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[MikeHarris]

some years ago a friend sent me info on these speakers.  Anyone heard of them...or try them
https://www.edcacoustics.com/
90 transducers..90 channels of DSP & power...WTF

[Chris Grimshaw]

some years ago a friend sent me info on these speakers.  Anyone heard of them...or try them
https://www.edcacoustics.com/
90 transducers..90 channels of DSP & power...WTF

Yeah, makes sense.

IIRC, when surround-sound was first gaining traction in home theatre, Yamaha made a soundbar with something like 72 drivers and amp channels, which was apparently very good at mimicking surround effects without putting speakers everywhere. Worked by bouncing sound off the walls etc.

Never experienced it myself, but Yamaha's still making similar sound bars with lots of drivers & DSP. Suspect they're doing something right.

Like any directional array, the LF cutoff of the direction control is based on the size of the array - it's still a point source at 20Hz.

I don't know how much (if any) advantage there is over a correctly-specced horn, but the option to vary directivity with the cabinet already installed can be attractive.

Chris

[Kevin Maxwell]

Like any directional array, the LF cutoff of the direction control is based on the size of the array - it's still a point source at 20Hz.

Did you mean to say 200Hz and maybe even higher?

[Tim McCulloch]

Did you mean to say 200Hz and maybe even higher?

How long is your.... array, Kevin, and at what freq do you need pattern control? 

Shameless plugs:

d&b has a great webinar on basic line array theory that is brand-agnostic.  It's well worth the 60-90 min time investment.  The guys from d&b do a very good job of explaining and illustrating a number of concepts that might otherwise be confusing or appear contradictory.  Highly recommended by this Cranky Old Guy as they confirmed and.or explained much of what I've learned over the last 15 years of using vertical arrays and reading white papers with more math than I can shake a calculator at...

If there's a bright side to the stay at home stuff it's the tremendous learning opportunities being given.  Literally given; a fair bit of what is now on webinar used to be paid training...  Harman/JBL, DigiCo, d&b, l'Acoustic, C-M Hoists & Harp Rigging, Rational Acoustics... in almost every facet of production the manufacturers, distributors, and even end users are stepping up the education.  This is mind-blowing for me.  I remember anxiously awaiting the trade magazines, 30 or more years ago, so I could learn a few new tricks, find a gem or nugget of wisdom or technique and try to experiment with it at a gig.  That was a trickle of information.  Today we hope to get a drink from the 3" fire hose of info being presented.  Priceless.  I hope folks are availing themselves of these opportunities.

edit ps:  I left out https://practicalshow.tech - our friends Mac Kerr, Pete Erskine, Henry Cohen, and new (to me) friend Kelly Epperson.  All kinds of stuff, mostly centered on broadcast, big-boy corporate work with tons of RF, fibre, intercom, and digital transport topics. 

[Kevin Maxwell]

How long is your.... array, Kevin, and at what freq do you need pattern control? 

Because I am aware of how the length on an array affects the frequency of the pattern control is why I was trying to make the point that a sound bar is going to be a point source a lot higher then 20hz like Chris wrote in his post. I thought it was a typo on his part. That is why I said even higher. I was trying to be nice.

Or are you saying that a sound bar can have pattern control at low frequencies?

[Tim McCulloch]

Because I am aware of how the length on an array affects the frequency of the pattern control is why I was trying to make the point that a sound bar is going to be a point source a lot higher then 20hz like Chris wrote in his post. I thought it was a typo on his part. That is why I said even higher. I was trying to be nice.

Or are you saying that a sound bar can have pattern control at low frequencies?

Nope, I'm a believer in fat copper and long vertical arrays.

But you actually hit on part of what d&b covered in their webinar - how long is the "line" that provide summation at X freq at a given spot in the listening plane and that was the source of "how long is your line", because depending on freq and location the answer changes.

[Chris Grimshaw]

Did you mean to say 200Hz and maybe even higher?

I was picking 20Hz as a frequency where it would definitely still be a point source.

IIRC, anything bigger than about 1/2-wavelength will start to show some directionality. At 200Hz, the wavelength is 1.7m, so half-wave is 0.85m. I can imagine that Yamaha has probably made a soundbar that approaches that in the horizontal dimension, so it's possible that there's a little directional control at 200Hz.
I expect the larger speakers from EDC Acoustics could be similar in size, but I didn't pull the datasheet to check.

Chris

[Luke Geis]

True directional control occurs when the length of the array is four times the wavelength of interest. Most full-size arrays don't get much longer than about 30-40' in length. A 100hz wavelength is roughly 11' so you would need 40' of array to have true directional control of frequencies above 100hz. Since most arrays are not that long though, 200hz is about the practical limit where some control can be achieved. 

The method of beam steering, in my understanding, is that you need multitudes of drivers within a single element in order to do it with great success. Your typical 3-4 driver line array element can do it to some degree at certain frequencies, but you really need several more in order to get a more granular and effective level of control. Think of EAW's Anya rig with 70 HF drivers per element, or Martins MLA with 7 drivers in total.

[Peter Morris]

True directional control occurs when the length of the array is four times the wavelength of interest. Most full-size arrays don't get much longer than about 30-40' in length. A 100hz wavelength is roughly 11' so you would need 40' of array to have true directional control of frequencies above 100hz. Since most arrays are not that long though, 200hz is about the practical limit where some control can be achieved. 

The method of beam steering, in my understanding, is that you need multitudes of drivers within a single element in order to do it with great success. Your typical 3-4 driver line array element can do it to some degree at certain frequencies, but you really need several more in order to get a more granular and effective level of control. Think of EAW's Anya rig with 70 HF drivers per element, or Martins MLA with 7 drivers in total.

FWIW - Anya has 2 x 15" + 6 x 5" + 14 x 1" per box and is a beam steer array.  MLA has 2 x 12" + 2 x 6.5" + 3 x 1" per box. It is not a beam steer array and the boxes must be arrayed as normal, it is however capable of doing some minimal steering.

[Chris Grimshaw]

True directional control occurs when the length of the array is four times the wavelength of interest.

Depends on your definitions.

An array that's 1/2-wave long, for example, will show a null at 90 degrees off-axis, pretty much by definition. That doesn't mean there's strong directional control, but some directivity is certainly being exhibited.

Chris

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