Ikea spherical speakers, first build done.

> To use the nominal 6 1/2" Alpair12 (red driver) you have to cut away a lot more of the bowls.

As shown in your drawing, you are not cutting away more than an A6 in the 20cm bowl.
I have not calculated the volume for closed box, but at least optically it will be just fine.

Again, there is still the A10 if you want smaller chassis.
A7 in a 28cm bowl is to my taste way too small.


Patrick
 
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I have not calculated the volume for closed box, but at least optically it will be just fine.

Optically it is probably fine

Again, there is still the A10 if you want smaller chassis.
A7 in a 28cm bowl is to my taste way too small.

When working with small boxes, the A10 wants about the same volume as the A12, so going to a slightly smaller driver doesn't gain you much in that respect, 28 cm bowls are still not large enuff.

The volume relationship of the A7 (or CHR) and the 28 cm bowls is just about perfect. The A7 is such a good speaker, and with the bowls you are going to quite an effort, why compromise performance?

dave
 
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The AP7 needs 7 litres for Q 0.702 and 85Hz at -3dB, sealed.
The AP10 needs 5.5 litres for Q 0.704 and 86Hz at -3dB, sealed.
The AP12 needs 6.3 litres for Q 0.703 and 100Hz at -3dB, sealed.

A full sphere 26cm diameter is 9.2 litres without any truncation.

All my numbers were based on optimum enclosures in the miniOnken style i've had so much success with.

A7/CHR 9 litre
A10/A12 13 litre

dave
 
I thought I should post pictures of my first build.

Project was inspired by Cabasse and the curves employed in B&W 800 series, although on a much smaller budget. Had the idea to use bowls, Ikea had the wooden Blanda which seemed perfect. After scouring the net, found several others using these, although none using the 28cm versions. Design is an active 2 way design.

An externally hosted image should be here but it was not working when we last tested it.


First completed photo (no tweeter), initially using Zero class T amps.

An externally hosted image should be here but it was not working when we last tested it.


Current incarnation, using rotel 6 channel amp, channel for tweeter and mid, bridged for 15" sub, experimenting with solid oak sleeper stands and granite plinths.

An externally hosted image should be here but it was not working when we last tested it.


Tweeters rather delicate positioning on top, seems to be fine without an enclosure, however I am experimenting with casting tapering tubes using champagne flutes.

The Sound: To my humble ears they sound rather good, haven't obtained a microphone to do testing. Definitely better than my Mission V63, which have an rrp of over £500. The 'no baffle' 15" add good low level sound reinforcement, as they don't go terrifically low or have very much bass

The drivers are Peerless M16GH (link below to drivers and excellent seller from eBay) Peerless & CO M16GH/4 Mid Woofers X 2 New/OldStock. on eBay (end time 25-Jan-10 10:15:24 GMT)


The tweeters are also Peerless metal domes, model unknown.

Currently crossed at 15" Sub 20-150Hz, Mid 50Hz-3Khz, tweeter 3Khz-20Khz

The sphere's come in at around 8L, (9.1L before cuts and driver displacement) One has eggfoam stuffing the other is naked will aquire some different materials for testing when I have a good mic.

They need another sand down, better integration with the stands and experiments with internal wadding, and the new tweeter housing, when time allows.

Great work so far! Hows it coming along?
 
Progressed has stopped, using some Celestion APT 'supertweeters' with the waveguides that sit comfortably on top. Sounding good, need to buy a measurement mic to see where they fall down.

Been trying to work out how best to use this:

16016_PE100292_S3.jpg

IKEA | Serveware | Serving dishes & bowls | BLANDA BLANK | Serving bowl

It fits perfectly over my Emminence 15" sub, but the volume is way to small, was thinking of emulating the B&O new BeoLab 11 sub, or trying to create something more unique without the need of cutting tightly spun aluminium:

BeoLab 11 - Bang & Olufsen

(on a side note, i have a second 15" that doesn't work, can it be used as a passive radiator, and does push pull style still work if one is a passive radiator?)

Still enjoying listening to them, building some solid oak sleeper plinths for them to sit on, and always looking at the next project, which is still my plaster cast baffle/waveguide and pretty rectangular plywood box, and still just waiting for a day to finally go to the wood shop.

Any other news from the Ikea Bowl speaker creators?

Louis
 
I will start on Monday on my Ikea speakers. I've seen the Focal Dome's which look stunning, so I will be going to the nearest ikea to buy some 20cm wooden blandas and to do a speaker influenced by the Dome's using my Fe103's. I hopefully will take pictures and do a build thread over my summer holidays before I go to Uni, which is why these are being built as Zigmahornets at 5ft tall will be a bit out of place. Plus using only 2 bowls not 4 like yours cuts down on the money coming form the limited funds. If their rubbish then ow well. On another note I recently saw that B&O sub and thought wow. A little more beautiful than my Wharfdale SW150.
 
as they dont overlap nicely and also miss some spacing to be perfectly round I think that is why people sand the whole ball. You sand 2/3 anyway to make the assembly between the 2 hemispheres smooth anyway so to get a nice finish you have to do all of the bowl and apply lacquer or similar.
 
Suitable crossover

Do the components of a passive filter handle alot of power? I'm making this speaker and I want to filter everything between 50-5000Hz and 5000-22000Hz. I know the theory about filters, but I don't know what power they handle. The amp delivers about 30Wsin. I'd like to make a LC-filter but inductors and capacitors have no power rating :scratch2: so it is logical they don't dissipate power?

If I solved my own question, I'm sorry, but I want to be sure. Thanks
 
You have to scale your components to your amp and your speaker. The coil absorbs power into heat depending on the ohmic value of the coil. You can go with thicker wire to lessen this effect, but as far as I have understood this only goes for serial coils and not parallel coils where you can choose a thinner wire = higher resistance.

I read that the capacitor should be sized as 3 times the output voltage of the amp somewhere, but can't find the reference after my pc reformat. As capacitors have very little resistance they do not dessipate power.
 
@Brian VG,

I sanded mine, because its lacquered or varnished in a thin shiny layer, which i could live with, but in putting them in a pack back and riding them home on my bike, sawing off a curved face, a few vice marks and the occasional drop, these indentations and scratches looked annoying and more obvious. Aesthetic decision only.
 
Sry for the late reply, didn't get an email about new messages.

They would look very nice I presume, similar to B&Ws sub, but I would take care with additional magnets and metal, maybe use a shielded sub for that application?

I'm confident that you cannot fix the driver with magnets. They would have to be very strong and would then interfere with the speaker. Less strain would result from an open enclosure (ported), but I would still not recommend it.

Why not just superglue a wooden piece on the inside of the bowl where you want to fasten the driver?



@Havoc08

Somewhere in this forum (Voodoo something) someone has build a isobarik or push pull sub with two 8" drivers and two of the larger bowls.

They looked very impressive, they are stainless steel and so magnetic, wondering if drivers could be fixed by magnets?