Zarathu's Line Arrays

JinMTVT said:
I don't believe that 2 different drivers can do different jobs and both be perfect ..

Current loudspeaker technology is maybe 10% of the way to perfect ... it is perfectly feasible to pick 2 different sets of perfectly valid trade-offs, get an excellent speaker and have them sound quite different

there is only 1 perfect solution ..a

With current technology there isn't anything that is anywhere near close.

Building line arrays with expensive drivers that would need to be 1.5m + high will get expensive very very fast

It sure is -- at least you could forget about a centre channel -- not needed and won't fit. 1st a line array should aim at being floor-to-ceiling ... shorter is a practical compromise. And to get the best drivers to do such a thing would be very expensive... you would need 2 or 3 long ribbons (only choice because they effectively give 0" C-C spacing)... newforms probably the low end @ $2500. Then a midbass line. Fortunately the newforms (or anything better -- there are some new scandinavian ribbons i don't know enuff about) goes quite low* -- because there are no stellar 3" and the Jordan JXr3 really doesn't go low enuff. So lets choose a really good 4 or 5". My 1st pick would be Fostex F120A = $8000, add in 4 15s a side, XOs and amps to suit ...

( since alot of the high end drivers aren't better than mid packs at lower spl ..they only tend to be able to go higher in spl before running into problems.. )

not true... but you could likely get close for a lot less ... even for a 1/4 or a 1/2 of that a lot less, you can but some pretty serious drivers.

dave
 
JinMTVT said:
Dave: i like ur room drawing ..
coudl you explain the dimensions and choice of back and front angles ?

why not use a larger front wich would permit more space for drivers and screen setup ?

2nd question 1st... you don't want to put the speakers right up against the wall -- here you have 2 depressions that help, and the screen doesn't care if the wall is flat.

This is just the 1st idea that came to mind.... feel free to get your pencil out and play...

I took the larger of the 2 optimal dimension rectangular boxes i described earlier. Keep in mind that you want to retain lateral symmetry.

the only 2 walls that lend them selves to non-parallel are the side walls, i kicked them out 2 ft at one end and in 2' at the other. that gives the basic trapezoid... then i just adjusted the end walls with zig-zads -- again maintaining the average dimension...

woofer boxes, amps all fit on the outside of the wall ... probably room for a bathroom too. All woring can be left accessible as well. The space also serves a secondary function of sound isolation.
 
Home Theater

If I was in a position to build my own theater room I'd be looking at 80Hz horns with midhorn / tweeter horns above. I'd definitely use a centre exactly the same as the left / rights. I'd build a block of 4 - 6 labhorns into the back wall, and use the spare space either side to do multiple sealed 15's for the bottom octaves (20Hz down - probably use 16 - 24 drivers) Probably use constant directivity horns for the mids / tweets.

I'd run a huge perf screen in front of the whole lot so none is visible.

Surrounds I'd do something similar to the jbl synthesis dipole surrounds.

Cheers,

Rob.

Re: Zarathus line arrays. Am I right in thinking it's only a line array from 165Hz up ? If so the midbass is missing out from all the benefits of line arrays ? Surely a nice line of 10's or 12's to fill in say 40Hz - 200Hz, with the sub/s running below that would give a big improvement in the 'impact frequencies' ?
 

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RobWells said:
So thats like 'little apple' midbass with 'big watermelon' vocals ?

Could be... the system could also just be taking advantage of the way bass works in a room.... the bass being more omnidirectional and not following the -6dB / distance doubling due to the room.

The system -- for such an ambitious array -- was done on a very tight budget.

dave
 
Rob,

Surely you jest!

What size room do you think I'm in? I'm not interested in vibrating the pictures off the wall. I don't listen to any music that operates like that, nor do I wish to replicate explosions in the music room.

I have TWO 250 watt 12 inch DVC inch woofers, each with a 15mm Xmax that really move the air. They run on a 350watt/ch amp, which provides plenty of reserve power.

Technically, a line array only needs to have the c-to-c distances at 13560/distance between them to have the crossover not above that amount. If I cross at 165 they can have their centers more than 75 inches apart and still make a line array. So two would make a line array, but that would also require a 14 cu ft box. I don't have the space for a 14 cu ft box in the music room.

Believe me when I tell you that the 2 12 inch DVC woofers provides more "punch" than I need in the room.

Very very people who make nearfield line arrays use a line of woofers for a house. Its not really necessary, unless you want to spend all your time being absolutely EXACT about every statement, rather than listening to music, unless you need to replicate C-4 explosions.

Now if you are making a farfield line array, a line of woofers is completely essential.

Zarathu
 
Zarathu said:
Rob,

Surely you jest!

What size room do you think I'm in? I'm not interested in vibrating the pictures off the wall. I don't listen to any music that operates like that, nor do I wish to replicate explosions in the music room.


Zarathu

Maybe a little bit of jesting 🙂

I was thinking more about the distortion benefits that would be gained by using multiple midbass. I've heard my midbass get much more 'real' by horn loading 15's. I was assuming you'd benefit in a similar vein by using multiple 10's or 12's.

Re: the second part of the quote (about replicating explosions etc....). Well this is for home cinema where explosions seem to happen all the time😀
 
ok

so here i go ///

try and picture that

6 18" woofers in front..sealed cases built in the concrete walls ( 3 on each side..one on top of each other )

something like 12 6-7inches drivers in line array boxes on each side of the screen to get near floor to ceiling presentation of mid bass

crossed up to some distortion master ribbons
( are there any ribbons that have low distortion as the best dome tweeters? ) of a definite
( calculated total height ...probably near 48" )


Surrounds provided by 4-6 foot long line arrays consisting of the exact same setup as the 2 front

probably 2 sides and 1 rear would be enough

all close enough to listening space that all the 6 seating spaces are in the nearfield of the arrays and are not off axis enough so we maintain the FR quite ok


non uniform-trapezoidal room with serious treatments for early reflections removal ..


would that do the trick ?

more 18" woofers?


let's say i use some 50-70$ mid woofers

and some let's say NEO3-PDR 3.5" @ 45$ each


~ 48 6-7" @ 60$ = 2880$
6-8 18" @ 250$each = 1500$
~36 neo3-pdr = 1620$

probably around 500$ of stuff for enclosures and connections ..

brings me at about : 6500$ for drivers and enclosures!!!

it's not that bad!

particulary after having attended montreal's FSI show
where the 10 000$ barriere is often crossed with 250$ worth of drivers in a shiny box 😀 😀 🙄

let's hope that i can find some very good but cheap class D amps to power all of that

and seriously, i wouldn't mind puttin the loudspakers pretty close to the seating area

as i said, i have almost NO compromises
( else than total room space and a good budget! )

what do you guys think ?
 
i could also replace the ribbons by similar performing
Vifa D26NC55 ($26)
wich i can't find available nowhere
( someone should notify Zaph to put a "dicsontinued"
aside of that superb tweeter 🙁 )

i'd have almost 2 of those for the same price
even more if i could find a big "remaining" stock batch somewhere ..wonder how alot of those would perform VS the Neo3
very similar distortion and CSD from zaph's 🙂
 
JinMTVT said:
crossed up to some distortion master ribbons
( are there any ribbons that have low distortion as the best dome tweeters? ) of a definite
( calculated total height ...probably near 48" )

and some let's say NEO3-PDR 3.5" @ 45$ each

~36 neo3-pdr = 1620$

Instead of the NEO3s you should consider the newform rsearch R45 .... 1 pair would do, $1450 CAD and made in Canada, No discontinuity and an XO point low enuff to meer your biggish midwoofers)

http://www.newformresearch.com/home.htm

dave
 
i had never heard of them ..

they don't seem to provide any measurements of their products on the website..any available ?
do you have any experience with their products?

1 thing though ...
i'd be more at ease replacing 1-2 50$ defective or blow up tweeters, than 1 1000$ worth ..

i'll have children later on, and this system is going to see alot of usage and abuse over the years..
i ain't going through all this just to use it once in a while by myself!

😛

any distortion measurements on those ribbons ?
i am always afraid of the distortion on the ribbons ..
 
JinMTVT said:
i had never heard of them ..

they don't seem to provide any measurements of their products on the website..any available ?
do you have any experience with their products?

1 thing though ...
i'd be more at ease replacing 1-2 50$ defective or blow up tweeters, than 1 1000$ worth ..

Contact them -- they were very helpful when i was researching them 20 years ago...

Ribbons are usually pretty easy to replace -- it isn't a case of toss the whole thing/

And with Centre-to-centre = 0 these will go up as high as they will go... and they will go loe (for a tweeter)

dave
 
distortion usually gets bad quick at low FS for ribbons ..

i'll probably be able to drive the mids up to 2.5-3K neway since i'll have so many ( probably perform better in group at those higher Fs ...if i don't use some funky metal with uncontrollable breakups 😛 )
 
JinMTVT said:
those vifas are only 0.75" top to bottom i believe

can't find the damn specs ..

It isn't how big the dome is, it is how close together you can get them.

To be able to get too 2.5-3 kHz with the midwoofer array you need to get them to ~5" centre-to-centre... you can't do that with a 7". 16 would be an appropriate number of 5".

The newform is designed to go down to 1k with low distortion, If you cross it an octave higher the distortion is going to be very low.

dave