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mauro
Starting Member
14 Posts |
 Posted - 2004/03/15 : 13:02:29
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Hi!,
do someboby tried the 21w8555-01 scan-speak woofer?
i need help.
i would know :
- how many liters are necessary;
- the diameter and length of the duct.
i will use the woofer in a 4-way system.
please answer |
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epkpeng
400.000-klubben
4228 Posts |
Posted - 2004/03/15 : 13:26:22
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Welcome Italy!
With these parameters:
quote:
Characteristic sensitivity (2.83V / 1m) : 87.5 dB
Recommended frequency range : 19 - 600 Hz
Free air resonance frequency, fs : 19 Hz
DC resistance, Re : 5.5 ohm
Voice coil inductance, Le : 0.6 mH
Effective piston area, Sd : 220 cm²
Moving mass incl. air, md : 36 g
Mechanical loss, Rm : 0.9 Ns/m
Force factor, BL : 9.3 Tm
Equivalent volume, Vas : 136 ltr.
Mechanical Q-factor, Qms : 4.8
Electrical Q-factor, Qes : 0.27
Total Q-factor, Qts : 0.26
Excursion, lin./max. : ±6.5 / ±12 mm
Voice coil diameter : 42 mm
Rated power handling : 100 W
Net weight : 2.4 kg
I'd say try with a well built ported box at aprox 50 litres. Tune the port low, some 20 25 Hz. Keep in mind that this low tuning will require a substantial portlenght - make room for the port inside the box!!! 
I hope that you will make the effort to build a testbox for this driver and please make sure that you do a proper "burn in" i.e. play it so that initial hardness in suspension dissapear and then do the critical listening.
I also recommend you to test diffrent portlenghts so that you not only look at the technically best box, but rather test the best tuning for your room (/and application). Same goes for boxvolume - test!
How are you ging to run it? With a seperate amplifier? Possible to EQ (if so, mayby use a seald box)?!! Passive cross over? Tell us more!!!
Best regards,
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Vänligen
// Pär Engelholm
// Driver och äger Engelholm Audio
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mauro
Starting Member
14 Posts |
Posted - 2004/03/15 : 15:21:24
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thanks indeed for your answer!
.....some boby says to use it in 30 l reflex box,it is possible,and why? |
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epkpeng
400.000-klubben
4228 Posts |
Posted - 2004/03/15 : 15:29:49
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Hi!
It's possible but from what I have tested, with this particular unit, small boxes makes it very "boomy" and with a loudness effect. Not my cup of tea...
Since it's a ported box it is very positive to have as low resonant freq as possible (since powerhandling will decrease dramatically below Fs).
If boxsize is a problem, you could always try a 30 litres ported box and mayby acustically decrase the port (with a pair of socks perhaps! )
Rock on and let us now how it turns out!
Edit: my spelling isn't that great... |
Vänligen
// Pär Engelholm
// Driver och äger Engelholm Audio
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