Jaycar cheepie

[PeteMcK]

Guys,

What do you think of this driver?
I was thinking of using it to add some bottom end
with an old 8" + Tweeter on an Open Baffle

Only $AUD 25 ea

This 250mm driver has a black paper cone, rubber surround and a high temperature voice coil former.
20oz magnet.

Specifications:
- Nom impedance: 8ohms
- Power handling: 40watts RMS
- Frequency range: 31Hz - 3kHz
- Sensitivity: 87dB 1watt 1metre
- Voice Coil Resistance (Re): 7.4ohms
- Resonant frequency (fs): 31Hz
- Mechanical Q factor (Qms): 2.898
- Electrical Q factor (Qes): 1.057
- Total Q factor (Qts): 0.775
- Equivalent Volume (Vas): 115Lt
- Cone Area (square metres): 0.0346

Typical Application:
Sealed Box
- Box volume (litres): 40 Lt
- Tuning Freq (Hz): 61Hz
- - 3db Frequency (Hz): 42.3Hz
- Qtc1.59

Pete McK

[sreten]

In any sort of box - yuk.

On an open baffle it will be fine, a lot better than most !

Wired in parallel if you roll it in 1st order as the baffle begins
to roll-off, you should be able to extend the flat region by
at least an octave, depending on the relative sensitivities
of the driver and your main 8" unit.

If your main 8" is a high efficiency unit, and your amp
can easily take 4 ohms, use two in parallel per baffle ?
This will give 93dB/W for the pair which is more like it.

Adding a first order c/o to the high efficiency 8" is a good
idea to relieve it of bass excursion that relative to the two
other units (as Q will be low) is pointless, and it will play
much cleaner as a result.

sreten.

[sreten]

http://www1.jaycar.com.au/productVie...=&SUBCATID=383

Is the 10" woofer, but for open baffle the 12" is even better !

http://www1.jaycar.com.au/productVie...=&SUBCATID=383

checkout that godawful Qts !

sreten.

[coolkhoa]

I agree with sreten. A Qts of 0.775? Definitely open-baffle...
And a "typical application" with a Qtc of nearly 1.6? Hah...

[PeteMcK]

I might give the 12'' version a go on an open baffle then,
with simple xover;

The 8" is probably not that high eff, & is 15 ohms;

Any hints as to baffle size wrt to Fs of the 8" unit ?
(haven't measured it yet)

thanks,
Pete McK

[sreten]

Originally posted by PeteMcK
Any hints as to baffle size wrt to Fs of the 8" unit ?
(haven't measured it yet)
thanks,
Pete McK

I can't see why the two should be related.

sreten.

[SkinnyBoy]

that 12inch woofer is the one I was always interested in mounting a couple of in the floor.. except... $$ ohh well..

tell us how it sounds, ok?

[sreten]

The 12" Qts = 1.46 in the floor would not work well.

Drivers with a Qts up to 3 can be used in an open baffle,
the baffle roll-off compensating for the rise in response
due to the Q of the driver.

In an open baffle the +4dB peak for Q = 1.5 will compensate for
some of the baffle roll-off. Below Fs, 32Hz, roll-off will become
18dB/octave so around 30 Hz will be the effective bass limit.

sreten.