Concrete line arrays

[Afflicted]

Well after 4 months of hard work, hard lessons and lots of skinned knuckles there finished. 650 lb monster line arrays

 

[Tadeusz]

Were they worth the weight?

 

[Max Headroom]

So the rowing machine is for warming up before attempting to adjust the speaker placements ?.

 

[djn]

Tell us more about the build? Good idea putting the tweets in front of the woofs. Did you have to do time alignment?

 

[Afflicted]

Well, they sound fantastic IMO.

There are 9 Peerless 830869 x 8” wired 3x3 to hold 8 ohms. The ribbons are Newform Research. Bryston 10Bsub sends everything 80hz and below to a twin 15”’ sub. The line arrays are passive x-overs at 1200 hz achieving an acoustic x-over at about 2000 hz. The x-sexction of the speaker is a half ellipse 18” x12” (major/minor). The concrete is 2” thick with 7 vertical post tensioned tie rods to 150 ft lb. Some more pictures to follow. Inner baffle is 3/4” Baltic birch with 1/2” thick 6061 aluminum on outer baffle. Packed with sheep’s wool. Concrete was polished but then I ended up coating in black epoxy.

 

[Afflicted]

DJN, no time alignment ( don’t know if I would no how). John Meyer of Newform Research has made similar configurations with the ribbon placement. Seems to work just fine

 

[6thplanet]

Dang, that's some real dedication. Good job

 

[planet10]

I’ve long had thots about using the Newform Ribbons with some Accoustat panels for lower down.

They can be used as low as 1k can’t they?

dave

 

[adason]

Well after 4 months of hard work, hard lessons and lots of skinned knuckles there finished. 650 lb monster line arrays

Why are they sideways?

 

[Juhazi]

Why are they sideways?

Canada?

 

[Afflicted]

I’ve long had thots about using the Newform Ribbons with some Accoustat panels for lower down.

They can be used as low as 1k can’t they?

dave

Yes I’m told they can. John Meyer recommends 1st order x-over at about 1200-1500 as he says below 1000 they roll off rapidly

 

[Cal Weldon]

Why are they sideways?

Just lower the arms on your chair and cradle your head in your left hand.

 

[Cal Weldon]

hehe, They may have been taken on a phone vertically, and auto corrected by the forum to be uploaded as portrait?

 

[HammerSandwich]

Why are they sideways?

He hasn't completed his DIY forklift.

 

[adason]

All jokes aside, i once made a subwoofer out of concrete. Actually, it was two subwoofers together in one box, each side had two 10" isobaric arranged woofers. Total of four woofers per sub. It took two people to move it. Its still in use, for some 20+ years, by my brother.

 

[Afflicted]

All jokes aside, i once made a subwoofer out of concrete. Actually, it was two subwoofers together in one box, each side had two 10" isobaric arranged woofers. Total of four woofers per sub. It took two people to move it. Its still in use, for some 20+ years, by my brother.

He who laughs first laughs last. The boxes can not resonate. The sound is incredible. And yes, twin concrete subs are on the drawing board.

 

[djn]

Some time ago a gent here build a sub-woofer using a concrete industrial wash tub. I thought it was a great idea but zero wife appeal.

 

[thecj]

Wow, hope there is enough support under the floorboards! These sound like they would warp the base boards with that much weight in one point.

 

[Afflicted]

Wow, hope there is enough support under the floorboards! These sound like they would warp the base boards with that much weight in one point.

Not really, they sit on 2” swivel feet on composite flooring on top of concrete slab. Yes they have low WAF but some does everything down in my man cave, key word MY.

Also if you look around at some of the bigger wooden speakers out there such as Montanas or Monitor PI 500 they don’t weigh a whole lot more.

All I can say is after all this work I’m glad they sound fabulous

 

[audiogod66]

I agree many years ago I got roped in to help move a set of those Montana monsters and you only do it Once ! How do the Newform ribbons sound? Do you think they are superior to normal quality tweeters?