Concrete Cube

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jimbob
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Re: Concrete Cube

Unread post by jimbob » Tue Jun 11, 2019 6:20 pm

I think this idea is deserving of its own thread...
Squeezebox Touch - Colin Wonfor mini pre - EWA M50 Power Amp - Modified NVA Cube 2 mk1 - SSP MK2 - LS6

NVA P90sa - NVA A60 MK1 - DIY Cubettes - SSC - LS3

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karatestu
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Location: North Yorkshire
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Re: Concrete Cube

Unread post by karatestu » Tue Jun 11, 2019 7:53 pm

jimbob wrote:
Tue Jun 11, 2019 6:12 pm
I’m thinking 355mm mdpe gas pipe. Wall thickness of approximately 20mm. Capped off at the bottom with 25mm plywood. A plywood insert at the top with a cut out for the bass driver. I haven’t decided on the length of the tube yet. A hole cut in the front for the tweeter and one in the side for the midrange.
I came up with a cylinder idea and doc poo pooed it. Said he had tried it and was awful.

Anyway cutting holes in cylinders is not easy.
DIY inspired by Richard "The Doc" Dunn RIP

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karatestu
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Re: Concrete Cube

Unread post by karatestu » Tue Jun 11, 2019 7:55 pm

jimbob wrote:
Tue Jun 11, 2019 5:33 pm
Have you heard the bbcube to determine how that affects the midrange driver?
I haven't heard the BBC's only my version of it with mid in it's own box.
DIY inspired by Richard "The Doc" Dunn RIP

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karatestu
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Re: Concrete Cube

Unread post by karatestu » Tue Jun 11, 2019 8:03 pm

jimbob wrote:
Tue Jun 11, 2019 6:07 pm
Also, how cube does the cube have to be? I’m pretty sure an upward firing driver would also work in a rectangular box too??
I tried the 12 inchers in a marantz cab and the bass was overblown on certain cd's with very low bass (Portishead, Jamiroquai etc). The driver was in the front baffle and right at the bottom. Cab was not so deep and quite high. Volume about 45L. I was going to try a clamshell isobaric arrangement with those cabs but never got round to it.

Soon as i made a cube of eighty odd litres it was fine. When i turned those into isobaric i simply divided the enclosure into two equal parts. So the drivers are no longer loaded by a cube but a cube cut in half. There are no problems with this arrangement, in fact they are amazing. Without a doubt the most pleasing speakers i have ever heard.
DIY inspired by Richard "The Doc" Dunn RIP

jimbob
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Joined: Wed Sep 26, 2012 8:35 pm
Great Britain

Re: Concrete Cube

Unread post by jimbob » Tue Jun 11, 2019 8:18 pm

Interesting... if I can get the mdpe tube for a reasonable enough price then I will give it a go anyway, just to scratch the itch! I would really like to hear some isobaric speakers to see what the fuss is about
Squeezebox Touch - Colin Wonfor mini pre - EWA M50 Power Amp - Modified NVA Cube 2 mk1 - SSP MK2 - LS6

NVA P90sa - NVA A60 MK1 - DIY Cubettes - SSC - LS3

Daniel Quinn
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Wales

Re: Concrete Cube

Unread post by Daniel Quinn » Tue Jun 11, 2019 8:23 pm

I've come to the conclusion that 2 bass drivers on the front baffle are better than isobarik configuration, but I await your findings with interest.

jimbob
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Re: Concrete Cube

Unread post by jimbob » Tue Jun 11, 2019 8:25 pm

Dan, what is it that you prefer about two front baffle mounted speakers?
Squeezebox Touch - Colin Wonfor mini pre - EWA M50 Power Amp - Modified NVA Cube 2 mk1 - SSP MK2 - LS6

NVA P90sa - NVA A60 MK1 - DIY Cubettes - SSC - LS3

Daniel Quinn
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Joined: Thu Jul 12, 2012 7:16 am
Wales

Re: Concrete Cube

Unread post by Daniel Quinn » Tue Jun 11, 2019 8:30 pm

More of everything. 2 doped bass drivers in series. I love the way it sounds.

Currently, I'm using celestion Ditton speaker boxes, but I have a sneaking suspicion that deeper boxes would be better.

jimbob
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Re: Concrete Cube

Unread post by jimbob » Wed Jun 12, 2019 5:41 am

Do you prefer the presentation of point and squirt over semi omni regardless of the number of drivers?

I think some custom built boxes would give you improvements.
Squeezebox Touch - Colin Wonfor mini pre - EWA M50 Power Amp - Modified NVA Cube 2 mk1 - SSP MK2 - LS6

NVA P90sa - NVA A60 MK1 - DIY Cubettes - SSC - LS3

Daniel Quinn
Posts: 7624
Joined: Thu Jul 12, 2012 7:16 am
Wales

Re: Concrete Cube

Unread post by Daniel Quinn » Wed Jun 12, 2019 7:54 am

I've got Bay windows and high ceilings, both mitigate against omnidirectional.

Also, only I listen in a particular seat, so again omnis are mitigated

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