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Everything you ever wanted to know about Line Arrays ( but we’re afraid to ask)

Purité Audio

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Educate me, I would really like to know more about Line Arrays, I have read the Sound on Sound piece on PA line arrays like these,

But what about for domestic audio , Benchmark used a pair of ‘The Note’ arrays designed by Mark Porzilli formerly of Pipedreams and the Sceana ceramic loudspeakers at this years Axpona,


What are the advantages/disadvantages of the line array used domestically?
Thanks in advance,
Keith
 

fpitas

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MaxwellsEq

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I'm not convinced of their domestic value, since their raison d'être is directional audio in big auditoria. Domestic speakers have a different task. However, I've not heard any domestic versions, so this is just conjecture on my part.
 

sarumbear

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Educate me, I would really like to know more about Line Arrays, I have read the Sound on Sound piece on PA line arrays like these,

But what about for domestic audio , Benchmark used a pair of ‘The Note’ arrays designed by Mark Porzilli formerly of Pipedreams and the Sceana ceramic loudspeakers at this years Axpona,


What are the advantages/disadvantages of the line array used domestically?
Thanks in advance,
Keith
I heard Don Keele’s speakers. They are OK but the concept has quite a few limitations. I personally am not preferred to live with them. A pretty decent application of CBT was done by JBL, tested here.


I used them as my surround speakers for a while. They sound decent but only when you stay away from them. As with all arrays the effect is achieved by beaming. When you are near some beams are obstructed and the effect diminishes.

However, on large listening distances that is not a problem and they work brilliantly. I am now using mine in the garden.
 

DVDdoug

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What are the advantages/disadvantages of the line array used domestically?
My understanding is that it "squeezes" the sound vertically to focus the sound and project it more efficiently to the audience instead of the sound going down to the ground or up into space (or the into ceiling). With a "low" ceiling at home it's probably not too important and a "high" home ceiling isn't usually that high and it might sound better with the reflections.

And it's probably the best way to configure multiple speakers in a "big" PA system for stage productions.

But a home system with multiple-small full-range drivers could benefit from avoiding the crossovers.
 

617

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OK, let's unpack line arrays. The history of line arrays in domestic audio goes back some time. Once upon a time, when amplification was expensive, people were looking for ways to make louder speakers that were more efficient. Using lots of drivers is an excellent way to accomplish this task, and the most cognitively simple way of making a big array is to arrange a bunch of drivers vertically. That's what you see in the pipe-dreams speakers and many others dating back to the 60s or before. At some point it became accepted audiophile wisdom that such an array was 'cylindrical' if it was sufficiently tall in the room, and the fall-off of volume vs. distance would be different from a normal speaker. In a way, it would not abide by the inverse square law. As always, the reality is much more complex, but back then nobody was doing 3d speaker measurements, so their illusions persisted through the decades.

The problems with line arrays? Well, they work okay for low frequencies, at least as well as any other speaker below the transition region of the room, but at high frequencies you get a rather chaotic interaction between all the drivers. Ideally, you want center to center spacing to be very low, but in reality the path length difference between your ear and the middle / end tweeters is always going to be significant. As a result, not a very hifi solution, but if the power response, ie the total radiated energy, is where it needs to be, they can sound good, and you can run them with a tiny amp.

So what do we see with PA systems? Well, don't quote me on the history, but if I remember correctly, Don Keele was doing some research into either microphones or speakers developed by the navy. Lots of acoustics doesn't actually deal with air; a lot of stuff is discovered in water. Thank the Russians I guess. Anyway, they developed a way of arraying these transducers so they either sensed or produced a very coherent wave, without the interference problems intrinsic to a bunch of drivers on a plane.

Keele took this idea, which used a spherical surface, and cut it down into a single curved array. This curved array was 'shaded' meaning the drivers at the extremes were quieter than the ones in the middle (maybe I have it backwards.) This is pretty clever; you can get a coherent line array, promising everything audiophiles promised back in the day, simply by curving the line array and making some of the drivers quieter. There are still problems with center to center spacing, but if you only want the speaker to play above 200hz or so, you can use a ton of tiny midrange drivers, and maybe even skip the tweeters. Parts express sold a kit which used this concept, and the room measurements of these speakers are remarkable and probably better suited to a large home theater than any other design. Don Keele was an engineer at EV but I'm not sure who he did this research for, needless to say, the cat is out of the bag, and these systems are ubiquitous now.

What you see in professional sound are arrays which use shading and also delay. If you delay the speaker, you don't need to curve it, or you can curve it differently. I'm not an expert on these systems, but they essentially accomplish the goal of high efficiency (especially at high frequencies - remember it's difficult to combine HF sources, so you either need a single HF source with incredible power handling, or a very clever method of combining HF sources). These systems generally have a HF transducer in the middle and two mids on either side. I think people like them because you can make the system bigger or smaller depending on the need for output and coverage. I personally think these systems sound terrible but that's just me.

So where does that leave us? Line arrays, like every other esoteric speaker design, tried to address a real design problem while sacrificing a bunch of other stuff. In this case, they sacrificed nice treble dispersion and price point for high efficiency and...not much else? Fidelity is not great compared to single radiators, but if you want super even coverage for thousands of people, it's the best technology out there if you combine it with some snazzy cardioid subs.
 

dasdoing

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56 drivers with 4cm spacing at 10000Hz

Captura de tela_2023-04-24_07-47-13.png


here is the simulator https://www.usound.in.ua/graphs/
 

NTK

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Forgot to mention one of the motivation behind the very tall "line arrays" is to make the speakers behave like a line source, instead of the usual PA applications that use the arrays for acoustic beamforming and beam steering. These floor to ceiling line arrays uses the floor and ceiling (if it is not sloped) as reflectors to create a 2-dimensional, height independent sound field. The sound radiates out from the line sources only horizontally, and minimizes the effects from floor and ceiling reflections. Line sources also have the characteristic that the attenuation with distance (when in an anechoic environment) that is 3 dB per double distance, whereas a point source is 6 dB per double distance.
 

dasdoing

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Forgot to mention one of the motivation behind the very tall "line arrays" is to make the speakers behave like a line source, instead of the usual PA applications that use the arrays for acoustic beamforming and beam steering. These floor to ceiling line arrays uses the floor and ceiling (if it is not sloped) as reflectors to create a 2-dimensional, height independent sound field. The sound radiates out from the line sources only horizontally, and minimizes the effects from floor and ceiling reflections. Line sources also have the characteristic that the attenuation with distance (when in an anechoic environment) that is 3 dB per double distance, whereas a point source is 6 dB per double distance.

yea, but not sure how realistic this is. look at the 60 degree reflections I posted above. the acoustical axis it the middle of the array. this reflection will bounce between floor and ceiling no matter what.


EDIT: ok, I might miss something here. the bounce might be anulated by the bigger direct stream
 

NTK

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yea, but not sure how realistic this is. look at the 60 degree reflections I posted above. the acoustical axis it the middle of the array. this reflection will bounce between floor and ceiling no matter what.


EDIT: ok, I might miss something here. the bounce might be anulated by the bigger direct stream
The idea is that, if you have a perfectly reflective floor and ceiling (which never happens), then the floor and ceiling will act as mirrors, and "images" of the speakers will be appear above and below the room, making the line array extend infinitely above the ceiling and below the floor. So, in your simulation, picture an infinitely tall array with infinite number of drivers, and the sound will only radiate horizontally and uniformly.
 

hex168

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@mitchco, can you comment on the subjective qualities /shortcomings of a line array like Wesayso's?
 
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Purité Audio

Purité Audio

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@mitchco and everyone really interesting , thank you, I don’t know how line arrays passed me by perhaps they are just not a U.K. smaller room thing?
I remember Howard Popeck had a pair of prototype , I am pretty sure they were Wharfdale line arrays and I seem to remember that Douglas Adams ( Hitchhikers Guide) bought a pair , but it could just be my age.
Keith
 

Emlin

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Educate me, I would really like to know more about Line Arrays, I have read the Sound on Sound piece on PA line arrays like these,

But what about for domestic audio , Benchmark used a pair of ‘The Note’ arrays designed by Mark Porzilli formerly of Pipedreams and the Sceana ceramic loudspeakers at this years Axpona,


What are the advantages/disadvantages of the line array used domestically?
Thanks in advance,
Keith
The Kii Three BXT are line array/source up to 250Hz are they not?
 
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Purité Audio

Purité Audio

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I will check, there isn’t as far as I know a KEF type ‘white paper’ on the BXTs, Kii simply state,
‘The BXT is an extension module which turns the Kii THREE into a veritable floor standing loudspeaker with 16 additional drivers. The Kii THREE BXT System is absolutely unique as it combines a line source with horizontal directivity control! The BXT makes full use of the Kii THREEs technology and adds more frequency range and SPL to the game while still being a cardioid system that, despite its size, does not interact with the room. Astoundingly enough small rooms profit a lot from the line source concept.’
I will look around I am sure there was something more tecynical.
Keith
 

Emlin

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I will check, there isn’t as far as I know a KEF type ‘white paper’ on the BXTs, Kii simply state,
‘The BXT is an extension module which turns the Kii THREE into a veritable floor standing loudspeaker with 16 additional drivers. The Kii THREE BXT System is absolutely unique as it combines a line source with horizontal directivity control! The BXT makes full use of the Kii THREEs technology and adds more frequency range and SPL to the game while still being a cardioid system that, despite its size, does not interact with the room. Astoundingly enough small rooms profit a lot from the line source concept.’
I will look around I am sure there was something more tecynical.
Keith
It says line source in there, and that seems to be another term for line array. There's a video where Bruno describes how it works.
 
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Purité Audio

Purité Audio

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I remember something, we haven’t had any BLTs here for a while.
Keith
 

Alex-D

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I really liked small floor-standing line array PA system in a hall with 7-10 meter tall reflective glass ceiling

It was a huge improvement in regards to excessive reverberation compared to traditional PA speakers on stands in the same space

Slower than usual distance falloff was also a nice bonus

Same system as described here, same pros and cons as reviewer mentions, not great for nearfield but nicer than expected in farfield
 
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