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Crossover-ManiaA Tale of Two Timings
System configuration used for these measurements(No acoustic elements)
EQ DelayPolarity
X-Over
Sum
Input(Ref)
Output(Meas)
Hi
Lo
EQ DelayPolarity
0 ms
24 dB/oct L-R
Sum
Input(Ref)
Output(Meas)
Hi
Lo1 kHz 0 ms
X-Over
Symmetrical Crossover: 24 dB/oct L-R at 1kHz
L-R Low-Pass L-R High-Pass Sum: Low-Pass + High-Pass
Overlapping phase traces through crossover
L-R filters –6dB at xover Perfect summation through xover
Two crossover filters measured separately. Two crossover filters summed back together
EQ DelayPolarity
0 ms
24 dB/oct L-R
Sum
Input(Ref)
Output(Meas)
Hi
Lo1 kHz 0 ms
X-Over
Filter Impulse Responses: Linear Views
High-Pass Filter
Low-Pass Filter
HPF Peak LPF Peak
Note: If you simply used the AutoSm or Lg Impulse Resp measurements to measure the “driver” arrival times, you would be given the peak arrival times – and the peak of the LF is .5ms behind that of the HF.
EQ DelayPolarity
0 ms
24 dB/oct L-R
Sum
Input(Ref)
Output(Meas)
Hi
Lo1 kHz 0 ms
X-Over
Filter Impulse Responses: Log & ETC Views
ETC: High-Pass Filter
ETC: Low-Pass Filter
HPF Peak LPF Peak
Log View
EQ DelayPolarity
0.5 ms
24 dB/oct L-R
Sum
Input(Ref)
Output(Meas)
Hi
Lo1 kHz 0 ms
X-Over
High-Pass Filter
Low-Pass Filter
Delay Added to High Filter to Align Peaks in Time
EQ Polarity
24 dB/oct L-R
Sum
Input(Ref)
Output(Meas)
Hi
Lo1 kHz
X-Over
L-R Low-Pass L-R High-Pass Sum: Low-Pass + High-Pass
Phase traces 180° out at crossover
Cancellation at xover!
Adjusted Timing Causes Cancellation at Crossover
Delay
0.5 ms
0 ms
EQ Polarity
24 dB/oct L-R
Sum
Input(Ref)
Output(Meas)
Hi
Lo1 kHz
X-Over
Inverting Polarity of Low Filter Shifts Phase Trace 180°
Phase traces 180° out at crossover
Phase traces in phase at crossover
Delay
0.5 ms
0 ms
EQ 24 dB/oct L-R
Sum
Input(Ref)
Output(Meas)
Hi
Lo1 kHz
X-Over
The Result is Addition Through Crossover
Addition at crossover not “perfect”
Polarity
Delay
0.5 ms
0 ms
EQ 24 dB/oct L-R
Sum
Input(Ref)
Output(Meas)
Hi
Lo1 kHz
X-Over
Addition at crossover not “perfect”
EQ Applied to Flatten Response at Crossover
EQ improves magnitude and phase responses
Polarity
Delay
0.5 ms
0 ms
Comparison of Two Alignments
