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     The Frequency Response Combiner is a utility for adding, subtracting, splicing, delaying, correcting, smoothing, adding filters, bending, changing sampling size, extending or reducing the bandwidth, and generally pre-processing FRD (Frequency Response Data) files. The purpose of this FRD compositing is to ease the exchange of FRD files between other design programs, and to preview and compare response, phase, group delay and impulses. Modes of operation include:
    Assigned Polarity Log Sum for correcting Measured and Traced speaker driver responses with Bass Box Models, Baffle Diffraction Signatures, Room EQ and Linkwitz Transforms. Part of this module includes a very wide band Minimum Phase Extraction tool, an Impedance Phase Extraction tool and an Impulse generator, for viewing the resulting responses in the time domain.
    Mag/Phase Vector Linear Sum for infield summation and subtractive creation of complex crossover responses. These responses can be trimmed in gain and also advanced or delayed in time prior to summation.

    Filter Response Generation of 1st through 6th order High Pass/Low Pass Linear Phase & Standard Minimum Phase Filters and Shelf/Notch/Peak corrections. Filters include Single Q, Standard Named Filters, like Butterworth, Linkwitz-Riley and Bessel, and Custom A Value filters where the user can enter any arbitrary list of Polynomial Coefficients up to 8th order. 		    Normalizing Resample Extrapolation for user controllable response extension. This module can be used to convert from linear to log spaced frequency sample sets and to standardize to user selected Frequency Range and sample set size. User selects the best method to extend response with a large toolset of "easy to use" fourth order spline bending processes. User can extend past existing bandwidth or bend existing response to conform to any roll-off rate and roll-off curve shape with Frequency Knee and Bend Rate Tailing control for Pre-DSP processing.

    Gain Scaling, Smoothing & Splicing Editor The first is to change the gain range of any response, and the second to smooth out the response bumps without decimation. The last editor lets the user select the splice frequencies and the hard/soft splicing transition bandwidth from hard cut to 2 octave transitions. Splicing includes low to high and high to low auto gain matching automation.

     
    Other operations are 2PI to baffle gain conversion, distance conversion, gain trim, and combining and mixing of response in series or parallel. All seven registers Input and Output Standard FRD Format files for later import into other Acoustic Design Programs. Outputting, input interpolation, filter generation and a limited process subset of operations is also supported in Rect Linear DSP FRD file format to preprocess and feed DSP preview applications.


 

Current Version 0.9965    Date: July 2005
Copyright - Paul Verdone 2001 -  2005

 

To Download Frequency Response Combiner

(A Self Extracting Archive for Windows containing 
an Excel Spreadsheet Based VBA Program)

Program File Size 3024 k  -  Download Size 508 K

To Download Manual and Support Files

(A Self Extracting Archive for Windows containing an Excel add-in XLL, 
a FFT DLL and a 33 page Word Illustrated Operations Manual)

Items File Size 454 k  -  Download Size 294 K
 

This version is Free for personal and DIY use only. 

All Rights Reserved. Commercial use prohibited. 
Please contact frdc@pvconsultants.com for licensing information.