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The Transient Perfect Subtractive Delay
Multiway for Higher Order Crossovers is a utility for calculating a complimentary High Pass
and Band Pass response, from a Linear Phase or Minimum Phase Low Pass, via a user controlled delay. The use of delay results in higher order high pass
filters than would be obtained using the more common Constant Voltage subtractive approach, without delay, based on the same low pass filter.
The utility builds standard higher order Bessel, Butterworth, Linkwitz-Riley and Truncated Exponent filter coefficients, and derives a
Group Delay from a Low Pass filter. It lets the user select the Low Pass filter type and filter order, adjust the coefficients, and adjust the
delay to derive a subtractive High Pass transfer function and select the number
of Band Pass elements in between and their effective frequencies.
It is a tool for interactive exploration of stop band attenuation and supports outputs to polar pattern simulation programs. It is especially useful, giving the user detailed simulation control of resulting impulses, their characteristics in terms of pre and post ringing, and relative timing, and how they would be affected by off-axis and nearer/farther listening, changes to driver separation and Z timing acoustic centering errors. It graphs and outputs Graphs of the Magnitude of the filters, their roll-off rate changes and lobing phase errors, the impulse symmetry and impulse as effected by parallax, all in Gif file format. It writes in FRD format files with seven standard log spaced bandwidth/resolutions as a target response template for other acoustic design programs. It also writes in Rect Linear FRD DSP ready files of six bandwidth/resolutions to support real time audio processed preview. It has a Load/Store Librarian for Filter/Delay parameter combination management.
Version 0.9071 Date: November 2003
(A Self Extracting Archive for Windows containing an Excel Spreadsheet and Word Doc abbreviated User Manual)
Excel File Size 2708 k - Download Size 564 K