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SB Acoustics SB16PFCR25-8 Paper Midwoofer

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The SB16PFCR25-8 by SB Acoustics is a 6 inch 8 ohm midwoofer speaker featuring a blended paper fibre cone, a vented reinforced plastic chassis and an optimised motor system with a high power ferrite magnet. Very smooth extended response with good transients; the performance is exceptional at this price point.

Also available in 4 ohms: SB16PFCR25-4.

Key Features:

  • Vented reinforced plastic chassis.
  • Proprietary cone material with natural fibers made in-house.
  • Soft low damping rubber surround for improved transient response.
  • Optimised motor system.
  • Vented coil former for low compression.
  • Non-resonant long life lead wires.

Basic parameters:

Resonant frequency (fs) 38 Hz Nominal impedance (Zn) 8 Ω
Mechanical  Q factor (Qms) 2.50
DC resistance (Re) 5.6 Ω
Electrical Q factor (Qes) 0.48
Max power handling 40 W
Total Q factor (Qts) 0.40
Sensitivity (2.83V/1m)
Equivalent volume (Vas) 27L
Chassis diameter

Here's the full datasheet:

.pdf link

Customer Reviews

Based on 2 reviews
David Pinfold
Great sounding bargain

This 6.5" woofer is really nicely built for the money and easy to use. The response is pretty flat and in a 23 cm wide baffle only exhibited about 3dB of baffle step, meaning a smaller inductor of just 1.3 mH could be used.

Used it in a vented design in 14.5 litres, Fb=38Hz, giving a measured F3 of 60 Hz. I paired it with Audax TW025A0 crossing at around 2.5 kHz. The breakup is pretty easy to deal with using a parallel RC tank across the inductor.

I have no complaints about the sound, with vocals being clear and bass extension acceptable and punchy given the small motor. Achieves reasonably good volumes in a smallish room such as a study. Absolute bargain!

Thanks for the comprehensive review David!

Will & Caroline


Initially intended for a centre speaker in an MTM but ended up in an atmos build with a SB26 005 tweeter . Measurements in a test box resulted in parts ordered from Will and the build . Its not the most efficient driver going with a final 84-85dB at 1m1 watt due to a relative high XO in a two way and BSL. Be prepared to attenuate the tweeter a fair bit to get to 84 dB in a two way . Measuring in a 14 litre stuffed 220mm wide sealed box gave very close correlation for the two drivers ordered. 4 parts in the XO and the measured FRD was near ruler flat from 72Hz to 1KHz (+/_ 1.5 dB, 1/12th smoothed outside ) .. Crossed 2nd order at 2K summed well with 3rd order Tweeter . Waterfall was as smooth as they come .. All looks great at this stage .. Until you come to play some music through them .These are thin , really really detailed, but thin. Getting a match with 90dB speakers needs to volume up by 6-8 dB . Swapped with some Peerless 830657's and these gave more mid range wholesomeness and bass . The sealed box gives good roll off bottom end with F3 at 63hz . No sign of the resonance hump as indicated in the manufacturers FR when tested. The speaker did not fair as well as the Peerless drivers for vertical off axis measurement , horizontally identical , but vertical especially above tweeter axis and the SBA suffers 10 degrees above tweeter axis with XO dropout . Perhaps a NF monitor best use ? Usual great service from Will and the team . Pack and delivery 1st class as per.

Thankyou for your review !
Will & Caroline