Overview:
The SB Acoustics SB17NRXC35-8 is an 8Ω 6″ mid-woofer from SB Acoustics.
The mid-woofer has a 35.5mm voice-coil with a healthy 11mm (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.
Key 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
Note! This driver has been discontinued, but can be found second hand and at some shops!
SB Acoustics Spec sheet: 6in SB17NRXC35-8
T/S Parameters:
(click on picture to zoom)
T/S Parameters measured using DATSv2. Higher Qts and lower sensitivity than the official specification.
Impedance:
(click on picture to zoom)
Blue: Mid-woofer sample #1
Green: Mid-woofer sample #2
A small resonance issue around 1.4kHz
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): 24×35cm with 18mm round-over on the baffle edges (r=18).
Driver position: Mounted on center-line with driver unit center 22cm from the top of the baffle.
Mic position: 1m distance, on mid-woofer-axis.
Smoothing: 1/24 octave 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).
0deg = Blue
15deg = Red
22.5deg = Green
30deg = Blue
45deg = Red
60deg = Green
Smooth frequency response up to 3kHz. The highest suitable cross-over frequency is around 2-2.5kHz.
Distortion:
Measurement setup:
- Mid-woofer near-field measurement at 18cm
- Frequency Range Mid-woofer: 200-10000Hz
- Baffle size WxH: 24×35cm
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 SB17NRXC35-8 mid-woofer is overall a low distorting driver. Note! Disregard the third-order spike at 1.4kHz. It’s unfortunately a measurement artifact caused by the enclosure.