Full range line array

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from my other thread, it looks like i will buy my crossover components for my other project from america, madisound looks best.

and i was thinking as i am already getting stuff from there, should i get some other things while i am there aswell, and seeing that they have some very cheap drivers there that i could get for a line array.

it would be used at home (as i am uni with my tannoy cheviots) and wont need to go all that loud, was looking at....

Foster 5.25" wide range (up to around 5khz) $3! (say 8 per side and get a seperate tweeter)
HiVi B3S 3" $9.55 (4 per side)

would this be a good idea.

And this is not another one of my 'crazy' ideas :D

Thanks :) :smash:
 
A while back Parts Express has a deal on Pioneer 4 "
for 50 cents USd each.

At that time Bill Fitzmaurice put together a project
for those which he may still have at

billfitzmaurice.com

I bought int o the deal and got 16.

But I have only one completed box wired to the
specification but no tweeter treatments.

A bit of a discussion on my build is over in the
full range driver forum:

http://fullrangedriver.com/forum/viewtopic.php?id=1136

That build was slow going and just recently got it stood up and
playing. So I'm interested in tips for line arrays.

I had questions in the thread about box volume but also
wanted to do minimal cutting on some reused pieces to retain
some round over corners. I'm doing a/b comparisons with
a BIB as I write during a radio broadcast.

At this stage of things the BIB has it all over the line.
The line takes more volume to get going too.
 
Intresting...OB line array.. with bass augmentation...mmmmm I am thinking on this also.. Can you curve the top & bottom forward to reduce combing effect..? seems I Have seen this before on arrays..I have a spare ribbon pair that I could also use in the project.. just need to figure out which drivers to use..& get to 150-180hz
 
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Joined 2005
Hi guys,

Please remember, if you do a closed or vented box, each driver should have its own seperate chamber, or maybe better split up in sections - otherwise you will get a nasty low end ressonanse, related to the tall box

Maybe three sections, with top and bottom tilted/slanted(?) forward

just my 2cents, good luck:)
 
adason said:
hi loninappleton,
my line array has no box, its open in the back
you are not going to get much bass out of 4" speaker anyway
why not open baffle line array
with subwoofer


I had the original arrangement on a board but it was difficult to
move around. The box is less delicate and is still an experiment.
And heavy. I have no idea how Fitzmaurice jacked his line arrays
up by the ceiling. His arrays (the original ones with the cheap drivers and tweeters) were in a V shape box open at the top like a BIB to pick up bass from the wall in a backhorn design.
 
Ex-Moderator R.I.P.
Joined 2005
And why they use FRS8 M, and not the FRS8 8/4

FRS8 seem to have a rise below 500hz (BSC?), but also less sensitivity


edit, yes I see, FRS8 M has Qt=0.58 and FRS 8 has Qt=1.04

FR8 M have lower mass and (I)mH and strongest magnet


Still, I would like to hear that "computer" HiVi A2S
 
I could live with it a little more if does have some tweeters on the back, but I still reckon this a poor implementation. I'm not convinced about the idea of an array of WR drivers on the front of a box with rearward firing tweeters as it's not going to work in quite the same way as a nearfield array should. And the WR drivers on the front are still spaced far too far apart for my liking, even with HF support. They must be corssed over at some seriously low frequency.

For the lowdown on the nearfield line array, you need the line array white paper by Dr. Jim Griffin (a frequent poster here): http://www.audiodiycentral.com/awpapers.shtml

Briefly, the issue I raised above (comb-filtering) is caused by the centre-to-centre spacing of drive-units. When the distance between the driver centres passes 1 wavelength of the highest frequency to be reproduced by said drivers, unpleasent things start to happen. Jim's aforementioned paper goes into this in considerable detail which I won't repeat here -suffice to say the result is severe attenuation of higher frequencies and severe ripple in the response. Arrays with FR drivers alone doth not a good idea make, even with major Eq. You can reduce the problem by curving the front baffle into a concave shape, to create a focused array, but these are not the same as a nearfield array, and throw away several of the benefits of an array in the first place, such as a gigantic 'sweet area' rather than a very specific 'sweet spot' for stereo imaging.
 
If I remember right they EQ the top end. What dodn't understand is the c-t-c spacing is too large to push the combing into the range where it is less audible and too far apart to get a really good high crossover point. For adding a tweeter. The other thing that bothers me is why not add a really sensitive tweeter. You might end up with a sweetspot for the highs but at least you'd have highs.
 
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