Overview:
The SB Acoustics Satori WO2P-4 is an 4Ω 9.5″ woofer from SB Acoustics. The woofer has a 49.5mm voice-coil with a 17mm (p-p) linear coil travel. It’s fitted with dual shorting rings in motor system for reduced distortion.
Key features:
- Hard paper cone for improved piston operation (made in-house)
- Large optimized motor system with under-cut pole piece and
- dual shorting rings
- Vented aerodynamic cast aluminium chassis for optimum
- strength and low compression
- Soft low damping rubber surround for optimum transient response
- Linear symmetric suspension design for improved dynamic
- performance
- Non-conducting fibre glass voice coil former for minimum damping
- 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: 9in Satori WO24P-4
T/S Parameters:
Impedance:
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Blue: Mid-woofer sample #1
Green: Mid-woofer sample #2
A small resonance issue around 1.1kHz
Frequency:
Frequency measurement conditions:
The mid-woofer is measured mounted on a baffle in an 27 liter closed enclosure with the following conditions:
Baffle size (WxH): 30×40cm, no flush mount.
Driver position: Mounted on center-line with driver unit center 24cm from the top of the baffle.
Mic position: 1m distance, on woofer-axis. Nearfield at 10cm from dust-cap.
Smoothing: 1/24 octave smoothing applied.
(click on picture to zoom)
Frequency response on-axis near-field 10cm from dust-cap (Blue=sample#1, Red=sample#2).
(click on picture to zoom)
Frequency response 1m, on-axis (Blue=sample#1 Red=sample#2).
(click on picture to zoom)
0deg = Blue
15deg = Red
22.5deg = Green
(click on picture to zoom)
30deg = Blue
45deg = Red
60deg = Green
Distortion:
Measurement setup:
- Woofer near-field measurement at 20cm
- Frequency range woofer: 100-10000Hz
- Baffle size WxH: 30×40cm
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 and 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 WO24P-4 woofer is a low distortion driver. The resonance issue shown in the impedance plot around 1.1kHz is shown here as an elevated odd order distortion. The woofer’s odd-order distortion is low below 0.8kHz and it has an increasing odd-order distortion above 0.8kHz.