Crossover-Mania A Tale of Two Timings

1
Crossover-ManiaA Tale of Two Timings
System configuration used for these
measurements (No acoustic elements)
2
Symmetrical Crossover 24 dB/oct L-R at 1kHz
Overlapping phase traces through crossover
L-R Low-Pass
L-R High-Pass
Sum Low-Pass High-Pass
L-R filters 6dB at xover
Perfect summation through xover
Two crossover filters measured separately.
Two crossover filters summed back together
3
Filter Impulse Responses Linear Views
HPF Peak
LPF Peak
High-Pass Filter
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.
Low-Pass Filter
4
Filter Impulse Responses Log ETC Views
HPF Peak
LPF Peak
Log View
ETC High-Pass Filter
ETC Low-Pass Filter
5
Delay Added to High Filter to Align Peaks in Time
High-Pass Filter
Low-Pass Filter

X-Over
Sum
0.5 ms
Hi
Output
24 dB/oct L-R
Input
S
EQ
Delay
Polarity

(Ref)
(Meas)
1 kHz
Lo
0 ms
6
Adjusted Timing Causes Cancellation at Crossover
Phase traces 180 out at crossover
L-R Low-Pass
L-R High-Pass
Sum Low-Pass High-Pass
Cancellation at xover!

X-Over
Sum
Hi
0.5 ms
Output
24 dB/oct L-R
Input
S
EQ
Polarity
Delay

(Ref)
(Meas)
1 kHz
Lo
0 ms
7
Inverting Polarity of Low Filter Shifts Phase
Trace 180
Phase traces 180 out at crossover
Phase traces in phase at crossover

X-Over
Sum
Hi
0.5 ms
Output
24 dB/oct L-R
Input
S
EQ
Polarity
Delay
-
(Ref)
(Meas)
1 kHz
Lo
0 ms
8
The Result is Addition Through Crossover
Addition at crossover not perfect

X-Over
Sum
Hi
0.5 ms
Output
24 dB/oct L-R
Input
S
EQ
Polarity
Delay
-
(Ref)
(Meas)
1 kHz
Lo
0 ms
9
EQ Applied to Flatten Response at Crossover
EQ improves magnitude and phase responses
Addition at crossover not perfect

X-Over
Sum
Hi
0.5 ms
Output
24 dB/oct L-R
Input
S
EQ
Polarity
Delay
-
(Ref)
(Meas)
1 kHz
Lo
0 ms
10
Comparison of Two Alignments
11
(No Transcript)
12
(No Transcript)