SALAD BOWL SPEAKER PROJECT

IKEA BLANDA MATT SALAD BOWL

Reproduced from Silicon-Chip for project inspiration and your interest only. Using our newly available SB Acoustics accoustic point source coaxial two-way drivers, however could be adapted to suit any suitably sized driver.

We do not have a kit available for resale.

These speakers are retro, stylish and surprisingly good performers. They're also pretty easy to make and offer a unique, attractive readily available speaker cabinet solution thats fun. Research spherical cabinet speakers and we discover that there are fundimental advantages in the design capitalised by some big name manufacturers and designers.

Salad bowl speaker concept has been spreading around the internet. This Silicon-Chip article describes a fully functioning pair of desktop / bookshelf speakers and gives some suggestions for tweaking the design to suit your needs. What initially attracted us to this idea was the mix of an old-school spherical speaker with extreme ease of construction. While the initial motive for building these was style and looks, it quickly became apparent that these little cuties had more to offer than that. Those who make speakers will be quick to comment that a sphere should be highly resonant; however, our tests show this is not the case. The fact that the driver forms a significant portion of the surface area of the sphere results in the Q of the internal resonance being relatively low. As a result, our measurements don't show resonant peaks in the response. Another benefit of a spherical speaker is that it has no edges. Or is it all one edge? Either way, concerns like edge diffraction and baffle effect are avoided. The fact that these speakers are spherical makes them extremely rigid. Edge diffraction is the effect of sound waves propagating from the driver across a speaker's front panel, then hilling the edge, which forms a discontinuity from propagation in 'half space' to 'free space·. This change causes diffraction at the speaker edges, affecting the frequency response and off-axis behaviour. There are many ways a spherical speaker can be mounted. Without creating a solution to this, they will tend to roll around! We have come up with a couple of options, including feet for the desk version and "rocket" Floor stands, both shown in the photos. The desktop version uses three small doorknobs as feet. The loudspeaker driver used is the SB Acoustics SB12PFCR25-4-COAX, a bass/mid driver with a coaxial tweeter (mounted in the centre). This allows us to achieve really good performance from about 70Hz upwards. These work brilliantly as desktop speakers and would also match well with many subwoofers crossed over at 80-1OOHz. We chose this specific SB Acoustics driver because it incorporates the tweeter, and neatly addresses the challenge of finding somewhere to mount the tweeter. The only other solution we could think of was to mount the tweeter externally, which we did with the Floor-standing version, but it was a real hassle. We have added a port to our enclosure. This allows us to extend the lower frequency response to about 70Hz, with some useful output below that. That is a good result for such a small speaker and is reasonable in its intended applications of desktop usage or placement in a small room. Don't try lo run a dance party using these speakers, though. There is a bit of a hump in the frequency response in the 100-200Hz region. This is a result of the port and helps fill out the bottom end, given the roll-off below 80Hz. The black line in Fig.2 shows the low frequency response you will achieve if you simply omit the port. If you use these on a desk backed up to a wall, om it the port. We used a 25mm port from Wagner Electronics, cut to 90mm in length. This tunes the system to resonance at 74Hz. In practice, the vent ends close to the driver magnet, so its effective length is over 90mm. This tuning gains us a couple of decibels of extra bass in the roll-off region. In an ideal world, this port would be 160mm long, tuning the enclosure to 58Hz, but there is not enough room in the enclosure for that.

Silicon-Chip - Sept 2023
IKEA salad bowl

Compact full-range loudspeakers with a unique appearance
Simple construction thanks to Ikea
Spherical enclosure minimises diffraction
Coaxial tweeter for good off-aiis response
Can be desk or floor mounted (the latter with a simple stand)
Frequency response: 70Hz to 20kHz (±3d8 lypical)
Power handling: 50W RMS per channel
Impedance: nominally 4Ω
Relatively low total cost

Not available as a kit. Read / Show More

Found in Category : Loudspeakers - Kits

SB12PFCR25-4-COAX - 4" COAXIAL More Info

Order Code	SB12PFCR25-4-COAX
Description	25mm Voice coil, paper cone, rubber surround, ferrite motor, round mounting injection chassis, coaxial midwoofer

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Order Code : SB12PFCR25-4-COAX

Availability: In Stock

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$89.50

SB12PACR25-4-COAX - SB COAXIAL DRIVER More Info

Order Code	SB12PACR25-4-COAX
Description	Dual Concentric Two-Way. Anodized aluminium Cone Mid-woofer + 12mm Dome Tweeter.

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Order Code : SB12PACR25-4-COAX

Availability: In Stock

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$95.00

XO2W-2.5K - 2 WAY CROSSOVER 2.5KHZ More Info

Order Code	XO2W-2.5K
Description	Crossover 2 Way 12dB 2.5KHz

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Order Code : XO2W-2.5K

Availability: In Stock

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$67.50

SB12PFCR25-4-COAX - 4" COAXIAL

$89.50

Order Code: SB12PFCR25-4-COAX

Availability : In Stock

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Order Code	SB12PFCR25-4-COAX
Description	25mm Voice coil, paper cone, rubber surround, ferrite motor, round mounting injection chassis, coaxial midwoofer

SB12PACR25-4-COAX - SB COAXIAL DRIVER

$95.00

Order Code: SB12PACR25-4-COAX

Availability : In Stock

Product Details

Add To Cart

Order Code	SB12PACR25-4-COAX
Description	Dual Concentric Two-Way. Anodized aluminium Cone Mid-woofer + 12mm Dome Tweeter.

XO2W-2.5K - 2 WAY CROSSOVER 2.5KHZ

$67.50

Order Code: XO2W-2.5K

Availability : In Stock

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Order Code	XO2W-2.5K
Description	Crossover 2 Way 12dB 2.5KHz

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SB12PFCR25-4-COAX - Product Downloads

Description	File	Size
Datasheet	SB12PFCR25-4-COAX.pdf	565 KB
SB Acoustics Catalogue	SB-Acoustics-Catalogue.pdf	26130 KB
Crossovers for PFC/PAC coaxial drivers	Crossover-for-PFC-or-PAC-Coaxial-Drivers.pdf	400 KB

SB12PACR25-4-COAX - Product Downloads

Description	File	Size
Datasheet	SB12PACR25-4-COAX.pdf	569 KB
SB Acoustics Catalogue	SB-Acoustics-Catalogue.pdf	26130 KB
Crossovers for PFC/PAC coaxial drivers	Crossover-for-PFC-or-PAC-Coaxial-Drivers.pdf	400 KB

XO2W-2.5K - Product Downloads

Description	File	Size
XLS Speakerkit Range - Archive	HDSK-Speaker-Kits_Archive.pdf	15967 KB
SB Acoustics Catalogue	SB-Acoustics-Catalogue.pdf	26130 KB
Crossovers for PFC/PAC coaxial drivers	Crossover-for-PFC-or-PAC-Coaxial-Drivers.pdf	400 KB