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Vifa two way [message #14619] Mon, 07 June 2004 17:35 Go to next message
GGeorge is currently offline  GGeorge
Messages: 4
Registered: May 2009
Esquire
Hello all, I'm thinking about building some line source speakers for left and right and smaller sealed two way speakers for center and surrounds. It would be really great to use the same drivers in both. I haven't decided ribbon or dome but for the small speakers, I'm thinking of something like a small sealed box with Qtc of 0.7 and drivers mounted in vertical alignment. 12dB crossovers with impedance compensation. Doesn't seem too difficult to get a speaker like that very right. See any downsides?

Re: Vifa two way [message #14620 is a reply to message #14619] Tue, 08 June 2004 08:20 Go to previous messageGo to next message
Bill Wassilak is currently offline  Bill Wassilak
Messages: 402
Registered: May 2009
Illuminati (1st Degree)
Go over to the array speaker section here and ask Jim Griffen, he'll be able to anser questions about line arrays for home. Also see message at

http://www.audioroundtable.com/ArraySpeakers/messages/26.html

You can see some of the line arrays he builds, your biggest problem with line arrays that I see is getting the mid and tweeters close enough to together so you don't get comb filtering problems.

HTH
Bill W.


Re: Vifa two way [message #14621 is a reply to message #14620] Tue, 08 June 2004 13:37 Go to previous messageGo to next message
Bill Fitzmaurice is currently offline  Bill Fitzmaurice
Messages: 335
Registered: May 2009
Grand Master
I've just finshed a line array TL using eight fours per side in a three foot box. Qts .77, Fs 105 Hz; they are very linear from 100 to 6kHz. They also cost $0.87 each. When it comes to arrays don't waste money on expensive drivers.

Bill's correct about the spacing; you can't have wide tweeter frames. I used a dozen 3/8" domes per side that were frameless round jobbies that I glued into holes in the baffle, so the dome to dome spacing came in at about an inch, which is good to about 10kHz for wavefront integration. Above that they comb, but only on the vertical plane of course, so that's a minor concern. BTW, they cost me $0.27 each.

These speakers cost me less than $60 for the pair, lumber included, and they sound quite literally like a thousand bucks.

Go with no less than 18dB slopes. Assuming the midwoofer and tweets are in lines that are side by side keep that distance as tight as possible and you need at least an 18dB slope to minimize crosstalk between the elements which would lead to serious combing on the horizontal near the crossover frequency.

Re: Vifa two way [message #14622 is a reply to message #14619] Wed, 09 June 2004 06:02 Go to previous messageGo to next message
Ben is currently offline  Ben
Messages: 6
Registered: May 2009
Esquire
Well, one thing you might consider is intermodulation. Back in the day, you had speakers that never saw 100 watts and excursion of a quarter inch, max, peak to peak. Intermodulation distortion wasn't such a big deal because the cones weren't moving very far. Many new small frame woofers are made to allow much more excursion, and that spells trouble for midrange if you push them hard. Think about it.

Re: Vifa two way [message #14623 is a reply to message #14621] Wed, 09 June 2004 23:40 Go to previous messageGo to next message
Adrian Mack is currently offline  Adrian Mack
Messages: 568
Registered: May 2009
Illuminati (1st Degree)
Have you got any pictures of that line array Bill? I would like to see them!

What sort of output could you get from this line array? Most of the

Re: Vifa two way [message #14624 is a reply to message #14623] Thu, 10 June 2004 05:19 Go to previous messageGo to next message
Bill Fitzmaurice is currently offline  Bill Fitzmaurice
Messages: 335
Registered: May 2009
Grand Master

These Onkyo tweeters are rated at 20w, so with 12 per side they're quite adequate; the same for the 15w midbass with eight per side.

line array [Re: Vifa two way] [message #14625 is a reply to message #14624] Fri, 11 June 2004 14:29 Go to previous messageGo to next message
lon is currently offline  lon
Messages: 760
Registered: May 2009
Illuminati (2nd Degree)

This looks like a good use for my fly cutter.

Will details be in _aX_?


lon (who still has all ten fingers)



Re: line array [Re: Vifa two way] [message #14626 is a reply to message #14625] Fri, 11 June 2004 15:19 Go to previous messageGo to next message
Bill Fitzmaurice is currently offline  Bill Fitzmaurice
Messages: 335
Registered: May 2009
Grand Master
Yes, but I just finished the speakers and haven't written the project up yet, so I doubt it will see print before winter. A fly cutter or hole saws are a must with all those holes to cut.

Re: line array [Re: Vifa two way] [message #14627 is a reply to message #14626] Fri, 11 June 2004 23:12 Go to previous messageGo to next message
lon is currently offline  lon
Messages: 760
Registered: May 2009
Illuminati (2nd Degree)

I noticed you cut holes in a lot of stuff like the Tuba
project.


So if I could draw in some remarks that TC had
about approaches to audio, do you see any of these
Tuba designs and Array designs coming together as a
complete solution or are they just discreet ideas?

I am still thinking back to the Snail designs of
yore and wonder if anybody ever built them (?) Or maybe
just for professional concert use. I liked the concept
for its complexity and elegance but it never has become
part of the vocabulary of the hobby... or has it?




Re: line array [Re: Vifa two way] [message #14628 is a reply to message #14627] Sat, 12 June 2004 07:45 Go to previous messageGo to previous message
Bill Fitzmaurice is currently offline  Bill Fitzmaurice
Messages: 335
Registered: May 2009
Grand Master
I cut holes in internal parts for a variety of reasons. The primary one is to reduce internal reflective surfaces, the secondary to reduce weight. In the Tubas holes in the cross braces are necessary for an unimpeded sonic pathway across the horn.

My current home hi-fi setup of a Tuba 18 sub with TLAH mains (Transmission Line Array Horn) takes advantage of the respective merits of each concept. The end result of full spectrum 99dB sensitivity with minimum size and cost is one that I'm quite pleased with.

With the exception of Snail III all those boxes were pro-sound oriented, as are my DR horns. I'm aware of some people using Snails and DRs in the home, but the designs are less than ideal for that, which is why I came up with the TLAH.

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