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Vandersteen 2Ce Signature loudspeaker Measurements
Sidebar 3: Measurements
The Signature version of the Vandersteen 2Ce seemed a bit more sensitive than the sample of the 2Ce that Tom Norton reviewed in April 1993 at an estimated 84dB(B)/2.83V/m compared with 82dB. The difference could well be within the margin of error on this measurement.
The impedance was lowest with the tone controls set to their maximum positions, and is shown in fig.1. Ranging between 8 ohms and 4 ohms between 90Hz and 4.2kHz, the impedance dropped to 3 ohms just below 6kHz, though the electrical phase angle was generally moderate. Moving the tone controls to their central, "0," settings raised the minimum value to 3.5 ohms. These minimum settings resulted in a value of 4 ohms at 6kHz. Nevertheless, a good 4 ohm-rated amplifier would work best with this speaker. There were no wrinkles in the impedance plots that would indicate the presence of cabinet resonances.
Fig.1 Vandersteen 2Ce Signature, electrical impedance (solid) and phase (dashed). (2 ohms/vertical div.)
The saddle at 42Hz in fig.1's magnitude trace indicates the tuning frequency of the 2Ce's active coupler, which appears to behave much as a passive radiator. The nearfield measurement of the radiator's response in fig.2 does show that it peaks at this frequency. However, the minimum-motion frequency of the woofer, when the back pressure from the acoustic coupler on the woofer cone is so great that it is prevented from moving, is a little lower in frequency, at 33Hz.
The overall response in fig.2, which was taken on the tweeter axis with the tone controls set to "0," is even and generally flat in balance, though there is a slight shelving-up of the midrange compared with the range covered by the tweeter. This can be easily compensated for with the tone controls, the sensible ±3dB actions of which are shown in fig.3. There appears to be no interaction between the HF and MF controls. The peak at 26kHz in fig.2 is due to the metal-dome tweeter and is inconsequential, lying well above the audible range.
Fig.2 Vandersteen 2Ce Signature, anechoic response on-axis on tweeter axis at 50", corrected for microphone response, with the nearfield woofer and acoustic coupler responses and their complex sum plotted below 300Hz, 1kHz, and 300Hz, respectively.
Fig.3 Vandersteen 2Ce Signature, effect of HF and MF tone controls set to "+3" and "-2," normalized to tweeter-axis response. (1dB/vertical div.).
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