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Line Array Speakers : Modular, Expandable, Out-of-the-Box Design for in-home use

benanders

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That title…
Sounds impossible, right?
Possible, and sounds right.

The project has spanned some years of (1) excessive backlit screen reading, (2) many in-person listening sessions to diverse high end systems, and (3) defining my preferences/expectations, then pursuing them with this particular speaker model (Gallo Acoustics Strada 2) through haphazard trial and error. The system may look finished, but it’s not. So let the judgement begin on where else to begin :)
 

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voodooless

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Looks impressive! I do see issues though. Those tweeters are some 50cm apart. That will lead to massive comb filtering. Luckily the tweeter will only play above 6 kHz, making the effect less noticeable.

They are also not box free, specs of the units state:
Sealed with Auxiliary Bass Cavity Supplementation
… whatever that means.

The claim that it contains no crossover is also false. The tweeter has a bunch op caps in series, making it a 1st order filter. This makes absolute sense to protect the thing.

Tear down video. Don’t mind the guy, he’s not the brightest bulb in town:

But credit where credit is due, we also get some measurements:
Horizontal
B92FF1BB-1908-4105-9B76-F62F69BE6E89.jpeg

Vertical:
140BC0FD-9C3C-4641-B48A-3DC43B717F35.jpeg

There is a lot wrong with this…
 
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alex-z

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The inexplicable gaps between the speakers, and vertical orientation is costing you a great deal of the directivity that actually qualifies a system as being a line array.

A good design has the high frequency drivers grouped as tightly as possible, flanked by another column of mid-range drivers, flanked by low-frequency drivers. For example, the Infinity IRS V.

Not having a crossover is an outright lie. Without one, you would damage the high frequencies drivers almost immediately, and the directivity would be an absolute mess.


-------

Technical facts aside, I don't understand the point of a line array in a home. If you dislike the room interaction characteristics of a monopole speaker, why not use a dipole like the Linkwitz LX521.4? Using a line array in a closed room is like deciding you wanted the room painted but opted to do so with water balloons.
 

BDE

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benanders

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Impressive, do you have inroom measurements?
First and simplest question is also one of the best possible - thank you.

Answer is: sort of. A friend took measurements - frequency response (not flat, no surprise), and a couple others but the analyses were Chinese software I’ve not heard of, let alone implemented, so not of great comparative value for me and needing follow-up with software I can make sense of.
 
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benanders

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Looks impressive! I do see issues though. Those tweeters are some 50cm apart. That will lead to massive comb filtering. Luckily the tweeter will only play above 6 kHz, making the effect less noticeable.
Tweeters ~35cm apart. Monitor spacing based on designer’s advice and my calculations of dispersion angles/intersects. It’s not perfect, but it’s also not something that went unaccounted for during planning.
They are also not box free, specs of the units state:

… whatever that means.
Fair technicality. Thread title edited accordingly since I meant to imply no need for one big cabinet.
The claim that it contains no crossover is also false. The tweeter has a bunch op caps in series, making it a 1st order filter. This makes absolute sense to protect the thing.
Another fair technicality. I think of XO’s as 2+ way filters vs. here, just a high pass filter. But given the additional low pass filter over each sub, and lacking expertise in electrical engineering terminology…
Thread title edited accordingly.
Tear down video. Don’t mind the guy, he’s not the brightest bulb in town:

But credit where credit is due, we also get some measurements:
Horizontal
View attachment 243016
Vertical:
View attachment 243020
There is a lot wrong with this…
Well-chosen link. Glad I had Strada 2’s years before he posted his vids, I may have steered clear based on the test results.

TBH, I’ve never known how to reconcile those NRD vid results vs. real-world performance without dismissing empirical tests’ value, as applied to Gallo speakers.

The shift in “handover” (okay, okay, CROSSover… grin) between woofers-tweeter from ~2500 Hz (Strada) to ~6,000 Hz (Strada 2) was something that made no sense to me, given the ~3.5”+ spread between paired transducers responsible for every wavelength up to 5.9 kHz.

Theoretically, that should sound disastrous.
But realistically, it does not, and in fact opinion sounds quite the improvement.
So far, that subjective improvement transfers to the lines.
 
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benanders

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what the size of tje listening room ?
Roughly 30 x 14 x 12’, L x W x H. Additional open space left / behind photo angle.
In-room features amplify both pros and cons of the approach.
Picture’s worth at least a thousand words in this case.
 

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Roughly 30 x 14 x 12’, L x W x H. Additional open space left / behind photo angle.
In-room features amplify both pros and cons of the approach.
Picture’s worth at least a thousand words in this case.
Ok I see ... The concept of line array is to have an ellipse shaped global front wave instead of a sphere shaped one , long story short the result is that the level diminish less with distance when using a line array arrangement. The main goal was to have en even volume distribution for the audience , no need to explode front rows ears for the last row to have enough volume. This come at a cost. As a line array is composed a line (or curve) of diaphragm, phase intermodulation of emitted waves from each speaker happens. The results is an uneven coverage in frequencies all across the listening area. The constructors have developed numerous techniques trough the years to minimize this problem with waveguide shapes and introduction of delays.
I don't see the point of a line array in such a small room. Try measure your FR at different points you will see the problem.
 
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benanders

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Your concerns are understandable. I knew of that link; others better address LA’s in home use / hifi.


The inexplicable gaps between the speakers, and vertical orientation is costing you a great deal of the directivity that actually qualifies a system as being a line array.
The gaps are explicable. Inexplicable suggests a query was made and no answer was available ;)

The vertical orientation is also by design, and assuredly not beyond what qualifies a line array.

A good design has the high frequency drivers grouped as tightly as possible, flanked by another column of mid-range drivers, flanked by low-frequency drivers. For example, the Infinity IRS V.
You are making assumptions about tweeter directivity that don’t always apply. However, you’re not incorrect about conventional line array format.

Not having a crossover is an outright lie. Without one, you would damage the high frequencies drivers almost immediately, and the directivity would be an absolute mess.
Lie’s a strong word, and implies intent to deceive. Although I didn’t consider a high pass filter to be a XO, fair enough - thread title now reflects proper terminology / mob rule :)

-------

Technical facts aside, I don't understand the point of a line array in a home. If you dislike the room interaction characteristics of a monopole speaker, why not use a dipole like the Linkwitz LX521.4? Using a line array in a closed room is like deciding you wanted the room painted but opted to do so with water balloons.
Re: using Linkwitz LX521.4:
Cool speaker.
But even ignoring all but any one goal of my project, it doesn’t tick a single box (pun!) I wanted.
I disagree with your analogy, but did have a chuckle at the idea of Jackson Pollock designing speakers.
 

Rja4000

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The main goal was to have en even volume distribution for the audience , no need to explode front rows ears for the last row to have enough volume.
And, especially, to allow (financially interesting) very large audience with decent (enjoyable) sound level for everyone, while respecting the very strict maximum SPL regulations (originaly 105dB SPL at any place in the venue for 15 minutes in France, as an example - now reduced to 102dB)
 

voodooless

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Tweeters ~35cm apart. Monitor spacing based on designer’s advice and my calculations of dispersion angles/intersects. It’s not perfect, but it’s also not something that went unaccounted for during planning.
That will give a lot of lobing:
1668415793568.png
 

Wesayso

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Technical facts aside, I don't understand the point of a line array in a home. If you dislike the room interaction characteristics of a monopole speaker, why not use a dipole like the Linkwitz LX521.4? Using a line array in a closed room is like deciding you wanted the room painted but opted to do so with water balloons.

If you would think a little harder, a line array concept in a home might make a lot more sense than you suggest here. Harman curves are the hot thing here, lets see what a line array can do in-room (see middle left graph):
25x 10F.png


Granted, this is a frequency shaded array with closer center to center spacing than the OP has. But still, it's a line array designed for in-home use and the DI and Power response should give you pause and make you think about your statement a little more.

What we see is that horizontally it has a CD like coverage, due to using 3.5" drivers in the array. Vertically it is like a beam of sound. except for a few lobes on top, as these are the result of the specific center to center spacing of this particular design. The result? Very even coverage over a wide area (that's what that Power & DI graph is trying to tell you too) and even over a large enough area to cover seated and standing, while almost totally avoiding floor and ceiling reflections.

Did you notice to what frequency the beam control spans? What size horn could give you that kind of behavior? Which is another plus for the array in a home, space saving. Would you believe this speaker fits on an A4 size paper?

Let's see an in-room prediction of a single 3.5" driver vs an array of 25x 3.5"drivers and the influence of floor and ceiling of both inside a room, horizontally, they will have the same coverage pattern...
singlevsarray.gif

Do I need to explain which graph is which? Or is it clear that the array is the one with more output.

Exactly the same setting on floor and ceiling absorption. I do realize this might not convince you right away, as it goes against that "painting with water balloons" idea, don't it?
But maybe, just maybe, it will make you think a little harder about the usefulness of arrays inside a home. I hope you get that message loud and clear, as that is what arrays sound like, in a home :D.

It should make you think about your attitude, barging in on a post/thread made by the OP, that clearly was made out of sheer enthusiasm, with all that negativity. It could have been brought with a little more tact, and quite frankly, with a better understanding of the use of arrays in a home.
 
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