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Jaycar 12 inch Precision Response Carbon Fibre

Jaycar Part no: 2279 - Cost $219.00aus (5th May 2005)

Estimated values area highlighted in red

Single coil driven2 series coils2 parallel coils
Z - Nominal Impedance4 ohm8 ohm2 ohm
Pe - Power Handling150W300W3000W
SPL - Sensitivity85.15288.15288.152 dB/watt@1m
Re - Voice coil resistance3.4 ohm6.8 ohm1.7 ohm
Fs - Resonant frequency28.77 hz28.77 hz28.77 hz
Qms - Mechanical Q3.2383.2383.238
Qes - Electrical Q0.8920.4460.446
Qts - Total Q0.6990.3920.392
Vas - Equivalent volume79.5 litres79.5 litres79.5 litres
Xmax - Maximum excursion9 mm9 mm9 mm
Sd - Cone Area514 sq cm514 sq cm514 sq cm
EBP - Efficiency Bandwidth Product32.3 - sealed64.5 - All rounder64.5 - All rounder

Driver files for WinISD Pro ver 0.50a7
Here is my parameter file for this driver ( single coil driven )
Here is my parameter file for this driver ( two series coils driven )
Here is my parameter file for this driver ( single coil driven, second coil shorted)

The Xmax figure is not stated in the catalog, but Jaycar provide a link on their website, where the details for this driver eventually lead to a screenshot of an analysis using "BassBox" software. On that page Xmax is shown as 9.0mm, which is the value I used above. The screen shows designs using the 1.7ohm parallel arrangement, which is not suitable for use with the HT plate amps. It also shows Sd = 708 sq cm as opposed to 514 in the catalog

Designs

Jaycar shows no designs in their catalog, so these are all mine
There are more designs here than usual, for several reasons:

 

Box size Tuning frequency Port details
Ported - single coil 550 litre - 100w-4ohm - 240w amp 22hz Four 86mm ports @ 198mm
Ported - single coil 130 litre - 150w-4ohm - 240w amp 26hz Two 102mm ports @ 482mm
Ported - series coils 230 litre - 240w-8ohm - 350w amp 24hz Two 102mm ports @ 294mm
Ported - series coils 130litre - 240w-8ohm - 350w amp 26hz Two 86mm ports @ 333mm
Ported - one coil driven
with second coil shorted
260litre - 150w-4ohm - 240w amp 25hz Two 102mm ports @ 226mm

Project files for WinISD Pro ver 0.50a7
550 litre ported 22hz tune (single coil)
130 litre 26hz tune (single coil)
230 litre 24hz tune (series coils)
130 litre 26hz tune (series coils)
260 litre 25hz tune (one coil driven, one coil shorted)

SPL

SPL graph
Unless you go to a very large box, you cant get a flat response, even with a ported design. The single coil arrangement gives better output than the series connection. The orange curve is the shorted coil option and still requires 260 litres.
 

Cone excursion

Excursion graph
The red graph which indicates that 130l/26hz design needs an infrasonic filter
The 550 litre ported design had to have power reduced because of excursion limits
 

Port air velocity

Velocity graph
All OK - Port flares would be required
 

Unlike the 10inch version, this driver won't produce a flat response in a 130litre box. Going up to 260 litres will give 107dB flat using the 350w amp.

 

Port Flares

Calculated with Flare-it

Ported - single coil design. Four 86mm ports, peak velocity 11.5m/sec @ 22hz
Minimum flare radius required 25mm. Use 25mm heat molded flares

Ported - single coil design. Two 102mm ports, peak velocity 10m/sec @ 25hz
Minimum flare radius required 13mm. Use 13mm routed flares. Alternatively, you could move to heat molded flares in 20mm or 25mm radius.

Ported - series coils design. Two 102mm ports, peak velocity 10m/sec @ 25hz
Minimum flare radius required 13mm. Use 13mm routed flares. Alternatively, you could move to heat molded flares in 20mm or 25mm radius.

Ported - series coils design. Two 86mm ports, peak velocity 11m/sec @ 25hz
Minimum flare radius required 25mm. Use 25mm heat molded flares

Ported - single driven second coil shorted design. Two 102mm ports, peak velocity 13m/sec @ 25hz
Minimum flare radius required 22mm. Use 25mm heat molded flares

In all designs, the intakes should be flange mounted with a 13mm routed flare or you could fit a donut ring. If you are using a heat molded flare, you could do a one-piece design with a 20mm flare on the inlet

See the Porting section for more detail on the design, construction and purchase of flared ports.

 

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