Oh, i did think of perhaps using finials, lots of shapes, can get oak, and pretty cheap.
Wooden Acorn Finial and Post cap for 3ins posts on eBay (end time 13-Mar-10 10:28:55 GMT)
Wooden Acorn Finial and Post cap for 3ins posts on eBay (end time 13-Mar-10 10:28:55 GMT)
How about something like this
http://www.sound-e-motion.com/en/catalogue.shtml
I was thinking along these lines. For the tweeter section you can use a wood curtain rod support. Wire the woofers in parallel for efficiency. Nice computer speaker system with a nice small SE tube amp.
Patrick, where/how did you source the middle aluminum ring? How will you secure it all together?
http://www.sound-e-motion.com/en/catalogue.shtml
I was thinking along these lines. For the tweeter section you can use a wood curtain rod support. Wire the woofers in parallel for efficiency. Nice computer speaker system with a nice small SE tube amp.
Patrick, where/how did you source the middle aluminum ring? How will you secure it all together?
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Hi guys, i was thinking about bilding a pair usign these blanda 28cm bouls and using Vifa widerange drivers!
http://www.lautsprechershop.de/pdf/vifa/lautsprecher/9bgs119.pdf
I am using them in the Picolino2 transmissionline spreaker and they are sounding very nice.
The question is how to make them sound good also in the sphere (bass reflex??)
cheers
Vasilis
P.S. Here are the cones now
http://www.hifisound.de/oxid/oxid.p...4/anid/91f49db1c60f1ab80.15539353/tpl//lang/1
http://www.lautsprechershop.de/pdf/vifa/lautsprecher/9bgs119.pdf
I am using them in the Picolino2 transmissionline spreaker and they are sounding very nice.
The question is how to make them sound good also in the sphere (bass reflex??)
cheers
Vasilis
P.S. Here are the cones now
http://www.hifisound.de/oxid/oxid.p...4/anid/91f49db1c60f1ab80.15539353/tpl//lang/1
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I would suggest trying to find a circular driver, when you cut through the bowl it leaves a thin flat edge in which you can screw in your drivers. If you try with Vifa one above it probably will not lie flat and you will have to bodge, fill and sand it all or add a faceplate, kinda ruins the spherical aesthetic.
An externally hosted image should be here but it was not working when we last tested it.
For those seeking a truly robust, easy to use, spherical enclosure here's one made from a 10" fishing float to house a B110 Linn Kan woofer.
The tweeter was housed in a polycarbonate light globe on top of the float.
These spheres are actually a form of torus where the rope passes through the centre in more normal, net fishing use. They come in many sizes. The hard, through-coloured, orange plastic from which they are made smells of styrene when sanded vigorously.
The rope tube provides a perfect site for a bolt to hold the enclosure down onto a stand by using large washers. I bolted mine down to a 24" speaker stand. It provides a diffraction free enclosure which should, in theory, provide the smoothest frequency response of any enclosure. The sharp edges of the pressed steel, B110 driver basket might be trimmed to achieve a flatter edge to this end. The plastic readily takes a tap, cut thread or self tapping screws.
Being pressure resistant, air-tight they make an ideal, simple enclosure for the experimenter. They are also remarkably cheap. No doubt they will take a spray paint to taste if the gloss is rubbed off with fine sandpaper. Tough as old boots, mine have been lying in the garden since I moved onto other things without sign of degradation.
About 20 years ago, there was a 2 way focal kit with a 6 inch woofer and their 1 inch inverted kevlar tweeter that came with a set of egg-shaped enclosures. The tweeter was mounted on the front of the egg rather than on top. I think the encolosure was fiberglass with some sort of smooth plastic covering poured over it. I was very happy with the sound. The imaging was terrific. I think I just got tired of the drivers themselves, particularly the tweeter. They were reviewed in the audio amateur I think.
Do you know where I might obtain a fishing float like one of those? Those Blanda bowls are a bit pricey, especially for the larger sizes.
Alternately, I might be able to use a stainless steel garden gazing globe. They're not cheap, but you can get them up to 15" in diameter and they're certainly very pretty. The only potential issue I see is that they're very thin - while it's no doubt possible to coat the inside walls with an automotive damping product to prevent ringing and spheres are VERY strong, I'm a bit perplexed as to how I'd flush-mount a speaker. Maybe a trim ring could be cut in half and assembled inside?
Alternately, I might be able to use a stainless steel garden gazing globe. They're not cheap, but you can get them up to 15" in diameter and they're certainly very pretty. The only potential issue I see is that they're very thin - while it's no doubt possible to coat the inside walls with an automotive damping product to prevent ringing and spheres are VERY strong, I'm a bit perplexed as to how I'd flush-mount a speaker. Maybe a trim ring could be cut in half and assembled inside?
These fishing floats are actually called trawler floats. I used them at KEF for the Eureka project and mounted 5" Uni-Q drivers into them. I built a total of around 40 of these for the project, all with active xovers and current drive amplifiers.
All the floats were hand cut by myself, done by marking a line around the float then using a big hand saw. Sounds difficult but in reality it proved fairly easy. The float has a wall thickness of around 6 or 7mm so it was very strong, and the cut edge was plenty wide enough to mount the chassis onto.
Do a google search and you will find sources of these floats. One source is:
Trawl Floats
Good luck
Andrew
All the floats were hand cut by myself, done by marking a line around the float then using a big hand saw. Sounds difficult but in reality it proved fairly easy. The float has a wall thickness of around 6 or 7mm so it was very strong, and the cut edge was plenty wide enough to mount the chassis onto.
Do a google search and you will find sources of these floats. One source is:
Trawl Floats
Good luck
Andrew
Trawlworks that Andrew linked to is based in RI, USA. I'm guessing they'd be happy to throw some floats in a box and mail them to you. It's worth a phone call anyway...
Has anyone tried the Mark Audio CHR-70 in a spherical enclosure? I'm thinking to use the larger (11") IKEA bowls as an enclosure. I might have to cut the volume by a bit as I calculated a 6-something liter enclosure being about optimal for a sealed enclosure and the bowls are more like 9 liters when assembled to a sphere. I was thinking to fill the void with an LM3886 + supply for a pretty neat active speaker.
The only drawback of the IKEA bowls is that they're $20 each, which means I'll spend more on bowls than on drivers.
~Tom
Has anyone tried the Mark Audio CHR-70 in a spherical enclosure? I'm thinking to use the larger (11") IKEA bowls as an enclosure. I might have to cut the volume by a bit as I calculated a 6-something liter enclosure being about optimal for a sealed enclosure and the bowls are more like 9 liters when assembled to a sphere. I was thinking to fill the void with an LM3886 + supply for a pretty neat active speaker.
The only drawback of the IKEA bowls is that they're $20 each, which means I'll spend more on bowls than on drivers.
~Tom
I think Andrew's "trawler floats" are also known by the name "Mooring buoys" in the US - there's quite a selection - I use an 8" one that has the rope "eye" at the top as a "sleeve" (or shroud, I think it's called) around the magnet/frame assembly of the 12' bass drivers - helps reduce freq variations and also better dynamics, especially with a 6dB Xover.
With the old Coral Betta8 drivers, I use a heavy duty 4"dia plastic sleeve (short length of 4" PVC plumbing pipe split down the side) around the magnet/frame assembly and a 5" round wooden Blanda bowl to round off the flat magnet at the rear - makes quite a difference - similar approach as the "Rethm" guys, but round - seems to work very well with most drivers - these thing have been done some years ago either by Ted Jordan or the Epsilon speakers - very useful little mod/addition to the Fostex drivers.
One simple way to reduce the internal "drama" going on inside these "balls" is to place a 4 or 5 leaf divider right across the width of the sphere (edge to edge) from just behind the rear of the driver's magnet (with/without blanda bowl!) to nearly the back of the sphere (like one of those round "orange type" chocolate balls) - and then just a SMALL amount of damping material at the rear for lower small signal loss. I haven't tried the EnABL idea on these yet.
Andrew, any more info about your current gain amps?
With the old Coral Betta8 drivers, I use a heavy duty 4"dia plastic sleeve (short length of 4" PVC plumbing pipe split down the side) around the magnet/frame assembly and a 5" round wooden Blanda bowl to round off the flat magnet at the rear - makes quite a difference - similar approach as the "Rethm" guys, but round - seems to work very well with most drivers - these thing have been done some years ago either by Ted Jordan or the Epsilon speakers - very useful little mod/addition to the Fostex drivers.
One simple way to reduce the internal "drama" going on inside these "balls" is to place a 4 or 5 leaf divider right across the width of the sphere (edge to edge) from just behind the rear of the driver's magnet (with/without blanda bowl!) to nearly the back of the sphere (like one of those round "orange type" chocolate balls) - and then just a SMALL amount of damping material at the rear for lower small signal loss. I haven't tried the EnABL idea on these yet.
Andrew, any more info about your current gain amps?
For UK buyers of trawl floats, these look good
Coastal Nets :: fishing nets, safety nets, sports netting suppliers
The 11" float is £12.50 - similar to the Ikea bowl but of course you only need half as many!
I remember seeing pics of the Eureka project. I must try and find them again. If only to help explain to my partner why I'm looking at deep sea trawler floats on the web.
Coastal Nets :: fishing nets, safety nets, sports netting suppliers
The 11" float is £12.50 - similar to the Ikea bowl but of course you only need half as many!
I remember seeing pics of the Eureka project. I must try and find them again. If only to help explain to my partner why I'm looking at deep sea trawler floats on the web.
In my basement i have the tops of two pelican/zebra crossing with holes already cut. Will have to measure, not sure how thick they are, but could work.
The other idea i had floating around before the Blanda bowls was to use solid granite pestle and mortar (size and cost became a limiting factor), drill the pestle for a tweeter housing ala B&W signature.
+1 for more pics and info on your KEF project Andrew. How were 40 of them implemented?
The other idea i had floating around before the Blanda bowls was to use solid granite pestle and mortar (size and cost became a limiting factor), drill the pestle for a tweeter housing ala B&W signature.
An externally hosted image should be here but it was not working when we last tested it.
+1 for more pics and info on your KEF project Andrew. How were 40 of them implemented?
Keep in mind that this mod works better at high frequencies than at low frequencies. There's a transition that occurs around 1600hz, or 8.44". (Not coincidentally, this is approximately the distance between your ears.)
A posted on the car audio forums found an *excellent* candidate for the spherical treatment, a neodymium Seas tweeter.
In the side view of these spheres, you can see that the tweeters is a near-perfect match for the spheres he selected. In the measurements that I've done, I've found that a smooth transition from the radiator to the baffle makes a big difference in how effective this mod works. You see this in the B&W speakers; the transition is basically flawless.
Improve Your Soundstage for $2 - Page 10 - DIYMA.com
Anyways, very cool work, and inexpensive too! I've seen the enclosures at Fry's electronics for about twenty bucks, and the Seas tweeters are about $60 a pair.