PHD FB 4.1 Midbass Testing
Note: Though these speakers are called ‘midbass’, I think their size and parameters lends them much more to a midrange use.
A set of these PHD speakers was loaned to me last year to test and I’m finally getting around to doing so. While PHD is a 20-year old company, their presence hasn’t been really known (at least in my past 5-6 years in the car audio hobby) until the past couple years. Given that, there’s very little actual testing on any of the PHD products that I’ve seen, and I hope to help change that.
Product info can be found at PHD’s website here.
Small Signal Parameters:
|Re||3.32||Ohm||electrical voice coil resistance at DC|
|Le||0.181||mH||frequency independent part of voice coil inductance|
|L2||0.257||mH||para-inductance of voice coil|
|R2||3.79||Ohm||electrical resistance due to eddy current losses|
|Cmes||319||µF||electrical capacitance representing moving mass|
|Lces||6.21||mH||electrical inductance representing driver compliance|
|Res||28.71||Ohm||resistance due to mechanical losses|
|fs||113||Hz||driver resonance frequency|
|fm||72.9||Hz||resonance frequency of driver with additional mass|
|(using add. mass)|
|Mms||5.335||g||mechanical mass of driver diaphragm assembly including air load and voice coil|
|Mmd (Sd)||4.933||g||mechanical mass of voice coil and diaphragm without air load|
|Rms||0.582||kg/s||mechanical resistance of total-driver losses|
|Cms||0.371||mm/N||mechanical compliance of driver suspension|
|Kms||2.69||N/mm||mechanical stiffness of driver suspension|
|Bl||4.088||N/A||force factor (Bl product)|
|Qtp||0.677||total Q-factor considering all losses|
|Qms||6.51||mechanical Q-factor of driver in free air considering Rms only|
|Qes||0.753||electrical Q-factor of driver in free air considering Re only|
|Qts||0.675||total Q-factor considering Re and Rms only|
|Vas||1.3283||l||equivalent air volume of suspension|
|n0||0.245||%||reference efficiency (2 pi-radiation using Re)|
|Lm||86.09||dB||characteristic sound pressure level (SPL at 1m for 1W @ Re)|
|Lnom||86.9||dB||nominal sensitivity (SPL at 1m for 1W @ Zn)|
Large Signal Parameters:
|Displacement Limits||thresholds can be changed in Processing property page|
|X Bl @ Bl min=82%||1.4||mm||Displacement limit due to force factor variation|
|X C @ C min=75%||2.6||mm||Displacement limit due to compliance variation|
|X L @ Z max=10 %||1.9||mm||Displacement limit due to inductance variation|
|X d @ d2=10%||9.4||mm||Displacement limit due to IM distortion (Doppler)|
|Asymmetry (IEC 62458)|
|Ak||6.41||%||Stiffness asymmetry Ak(Xpeak)|
|Xsym||0.91||mm||Symmetry point of Bl(x) at maximal excursion|
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.
- Black= 0 Degrees (on-axis)
- Red = 30 Degrees
- Green = 60 Degrees
Harmonic Distortion, measured at approximately 5 inches from the cone, SPL emulating 90dB @ 1m and 96dB @ 1m.
- Blue = THD
- Red = 2nd Order
- Pink = 3rd Order
- Green = 4th Order
- Teal = 5th Order
96dB @ 1m equivalent:
IMD at 90dB/1m. F1=110hz, F2=880hz (-6dB from F1).
IMD at 96dB/1m. F1=110hz, F2=880hz (-6dB from F1).