great minds almost think alike - I was eyeballing stone pestle and mortars in ikea today thinking they'd make a good base/stand for a spherical speaker. about 8 quid.
Looking at the Seas 27TAFNC/G data sheet, it appears the speaker is quite directional above 6-7 kHz. I'd almost call it a midrange rather than a tweeter. This might appeal to some, but it's not what I'm looking for.
I'd love a fullrange driver in a sphere. That would be cool. A 2-way with a woofer/mid in a sphere and a tweeter in a Nautilus-style enclosure on top could be sweet.
Tom
I love it! What an awesome, out-of-the-box thinking!
I am inspired to make a trip to ikea now... 🙂
I am inspired to make a trip to ikea now... 🙂
The Eureka project was funded by the EU, as a joint research program. The other partners were Bang and Olufsen and the Technical University of Copenhagen. The university has one of europes largest anechoic chambers. We fitted it out with over 30 of these speakers fed from a 32 channel DSP engine, and used it to simulate all the reflections you would get in a real room. This way we were able to simulate any room size or speaker directivity and listen to the results. We did experiments to determine thresholds for reflections from different surfaces, optimum speaker directivities, etc.
All the speakers were 2-way active. The drivers were 5" UNI-Q drivers. These were experimental drivers, built before UNI-Q became a product. Special bass cones, surrounds, tweeters etc, all hand assembled. I measured every driver, designed a custom xover for them and built this as an active EQ matched to the driver. The amplifiers started life as a custom modified Quad 405, modified to be current drive (ie high output impedance) using a technique developed for us by Peter Baxandall. Later in the project these were replaced by B&O Penta amplifiers.
Using current drive resulted in a significant drop in distortion in the mid-band, and elimination of thermal compression, but made the EQ challenging!
I don't have any pictures of the set-up, but will search and see what I can find.
The speakers were built into trawl floats to minimize diffraction and give smooth of axis response, as well as minimize the effects of reflections from adjacent speakers in the 3D array.
Andrew
All the speakers were 2-way active. The drivers were 5" UNI-Q drivers. These were experimental drivers, built before UNI-Q became a product. Special bass cones, surrounds, tweeters etc, all hand assembled. I measured every driver, designed a custom xover for them and built this as an active EQ matched to the driver. The amplifiers started life as a custom modified Quad 405, modified to be current drive (ie high output impedance) using a technique developed for us by Peter Baxandall. Later in the project these were replaced by B&O Penta amplifiers.
Using current drive resulted in a significant drop in distortion in the mid-band, and elimination of thermal compression, but made the EQ challenging!
I don't have any pictures of the set-up, but will search and see what I can find.
The speakers were built into trawl floats to minimize diffraction and give smooth of axis response, as well as minimize the effects of reflections from adjacent speakers in the 3D array.
Andrew
Studio AU, you can alwasy mix sharp sand with epoxy and any oil based colour and cast them.... Very solid
sharp sand
Which type of sand Should I use
A curious english expression!
The point is that it is rather coarse, compared with, say, bread flour, and washed clean of salts and other stuff.
What's the wall thickness of the 11" Ikea bowls? I'd like to use them as a starting point to make a mold for casting concrete.
i think 11mm off the top of my head, obviously this gets greatly reduced when you take a slice out for the hole, i'd guess between 1-6mm thickness where the screw will fit in.
If your not gonna use the wood as is, then they seem a little expensive. You can buy semi-spheres from supermarket kitchen departments, bowls, and such for a couple of bucks, or many other plastic based products very inexpensively.
good luck!
If your not gonna use the wood as is, then they seem a little expensive. You can buy semi-spheres from supermarket kitchen departments, bowls, and such for a couple of bucks, or many other plastic based products very inexpensively.
good luck!
Yes Studio Au,
And cheaper you can buy a cheap (playground) ballon if you are to mold from outside.
And cheaper you can buy a cheap (playground) ballon if you are to mold from outside.
Balloons, in my experience, make very poor moulds if one is using resin/composites including FG. They tend to leak and deflate slightly And that leads to a poor result. If they don't leak, they are highly susceptible to being punctured and then you get a rather nasty mess.
I used a childs plastic ball as a form and made an internal mould of half of it using silicon moulding rubber, supported by a frame. Then I made these:
I used carbon fibre epoxy. I made two back shells and then made two flat front baffles, placed them in the bottom of the mould and then built up the front shells. Then I made two smaller carbon fibre spheres using a smaller childs plastic ball covered in cling film. The smaller spheres have a short collar/throat which was joined to the back of the front baffle (after incorporating captive nuts) Then the back of the outer shell was joined to the front shell. I then put in a short CF tube between the shells as a cable via and then filled the gap between the inner and outer shells with sand and then installed a second CF tube for mounting the tweeter shell.
The midrange drivers are 100mm B&W LM 50 while the 25mm Titanium tweeters are MB-Quart RTC25. Both were intended as car audio components. I used B&W LX30 crossovers.
Now I need to make some stands.
I used a childs plastic ball as a form and made an internal mould of half of it using silicon moulding rubber, supported by a frame. Then I made these:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I used carbon fibre epoxy. I made two back shells and then made two flat front baffles, placed them in the bottom of the mould and then built up the front shells. Then I made two smaller carbon fibre spheres using a smaller childs plastic ball covered in cling film. The smaller spheres have a short collar/throat which was joined to the back of the front baffle (after incorporating captive nuts) Then the back of the outer shell was joined to the front shell. I then put in a short CF tube between the shells as a cable via and then filled the gap between the inner and outer shells with sand and then installed a second CF tube for mounting the tweeter shell.
The midrange drivers are 100mm B&W LM 50 while the 25mm Titanium tweeters are MB-Quart RTC25. Both were intended as car audio components. I used B&W LX30 crossovers.
Now I need to make some stands.
This is a very cool project. I've been looking for new computer speakers and these would work great.
I think I will try to mate them with the Insubnia over at the other site. That is another low cost but excellent build.
AK Design Collaborative - Insubnia - AudioKarma.org Home Audio Stereo Discussion Forums
I think I will try to mate them with the Insubnia over at the other site. That is another low cost but excellent build.
AK Design Collaborative - Insubnia - AudioKarma.org Home Audio Stereo Discussion Forums
This is such a nice build 🙂.
Does anyone have recommendations regarding a full-range or coax unit for the large ikea bowls?
I want to use the large bowls to get decent F3 to couple to a sub and I was considering something like the seas T18RE, but haven't emulated its response yet or whether it will fit the volume.
Advice or comments on unit selection for a large bowl IKEA speaker would be appreciated! 🙂
BTW. my music taste is broad, but with focus on vocal, acoustic and easy listening jazz like jamie cullum, norah jones etc.
I have also been contemplating the 2 way approach (but I really like the UNI-Q sound and fulltones in general). With the given volume of 2 bowls, would it be a better solution to find a midbass that fits the volume perfectly and a seperate bullet style tweeter (nice idea with the champagne glass), soundwise?
Does anyone have recommendations regarding a full-range or coax unit for the large ikea bowls?
I want to use the large bowls to get decent F3 to couple to a sub and I was considering something like the seas T18RE, but haven't emulated its response yet or whether it will fit the volume.
Advice or comments on unit selection for a large bowl IKEA speaker would be appreciated! 🙂
BTW. my music taste is broad, but with focus on vocal, acoustic and easy listening jazz like jamie cullum, norah jones etc.
I have also been contemplating the 2 way approach (but I really like the UNI-Q sound and fulltones in general). With the given volume of 2 bowls, would it be a better solution to find a midbass that fits the volume perfectly and a seperate bullet style tweeter (nice idea with the champagne glass), soundwise?
I wish larger bowls were not so expensive, I have some waveguides I would love to put on a sphere.
The only bowls online (15 or 18" diameter) are > $60 each.
The only bowls online (15 or 18" diameter) are > $60 each.
I'd think that the Mark Audios with there large round bezels would work well... CHR70, Alpair7, or EL70 would all be suitable. Getting the rebate right could be a bit tricky thou.
dave
dave
This is awesome. I'm in the process of building my monitors and on top will be a sphere made of fiberglass housing a Mark Audio A7 for mid-tweet duties and an Exodus audio in a traditional cabinet providing the bass duties.
I watched some videos on working with fiberglass. So I plan on cutting out round mounting 'baffles' and putting in the bottom of the bowl and then lay fiberglass up to the rim and them make a back and sandwidth together. Then put a gloss black finish on it. Inspiration is the B&W 800 series as well.
I watched some videos on working with fiberglass. So I plan on cutting out round mounting 'baffles' and putting in the bottom of the bowl and then lay fiberglass up to the rim and them make a back and sandwidth together. Then put a gloss black finish on it. Inspiration is the B&W 800 series as well.