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robtr8

Bored.

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robtr8

<iframe width="560" height="315" src="http://www.youtube.com/embed/6J_AUBT-PAo" frameborder="0" allowfullscreen></iframe>

I need a project so my mind has run amok.

My detailer trash picked a set of 901's from a client. Even at Parts Express' price for replacement drivers I'm not sure they are worth resurrecting for anything other than mid-century modern plant stands. But they got me to thinking about the 802's possible use as a tower speaker. Except for the fact that they're overpriced, ugly and require a special 120 volt EQ, I think they "could".

So I contracted with Pete at PWK to design a line array box with a similar idea but a more thin (single row of drivers), wide and deep enclosure. He recommended using 4 Galaxy Audio S5N-16 drivers. And that's as far as I've gotten. Pete's got my fee, I can't wait to see what he comes up with.

Edited by robtr8

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Earmark Marine

robtr8,

Okay, I'm just as bored so I'll play along....which won't be hard since it's one of my favorite subjects.

Look, the Bose 901 is not an esoteric speaker by other standards. However, if I had a very large game room where I'm never positioned in that perfect sweet spot and I want the ultimate ambient speaker, I would take four Bose 901s over just about anything. You can use them on their stands or suspend them from the ceiling. Placement from the back wall and outside walls is important. From there they will create a false but super wide, larger than life, image across the entire wall. Now, they can't produce an authentic 30 Hz to 20 kHz bandwidth with only nine of the same single-way 4.5" drivers (no tweeters). But if you aren't in the hyper-critical listening mode, then they do an incredible imitation.

David

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robtr8

OK, I'll fix the 901's. And source an EQ off eBay. And hang them from my back porch and blast Porqupine Tree upon the idiot golfers.

What are your thoughts on a line array tower speaker thingy?

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Earmark Marine

OK, I'll fix the 901's. And source an EQ off eBay. And hang them from my back porch and blast Porqupine Tree upon the idiot golfers.

What are your thoughts on a line array tower speaker thingy?

robtr8,

I don't do home audio anymore other than a hobby. I have no experience or knowledge of the Galaxy speakers. The Neo and cooling system certainly looks awesome. But, I only know what I read in the specs. If you are thinking of how Bose 4.5" speakers are used then keep in mind that the Bose 901 speaker has an Fs of 83 Hz and the Galaxy has an Fs of 140 Hz. So that makes the Bose a fullrange speaker with midbass capabilities and the Galaxy more of a midrange speaker. Plus, Bose uses a proprietary EQ, waveguides (transmission lines) and bass-reflex to extend the low frequency production and tap the max from these little drivers. But you cannot cheat much below the resonance a speaker can play no matter how skilled you are at enclosure design. That would be my concern and that is the main question I would ask.

David

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robtr8

I did wonder at the Fs as well. I just shot an email off to Pete asking about using Scott's Imagine drivers in 5 1/4" with the phase plug. Seems like that would keep decent power handling, extend the range a bit lower and gain an all weather cone.

He just got back to say Hybrid's components are optimized for nearfield performance. He's been happy with the Galaxy's for PA applications. He explained that Fs is simply the point of peak electrical impedance and doesn't constitute a high pass limit. I learned something new today.

Edited by robtr8

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robtr8

Design is in. Pete describes it as a compound horn with bass reflex. The design parameters were for a 90 Hz to 12k Hz response using a single driver. I've been pondering the construction. Even though I asked for a line array 40" wide I'm now thinking I could do this 2 cells wide by 2 cells deep and use common walls, should reduce the weight. I looked at core materials from Jamestown Distributors but 3/4" end grain balsa or Core-Cell is pricey. The biggest challenge will be having it not look too "home built". Keeping the spiders and birds out might be fun as well. $65 design, $60 sheet, $200 in drivers. Nice project to get me to March.

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Edited by robtr8

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Bozboat

Wow, a complete thread written in a foreign language

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RTS

And all to wreak havoc on those pesky golfers....

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Steve B.

If you go two wide and two tall, you may lose the benefits of a line array. (rather than 4 tall). And you want the line array for distant throw with good volume?

Steve B.

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Earmark Marine

A line array would have several properties.

When the array diameter is appreciably shorter than the wavelengths being produced the collected multiple speakers will tend to compound load similar to speakers against a wall that are boundary loading. It's not major but there is something to it. A tight square pattern would be superior to a line in this respect.

A horizontal line array will exhibit good verticle dispersion but will create narrower dispersion and cancellations off-axis in the horizontal plane due to comb filtering. A verticle line array will exhibit the inverse properties. When the speakers are in a wide fanned pattern then the dispersion is broadened and the negative comb filtering effects are minimized.

All relevant in open Prosound applications with suspended speakers. On a boat, you generally have to take what the tower gives you and like it.

David

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