ScanSpeak Revelator 22W/8857T-00 8″ Woofer, Aluminum Cone


Up for test is the ScanSpeak 22w Aluminum Cone, 8″ woofer.

I purchased two drivers and tested both in the small signal suite.  I only tested one driver for large signal results.

 

IMG_8765

IMG_8770 IMG_8772

 

Small Signal Testing:

Driver 1 Driver 2 Units
Electrical Parameters
Re 6.34 6.21 Ohm electrical voice coil resistance at DC
Le 0.264 0.251 mH frequency independent part of voice coil inductance
L2 0.546 0.46 mH para-inductance of voice coil
R2 1.56 1.57 Ohm electrical resistance due to eddy current losses
Cmes 442 450 µF electrical capacitance representing moving mass
Lces 53.61 54.35 mH electrical inductance representing driver compliance
Res 97.95 80.22 Ohm resistance due to mechanical losses
fs 32.7 32.2 Hz driver resonance frequency
——————
fm 23.2 28.3 Hz resonance frequency of driver with additional mass
Mechanical Parameters
(using add. mass)
Mms 34.936 30.36 g mechanical mass of driver diaphragm assembly including air load and voice coil
Mmd (Sd) 31.249 26.673 g mechanical mass of voice coil and diaphragm without air load
Rms 0.806 0.842 kg/s mechanical resistance of  total-driver losses
Cms 0.679 0.805 mm/N mechanical compliance of driver suspension
Kms 1.47 1.24 N/mm mechanical stiffness of driver suspension
Bl 8.886 8.218 N/A force factor (Bl product)
Loss factors
Qtp 0.541 0.524 total Q-factor considering all losses
Qms 8.898 7.296 mechanical Q-factor of driver in free air considering Rms only
Qes 0.576 0.564 electrical Q-factor of driver in free air considering Re only
Qts 0.541 0.524 total Q-factor considering Re and Rms only
Other Parameters
Vas 46.5122 55.1206 l equivalent air volume of suspension
n0 0.271 0.313 % reference efficiency (2 pi-radiation using Re)
Lm 86.53 87.16 dB characteristic sound pressure level (SPL at 1m for 1W @ Re)
Lnom 87.54 88.26 dB nominal sensitivity (SPL at 1m for 1W @ Zn)

22W_8857T impedance

 

Large Signal Testing:

Displacement Limits thresholds can be changed in Processing property page
X Bl @ Bl min=82% 9.1 mm Displacement limit due to force factor variation
X C @ C min=75% 10.4 mm Displacement limit due to compliance variation
X L @ Z max=10 % >11.8 mm Displacement limit due to inductance variation
X d @ d2=10% 38 mm Displacement limit due to IM distortion (Doppler)
Asymmetry (IEC 62458)
Ak 9.75 % Stiffness asymmetry Ak(Xpeak)
Xsym -0.09 mm Symmetry point of Bl(x) at maximal excursion

22W_8857T bl 22W_8857T bl symmetry 22W_8857T cms

22W_8857T kms

22W_8857T kms symmetry  22W_8857T lx 22W_8857T li

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