TOA Electronics TDX2 Configurations 7.1. Introduction, Crossover Modes, Filter slopes

7. TDX2 Configurations

7.1. Introduction

To simplify set-up of the TDX2, 5 crossover modes are menu selectable. These all have parametric equalisers, high and low pass filters, limiters, gain and delay. For detailed information on these modes please study the block diagrams along with the following descriptions. 2 x 3 way and 2 x 2 way crossover modes have the option available to provide precise 'ganged' parameter adjustment for stereo sources.

7.2. Crossover Modes

Please see block diagram. All crossover modes feature adjustable crossover frequencies with a choice of slopes, 5 bands of driver compensation E.Q. per output and delay time plus limiters for each output. Phase reverse is provided for each output.

7.3. Filter slopes

A choice of Bessel or Butterworth slopes at 12/18/24dB per octave and Linkwitz- Riley at 24dB per octave are provided. Since Low and High pass functions are separately adjusted, asymmetric slopes are easily achieved, if required. It should also be noted that the turnover frequency displayed on the TDX2 is the -3dB point for all slopes except 24dB 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 TDX2’s display.

Filter Type	High pass filter factors	Low pass filter factors
Bessel 12dB/octave	1.45	0.69
Butterworth 12dB/octave	1.31	0.76
Bessel 18dB/octave	1.37	0.73
Butterworth 18dB/octave	1.19	0.84
Bessel 24dB/octave	1.35	0.74
Butterworth 24dB/octave	1.15	0.87

Please note that unlike conventional analogue crossovers, crossover points and slopes are set with absolute accuracy since component tolerance problems do not occur.

7.4. Time Alignment

A further advantage of the TDX2 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 be aligned precisely rather than relying on the compromise 'phase adjust' approach. Delay time can be input in either time or

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