SB Acoustics “Satori” MW16P-8

Overview:

 

The MW16P-4 is an 8Ω mid-woofer from the SB Acoustics Satori series. Satori in Japanese is a Zen Buddhist term for enlightenment. The word literally means “awakening”, “comprehension” and understanding”.

The driver has a very nice looks and build quality. The small but yet powerful neodymium magnet together with the shape of the chassis contributes to an optimal airflow behavior.

It has a for its size great excursion capabilities with a linear coil travel of +/- 6mm.

Key features:

  • Proprietary cone material with EGYPTIAN PAPYRUSTM 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
  • Vented aerodynamic cast aluminum chassis for optimum strength and low compression
  • CCAW voice coil for reduced moving mass
  • Long life silver lead wires attached 180° apart for improved stability
  • Vented pole piece for reduced compression
  • High piston to chassis diameter ratio
  • Gasket and bolt hole protrusions for reduced coupling to speaker cabinet

 

SB Acoustics Spec sheet: SATORI MW16P-8

 

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.

Both driver samples measure very close to the Manufacturer specification.

 

Impedance:

 

(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.

The MW16P-8 has a very sharp and narrow impedance peak at the resonance frequency of the driver unit, which indicates a mid-woofer with low mechanical losses.

Some wrinkles in the impedance plot are visible at about 1.0-1.2kHz. The 1.0-1.2kHz wrinkle is the mid-woofers cone edge resonance due to the low mechanical damping of the surround.

Frequency:

 

Frequency measurement conditions:

The mid-woofer is measured mounted on a baffle in an 14 liter closed enclosure with the following conditions:

Baffle size (WxH): 24,8×35,8cm with 18mm round-over on the baffle edges (r=18).
Driver position: Mounted on center-line with driver unit center 19,5cm from the top of the baffle.
Mic position: 1m distance, on mid-woofer-axis.
Smoothing: No smoothing applied.

(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).

The two mid-woofer samples measures virtually the same, which indicates good consistency in the manufacturing process.

(click on picture to zoom)

Due to the mid-woofers very low inductance and flat impedance response, the on-axis frequency response has an extremely linear and extended response up to 15kHz.

The broad hump between 0.5-1.4kHz is partly due to the shape of the baffle and the baffle step. When the baffle step is taken care of in the cross-over design, we have a very linear frequency response up to 3kHz which is about the highest suitable cross-over frequency for this mid-woofer.

Distortion:

 

Measurement setup:

  • Mid-woofer near-field measurement at 15cm
  • Frequency Range Mid-woofer: 200-10000Hz
  • Baffle size WxH: 24,8×35,8cm

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.

90dB @ 1m (click on picture to zoom)

Left: = Sample #1

Right: = Sample #2

95dB @ 1m (click on picture to zoom)

Left: = Sample #1

Right: = Sample #2

Overall this is a very low distorting mid-woofer. We have the expected harmless elevated second-order harmonics around 1.2KHz due to the cone edge resonance, but in this case we also have some elevated third-order harmonics at the same frequency.