Frequency response
The frequency response is flat, the phase coupling is ideal. That's clearly
noticeable since the intersection of the Thiel tweeter and bass driver
(green and red line) is 6 dB below the total curve.
Even though there are loudspeaker with an even flatter frequency response
this speaker has an incredible sound. 
The sound pressure level depending on the dispersion angle is shown
below. The sound pressure war measured at 0, 15, 30, and 45 degrees
from the main direction. From 45 degrees onwards the level drops by
approx. 3 dB. The decrease is even over the entire frequency range.
This is probably the reason for the excellent three-dimensionality.
The One Point Monitor, like almost no other speaker, shows this ability
not only within the equilateral triangle but also outside. 
Decay spectrum / waterfall spectrum
The waterfall spectrum indicates whether the speaker shows any unwanted
resonance. Unwanted resonance is shown by a peak that is repeated to the
right. Not to be seen here. The One Point Monitor's decay is quick. 
Picture left::
Waterfall Spectrum
The One Point Monitor's impedance response
Picture left:
Impedance response
of the One Point Monitor
black: standard crossover
red: with impedance correction
At approx. 22Hz the resonance of the bass reflex tube and at approx. 72
Hz the resonance of the Thiel driver can be seen. The speaker's impedance
peaks at 1.7 kHz.
This peak at 1.7 kHz should be flattened when a valve amp is being
used. An absorption circuit consisting of the following components does
the trick:
- 1 x 4.7 Ohm resistor
- 1 x 0.22 mH coil and
- 1 x 47 uF MKT capacitor
When the components are wired up like shown in the picture above right
and the two leads connected to the terminal (i.e. in parallel to the
speaker) the impedance is flattened, indicated by the red curve (pictured
above). The circuit was calculated with the help of our impedance
correction calculator available on the tools page.
Crossover comparison: One Point Monitor and Satellite
Many customers have asked the question whether a simple crossover flattens
the frequency response less than the crossover designed by Bernd Timmermanns.
Or vice versa: is it a bad sign when a Thiel driver needs so many components?
The answer to both questions: a crossover with many components does
not necessarily indicate a bad crossover or driver. It mainly depends
on the design of the circuit.
The One Point Monitor's frequency response with:
- standard crossover (blue)
- Cumulus Satellite crossover (red)
The frequency response is quite similar. But bear in mind that Bernd
Timmermanns' crossover is mounted in the "wrong" speaker.
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