SYSTEM FREQUENCY RESPONSE
37 is the result of the sweep. Note that 6dB above the crossover
point (1,600Hz), the woofer and tweeter sum at unity, that
is there is no peaking and no depression.
Figure 38, the graph was smoothed by 0.1dB to remove the gating
artifacts. For all intents and purposes, this would be an
accurate representation of the speaker's frequency response.
the response now finalized, an impedance sweep is done to
to determine the load presented to the amplifier.
Figure 39, we can see that the port is well centered at 40Hz.
out of the ordinary along the way till the crossover at 1,600Hz.
At this point, the transition from woofer to tweeter caused
a bump after which it nose dived to a low of 4 ohms at about
2,700Hz before leveling off at 5 ohms. At 8kHz onwards, the
tweeter impedance started climbing due to the inductive nature
of the voice coil.
speakers will not present any problems to power amplifiers.
Most modern day amplifiers are designed to operate down to
4 ohms after all. On hindsight, a series resistor could have
been used instead of a L-Pad. This would raise the mean impedance
of the tweeter to be more in line with the woofer but being
a purist at heart, I have never been comfortable with any
series resistors in my networks. I see them as current limiting