Parametric Equalizer (PEQ)

Overview

The Parametric Equalizer (PEQ) is a cascade of configurable EQ filters.

Description

This component can work both for mono and stereo channels.

For stereo operation, the same set of filters is applied to both the channels.

The EQ filters have the following programmable properties:

a) number of bands (design time)

b) gain level for each band (run time)

c) gain presets (run time)

PEQ supports

• 5, 7, 9, 10, 11, 15 and 20 bands for 24-bit miniDSPs
• 5, 7, 9 and 10 bands for 16-bit miniDSPs

The gain indices can take values from -12 to +12 in steps of 0.25. A value of -12 will apply a -12 dB gain at the centre frequency of the corresponding band. A value of 12 will apply a 12 dB gain at the centre frequency of the corresponding band. The gain change is soft-stepped to provide smooth transitions

Each of the EQ filters has a fixed centre frequency and the Q value is unity (constant-Q filter)

For 24-bit miniDSPs, the centre frequencies are:

	8K	11K	16K	22K	24K	32K	44.1K	48K
5-bands	121 243 490 986 1986	127 271 574 1220 2590	136 307 693 1566 3539	143 341 812 1936 4615	145 351 849 2052 4962	152 386 980 2486 6307	161 430 1150 3078 8239	163 442 1200 3257 8842
7-bands	101 171 290 490 828 1400 2366	106 186 327 574 1010 1778 3127	111 204 376 693 1277 2354 4340	115 221 424 812 1558 2989 5734	116 226 438 849 1645 3191 6188	121 242 487 980 1970 3959 7959	126 263 550 1150 2407 5036 10538	127 268 567 1200 2538 5367 11349
9-bands	91 139 212 322 490 746 1135 1727 2628	94 148 233 366 574 903 1418 2228 3501	98 160 260 425 693 1130 1843 3007 4905	101 170 286 482 812 1368 2304 3879 6532	102 173 294 500 849 1441 2448 4159 7064	105 183 321 560 980 1713 2995 5235 9152	108 196 353 637 1150 2076 3748 6766 12215	109 199 362 659 1200 2185 3977 7241 13183
10-bands	88 129 189 276 405 593 869 1272 1864 2731	90 136 206 310 468 705 1064 1604 2419 3647	94 146 228 356 555 865 1350 2106 3287 5128	96 155 249 399 641 1030 1653 2655 4265 6849	97 157 255 412 667 1080 1748 2829 4579 7413	100 166 275 457 760 1263 2099 3487 5795 9629	103 176 300 514 879 1504 2574 4403 7534 12889	103 178 307 530 914 1576 2716 4683 8074 13921
11-bands	85 121 171 243 345 490 695 986 1400 1986 2819	87 127 186 271 394 574 837 1220 1778 2590 3774	90 136 204 307 461 693 1042 1566 2354 3539 5321	93 143 221 341 526 812 1254 1936 2989 4615 7125	93 145 226 351 546 849 1320 2052 3191 4962 7717	96 152 242 386 615 980 1561 2486 3959 6307 10045	98 161 263 430 703 1150 1882 3078 5036 8239 13478	99 163 268 442 728 1200 1977 3257 5367 8842 14567
15-bands	78 101 132 171 223 290 377 490 637 828 1077 1400 1820 2366 3077	80 106 140 186 246 327 433 574 762 1010 1340 1778 2357 3127 4147	81 111 150 204 277 376 510 693 941 1277 1734 2354 3196 4340 5892	83 115 159 221 306 424 587 812 1125 1558 2158 2989 4140 5734 7942	84 116 162 226 314 438 609 849 1182 1645 2291 3191 4444 6188 8617	85 121 171 242 344 487 691 980 1389 1970 2793 3959 5614 7959 11285	87 126 182 263 380 550 795 1150 1664 2407 3481 5036 7285 10538 15243	87 127 185 268 390 567 825 1200 1745 2538 3690 5367 7804 11349 16504
20-bands	73 90 109 134 163 199 243 297 363 443 541 661 808 986 1205 1472 1797 2195 2681 3275	74 92 114 142 176 218 271 335 416 516 640 793 984 1220 1513 1876 2326 2884 3577 4435	76 96 121 152 192 243 307 387 488 617 778 983 1240 1566 1977 2495 3150 3977 5020 6337	77 99 126 162 208 266 341 437 560 718 920 1179 1511 1936 2482 3181 4077 5225 6696 8583	77 99 128 165 212 273 351 452 581 748 963 1239 1594 2052 2641 3399 4374 5629 7245 9324	78 102 133 174 227 296 386 504 657 858 1119 1460 1905 2486 3243 4232 5521 7204 9399 12263	79 105 140 185 245 324 430 569 754 999 1324 1754 2324 3078 4078 5403 7158 9483 12563 16644	80 106 141 188 250 332 442 588 782 1040 1384 1841 2449 3257 4333 5763 7666 10197 13564 18043

For 16-bit miniDSPs, the centre frequencies are:

	8K	11K	16K	22K	24K	32K	44.1K	48K
5-bands	936 1251 1673 2237 2992	987 1392 1962 2767 3901	1051 1577 2366 3552 5330	1108 1753 2775 4392 6950	1124 1805 2898 4654 7473	1179 1987 3347 5638 9498	1244 2211 3929 6982 12408	1262 2274 4099 7388 13316
7-bands	870 1082 1346 1673 2081 2587 3217	906 1172 1516 1962 2539 3285 4251	949 1287 1745 2366 3209 4351 5900	988 1394 1967 2775 3915 5525 7796	999 1424 2032 2898 4134 5897 8412	1035 1531 2263 3347 4949 7318 10820	1077 1658 2552 3929 6047 9307 14326	1089 1694 2635 4099 6376 9918 15428
9-bands	833 992 1181 1406 1673 1992 2371 2823 3360	860 1057 1299 1597 1962 2411 2963 3642 4475	893 1139 1454 1855 2366 3019 3852 4915 6270	922 1214 1600 2107 2775 3655 4814 6341 8351	930 1236 1642 2181 2898 3851 5116 6798 9032	957 1309 1790 2447 3347 4576 6258 8557 11701	988 1396 1971 2782 3929 5547 7833 11060 15616	997 1419 2021 2878 4099 5837 8311 11836 16854
10-bands	820 961 1126 1319 1546 1811 2122 2487 2914 3414	844 1018 1228 1481 1787 2155 2599 3135 3781 4560	874 1090 1360 1698 2118 2644 3299 4117 5137 6411	899 1155 1484 1906 2448 3145 4040 5190 6666 8563	906 1173 1519 1967 2547 3298 4270 5529 7158 9268	930 1236 1643 2184 2903 3858 5128 6815 9058 12039	958 1311 1794 2454 3359 4596 6289 8606 11776 16114	965 1331 1836 2531 3490 4813 6637 9153 12621 17404

The figures below show +12 and -12 dB frequency plots for 5-,7-,9-,10-,11-,15- and 20-bands PEQ filters at 48 KHz. for 24-bit miniDSPs.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Configurable Properties (Design Time)

The properties described below can be changed during compilation of the PEQ component

Property	Scaling	Description
Instances	Enum	Number of bands of the PEQ component 5, 7, 9, 10, 11, 15, 20 for 16-bit miniDSPs 5, 7, 9, 10, for 24-bit miniDSPs

Configurable Properties (Runtime)

The properties described below can be changed runtime when the DRC is running in the device.

Property	Scaling	Description	Range	Default Value
1_Gain	5.x	Band1 Gain	-12 to +12 dB	0
2_Gain	5.x	Band2 Gain	-12 to +12 dB	0
3_Gain	5.x	Band3 Gain	-12 to +12 dB	0
4_Gain	5.x	Band4 Gain	-12 to +12 dB	0
5_Gain	5.x	Band5 Gain	-12 to +12 dB	0
6_Gain	5.x	Band6 Gain	-12 to +12 dB	0
7_Gain	5.x	Band7 Gain	-12 to +12 dB	0
8_Gain	5.x	Band8 Gain	-12 to +12 dB	0
9_Gain	5.x	Band9 Gain	-12 to +12 dB	0
10_Gain	5.x	Band10 Gain	-12 to +12 dB	0
11_Gain	5.x	Band11 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
12_Gain	5.x	Band12 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
13_Gain	5.x	Band13 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
14_Gain	5.x	Band14 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
15_Gain	5.x	Band15 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
16_Gain	5.x	Band16 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
17_Gain	5.x	Band17 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
18_Gain	5.x	Band18 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
19_Gain	5.x	Band19 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
20_Gain	5.x	Band20 Gain	-12 to +12 dB	0 (24-bit miniDSP only)
Presets		Set of gain coefficients	Enum	Rock Pop Jazz Blues Classical Reggae Reggaeton Hip-hop Rap Flat