SB Acoustics “Satori” MW13P-4



The SB Acoustics Satori MW13P-4 is a 4Ω 5″ mid-woofer from SB Acoustics. The mid-range has a 30.5mm voice-coil with a 10.0mm (p-p) linear coil travel. It’s fitted with an extende copper sleeve on the pole piece for reduced distortion.

Key features:

  • Vented aerodynamic cast aluminium chassis for optimum strength and low compression.
  • Proprietary cone material with EGYPTIAN PAPYRUS™ fibres made in-house.
  • Soft low damping rubber surround for optimum transient response.
  • Advanced BIMAX spider for improved linearity.
  • Powerful optimized low distortion neodymium motor system.
  • Non-conducting fibre glass voice coil former for minimum damping.
  • Extended copper sleeve on pole piece for low inductance and reduced distortion.
  • CCAW voice coil for reduced moving mass.
  • Long life silver lead wires attached 180° apart for improved stability.
  • Vented pole piece and coil former for reduced compression.
  • High piston to chassis diameter ratio.
  • Gasket and bolt hole protrusions for reduced coupling to speaker cabinet.


SB Acoustics Spec sheet: 5in SATORI MW13P-4

T/S Parameters:


(Click on picture to zoom)

Left: T/S parameters measured using “added” mass method in horizontal position.

Right: T/S parameters measured using “known” mass method in vertical position.

The drivers where burnt-in for 3 hours at 5 Volts using a 41Hz tone and then cooled off before measuring.



(click on picture to zoom)

Left: Free-air impedance driver sample #1 vs. sample #2.
Right: Close-up of free-air impedance driver sample #1 vs. sample #2.

Some wrinkles in the impedance plot are visible at ~1.35kHz and ~8.6kHz. The wrinkle at 1.35kHz is the cone edge resonance and 8.6kHz is the cone break-up frequency.



Frequency measurement conditions:

The mid-woofer is measured mounted on a baffle in a 11 liter closed enclosure with the following conditions:

Baffle size (WxH): 27×106cm. No baffle edge round-over.
Driver position: Mounted on center-line with driver unit center 24cm from the top of the baffle.
Mic position: 1m distance, on mid-woofer axis.
Smoothing: No smoothing applied. Measurement valid down to 275Hz.

(click on picture to zoom)

Left: Frequency response on-axis (Blue=sample #1, Red=sample #2).
Right: Frequency response 15deg off-axis (Blue=sample #1, Red=sample #2).

(click on picture to zoom)

Smooth frequency response up to 4.5kHz. Rising frequency response above 4.5kHz. A dip in the frequency response ~1.4kHz due to the cone edge resonance.

4kHz is about the highest suitable cross-over frequency for this mid-woofer.



Measurement setup:

  • Mid-range near-field measurement at 12cm
  • Frequency Range Mid-woofer: 200-20000Hz
  • Baffle size WxH: 27×106cm
  • Equipment: Steinberg UR12


The distortion measurements are done in near-field and the amplifier output level was adjusted for each driver so that the fundamental is 90dB and 95dB at 1m. This setting simulates medium-high to high listening levels.

(click on picture to zoom)

90dB @ 1m

Left = Sample #1

Right = Sample #2

(click on picture to zoom)

95dB @ 1m

Left = Sample #1

Right = Sample #2

The Satori MW13P-4 mid-woofer is overall a very low distortion driver. The resonance issue shown in the impedance plot around 1.35kHz is shown here as a spike of second order distortion.