soft/tune/eq/example_iir_eq.m

%% Design effect EQs and bundle them to parameter block

%%
% Copyright (c) 2016, Intel Corporation
% All rights reserved.
%
% Redistribution and use in source and binary forms, with or without
% modification, are permitted provided that the following conditions are met:
%   * Redistributions of source code must retain the above copyright
%     notice, this list of conditions and the following disclaimer.
%   * Redistributions in binary form must reproduce the above copyright
%     notice, this list of conditions and the following disclaimer in the
%     documentation and/or other materials provided with the distribution.
%   * Neither the name of the Intel Corporation nor the
%     names of its contributors may be used to endorse or promote products
%     derived from this software without specific prior written permission.
%
% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
% POSSIBILITY OF SUCH DAMAGE.
%
% Author: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>
%

function example_iir_eq()

blob_fn = 'example_iir_eq.blob';
alsa_fn = 'example_iir_eq.txt';
endian = 'little';
fs = 48e3;

%% Design IIR loudness equalizer
eq_loud = loudness_iir_eq(fs);

%% Define a passthru IIR EQ equalizer
b_pass = [1 0 0];
a_pass = [1 0 0];

%% Quantize and pack filter coefficients plus shifts etc.
bq_pass = eq_iir_blob_quant(b_pass, a_pass);
bq_loud = eq_iir_blob_quant(eq_loud.b_p, eq_loud.a_p);

%% Build blob
platform_max_channels = 4;   % Setup max 4 channels EQ
assign_response = [1 1 1 1]; % Switch to response #1
num_responses = 2;           % Two responses: pass, loud
bm = eq_iir_blob_merge(platform_max_channels, ...
		       num_responses, ...
		       assign_response, ...
		       [bq_pass bq_loud]);

%% Pack and write file
bp = eq_iir_blob_pack(bm);
eq_blob_write(blob_fn, bp);
eq_alsactl_write(alsa_fn, bp);

end

%%

function eq = loudness_iir_eq(fs)

%% Derived from Fletcher-Munson curves for 80 and 60 phon
f = [ 20,21,22,24,25,27,28,30,32,34,36,38,40,43,45,48,51,54,57,60,64, ...
        68,72,76,81,85,90,96,102,108,114,121,128,136,144,153,162,171, ...
        182,192,204,216,229,243,257,273,289,306,324,344,364,386,409, ...
        434,460,487,516,547,580,614,651,690,731,775,821,870,922,977, ...
        1036,1098,1163,1233,1307,1385,1467,1555,1648,1747,1851,1962, ...
        2079,2203,2335,2474,2622,2779,2945,3121,3308,3505,3715,3937, ...
        4172,4421,4686,4966,5263,5577,5910,6264,6638,7035,7455,7901, ...
        8373,8873,9404,9966,10561,11193,11861,12570,13322,14118,14962, ...
        15856,16803,17808,18872,20000];

m = [ 0.00,-0.13,-0.27,-0.39,-0.52,-0.64,-0.77,-0.89,-1.02,-1.16,  ...
        -1.31,-1.46,-1.61,-1.76,-1.91,-2.07,-2.24,-2.43,-2.64,-2.85, ...
        -3.04,-3.21,-3.35,-3.48,-3.62,-3.78,-3.96,-4.16,-4.35,-4.54, ...
        -4.72,-4.90,-5.08,-5.26,-5.45,-5.64,-5.83,-6.02,-6.19,-6.37, ...
        -6.57,-6.77,-6.98,-7.19,-7.40,-7.58,-7.76,-7.92,-8.08,-8.25, ...
        -8.43,-8.60,-8.76,-8.92,-9.08,-9.23,-9.38,-9.54,-9.69,-9.84, ...
        -9.97,-10.09,-10.18,-10.26,-10.33,-10.38,-10.43,-10.48,-10.54, ...
        -10.61,-10.70,-10.78,-10.85,-10.91,-10.95,-10.98,-11.02, ...
        -11.05,-11.07,-11.10,-11.11,-11.11,-11.10,-11.10,-11.11, ...
        -11.14,-11.17,-11.20,-11.21,-11.22,-11.21,-11.20,-11.20, ...
        -11.21,-11.21,-11.20,-11.17,-11.11,-11.02,-10.91,-10.78, ...
        -10.63,-10.46,-10.25,-10.00,-9.72,-9.39,-9.02,-8.62,-8.19, ...
        -7.73,-7.25,-6.75,-6.25,-5.75,-5.28,-4.87,-4.54,-4.33,-4.30];

%% Get defaults for equalizer design
eq = eq_defaults();
eq.fs = fs;
eq.target_f = f;
eq.target_m_db = m;
eq.enable_iir = 1;
eq.norm_type = 'loudness';
eq.norm_offs_db = 0;

%% Manually setup low-shelf and high shelf parametric equalizers
%
% Parametric EQs are PEQ_HP1, PEQ_HP2, PEQ_LP1, PEQ_LP2, PEQ_LS1,
% PEQ_LS2, PEQ_HS1, PEQ_HS2 = 8, PEQ_PN2, PEQ_LP4, and  PEQ_HP4.
%
% Parametric EQs take as second argument the cutoff frequency in Hz
% and as second argument a dB value (or NaN when not applicable) . The
% Third argument is a Q-value (or NaN when not applicable).
eq.peq = [ ...
                 eq.PEQ_LS1 40 +2 NaN ; ...
                 eq.PEQ_LS1 80 +3 NaN ; ...
                 eq.PEQ_LS1 200 +3 NaN ; ...
                 eq.PEQ_LS1 400 +3 NaN ; ...
                 eq.PEQ_HS2 13000 +7 NaN ; ...
         ];

%% Design EQ
eq = eq_compute(eq);

%% Plot
eq_plot(eq);

end