Research done by Dr. Harry Olsen (an early audio pioneer) in the late 1930s showed that spherical speaker enclosures were best for loudspeakers because they did not alter the frequency response of the installed driver as do other shapes of enclosures (rectangular, cylinders, pyramid shaped, etc.). He published a formal paper in 1951 in Audio Engineering. Here’s a detailed article about his work:
Many DIYers have built “full range” speakers using a single sphere from IKEA bowls. I set out to build a true full frequency spectrum 4-way speaker from IKEA bowls, using all three sizes, 5”, 8” and 11”.
The speakers are shown below with two large spheres made from IKEA salad bowls: 11” bowls for a 6.5” subwoofer (down firing in the bottom sphere) and a 7” woofer (front firing on the next sphere). Then an 8” sphere for a 2” dome midrange driver and finally a 5” sphere for a 1” dome tweeter. The spherical speakers as part of a home theater setup below.
Summary of spherical speaker construction:
The bowls were used in their natural color and glued together using Gorilla Ultimate™ wood glue (which really holds well) and joined by an internal center 2” wood pole. Wood collars cut from ¾” pine board were made to separate the spheres and were stained to match. Holes were cut in the bowls to mount the speakers using a hand drill with appropriately-sized hole saws. The wiring runs internally up the pole and the crossover board is housed in the woofer sphere (second one up from bottom). The crossover is a three-way. The subwoofer is series wired into the crossover. It is a 2 Ohm driver combined with an 8 Ohm nominal crossover board that serves the other three drivers, making the system a nominal 10 Ohms.
The speakers are mounted and glued to metal stands as shown that nicely fit the 11” bottom subwoofer sphere, with the subwoofer fitting inside the ring of the stand. The subwoofer is down firing. The speakers weigh about 30 lbs. each.
The 6.5 inch subwoofer drivers are from Skar Audio and all the other drivers are Dayton Audio™ Reference Series with coated aluminum diaphragms – a 7” woofer with phase plug, a 2” dome midrange and 1” dome tweeter. The mid and tweeters feature neodymium magnets for size efficiency and also have built in screens. The 3-way crossover is also from Dayton Audio™ (800Hz / 4,500Hz).
The speakers were built using conventional work bench, hand tools, power drill, hole saws and a miter saw. Ten highlight photos are provide below with some description for each.
Overall the speakers have excellent bass response (bass or kettle drums sound as if they are right in the room with you), and crisp, well-defined midranges and highs. Transient response is excellent with the aluminum diaphragms. The speakers create an open sound that makes them almost “disappear”. They cover 40 Hz to 20,000 Hz, have a nominal impedance of 10 Ohms, and have approx. 87b sensitivity at the standard 1 watt rating and measurement distance. They will fill your living room or family room with excellent fidelity and dynamic range, especially at the 90+ db level. There is very little to no resonance relative to the deep base (see next section).
The sonic advantages of spherical speaker enclosures:
The sound coming from the various drivers does not reflect off of the curved surfaces as happens with conventional flat baffles, making the sound very open and spacious. Cup your hands around your mouth (simulates a baffle) and it changes the tonality of your voice. This happens to speakers as well especially in the midrange area. Using spheres eliminates “diffraction” effects and enhances the “soundstage” of the music.
The sphere internally does not have parallel sides that can create standing waves (as can happen in traditional “box” enclosures). Standing waves can cause internal resonances. Resonances can result in “boomy” bass. These spherical speakers also have a lot of special damping treatment and materials.
Spheres are extremely strong and can only resonate if they actually vibrate by “pulsing” in and out, and the bamboo material is very rigid. As a result, the bass is very clean and tight. No porting is used. The 11” spheres are approx. 1/3 cu. ft. volume which is about right for each of the subwoofer and woofer drivers.
A sphere system can also be rotated to point at you “on-axis” where you normally sit in the room (if you desire) without looking askew. A “box” shaped enclosure, if turned, would look out of place relative to a nearby wall.
These bowl speakers are not easy to build:
Details of the design and construction are available by emailing me at firstname.lastname@example.org, I have dozens on photos and several pages of step-by-step instructions including a list of all the parts you need and where to get them. You will have to commit serious time to this and the cost will be about $1,200 or so for the pair. But you will wind up with something very unique. Other drivers of similar size could be used instead of the ones chosen, as well as a different crossover board, that would be up to you.
Other manufacturers of spherical speakers:
Don’t take my word for it though, visit these websites for some well respected manufacturers of spherical speakers …
… and see some very high-end products that use spherical designs (there others too).
Highlight of build process:
These 10 photos are included here to highlight important steps but these are by no means comprehensive.
1. Drill pilot holes at the bottom of the salad bowls
Mark the center of the bowl for drilling the hole for the speaker driver (here the woofer). You can tape the bowl to a workbench at four places using Gorilla tape, so making a jig is unnecessary. Drill a ¼ inch pilot hole first then use the appropriate sized hole saw.
2. Paint and line the inside of the sphere
Paint the inside of the bowls to be used for the subwoofers and woofers with a thick paint and cement mixture to in essence make the wood act like a lower resonance cement board. Then line the inside with rug underlay using Gorilla glue to adhere to the painted inside.
3. Constructing the support board and peg
Cut and fit a horizontal support board that will be pegged and glued on the inside top of the subwoofer sphere. This will serve as a support for the inner 2” wood pole that will support the other three spheres. Wood collars are cut (using hole saws) from 3/4” pine board, and are glued above and below the 2” pole hole to make a “channel” at the top of the subwoofer sphere that will locate and support the bottom of the support pole. The 2” support pole will be later glued in place.
4. Building the subwoofer sphere
This photo shows the subwoofer sphere. The bottom will have the driver screwed in while the top will have the support pole coming through (the pole shown here is not full length, just shown for example).
5. Installation of the crossover board
The center points for later drilling the 2” pole holes are located and marked. The various wires going to the drivers are soldered in place on the board (and coiled for later use). And the board is then glued to the inside rear of the woofer sphere. Later on, the 2” pole hole will be drilled when the bowl halves are glued together – the rear half containing the crossover and the front half the hole for the woofer driver.
6. Gluing the bowls together
The spheres are glued together using Gorilla™ glue along the edge of the bowls, and by aligning and pressing the bowl halves together. Place a weight on top (as shown). While the glue is drying place four pieces of tape temporarily on the outside to maintain alignment. Note, Gorilla™ glue is strong enough to hold the bowls together even with the weight of the drivers.
7. Adding the support pole
The support pole is glued onto the support board of the subwoofer sphere and through the collar “channel” at the top of the sphere. The pole must be well seated and the wires from the subwoofer are shown coming through the top of the sphere and will then go to the woofer sphere. An outer collar is also placed and glued that will sit between the subwoofer and woofer spheres.
8. Placing the spherical speaker on its stand
The subwoofer sphere and glued-in support pole is then placed on the three-legged speaker stand and the glued-together woofer sphere (with crossover board inside) is then slid onto the support pole and glued in place. The wires from the subwoofer are also threaded into the woofer sphere for joining to the crossover.
9. Crossover board
This photo shows the wires from the crossover board for the midrange and tweeter spheres threaded through a channel groove cut into the support pole.
10. Final touch
After all spheres are glued into position and the speaker drivers installed, the stand will be positioned, aligned and glued in place onto the bottom of the subwoofer sphere. (This shows the subwoofer sphere only to illustrate).
~ by Steve Fisher
This Salad Bowl sounds good
Salad bowls are not only good for tossing greens, they make good spherical speakers too. Here’s a pair from Robert that are getting the kudos.
The build is documented on this forum but the basic steps are as follows:
1. Saw off the bottom of the BLANDA MATT bowls to fit the speaker according to the size of the round speaker. I used a Tang Band w4-657. (Similar on Amazon)
2. Make rings to lie between the bowls to ensure a good fit as not all the bowls are the same.
3. Glue two bowls together, sandwiching the ring, to form a ball or sphere.
4. Paint them (or not). I chose to spray paint them white to match my decor. First, I applied several coats of primer, then the spray paint and clearcoat at the end. Wet sand between each time varnish.
5. Place an O-ring around the ring to finish the joint neatly.
6. Drill holes for the terminals and drop in the Tang Band speaker.