SB Acoustics SB26STAC-C000-4

Overview:

SB26STAC-C000-4_1

The SB Acoustics SB26STAC-C000-4 is a 4Ω coated textile dome tweeter using a 1” voice coil together with copper cap pole piece. The 100mm aluminium faceplate enhances the sturdy build quality and looks.

Key features:

  • Cast aluminium faceplate
  • Copper cap for reduced voice coil inductance and minimum phase shift
  • Non-reflective rear chamber with optimized damping for improved dynamics
  • Flow optimized vented pole piece for optimum coupling to rear chamber
  • Fine weave soft fabric dome for smooth frequency response
  • Saturation controlled motor system for low distortion
  • CCAW voice coil for low moving mass
  • Long life silver lead wires
  • Low resonance frequency

 

SB Acoustics Spec sheet: SB26STAC-C000-4

T/S Parameters:

 

SB26STAC-C000-4 T-S

 

 

 

 

 

 

 

 

 

 

Very good consistency between the two tweeter samples and they match very close to the manufacturer’s specification.

Impedance:

 

SB26STAC-C000-4_Imp 1L vs 2R WT2

(click on picture to zoom)
Sample 1 = Green
Sample 2 = Blue

Almost identical impedance curves between the tweeter samples.

Frequency:

 

Frequency measurement conditions:

The tweeter is measured mounted on a baffle with the following conditions:

Baffle size (WxH): 24×35cm with 18mm round-over.
Driver position: Mounted on center-line with driver unit center 8cm from the top of the baffle.
Mic position: 1m distance, on tweeter-axis.
Smoothing: 1/24 octave smoothing applied.

SB26STAC-C000-4_Freq 1L vs 2R 0degSB26STAC-C000-4_Freq 1L vs 2R 15deg

(click on picture to zoom)

Left: Frequency response on-axis (Blue=sample1, Red=sample2).
Right: Frequency response 15deg off-axis (Blue=sample1, Red=sample2).

Almost identical frequency response up to about 15kHz where the two driver samples starts to deviate somewhat in level.

SB26STAC-C000-4_Freq 0-15-22deg

0deg = Blue
15deg = Red
22.5deg = Green

SB26STAC-C000-4_Freq 30-45-60deg

30deg = Blue
45deg = Red
60deg = Green

The tweeter has a very nice off-axis frequency response.

Distortion:

 

Measurement setup:

  • Tweeter near-field measurement at 10cm
  • Frequency Range Tweeter: 500-10000Hz
  • 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.

SB26STAC-C000-4-1L -- 10cm 90dbSB26STAC-C000-4-2R -- 10cm 90db

(click on picture to zoom)

90dB @ 1m
Left = Sample 1
Right = Sample 2

SB26STAC-C000-4-1L -- 10cm 95dbSB26STAC-C000-4-2R -- 10cm 95db

(click on picture to zoom)

95dB @ 1m
Left = Sample 1
Right = Sample 2

Considering the price of this tweeter there isn’t much to complain about its distortion profile. Low odd-order distortion even at higher levels and somewhat elevated second-order distortion, which gradually raises below 2.5kHz.

This tweeter should be able to work nicely crossed-over at 2-2.5kHz or higher.