The crossover to the tweeter shows a slight dip, but it's hardly audible (the human hear is quite sensitive towards exaggeration, but not towards drops).
Below the impedance response and electrical phase. Since the total impedance of the three bass drivers is considerably below 3 Ohm only powerful and stable amplifiers should be used. Picture 3: the Empress' impedance response (blue) and electrical phase (red)
It's extremely important for a high-end speaker to have a low harmonic distortion. Therefore, this value was measured at 80, 85, 90 and 95 dB (1 metre) over the entire frequency range.
First, for better differentiation the non-linear distortion 2nd order. Important is the gap between the two lines of the sae colour. The upper line depicts the key note, the lower one the distortion part. A gap of 40 dB is good, 60 dB is exemplary. It's noticeable that at 95 dB the distortion is still good, at lower levels it's even excellent. Below 200 Hz the distortion is somewhat higher due to the considerable excursion of the drivers, a symptom common to most drivers.
Klang+Ton magazine regards the distortion values in the diagram below above 200 Hz (in Klang+Ton 5/2007) as absolutely outstanding. Picture 4: the levels in different colours, the upper line depicts the key note, the lower one the distortion part.
Here the values for the 3rd harmonic distortion: Picture 5: the levels in different colours, the upper line depicts the key note, the lower one the distortion part.
A quick decay of a short note is desirable. Ideally, a tone should have decayed after a few milliseconds. The diagram shows that the Empress achieves this with flying colours. All frequencies above 500 Hz dropped by 20 dB after 2 milliseconds. Picture 6: the Empress' waterfall spectrum
The Empress' Description Building Instruction Home