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Cubist Subwoofer to go with Ikea bowl Speakers - just looks wrong!

Posted 1st June 2014 at 12:20 PM by googlyone
Updated 1st June 2014 at 12:24 PM by googlyone

A while back I built some Ikea bowl speakers using Vifa bassmids and tweeters. The performance came out very good indeed, but when you are dealing with a 5 odd inch driver, there will never be masses of bass.

A subwoofer was always on the cards.

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Given the spherical speakers perched on the retro "rocket like" stands, I initially thought of doing a spherical subwoofer - but in the end concluded that while I could do this, I was looking at using fibreglass on a "fit-ball", placement in the room was looking to be a challenge.

So I chose to do the absolute opposite - and came up with an off the wall approach to a conventional sub.

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The idea was to move the implementation of a conventional sub well away from the "box with a driver stuck on the front".

I find it fascinating that by slicing a corner off a cube, you can get a triangle - which I think in this case is rather striking.

Well, in some ways it just looks wrong. But I think I like it.

There was a fair old bit of fiddling around. I started by building the cube, then literally grabbed the circular saw, set it to (in this case 54 degrees) and chopped the corner off.

Fabricating the triangular face was again more fiddling around. On the inside there is a fair bit of acrylic filler. There are braces between all the walls and across each wall.

The black material on the front of the triangular section is there to hide the surface. Initially I was thinking of getting this super smooth and painting it gloss black. I think that with an extra layer or two of bog I might have got there. What I did not have was the time - and while poking in a cupboard stumbled across a 30 year old roll of vinyl. So on it went.

The driver is a Richard Allan HP-12B, straight from the 70's. Interestingly, in this box of about 160 litres, and tuned to around 30Hz delivers a -3dB point of below 30Hz, which is pretty respectable. (the actual driver Fs is 22Hz, not 25Hz which gives a slight low end extension on the original published data for the driver).

Some of these old Richard Allan drivers are bloody great given their age. OK, this thing will never remove plaster from the walls, but Xlim on the driver is +/-12mm, and in a 100W driver this can deliver very solid SPL's (in the region of 110dB) down to below 30Hz. I imagine Xmax on this driver is more like +/-5mm. More than enough for hifi use. All from a 40 year old "vintage driver".

Paired with the Ikea Bowl speakers, and crossing at 80Hz, these integrate very well indeed.
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  1. Old Comment
    Very nice indeed
    Posted 21st June 2014 at 01:53 PM by SteB SteB is offline

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