Aura Sound NS6-255-8A

Aura Sound NS6-255-8A 6.5″ Midwoofer

IMG_8375 IMG_8379 IMG_8377

Small Signal Parameters:

Electrical Parameters
Re 5.69 Ohm electrical voice coil resistance at DC
Le 0.458 mH frequency independent part of voice coil inductance
L2 0.845 mH para-inductance of voice coil
R2 4.4 Ohm electrical resistance due to eddy current losses
Cmes 319 µF electrical capacitance representing moving mass
Lces 18.56 mH electrical inductance representing driver compliance
Res 83.75 Ohm resistance due to mechanical losses
fs 65.4 Hz driver resonance frequency
fm 41.9 Hz resonance frequency of driver with additional mass
Mechanical Parameters
(using add. mass)
Mms 8.984 g mechanical mass of driver diaphragm assembly including air load and voice coil
Mmd (Sd) 7.477 g mechanical mass of voice coil and diaphragm without air load
Rms 0.336 kg/s mechanical resistance of  total-driver losses
Cms 0.659 mm/N mechanical compliance of driver suspension
Kms 1.52 N/mm mechanical stiffness of driver suspension
Bl 5.307 N/A force factor (Bl product)
Loss factors
Qtp 0.702 total Q-factor considering all losses
Qms 10.98 mechanical Q-factor of driver in free air considering Rms only
Qes 0.746 electrical Q-factor of driver in free air considering Re only
Qts 0.698 total Q-factor considering Re and Rms only
Other Parameters
Vas 13.6902 l equivalent air volume of suspension
n0 0.494 % reference efficiency (2 pi-radiation using Re)
Lm 89.13 dB characteristic sound pressure level (SPL at 1m for 1W @ Re)
Lnom 89.37 dB nominal sensitivity (SPL at 1m for 1W @ Zn)
Sd 121.15 cm² diaphragm area


NS6 Impedance Klippel


Large Signal Parameters:


Displacement Limits thresholds can be changed in Processing property page
X Bl @ Bl min=82% 2.5 mm Displacement limit due to force factor variation
X C @ C min=75% >7.3 mm Displacement limit due to compliance variation
X L @ Z max=10 % 5.2 mm Displacement limit due to inductance variation
X d @ d2=10% 18.3 mm Displacement limit due to IM distortion (Doppler)
Asymmetry (IEC 62458)
Ak 5.03 % Stiffness asymmetry Ak(Xpeak)
Xsym 0.63 mm Symmetry point of Bl(x) at maximal excursion





Frequency Response:

The below is FR measured at 2.83v/1m, 0, 15, 30, 45, and 60 degrees with the accompanying polar.  You can see I stitched NF and FF at approximately 400hz, as this is where they lined up best for all axes.  These are smoothed to 1/12 octave.

  • 0 Degrees (on-axis) = Green
  • Black = 15 Degrees
  • Dark Red = 30 Degrees
  • Red = 45 Degrees
  • Orange = 60 Degrees


NS6 Polar

Non-Linear Distortion:

Harmonic Distortion, measured at approximately 5 inches from the cone, SPL emulating 90dB @ 1m.

  • Blue = THD
  • Red = 2nd Order
  • Pink = 3rd Order
  • Green = 4th Order
  • Teal = 5th Order

NS6 HD at 90db_1m

HD with a single tone in the spectrum view (I did this to verify the high odd order distortion seen above): NS6 HD at 1khz

IMD at 90dB/1m.  F1=55hz, F2=440hz (-6dB from F1).

NS6 IMD (1)

IMD at 96dB/1m.  F1=55hz, F2=440hz (-6dB from F1).

NS6 IMD (2)

One thought on “Aura Sound NS6-255-8A

Leave a Reply

Your email address will not be published. Required fields are marked *