Scan-Speak aluminium woofer

[cyclo]

Scan-Speak has now two very good looking alu woofers: 26W/4667T00 and 26W/8867T00. I have planned to use one of this in a 30l closed box. But what to choose? They will used with a TACT S2150 amplifier (internal digital crossover). I do not know the criteria for choosing the 4ohm or the 8ohm version of this driver.
Christophe


The specificitations are:

26W/4867T00
Characteristic sensitivity (2.83V / 1m) :89 dB
Recommended frequency range:18 - 1000 Hz
Free air resonance frequency, fs:18 Hz
DC resistance, Re:3.7 ohm
Voice coil inductance, Le:0.25 mH
Effective piston area, Sd:320 cm²
Moving mass incl. air, md:51 g
Mechanical loss, Rm:1.0 Ns/m
Force factor, BL:8.3 Tm
Equivalent volume, Vas: 223 ltr.
Mechanical Q-factor, Qms:5.8
Electrical Q-factor, Qes:0.31
Total Q-factor, Qts:0.30
Excursion, lin./max.:±9 / ±14 mm
Voice coil diameter:50 mm
Rated power handling:170 W
Net weight:3.7 kg


26W/8867T00
Characteristic sensitivity (2.83V / 1m):87 dB
Recommended frequency range:22 - 1000 Hz
Free air resonance frequency, fs:22 Hz
DC resistance, Re:5.8 ohm
Voice coil inductance, Le:0.4 mH
Effective piston area, Sd:320 cm²
Moving mass incl. air, md:56 g
Mechanical loss, Rm:1.5 Ns/m
Force factor, BL:11.1 Tm
Equivalent volume, Vas:136 ltr.
Mechanical Q-factor, Qms:5.2
Electrical Q-factor, Qes:0.36
Total Q-factor, Qts:0.34
Excursion, lin./max.:±9 / ±14 mm
Voice coil diameter:50 mm
Rated power handling:170 W
Net weight:3.7 kg

 

[demogorgon]

since your gonna put them in a 30 liter closed box, the 8867T00 looks like the way to go, based on Q factor and VAS.

I have no experience with those drivers, way out of my pricerange, but i have found that making sealed boxes closest possible to VAS is generally a good idea.

my thoughts
Marius

 

[bjackson]

That seems like an awfully small sized box for a VAS of 1xx-2xx liters. Have you modelled that in a simulation, my guess is that i'd be awfully peaky.

 

[cyclo]

It gives a Qtc of 0.63 for the 26W/4867 and 0.59 for the 26W/8867 in 30l. Not critically damped but it seems enough for me. I have never heard so much difference in quality between a Qt of 0.5 and another of 0.7 in room conditions (tested with a Scan-Speak 22W).
40l is the max I could use.
Christophe

 

[demogorgon]

It gives a Qtc of 0.63 for the 26W/4867 and 0.59 for the 26W/8867 in 30l. Not critically damped but it seems enough for me. I have never heard so much difference in quality between a Qt of 0.5 and another of 0.7 in room conditions (tested with a Scan-Speak 22W).
40l is the max I could use.
Christophe

Which strengthens my belif that the 26W/8867T00 is the correct choise.

I'd use lots of *good* dampening whool to compensate for the low internal volume.

regards
Marius