Method, apparatus, and system for analysis, evaluation, measurement and control of audio dynamics processing

Abstract

A method, apparatus, and system for measuring and analyzing the effects of dynamics modifying processors on a signal. This new approach utilizes statistical analysis techniques to provide a direct comparison and evaluation between the processed signal and the unprocessed signal's dynamic characteristics. The method identifies and quantifies Effective Dynamic Range, Clip Tolerance, Lower Limit Tolerance, Crest Factor, and Diminuendo Factor, using either peak or r.m.s values. In an alternative embodiment, the invention allows for user adjustment and control of the relative relationship of Crest Factor and Diminuendo Factor, which the user may perceive as loudness.

I claim: 
     
         1 . A method for allowing a user to adjust the compression levels of an audio signal, the method comprising: an audio signal input; an audio output signal; a means of measuring the probability density function of a signal for a given time window; a processor that can calculate the Effective Dynamic Range (difference between Clip Tolerance and Lower Limit Tolerance) and the Crest Factor (ratio of the median signal value to the Clip Tolerance), and the Diminuendo Factor (ratio of the median signal value to the LLT); and a means for control that allows for an adjustment of the sequence of voltage values to alter the relative relationship of Crest Factor, Effective Dynamic Range, Diminuendo Factor, and Lower Limit Tolerance within total frequency bands of interest (e.g., the audio band from 20-20 kHz) or a sub-band or sub-bands of the frequency band of interest, such as the bass range or the middle frequency range; or multiple sub-bands analyzed and processed separately and simultaneously. 
     
     
         2 . The invention described in  1 , in which the means for control further comprises a method that can be used as an integral element within the control loop of a dynamics processor to allow the user to set target values for the outcomes for both absolute characteristics, in particular, two out of: Effective Dynamic Range, Effective Crest Factor and Diminuendo Factor, and relative characteristics in particular the ratios of Relative Loudness, Skew, Kurtosis, and Median r.m.s. 
     
     
         3 . The invention described in  1 , in which the means of setting user-defined levels for Clip Tolerance and Lower Limit Tolerance is further comprised as a control which allows the user to adjust the relationship between CT, LLT, Diminuendo Factor, and Effective Dynamic Range, such as a voltage-controlled potentiometer, or a digital means of mimicking such a potentiometer, including the digital output from a rotary encoder, the output of a digital counter incremented using up and down buttons or from graphical representations of such controls within a graphical user interface in a computer device (desktop, laptop, tablet, smartphone etc.). 
     
     
         4 . The invention described in  1 , further comprising a means for setting user-defined levels for Short Term Time Window (T rms ), and Long Term Time Window (LT rms ) {or its upper limit value T pop }, in which the user uses a potentiometer that linearly scales the time window, or a digital means which mimics such a potentiometer, in order to adjust the T rms , LT r.m.s.  and T pop . 
     
     
         5 . The invention described in  1 , further comprising a means for displaying the Effective Dynamic Range, Clip Tolerance, Lower Limit Tolerance, Crest Factor, and Diminuendo Factor. 
     
     
         6 . A apparatus for allowing a user to adjust the compression levels of an audio signal, the apparatus comprising: an audio input; an audio output; a processor that can calculate the Effective Dynamic Range (difference between Clip Tolerance and Lower Limit Tolerance), the Crest Factor (ratio of the median signal value to the Clip Tolerance), and the Diminuendo Factor (ratio of the median signal value to the LLT); and a means for setting user defined levels for Clip Tolerance, and Lower Limit Tolerance. 
     
     
         7 . The invention described in  6 , further comprising a means for setting user-defined levels for Short Term Time Window (Tr.m.s.), and Long Term Time Window (LT r.m.s ) {or its upper limit value T pop }. 
     
     
         8 . The invention described in  6 , further comprising a means for displaying the Effective Dynamic Range, Clip Tolerance, Lower Limit Tolerance, Crest Factor, and Diminuendo Factor. 
     
     
         9 . A system for allowing a user to adjust audio compression levels, the system comprising: an electrical-to-audio transducer; a device for processing the Effective Dynamic Range (difference between Clip Tolerance and Lower Limit Tolerance), the Crest Factor (ratio of the median signal value to the Clip Tolerance) and the Diminuendo Factor (ratio of the median signal value to the LLT), said device having an audio input and an audio output; an amplifier for raising the voltage of the output signal into the transducer to a user-definable level; and a means for setting user-defined levels for Clip Tolerance, and Lower Limit Tolerance. 
     
     
         10 . The invention described in  9 , further comprising a means for setting user-defined levels for Short Term Time Window (Tr.m.s.), and Long Term Time Window (LT r.m.s ) {or its upper limit value T pop }. 
     
     
         11 . The invention described in  9 , further comprising a means for displaying the Effective Dynamic Range, Clip Tolerance, Lower Limit Tolerance, Crest Factor, and Diminuendo Factor.