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Jaycar 10 inch Precision Response Carbon Fibre

Jaycar Part no: 2278 - Cost $179.95aus (5th May 2005)

Estimated values area highlighted in red

Single coil driven2 series coils2 parallel coils
Z - Nominal Impedance4 ohm8 ohm2 ohm
Pe - Power Handling125W250W250W
SPL - Sensitivity84.10587.10587.105 dB/watt@1m
Re - Voice coil resistance3.4 ohm6.8 ohm1.7 ohm
Fs - Resonant frequency38.3 hz38.3 hz38.3 hz
Qms - Mechanical Q3.7883.7883.788
Qes - Electrical Q0.9040.4520.452
Qts - Total Q0.7300.4040.404
Vas - Equivalent volume26.95 litres26.95 litres26.95 litres
Xmax - Maximum excursion9 mm9 mm9 mm
Sd - Cone Area346 sq cm346 sq cm346 sq cm
EBP - Efficiency Bandwidth Product42.3 - sealed84.6 - All rounder84.6 - 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 = 615 sq cm as opposed to 346 in the catalog


There are more designs here than usual, for several reasons:


Box size Tuning frequency Port details
Ported - single coil 180 litre - 130w-4ohm - 240w amp 27hz Four 86mm ports @ 467mm
Ported - single coil 130 litre - 130w-4ohm - 240w amp 25hz Two 102mm ports @ 527mm
Ported - series coils 130 litre - 240w-8ohm - 350w amp 25hz Two 86mm ports @ 365mm
Ported - one coil driven
with second coil shorted
100 litre - 125w-4ohm - 240w amp 27hz Two 86mm ports @ 414mm

Project files for WinISD Pro ver 0.50a7
180 litre ported 27 hz tune (single coil)
130 litre ported 25 hz tune (single coil)
130 litre ported 25 hz tune (series coils)
100 litre ported 27 hz tune (one coil driven, one coil shorted)


SPL graph
If you can live with a 180 litre box, the light blue design gives about 108dB
The orange graph of single-shorted arrangement gets box size down to 100 litres

Cone excursion

Excursion graph
No problem here

Port air velocity

Velocity graph
All OK - Port flares would be required

This driver likes a large box - most designs are 130 litre. The single coil arrangement gives better results than the series arrangement, and requires the smaller amplifier


Port Flares

Calculated with Flare-it
I would recommend 19mm routed flares. for the 103mm ports. Alternatively, you could move to heat molded flares in 20mm or 25mm radius.
For the 86mm ports, 25mm heat molded flares would be required. For the blue design only, the flare radius could be reduced to 20mm.
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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