasen]

I was looking at options for a long, narrow room and the list of line arrays with "narrow" horizontal dispersion (roughly 70 deg) is suprisingly short.

A quick search came up with four systems, K2, Flex array, KF737 and J8 (80deg).

Is there a reason for this?

Another 80* option is Nexo S12
https://nexo-sa.com/products/geo-s1210-st/

[Stelios Mac]

There's also:
d&b Q1 (75*, claiming down to 400)
d&b V8 (80*, claiming down to 250)
d&b Y8 (80*, claiming down to 500)
EAW KF760 (80*)
And I'm sure quite a few more.
The list for 90* boxes is much larger, but that's not quite you're looking for.

Like others have said however, I'd rather have smooth response off-axis - which is not easy to achieve in compact line array boxes. It's the same reason why you wouldn't treat a venue by using carpet to cover up all of the walls; you'd kill all HF and end up with a horrible boomy-sounding room. Obviously going with a narrow coverage box isn't going to be as dramatic, but constant directivity is quite a big deal.
Perhaps some point source boxes would be better suited for this application?

[Stephen Kirby]

Another 80* option is Nexo S12
https://nexo-sa.com/products/geo-s1210-st/

The datasheet polars only go down to 1250, and they're spreading by then.  With the single 12 and the thingy they put in front of it to improve LA coupling, I seriously doubt there's any pattern control off the woofer.

[Riley Casey]

Because long wavelengths require physically large sources in the plane of interest.  I just love it when any manufacturer quotes horizontal pattern control in boxes with a single 10 or 12 " LF driver.  Doesn't anyone read the coverage plots anymore?

I was looking at options for a long, narrow room and the list of line arrays with "narrow" horizontal dispersion (roughly 70 deg) is suprisingly short.
...
Is there a reason for this?

[Ivan Beaver]

Doesn't anyone read the coverage plots anymore?

I think most of the industry simply doesn't care or realize the importance of pattern control.

That is why some manufacturers are leaving it off the spec sheets completely and simply putting in "wide" and "narrow".

It is up to the user to determine if those simple terms meet their needs or what they actually are.

[Keith Broughton]

I think most of the industry simply doesn't care or realize the importance of pattern control.

That is why some manufacturers are leaving it off the spec sheets completely and simply putting in "wide" and "narrow".

It is up to the user to determine if those simple terms meet their needs or what they actually are.

We wouldn't want to attract attention to the elephant in the room 
If pattern control over a wide frequency range is required for a room, then perhaps a line array is not the right tool.
Just sayin'...

[Jason Raboin]

EAW Anya is 60 degrees, isn't it?
Kudo?

[Lee Buckalew]

EAW Anya is 60 degrees, isn't it?
Kudo?

Anya is 70 degrees down to approximately 800 Hz.

Lee

[Helge A Bentsen]

Anya is 70 degrees down to approximately 800 Hz.

Lee

Anya is 70 degrees for single colums and 60 degrees for multiple colums.

[Lance Hallmark]

The Noesis 3tx can be had with a 60x40 or 90x60 rotatable horn.

[Kevin McDonough]

Because long wavelengths require physically large sources in the plane of interest.  I just love it when any manufacturer quotes horizontal pattern control in boxes with a single 10 or 12 " LF driver.  Doesn't anyone read the coverage plots anymore?

Exactly.

It's simply the case that for a single cone driver on the front of a box, with no horn or wave guide or anything in front of it, there is simply pattern control as such. There is nothing there to control the pattern.  The driver will have a very wide dispersion at lower frequencies, and this will progressively narrow until the wavelengths start to become of similar size to, and then smaller than, the size of the driver/cab. This is just the natural dispersion of any reflex loaded driver and is just a function of wavelength vs size.

With the usual single driver, speaker on a stick tops, or with single cone driver line array cabs, you can only hope that when the speaker was designed they took dispersion into consideration and chose a crossover point and processing that worked to control this as well as just based on frequency response. The actual degrees figure quoted will usually refer more to the HF horn than the cone driver.

With bigger line array cabs this obviously becomes a little easier at the low end. The usual dipole setup of a driver on each end of the cab controls dispersion to a much lower frequency. But then you start to have problems at the upper end of the con driver's range, and their dispersion also narrows and begins to beam and lobe much earlier. Often as someone said this is overcame by rolling off one of the drivers early, or by changing over to smaller drivers at a suitable frequency.

But it still applies that pattern control is a pretty nebulous thing, dipole arrangements can only do so much. Even in large line array cabs, the dispersion quoted will often refer more to the HF horn or wave guide than the cone drivers, and the dispersion will vary throughout the range of the cab.

If you really want/need pattern control over the full range of the box, then you needed point source boxes. And big, fully horn loaded ones at that if you want that pattern control to extend down to as low a frequency as possible. While line arrays are sexy in the eyes of bands and promoters and that's what they will often spec, as people have said it doesn't seem like the right tool in this case

Some of the Danley boxes would be a perfect fit for this venue in that respect, and big hornloaded boxes like the EM acoustics X3  (http://www.emacoustics.co.uk/docs/products/X3.shtml) spring to mind, though these types of boxes have fallen out of favour and there are far less available than there used to be.


(You've not gave much detail about the venue/size/capacity etc, but three X3 a side would give you a VERY controlled 60 degree system that would sound phenomenal and give you great bang for buck. The SPL from the fully hornloaded high sensitivity system is prestigious and I'm willing to bet you'd have to pay a LOT more to get the equivalent SPL from line array cabs.)

Smaller narrow dispersion boxes like Arcs or JM-1P have great pattern control at the top end with their HF horns, and while the reflex loaded woofer has little pattern control on its own other than the natural roll off as mentioned, once you stick a few together in an array the width of the sources (just like the dipole of the LA cabs) starts to provide that for you.

At the end of the day it comes down to the same thing rental companies and installers deal with all the time. Do you spec the system that is absolutely best for the room sound wise, or are you forced to take other considerations into account; in this case do the acts or entertainment expect and specify particular brands or set ups, and do they have enough swaying power that their wishes take priority. 



K

[Stephen Kirby]

That EM acoustics box has an interesting solution to getting enough HF to keep up with the rest of the box.

I know that compression manifolds don't work very well, but I wonder if multiple cellular waveguides could be fed into the throat of a synergy type box if the waveguide exits were large enough for pattern control in their bandpass.  That is, each feeding it's own section of the throat.

[ProSoundWeb Community]