XTA 4 Series, Руководство оператора, Страница: 43 / 58

Operators Manual Page 43
Crossover Filter Slopes
It should also be noted that the turnover frequency displayed on the screen is the -3dB point for all types except Linkwitz-
Riley where the -6dB point is shown. If the -6dB point is to be used for the Bessel or Butterworth filter, take the required
crossover frequency, multiply this by the appropriate factor from the following table and then select the closest available
frequency on the display.
Filter Type High pass factors Low pass factors
Bessel 12dB/Oct. 1.45 0.69
Butterworth 12dB/Oct. 1.31 0.76
Bessel 18dB/Oct. 1.37 0.73
Butterworth 18dB/Oct. 1.19 0.84
Bessel 24dB/Oct. 1.35 0.74
Butterworth 24dB/Oct. 1.15 0.87
Bessel 48dB/Oct. 1.39 0.72
Butterworth 48dB/Oct. 1.08 0.93
Please note that unlike conventional analogue crossovers, crossover points and slopes are set with absolute accuracy since
component tolerance problems do not occur.
Please see page 18 for details of how to adjust the high and low pass crossover filter settings.
Time Alignment
A further advantage of the
4 Series 4 Series 4 Series 4 Series
over conventional products is the provision of an independently adjustable delay
section for each output. This allows the true arrival time from multiple drivers to precisely aligned rather than relying on
the compromise 'phase adjust' approach. Delay time is adjustable in 0
. 3
µ
S steps (0.1mm).
Please see page 17 for details of how to adjust the delay times.
To convert from units of time (i.e. milliseconds) to units of distance use the following formula:
1 millisecond = 343mm (1.126ft) @ 20
°
C (68
°
F)
To calculate time delay for a known distance, use:
Time delay =
Distance in meters
20.06 x
√
273+
°
C
where
°
C is the temperature in
°
C.
To simplify this equation at 20
°
C.
Delay time in milliseconds =
(Distance in meters x 2.192) or (Distance in feet x 0.955)
Note: Centigrade = (Fahrenheit –32) x 0.5555.