SPL Meter Correction Tables

I don't think a lot of people know about the correction factors so making it a sticky would be a good idea. SVS has a page on it, too:

http://www.svsound.com/questions-faqs-rscomp.cfm

Yea sounds good. Correct information is good

That qti.net link is very interesting. I had assumed that it was the mic that gave the meter its lousy response (lousy as far as calibrated mics go). Turns out it's mostly the electronics.

Still, so long as we compensate for the deficiencies, it's good enough for our uses in audio.

Note also that the 'Quick Tip' on the danmark.com web page refers to measuring loudspeaker response, NOT something that the typical audiophile uses his meter for. So ignore the Tip. When calibrating speaker levels or checking room response, the meter goes as close to your head in the primary listening position as you can get it. Point it up. It mounts on a standard camera tripod which makes the process a lot easier.

Last week, I received a test CD from Rives Audio. It has 2 sets of 1/3 octave test tones recorded from 20 Hz to 20 kHz. One set is the standard set of test tones and the second set is "corrected" for the Radio Shack meter. I used the RS corrected tones to measure my system, and I got some confusing results. I then had the following e-mail exchange with "technical support" at Rives Audio:

"My center channel speaker appears to have severely reduced output above 10kHz, (down ~25 dB compared to the 80 dB reference). I moved one of my mains in front of the CC and hooked it to the CC cable. It too has limited output above 10 kHz, but not quite as severe, (down ~20 dB). However, it was also about 2 feet closer to the meter, which may explain the difference."

Response fro Rives Audio:

"Above 10k, the RS meter is not terribly reliable. I would not be too concerned with measurements above 10k."

Reply from me:

"The Test CD is billed as having a set of tracks that are specifically corrected for the Radio Shack SPL meter. If the Radio Shack meter is really that unreliable above 10k, maybe you should delete tracks 59, 60 and 61, and instead include an explanation that the meter is too unreliable to correct at those frequencies. It would keep people, (like me) from freaking out thinking that a tweeter is blown."

Response from Rives Audio:

"That's a reasonable idea, but people would then freak out and buy other Test CD's that had the full bandwidth."


According to the charts in the links in the original post, the RS meter is within +/- 1 dB from 10k to 20 kHz. So, who's right? I'm thinking that my meter is damaged. I sure HOPE its not my speakers!

Thoughts?

Craig

In the qti.net link the author refers to the digital meter being -3dB at 12 KHz, yet notes that the analog meter is better up top. -25 dB cannot be explained by meter foibles.

I think you should test it in free air - outside - at 1m and then (assuming the same result) worry about your electronics. If both speakers do it, it's not a blown tweeter.

Btw, since this is a sticky thread now, we should continue this elsewhere.

Here's a free Excel spreadsheet with the comp values that you can download. Makes it quicker than doing by hand. Also a PDF version for those without Excel:

http://www.audioc.com/library1/testcd/testcd.htm

When calibrating your Sub with SPL meter, Is it best to use the SPL in your primary seating location and point the SPL meter towards your sub?

OR is it better to measure with the SPL meter closer to the sub (if so, how close should you be to the sub?)

Thx,
Claude

Claude,

I've always heard to place it in the exact location that your ears would be in your primary setaing position, angled slightly forward.. maybe 20 to 30 degrees down from the ceiling towards the front of your room. Some people point it directly at the front of the room... others use 45 degrees.

Regs,
Jeff

Here's a somewhat more anal version of the table, courtesy of Ilkka and apparently appropriate to TrueRTA:

10 -14.33259693
10.59463094 -13.52968703
11.22462048 -12.74595335
11.89207115 -11.98268094
12.5992105 -11.24113838
13.34839854 -10.52255777
14.14213562 -9.828113197
14.98307077 -9.158898305
15.87401052 -8.515903684
16.81792831 -7.899994991
17.81797436 -7.311892737
18.87748625 -6.752154684
20 -6.221161728
21.18926189 -5.719108023
22.44924097 -5.24599587
23.7841423 -4.801635653
25.198421 -4.38565084
26.69679708 -3.997487754
28.28427125 -3.6364296
29.96614154 -3.30161399
31.74802104 -2.992053117
33.63585661 -2.706655603
35.63594873 -2.444249093
37.75497251 -2.203602722
40 -1.983448665
42.37852377 -1.782502185
44.89848193 -1.599479687
47.5682846 -1.43311451
50.396842 -1.282170279
53.39359417 -1.145451828
56.56854249 -1.021813749
59.93228308 -0.910166743
63.49604208 -0.809481987
67.27171322 -0.718793751
71.27189745 -0.63720053
75.50994501 -0.563864932
80 -0.498012574
84.75704755 -0.438930194
89.79696386 -0.385963182
95.1365692 -0.338512687
100.793684 -0.296032457
106.7871883 -0.258025523
113.137085 -0.224040813
119.8645662 -0.193669799
126.9920842 -0.1665432
134.5434264 -0.142327811
142.5437949 -0.12072348
151.01989 -0.101460247
160 -0.08429567
515.625 0.000 0.000
539.063 0.015 0.181
562.500 0.029 0.364
585.938 0.041 0.544
609.375 0.052 0.739
632.813 0.063 0.949
656.250 0.076 1.187
679.688 0.091 1.444
703.125 0.111 1.711
726.563 0.135 1.978
750.000 0.162 2.237
773.438 0.191 2.488
796.875 0.222 2.729
820.313 0.255 2.962
843.750 0.288 3.187
867.188 0.322 3.408
890.625 0.357 3.625
914.063 0.392 3.839
937.500 0.428 4.051
960.938 0.465 4.265
984.375 0.503 4.474
1007.813 0.541 4.682
1031.250 0.580 4.888
1054.688 0.619 5.088
1078.125 0.660 5.293
1101.563 0.700 5.492
1125.000 0.741 5.687
1148.438 0.781 5.880
1171.875 0.818 6.069
1195.313 0.857 6.259
1218.750 0.893 6.451
1242.188 0.931 6.646
1265.625 0.968 6.841
1289.063 1.008 7.039
1312.500 1.049 7.236
1335.938 1.091 7.433
1359.375 1.134 7.633
1382.813 1.179 7.830
1406.250 1.224 8.031
1429.688 1.272 8.221
1453.125 1.322 8.409
1476.563 1.376 8.581
1500.000 1.433 8.724
1523.438 1.491 8.832
1546.875 1.547 8.900
1570.313 1.599 8.938
1593.750 1.648 8.947
1617.188 1.693 8.938
1640.625 1.733 8.920
1664.063 1.770 8.906
1687.500 1.804 8.900
1710.938 1.837 8.902
1734.375 1.868 8.910
1757.813 1.900 8.920
1781.250 1.931 8.935
1804.688 1.961 8.947
1828.125 1.990 8.952
1851.563 2.020 8.959
1875.000 2.049 8.964
1898.438 2.076 8.963
1921.875 2.102 8.967
1945.313 2.128 8.969
1968.750 2.152 8.976
1992.188 2.177 8.987
2015.625 2.203 8.996
2039.063 2.227 9.005
2062.500 2.250 9.012
2085.938 2.275 9.017
2109.375 2.301 9.020
2132.813 2.327 9.017
2156.250 2.351 9.012
2179.688 2.374 9.004
2203.125 2.395 8.999
2226.563 2.415 8.991
2250.000 2.435 8.987
2273.438 2.453 8.985
2296.875 2.471 8.978
2320.313 2.489 8.973
2343.750 2.505 8.962
2367.188 2.519 8.962
2390.625 2.532 8.963
2414.063 2.543 8.980
2437.500 2.555 9.013
2460.938 2.568 9.070
2484.375 2.586 9.136
2507.813 2.608 9.198
2531.250 2.633 9.246
2554.688 2.659 9.280
2578.125 2.683 9.299
2601.563 2.706 9.307
2625.000 2.728 9.305
2648.438 2.749 9.295
2671.875 2.770 9.280
2695.313 2.788 9.261
2718.750 2.806 9.238
3164.063 2.938 9.082
3187.500 2.935 9.122
3210.938 2.932 9.173
3234.375 2.929 9.248
3257.813 2.926 9.333
3281.250 2.926 9.432
3304.688 2.928 9.535
3328.125 2.931 9.637
3351.563 2.936 9.743
3375.000 2.941 9.846
3398.438 2.947 9.948
3421.875 2.953 10.045
3445.313 2.958 10.146
3468.750 2.962 10.243
3492.188 2.968 10.345
3515.625 2.975 10.449
3539.063 2.982 10.557
3562.500 2.990 10.671
3585.938 2.998 10.789
3609.375 3.006 10.916
3632.813 3.015 11.053
3656.250 3.025 11.199
3679.688 3.039 11.354
3703.125 3.055 11.520
3726.563 3.074 11.682
3750.000 3.095 11.837
3773.438 3.118 11.983
3796.875 3.142 12.112
3820.313 3.167 12.230
3843.750 3.192 12.331
3867.188 3.217 12.422
3890.625 3.243 12.502
3914.063 3.270 12.578
3937.500 3.297 12.648
3960.938 3.325 12.710
3984.375 3.352 12.766
4007.813 3.379 12.815
4031.250 3.406 12.855
4054.688 3.433 12.890
4078.125 3.461 12.912
4101.563 3.488 12.930
4125.000 3.514 12.938
4148.438 3.540 12.939
4171.875 3.565 12.929
4195.313 3.591 12.915
4218.750 3.616 12.892
4242.188 3.640 12.863
4265.625 3.664 12.828
4289.063 3.686 12.780
4312.500 3.706 12.725
4335.938 3.724 12.661
4359.375 3.740 12.599
4382.813 3.753 12.535
4406.250 3.764 12.483
4429.688 3.772 12.440
4453.125 3.781 12.409
4476.563 3.788 12.392
4500.000 3.795 12.383
4523.438 3.804 12.391
4546.875 3.812 12.404
4570.313 3.820 12.427
4593.750 3.829 12.456
4617.188 3.838 12.492
4640.625 3.849 12.533
4664.063 3.860 12.585
4687.500 3.872 12.651
4710.938 3.885 12.729
4734.375 3.901 12.822
4757.813 3.919 12.924
4781.250 3.938 13.032
4804.688 3.961 13.143
4828.125 3.986 13.258
4851.563 4.013 13.369
4875.000 4.043 13.476
4898.438 4.076 13.576
4921.875 4.112 13.664
4945.313 4.150 13.741
4968.750 4.190 13.803
4992.188 4.230 13.850
5015.625 4.269 13.883
5039.063 4.309 13.900
5062.500 4.350 13.906
5085.938 4.391 13.904
5109.375 4.432 13.895
5132.813 4.471 13.885
5156.250 4.510 13.873
5179.688 4.550 13.870
5203.125 4.592 13.879
5226.563 4.638 13.894
5250.000 4.687 13.913
5273.438 4.742 13.923
5296.875 4.802 13.913
5320.313 4.866 13.871
5343.750 4.933 13.790
5367.188 5.002 13.667
5390.625 5.071 13.501
5414.063 5.141 13.288
5437.500 5.211 13.035
5460.938 5.280 12.732
5484.375 5.347 12.388
5507.813 5.413 11.997
5531.250 5.472 11.564
5554.688 5.525 11.091
5578.125 5.570 10.586
5601.563 5.606 10.061
5625.000 5.635 9.528
5648.438 5.655 8.999
5671.875 5.670 8.481
5695.313 5.680 7.985
5718.750 5.684 7.507
5742.188 5.686 7.050
5765.625 5.685 6.613
5789.063 5.681 6.190
5812.500 5.675 5.783
5835.938 5.666 5.395
5859.375 5.653 5.024
5882.813 5.638 4.674
5906.250 5.622 4.345
5929.688 5.607 4.037
5953.125 5.595 3.750
5976.563 5.584 3.484
6000.000 5.574 3.229
6023.438 5.565 2.986
6046.875 5.557 2.748
6070.313 5.552 2.508
6093.750 5.548 2.264
6117.188 5.544 2.005
6140.625 5.540 1.731
6164.063 5.536 1.443
6187.500 5.530 1.145
6210.938 5.521 0.846
6234.375 5.509 0.551
6257.813 5.496 0.265
6281.250 5.480 -0.010
6304.688 5.464 -0.274
6328.125 5.448 -0.526
6351.563 5.430 -0.767
6375.000 5.412 -0.999
6398.438 5.393 -1.222
6421.875 5.375 -1.437
6445.313 5.359 -1.643
6468.750 5.344 -1.845
6492.188 5.332 -2.041
6515.625 5.322 -2.237
6539.063 5.316 -2.442
6562.500 5.310 -2.658
6726.563 5.246 -4.667
6820.313 5.171 -5.937
6843.750 5.152 -6.257
6867.188 5.130 -6.583
6890.625 5.105 -6.919
6914.063 5.077 -7.264
6937.500 5.048 -7.617
6960.938 5.018 -7.980
6984.375 4.985 -8.350
7007.813 4.950 -8.725
7031.250 4.910 -9.102
7054.688 4.867 -9.478
7078.125 4.820 -9.848
7101.563 4.769 -10.206
7125.000 4.713 -10.548
7148.438 4.652 -10.870
7171.875 4.589 -11.169
7195.313 4.523 -11.442
7218.750 4.454 -11.689
7242.188 4.384 -11.906
7265.625 4.313 -12.093
7289.063 4.241 -12.249
7312.500 4.168 -12.371
7335.938 4.097 -12.459
7359.375 4.026 -12.513
7382.813 3.958 -12.537
7406.250 3.892 -12.530
7429.688 3.830 -12.501
7453.125 3.772 -12.453
7476.563 3.718 -12.393
7500.000 3.668 -12.324
7523.438 3.620 -12.246
7546.875 3.575 -12.166
7570.313 3.533 -12.081
7593.750 3.495 -11.994
7617.188 3.460 -11.907
7640.625 3.428 -11.825
7664.063 3.400 -11.753
7687.500 3.374 -11.696
7710.938 3.351 -11.656
7734.375 3.329 -11.637
7757.813 3.307 -11.637
7781.250 3.283 -11.656
7804.688 3.260 -11.689
7828.125 3.234 -11.731
7851.563 3.207 -11.776
7875.000 3.178 -11.819
7898.438 3.146 -11.854
7921.875 3.113 -11.875
7945.313 3.080 -11.881
7968.750 3.047 -11.872
7992.188 3.016 -11.847
8015.625 2.988 -11.812
8039.063 2.964 -11.771
8062.500 2.943 -11.732
8085.938 2.927 -11.699
8109.375 2.914 -11.679
8132.813 2.905 -11.679
8156.250 2.897 -11.701
8179.688 2.891 -11.750
8203.125 2.885 -11.826
8226.563 2.878 -11.933
8250.000 2.870 -12.070
8273.438 2.860 -12.238
8296.875 2.848 -12.434
8320.313 2.830 -12.654
8343.750 2.808 -12.896
8367.188 2.780 -13.146
8390.625 2.746 -13.399
8414.063 2.706 -13.645
8437.500 2.661 -13.875
8460.938 2.611 -14.087
8484.375 2.557 -14.275
8507.813 2.500 -14.438
8531.250 2.442 -14.573
8554.688 2.381 -14.678
8578.125 2.319 -14.750
8601.563 2.256 -14.787
8625.000 2.192 -14.787
8648.438 2.129 -14.751
8671.875 2.068 -14.680
8695.313 2.012 -14.579
8718.750 1.959 -14.452
8742.188 1.912 -14.310
8765.625 1.871 -14.156
8789.063 1.834 -13.998
8812.500 1.803 -13.841
8835.938 1.775 -13.691
8859.375 1.751 -13.550
8882.813 1.730 -13.423
8906.250 1.712 -13.312
8929.688 1.697 -13.219
8953.125 1.683 -13.144
9375.000 1.294 -13.518
9398.438 1.280 -13.492
9421.875 1.270 -13.481
9445.313 1.262 -13.489
9468.750 1.255 -13.518
9492.188 1.248 -13.568
9515.625 1.241 -13.640
9539.063 1.233 -13.732
9562.500 1.225 -13.841
9585.938 1.215 -13.965
9609.375 1.203 -14.101
9632.813 1.188 -14.245
9656.250 1.171 -14.395
9679.688 1.152 -14.546
9703.125 1.131 -14.698
9726.563 1.109 -14.851
9750.000 1.088 -15.008
9773.438 1.066 -15.168
9796.875 1.043 -15.335
9820.313 1.018 -15.510
9843.750 0.989 -15.692
9867.188 0.958 -15.877
9890.625 0.922 -16.059
9914.063 0.883 -16.234
9937.500 0.841 -16.390
9960.938 0.796 -16.520
9984.375 0.748 -16.619
10007.810 0.700 -16.684
10031.250 0.653 -16.714
10054.690 0.608 -16.712
10078.130 0.567 -16.684
10101.560 0.530 -16.639
10125.000 0.499 -16.593
10148.440 0.472 -16.560
10171.880 0.449 -16.552
10195.310 0.427 -16.576
10218.750 0.405 -16.628
10242.190 0.382 -16.706
10265.630 0.359 -16.801
10289.060 0.333 -16.910
10312.500 0.305 -17.028
10335.940 0.275 -17.154
10359.380 0.243 -17.281
10382.810 0.208 -17.411
10406.250 0.173 -17.540
10429.690 0.136 -17.670
10453.130 0.099 -17.798
10476.560 0.061 -17.926
10500.000 0.023 -18.060
10523.440 -0.015 -18.194
10546.880 -0.055 -18.333
10570.310 -0.095 -18.478
10593.750 -0.137 -18.629
10617.190 -0.180 -18.784
10640.630 -0.225 -18.942
10664.060 -0.273 -19.098
10687.500 -0.323 -19.252
10710.940 -0.376 -19.397
10734.380 -0.429 -19.529
10757.810 -0.482 -19.643
10781.250 -0.535 -19.741
10804.690 -0.586 -19.826
10828.130 -0.635 -19.905
10851.560 -0.684 -19.977
10875.000 -0.731 -20.056
10898.440 -0.777 -20.146
10921.880 -0.823 -20.253
10945.310 -0.867 -20.375
10968.750 -0.914 -20.511
10992.190 -0.961 -20.662
11015.630 -1.012 -20.817
11039.060 -1.066 -20.976
11226.560 -1.592 -21.844
11250.000 -1.664 -21.887
11273.440 -1.737 -21.919
11296.880 -1.810 -21.945
11320.310 -1.883 -21.962
11343.750 -1.957 -21.974
11367.190 -2.034 -21.980
11390.630 -2.113 -21.977
11414.060 -2.194 -21.958
11437.500 -2.278 -21.920
11460.940 -2.362 -21.855
11484.380 -2.448 -21.758
11507.810 -2.533 -21.630
11531.250 -2.616 -21.462
11554.690 -2.696 -21.261
11578.130 -2.773 -21.031
11601.560 -2.845 -20.780
11625.000 -2.911 -20.517
11648.440 -2.971 -20.251
11671.880 -3.026 -19.986
11695.310 -3.076 -19.738
11718.750 -3.122 -19.504
11742.190 -3.164 -19.295
11765.630 -3.203 -19.111
11789.060 -3.238 -18.957
11812.500 -3.272 -18.832
11835.940 -3.305 -18.741
11859.380 -3.337 -18.678
11882.810 -3.370 -18.648
11906.250 -3.403 -18.644
11929.690 -3.439 -18.667
11953.130 -3.475 -18.712
11976.560 -3.514 -18.773
12000.000 -3.555 -18.849
12023.440 -3.598 -18.933
12046.880 -3.645 -19.025
12070.310 -3.693 -19.126
12093.750 -3.744 -19.225
12117.190 -3.796 -19.321
12140.630 -3.850 -19.415
12164.060 -3.906 -19.502
12187.500 -3.963 -19.584
12210.940 -4.021 -19.644
12234.380 -4.081 -19.694
12257.810 -4.141 -19.730
12281.250 -4.199 -19.739
12304.690 -4.257 -19.737
12328.130 -4.311 -19.725
12351.560 -4.362 -19.706
12375.000 -4.411 -19.694
12398.440 -4.456 -19.701
12421.880 -4.499 -19.715
12445.310 -4.542 -19.754
12468.750 -4.586 -19.807
12492.190 -4.633 -19.880
12515.630 -4.681 -19.970
12539.060 -4.732 -20.052
12562.500 -4.789 -20.133
12585.940 -4.847 -20.205
12609.380 -4.909 -20.243
12632.810 -4.974 -20.268
12656.250 -5.038 -20.273
12679.690 -5.103 -20.244
12703.130 -5.169 -20.203
12726.560 -5.234 -20.138
12750.000 -5.301 -20.060
12773.440 -5.366 -19.969
12796.880 -5.431 -19.856
12820.310 -5.496 -19.738
12843.750 -5.559 -19.601
12867.190 -5.622 -19.443
12890.630 -5.685 -19.283
12914.060 -5.745 -19.107
12937.500 -5.804 -18.918
12960.940 -5.862 -18.733
12984.380 -5.916 -18.536
13007.810 -5.971 -18.342
13031.250 -6.022 -18.158
13054.690 -6.072 -17.983
13078.130 -6.122 -17.828
13101.560 -6.170 -17.697
13382.810 -6.945 -17.103
13406.250 -7.018 -17.029
13429.690 -7.090 -16.947
13453.130 -7.163 -16.891
13476.560 -7.236 -16.856
13500.000 -7.313 -16.839
13523.440 -7.395 -16.845
13546.880 -7.483 -16.866
13570.310 -7.579 -16.881
13593.750 -7.682 -16.880
13617.190 -7.791 -16.843
13640.630 -7.906 -16.754
13664.060 -8.023 -16.616
13687.500 -8.142 -16.410
13710.940 -8.258 -16.156
13734.380 -8.372 -15.840
13757.810 -8.483 -15.473
13781.250 -8.591 -15.085
13804.690 -8.695 -14.661
13828.130 -8.795 -14.217
13851.560 -8.892 -13.745
13875.000 -8.986 -13.243
13898.440 -9.078 -12.714
13921.880 -9.167 -12.161
13945.310 -9.251 -11.577
13968.750 -9.330 -10.959
13992.190 -9.404 -10.311
14015.630 -9.471 -9.650
14039.060 -9.531 -8.957
14062.500 -9.586 -8.258
14085.940 -9.633 -7.564
14109.380 -9.673 -6.868
14132.810 -9.708 -6.188
14156.250 -9.738 -5.526
14179.690 -9.767 -4.893
14203.130 -9.796 -4.285
14226.560 -9.826 -3.700
14250.000 -9.859 -3.115
14273.440 -9.894 -2.530
14296.880 -9.930 -1.920
14320.310 -9.969 -1.304
14343.750 -10.005 -0.668
14367.190 -10.037 -0.013
14390.630 -10.069 0.673
14414.060 -10.096 1.343
14437.500 -10.119 2.033
14460.940 -10.138 2.712
14484.380 -10.152 3.380
14507.810 -10.160 4.050
14531.250 -10.166 4.685
14554.690 -10.166 5.305
14578.130 -10.163 5.893
14601.560 -10.156 6.445
14625.000 -10.147 6.982
14648.440 -10.139 7.481
14671.880 -10.127 7.929
14695.310 -10.112 8.354
14718.750 -10.094 8.732
14742.190 -10.072 9.078
14765.630 -10.051 9.384
14789.060 -10.027 9.615
14812.500 -10.002 9.801
14835.940 -9.982 9.923
14859.380 -9.963 9.983
14882.810 -9.951 10.019
14906.250 -9.946 10.008
14929.690 -9.944 9.980
14953.130 -9.950 9.972
14976.560 -9.959 9.945
15000.000 -9.967 9.971
15023.440 -9.980 10.020
15046.880 -9.989 10.071
15070.310 -9.995 10.169
15093.750 -10.000 10.248
15117.190 -9.993 10.337
15140.630 -9.981 10.432
15164.060 -9.965 10.507
15187.500 -9.940 10.542
15210.940 -9.912 10.568
15234.380 -9.880 10.524
15257.810 -9.841 10.478
15281.250 -9.805 10.399
15304.690 -9.764 10.266
15328.130 -9.722 10.107
15351.560 -9.678 9.892
15375.000 -9.631 9.621
15398.440 -9.587 9.315
15421.880 -9.546 8.935
15750.000 -9.716 3.011
15773.440 -9.751 2.720
15796.880 -9.789 2.443
15820.310 -9.826 2.162
15843.750 -9.866 1.882
15867.190 -9.908 1.611
15890.630 -9.956 1.333
15914.060 -10.007 1.083
15937.500 -10.063 0.842
15960.940 -10.122 0.626
15984.380 -10.183 0.420
16007.810 -10.247 0.222
16031.250 -10.310 0.030
16054.690 -10.376 -0.157
16078.130 -10.446 -0.335
16101.560 -10.520 -0.547
16125.000 -10.602 -0.717
16148.440 -10.697 -0.908
16171.880 -10.803 -1.025
16195.310 -10.928 -1.069
16218.750 -11.062 -0.992
16242.190 -11.202 -0.750
16265.630 -11.336 -0.296
16289.060 -11.465 0.288
16312.500 -11.569 1.022
16335.940 -11.663 1.843
16359.380 -11.733 2.688
16382.810 -11.780 3.597
16406.250 -11.819 4.526
16429.690 -11.829 5.411
16453.130 -11.828 6.380
16476.560 -11.821 7.299
16500.000 -11.799 8.195
16523.440 -11.770 9.101
16546.880 -11.734 9.955
16570.310 -11.686 10.818
16593.750 -11.636 11.670
16617.190 -11.577 12.488
16640.630 -11.510 13.296
16664.060 -11.440 14.086
16687.500 -11.362 14.822
16710.940 -11.280 15.585
16734.380 -11.205 16.294
16757.810 -11.119 16.974
16781.250 -11.036 17.703
16804.690 -10.952 18.372
16828.130 -10.851 19.047
16851.560 -10.751 19.751
16875.000 -10.644 20.353
16898.440 -10.524 20.959
16921.880 -10.406 21.530
16945.310 -10.281 22.030
16968.750 -10.154 22.550
16992.190 -10.032 22.982
17015.630 -9.903 23.382
17039.060 -9.778 23.758
17062.500 -9.652 24.046
17085.940 -9.519 24.337
17109.380 -9.397 24.542
17132.810 -9.264 24.627
17156.250 -9.133 24.649
17179.690 -9.015 24.534
17203.130 -8.910 24.253
17226.560 -8.817 23.951
17250.000 -8.757 23.592
17273.440 -8.702 23.196
17296.880 -8.667 22.892
17601.560 -8.770 20.120
17625.000 -8.782 20.017
17648.440 -8.793 19.881
17671.880 -8.790 19.757
17695.310 -8.791 19.580
17718.750 -8.776 19.347
17742.190 -8.765 19.127
17765.630 -8.762 18.828
17789.060 -8.756 18.462
17812.500 -8.755 18.139
17835.940 -8.760 17.762
17859.380 -8.765 17.409
17882.810 -8.773 17.069
17906.250 -8.782 16.712
17929.690 -8.788 16.390
17953.130 -8.793 16.034
17976.560 -8.791 15.712
18000.000 -8.791 15.381
18023.440 -8.790 15.003
18046.880 -8.782 14.619
18070.310 -8.782 14.224
18093.750 -8.781 13.772
18117.190 -8.781 13.359
18140.630 -8.792 12.935
18164.060 -8.803 12.508
18187.500 -8.817 12.102
18210.940 -8.836 11.728
18234.380 -8.860 11.360
18257.810 -8.887 10.990
18281.250 -8.914 10.632
18304.690 -8.945 10.293
18328.130 -8.986 9.976
18351.560 -9.029 9.618
18375.000 -9.077 9.333
18398.440 -9.135 9.034
18421.880 -9.195 8.765
18445.310 -9.264 8.577
18468.750 -9.341 8.383
18492.190 -9.417 8.264
18515.630 -9.501 8.208
18539.060 -9.587 8.172
18562.500 -9.669 8.190
18585.940 -9.750 8.254
18609.380 -9.828 8.346
18632.810 -9.901 8.491
18656.250 -9.981 8.620
18679.690 -10.048 8.709
18703.130 -10.116 8.825
18726.560 -10.187 8.900
18750.000 -10.255 8.942
18773.440 -10.329 8.992
18796.880 -10.404 9.002
18820.310 -10.482 9.031
18843.750 -10.564 9.054
18867.190 -10.647 9.089
18890.630 -10.730 9.150
18914.060 -10.815 9.228
18937.500 -10.897 9.311
18960.940 -10.974 9.418
18984.380 -11.049 9.519
19007.810 -11.114 9.610
19031.250 -11.176 9.724
19054.690 -11.237 9.774
19078.130 -11.286 9.804
19101.560 -11.336 9.848
19570.310 -11.889 6.085
19593.750 -11.922 5.741
19617.190 -11.955 5.439
19640.630 -11.986 5.144
19664.060 -12.015 4.873
19687.500 -12.040 4.626
19710.940 -12.064 4.382
19734.380 -12.084 4.147
19757.810 -12.101 3.910
19781.250 -12.115 3.679
19804.690 -12.127 3.446
19828.130 -12.139 3.215
19851.560 -12.150 2.966
19875.000 -12.158 2.731
19898.440 -12.169 2.491
19921.880 -12.175 2.263
19945.310 -12.188 2.059
19968.750 -12.201 1.822
19992.190 -12.212 1.606

You could have just posted the link...

http://personal.inet.fi/private/ilkka/RSAnalogueSPL.txt

And yes, save that as a txt file and use as a mic correction file with TrueRTA.

Thanks for responding....I really appreciate the advice. My sub it positioned right behind my recylner. Would I still want it at my seating ear level position and pointed slightly towards the front as you mentioned?

I should have my SPL Meter tomorrow.

Thx,
Claude

Please take the setup questions to a non-sticky thread.

According to the instructions on Avia and DVE test DVDs, point the meter straight UP (at your listening position(s) -- or between them. This is also what I have read on SVS and other sites.

This is also what the Pionner MCACC and other Auto-Calibration receivers also recommend.

Leaning the meter forward biases the meter readings falsely. The only time you want to point towards any speaker is if you are making "Near Field" measurements -- done outside (or in an anechioc chamber).

ACI says to add 6.2 at 20Hz. The other ones say to add 7.5 at 20Hz. What gives?

6.2dB's comes from the general c-weighting correction. 7.5dB's comes from one guy's measurements. I believe 6.2dB is more closer to the "truth".

Would the Digital Radio Shack SPL Meter have the same correction table?

Yes.

Thanks.

Ed Mullen posted the correction factors for a B&K SPL meter in C-weighted mode:

====================
You can clearly round these off - the program simply calc'd them out to several significant digits.

Frequency C-Weight
10 -14.33259693
10.59463094 -13.52968703
11.22462048 -12.74595335
11.89207115 -11.98268094
12.5992105 -11.24113838
13.34839854 -10.52255777
14.14213562 -9.828113197
14.98307077 -9.158898305
15.87401052 -8.515903684
16.81792831 -7.899994991
17.81797436 -7.311892737
18.87748625 -6.752154684
20 -6.221161728
21.18926189 -5.719108023
22.44924097 -5.24599587
23.7841423 -4.801635653
25.198421 -4.38565084
26.69679708 -3.997487754
28.28427125 -3.6364296
29.96614154 -3.30161399
31.74802104 -2.992053117
33.63585661 -2.706655603
35.63594873 -2.444249093
37.75497251 -2.203602722
40 -1.983448665
42.37852377 -1.782502185
44.89848193 -1.599479687
47.5682846 -1.43311451
50.396842 -1.282170279
53.39359417 -1.145451828
56.56854249 -1.021813749
59.93228308 -0.910166743
63.49604208 -0.809481987
67.27171322 -0.718793751
71.27189745 -0.63720053
75.50994501 -0.563864932
80 -0.498012574
84.75704755 -0.438930194
89.79696386 -0.385963182
95.1365692 -0.338512687
100.793684 -0.296032457
106.7871883 -0.258025523
113.137085 -0.224040813
119.8645662 -0.193669799
126.9920842 -0.1665432
134.5434264 -0.142327811
142.5437949 -0.12072348
151.01989 -0.101460247
160 -0.08429567
====================

Has anyone looked through all of youngho's nice links and noted what the unit-to-unit variation is for the RS meter?

Thanks

I didn't see one.

I looked; they all seem to be pretty much the same.

Sorry if this has been asked before but what frequency are the internal test tones at on a THX certified receiver? I currently have mine set up where the SPL meter bounces between 75-78dB.

Pink noise, which is a mix of many frequencies. And the THX certification has nothing to do with it (or much else).

gti.net link is gone.

Here's the new site (Eric Wallin's RS meter mods).

And here is a discussion of the mods with some interesting related notes.
.

Thanks for the update, heading out in an hour to get an anolog meter.

One question, if I get 'it', the correction talk, (and I may not), I can either use the stock unit and apply the correction values published in various places, "OR", change out the caps. as discussed in the Wallin meter mod.

I shouldn't do both - correct???

Are the correction factors the same for the digital version of the Radio Shack SPL meter?

Editted:

No, especially below about 150 Hz. Nor is the new analog meter (new after the question was originally posted) the same as the old, although the digital and new analog meters are quite similar. See page 3 of this thread for new data.