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-   -   New Line Array design with Aurum Cantus Drivers (https://www.avsforum.com/forum/155-diy-speakers-subs/1029299-new-line-array-design-aurum-cantus-drivers.html)

Andrikos 05-14-2008 09:38 AM

Alright, after 4 years of living with my line arrays and loving them, it's time to make another pair and send the old ones to the back as surrounds.

Before I start with the new design, let me briefly describe the 1st line array design:

Drivers:

8 x Vifa PL19W09-04 for midwoofs,




6 x BG Neo8 PDR for tweeters





(bass is sent to a 16c.f. 600lb sealed "coffee table" sub with 2 15" Atlas sub drivers. Each sub is driven from each of the stereo channels.




Xover: Behringer DCX2496 (LMHLMH). Always meant to modify this with OPA627s and BB DACs but never got around to it... Xover f = 80Hz, 2kHz slope + 3rd order linkwitz riley.

Enclosures: 1.5" thick all around. From outside in: 13-ply Baltic Birch plywood - dynamat - MDF - stuffing. Sealed ~1.5c.f. internal volume, 150lbs each.









Amps: Mids and Tweeters are powered by 4 Parasound HCA1000s. Each amp is bridged to a single side (MHMH). 2 x Crown XLS602s with fan mod and various other power supply, driver stage and output stage mods. 2 channels bridged for each sub driver (LL).

Room: 18 x 40 x 9 home theater with moderate sound treatments (still have a lot of work to do) with a 720 DLP projector and a High Power 133" screen.
Seating for 10 people, coffee table in the middle of the room. I need an IB setup just for LFE from receiver. Right now, the bass comes from the stereo channels. The bass is excellent but there's always room for improvement. The subs are set to low Q and I've measured 110dB from the seating position at 20Hz (room gain included). I don't remember the #s for lower frequencies but IB will be used to fill them up.

Speakers are ~4ft from back wall, ~3ft from side wall, flanking the screen (about 1' in front of the screen). They are 5' tall (that's how long the Baltic birch plywood sheet is). There's no center speaker, I'm using the "phantom center" setting from the receiver and it works great, the soundstage is huge with line arrays. The tweeters work as dipoles and the midwoofers are sealed. I find this combination very good. The front wall is covered with heavy-thick drapes which helps diffusing the sound but not dulling it. The whole room is fully carpeted with thick pads and the side walls are also covered in thick drapes.

ScottS 05-14-2008 09:46 AM

Sounds interesting. I'll be following your progress!

Andrikos 05-14-2008 10:11 AM

New Design:

I will stick to a sealed line array design but this time the ribbon tweeters will be monopoles instead.
I may or may not design a center speaker (with same drivers) that will suspend from the ceiling (on top of the screen) and point to the primary seating position.

Drivers:

Midwoofers:


8 x Aurum Cantus AC-130F1s. Carbon fiber / polypropylene composite. These drivers are wide bandwidth (7kHz) and have a very smooth midrange. There is a 2dB dip at around 4kHz but otherwise very flat. I find them very fitting for what I want. They will give me flexibility in Xover f point and slope.

Tweeters:


6 x Aurum Cantus G3 Si. Silky smooth sounding ribbons with xover point at around 2.5kHz and up.

With the above driver combination I have the luxury to move the xover point by at least an octave.
I'll experiment in my room until i hit the sweet spot.
You can't do that with passive crossovers unless you have the patience of a camel and $$$$ of R L Cs laying around...
Active crossovers are unbeatable in that respect.

Amplification:

This is where I'm venturing into new ground: Class D amplification.
I'm planning to use Hypex UCD modules



for each tweeter and midwoofer line.
This is just at the beginning of my research so my plans may change multiple times...
I was originally planning to use some TPA3106D1s for each driver but the whole module design and power supply design would become exceedingly complex before long. I'd like to focus to speaker design and not amp design at this time.

Enclosure:

Hmmmm... do I go the classic MDF route or do something really out there?
Internal volume is not that critical since I'll be crossing over at 80Hz anyway and the cabinets will be sealed.
I may do something crazy like a fiber glass enclosure with sound absorbing foam and stuffing.
http://www.soundprooffoam.com/acoust...d%20Absorption
This is still up in the air and will be an interesting exercise in organic design.

Crossovers and Parametric equalization:
I intend to buy another DXC2496 but this one I'll fully modify before using.

These are my thoughts so far, I'll be posting more (with pics) as the project moves on.

Looneybomber 05-14-2008 10:14 AM

Pictures of old line array's? This AC line array sounds a bit more expensive than your last proposed plan And you may want to reserve a couple spots just in case.

Andrikos 05-14-2008 10:51 AM

LB, click on my .sig link and you can see pics of the line arrays and the sub too.

It's quite a bit more expensive but I may have found a driver source that is way cheaper than Parts Express. Keeping fingers crossed.

jholtz 05-29-2008 05:45 AM

Interesting. Your linearrays sound similar to mine.

My linearrays are a custom design by Selah Audio that uses Fountek ribbons and Aurum Cantus AC130 MKII woofers which are a carbon fiber/Kevlar blend cone design. They are very detailed and extremely dynamic.

Jim
LL
LL

AlexE 05-29-2008 05:44 PM

This is my dream come true, please finish this before long

I keep kicking something like this around... Making a center would be 1/3 as much work so I figured I would run it in phantom like Jholtz. I do that now anyway.

jholtz 05-30-2008 09:35 AM

Quote:
Originally Posted by AlexE View Post

This is my dream come true, please finish this before long

I keep kicking something like this around... Making a center would be 1/3 as much work so I figured I would run it in phantom like Jholtz. I do that now anyway.

Actually, I prefer HT with a center channel even with the linearrays. The sweet spot is much wider with the line arrays and phantom works OK but a center is better on home theater, IMHO. I'm strictly 2-channel for music however.

Jim

AlexE 05-30-2008 12:55 PM

Quote:
Originally Posted by jholtz View Post

Actually, I prefer HT with a center channel even with the linearrays. The sweet spot is much wider with the line arrays and phantom works OK but a center is better on home theater, IMHO. I'm strictly 2-channel for music however.

Jim

Well given something that can match my mains I'd do it also. imaging gets a bit lost for other seats in the room because I'm lacking a center, but until I move (soon) I'm not too worried.


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