The frequency response is good. It's not smoothed (some manufacturers a smoothed
curve over half an octave or an entire one) and flat. At 7.5 kHz there
is a slight unevenness.
The following diagram shows the sound pressure depending on the dispersion
angle, at 0, 15 and 30 degrees from the main direction. Also here, the
frequency response is flat.
Decay spectrum/waterfall spectrum
The waterfall spectrum indicates whether the speaker has any unwanted resonance.
In this case the peak is repeated over several lines to the front. The
Simon doesn't show any resonance, the speaker's decay is quick.
For valve amps the Simon's impedance may be smoothed. The left area shows that
the resonance of the bass reflex tube is at approx. 50 Hz, the resonance
of the Tangband driver at approx. 120 Hz.
At 1.5 to 2 kHz the speaker is highly resistive, since the Tangband
shows here a high efficiency. As a result little power is needed; that's
the reason why the crossover has a high input impedance.