Overview:
The D2905/950000 is a 6Ω tweeter from the ScanSpeak Clasic series.
The tweeter uses a non-resonant chamber. The optimized pole piece geometry reduces flow resistance and the anti-resonator-plug in the rear chamber eliminates turbulence. A light ferrofluid is used in the air gap to ensure optimal linear mechanical behavior and minimal micro-dynamic non-linearity.
Key features:
- 1″ Textile Dome Diamphragm
- Low Resonance Rear Chamber
- Ferro Fluid
- Black Painted Alu Face Plate
ScanSpeak Spec sheet: D2905/950000
T/S Parameters:
(click on picture to zoom)
One of the tweeter driver samples have slightly lower Fs than the official specification while the other have slightly higher.
Impedance:
(click on picture to zoom)
Sample 1 = Blue
Sample 2 = Green
Of the four tweeter samples tested all had some variation in the impedance peak and shape around the resonance frequency (Fs). In the usable frequency range above 2kHz, all the tweeter samples measured virtually the same.
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 8,2cm from the top of the baffle.
Mic position: 1m distance, on tweeter-axis.
Smoothing: 1/24 octave smoothing applied.
(click on picture to zoom)
Left: Frequency response on-axis (Blue=sample1, Red=sample2).
Right: Frequency response 15deg off-axis (Blue=sample1, Red=sample2).
The two tweeter samples measures virtually the same, which indicates good consistency in the manufacturing process.
Very smooth and extended on-axis frequency response. Measuring from 15deg off-axis, the response is even smoother with a slowly dropping frequency response from 15kHz.
The bump at 2kHz and the dip at 3.5kHz are baffle diffraction effects.
0deg = Blue
15deg = Red
22.5deg = Green
30deg = Blue
45deg = Red
60deg = Green
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.
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
The ScanSpeak D2905/950000 tweeter have a remarkable low third-order distortion profile below 2kHz. This tweeter has the ability to be crossed over very low and a cross-over between 1.5-2kHz should be feasible.