This time I have the SB Acoustics SB15NRXC30-8 driver unit on the test bench. This is a 5” mid-woofer with a nice and sturdy build quality, especially considering its modest price of 55$.
Features:
- Vented cast aluminum chassis for optimum strength and low compression
- Proprietary cone material with natural fibers made in-house
- Soft low damping rubber surround for improved transient response
- Non-conducting fiber glass voice coil former for minimum damping
- Extended copper sleeve on pole piece for low inductance and low distortion
- CCAW voice coil for reduced moving mass
- Long life silver lead wires
- Vented pole piece for reduced compression
The mid-woofer has a 30.5mm voice-coil with a healthy 10mm (p-p) linear coil travel. It has a very low voice-coil inductance and is fitted with a copper sleeve on the pole piece to ensure a low distortion performance. At this price range, quite impressive features that SB Acoustics managed to fit into this mid-woofer.
T/S Parameters:
Preliminary data:
The four driver unit samples are from two different manufactoring batches. At this price range not much to complain about. Good consistency between the driver unit samples and it matches the official spec sheet reasonably well, with a higher Mms and lower sensitivity compared to official specs.
The mid-woofer has a low “fs” for its size and has a high mechanical Q-factor (Qms) and low mechanical loss (Rms), which ensures chances of good dynamic bass performance.
Impedance:
Preliminary data:
Note the very low inductance. Impedance minimum of 6.3Ω @ 300Hz.
Frequency and distortion measurements will follow soon…..