| function example_spk_eq() |
| |
| %% Design an example speaker equalizer with the provided sample data |
| % This equalizer by default uses a FIR and IIR components those should be |
| % both in the speaker pipeline. |
| % |
| % Note that IIR should be first since the included band-pass response provides |
| % signal headroom. |
| |
| %% |
| % 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> |
| % |
| |
| %% Get defaults for equalizer design |
| eq = eq_defaults(); |
| |
| %% Settings for this EQ |
| eq.fs = 48e3; % Default sample rate in SOF |
| eq.enable_fir = 1; % Try enabling and disabling FIR part |
| eq.enable_iir = 1; % Try enabling and disabling IIR part |
| eq.norm_type = 'peak'; % Scale filters to have peak at 0 dB |
| eq.norm_offs_db = 0; % Can be used to control gain |
| eq.p_fmin = 100; % With this data start plots from 100 Hz |
| eq.p_fmax = 20e3; % and end to 20 kHz. |
| |
| %% Get acousticial frequency response measurement data. This is |
| % a quite typical response for a miniature speaker. Alternatively |
| % the response could be read from spreadsheet column format that is |
| % commonly supported by audio measurement equipment. Then extract |
| % the frequency and magnitude columns. E.g. |
| % |
| % data = xlsread('spkr.xlsx', 1, 'A5:B78'); |
| % eq.raw_f = data(:,1); |
| % eq.raw_m_db = data(:,2); |
| |
| eq.raw_f = [ ... |
| 298.533, 316.232, 334.971, 354.813, 375.838, 398.106, ... |
| 421.699, 446.685, 473.153, 501.186, 530.887, 562.342, ... |
| 595.663, 630.958, 668.345, 707.946, 749.895, 794.329, ... |
| 841.397, 891.252, 944.062, 1000, 1059.26, 1122.02, ... |
| 1188.5, 1258.93, 1333.52, 1412.54, 1496.24, 1584.9, ... |
| 1678.81, 1778.28, 1883.65, 1995.27, 2113.49, 2238.72, ... |
| 2371.38, 2511.89, 2660.73, 2818.39, 2985.39, 3162.28, ... |
| 3349.66, 3548.14, 3758.38, 3981.08, 4216.97, 4466.84, ... |
| 4731.52, 5011.88, 5308.85, 5623.42, 5956.63, 6309.58, ... |
| 6683.45, 7079.47, 7498.95, 7943.3, 8413.97, 8912.52, ... |
| 9440.62, 10000, 10592.6, 11220.2, 11885, 12589.3, ... |
| 13335.2, 14125.4, 14962.4, 15849, 16788.1, 17782.8, ... |
| 18836.5, 19952.7 ... |
| ]; |
| |
| eq.raw_m_db = [ ... |
| 58.1704, 60.074, 60.4541, 61.3079, 62.8198, 64.3749, ... |
| 65.1556, 66.512, 67.5916, 68.6344, 69.9276, 70.7658, ... |
| 71.1125, 72.0627, 73.5348, 75.4887, 77.3088, 79.1541, ... |
| 80.9627, 82.0607, 81.943, 81.2228, 81.9497, 83.1848, ... |
| 84.3375, 85.4993, 86.4642, 87.1179, 87.4424, 87.53, ... |
| 85.7425, 85.0095, 82.9405, 82.9242, 82.7327, 83.6423, ... |
| 83.2839, 82.4201, 84.1403, 84.6485, 83.9274, 83.3366, ... |
| 83.3005, 84.2598, 85.1544, 86.015, 86.6519, 87.2118, ... |
| 87.5498, 88.1742, 88.5215, 88.3801, 89.8762, 91.4418, ... |
| 93.1845, 94.3355, 95.0918, 95.0258, 94.0337, 91.1068, ... |
| 88.7303, 87.4853, 86.2916, 83.037, 79.8056, 78.2022, ... |
| 76.0341, 74.5674, 69.2288, 56.1308, 68.697, 69.687, ... |
| 68.0005, 64.698 ... |
| ]; |
| |
| %% With parametric IIR EQ try to place peaking EQ at |
| % resonant frequencies 1.4 kHz and 7.5 kHz. The gain |
| % and Q values were experimented manually. Additionally |
| % The lowest and highest frequeciens below and above speaker |
| % capability are attenuated with high-pass and low-pass |
| % filtering. |
| if eq.enable_iir; |
| eq.peq = [ ... |
| eq.PEQ_HP2 100 NaN NaN; ... |
| eq.PEQ_PN2 1480 -7 2.0; ... |
| eq.PEQ_PN2 7600 -11 1.3; ... |
| eq.PEQ_LP2 14500 NaN NaN; ... |
| ]; |
| end |
| |
| %% With FIR EQ try to flatten frequency response within |
| % 1 - 13 kHz frequency band. |
| if eq.enable_fir |
| eq.fir_minph = 1; |
| eq.fir_beta = 4; |
| eq.fir_length = 63; |
| eq.fir_autoband = 0; |
| eq.fmin_fir = 900; |
| eq.fmax_fir = 10700; |
| end |
| |
| %% Design EQ |
| eq = eq_compute(eq); |
| |
| %% Plot |
| eq_plot(eq, 1); |
| |
| %% Export FIR part |
| platform_max_channels = 2; % Identical two speakers |
| assign_response = [0 0]; % Switch to response #0 |
| num_responses = 1; % Single response |
| if eq.enable_fir |
| bq_fir = eq_fir_blob_quant(eq.b_fir); |
| bm_fir = eq_fir_blob_merge(platform_max_channels, ... |
| num_responses, ... |
| assign_response, ... |
| [ bq_fir ]); |
| bp_fir = eq_fir_blob_pack(bm_fir); |
| eq_alsactl_write('example_spk_eq_fir.txt', bp_fir); |
| eq_blob_write('example_spk_eq_fir.blob', bp_fir); |
| eq_tplg_write('example_spk_eq_fir.m4', bp_fir, 'FIR'); |
| end |
| |
| %% Export IIR part |
| if eq.enable_iir |
| bq_iir = eq_iir_blob_quant(eq.p_z, eq.p_p, eq.p_k); |
| bm_iir = eq_iir_blob_merge(platform_max_channels, ... |
| num_responses, ... |
| assign_response, ... |
| [ bq_iir ]); |
| bp_iir = eq_iir_blob_pack(bm_iir); |
| eq_alsactl_write('example_spk_eq_iir.txt', bp_iir); |
| eq_blob_write('example_spk_eq_iir.blob', bp_iir); |
| eq_tplg_write('example_spk_eq_iir.m4', bp_iir, 'IIR'); |
| end |
| |
| end |
