SPL Correction Tables- Why So Many?

[tonybradley]

Can anyone let me know why there are so many Correction Tables for the same RS SPL meter? How does one know which to use, or know that the one built in to REW is the correct correction table when there are many, and vastly different. AVS has a sticky of correction tables, and they are all different. Just confusing.

Examples:

From SVS Site:
http://www.svsound.com/questions-faqs-rscomp.cfm
12Hz add 16.5dB
16Hz add 11.5dB
20Hz add 7.5dB
25Hz add 5dB
31.5Hz add 3dB
40Hz add 2.5dB
50Hz add 1.5dB
63Hz add 1.5dB
80Hz add 1.5dB
100Hz add 2dB
125Hz add .5dB

And here are the ones from the Download section of this site (both sites I've listed are correction values for the 33-2050 Old Analog RS SPL meter. If you look, they are not even close. Example: at 16Hz, SVS says to add only 11.5dB. However, the correction tables on here say to add 20.63dB. That's over a 9dB difference, which is HUGE. Same for the other correction values I've seen. So, which ones does one use???????????
http://www.hometheatershack.com/foru...oads-page.html


10.0 -37.20
11.2 -32.88
12.5 -27.15
14.0 -23.29
16.0 -20.63
18.0 -18.69
20.0 -17.04
22.4 -15.40
25.0 -13.69
28.0 -11.99
31.5 -10.44
35.5 -9.08
40.0 -7.97
45.0 -6.99
50.0 -6.09
56.0 -5.39
63.0 -4.84
71.0 -4.29
80.0 -3.76
90.0 -3.25
100.0 -2.93
112.0 -2.69
125.0 -2.41
140.0 -2.20
160.0 -2.07
180.0 -1.97
200.0 -1.83
224.0 -1.69
250.0 -1.60
280.0 -1.44
315.0 -1.27
355.0 -1.05
400.0 -0.80
450.0 -0.67
500.0 -0.62
560.0 -0.55
630.0 -0.55
710.0 -0.58
800.0 -0.52
900.0 -0.28
1000.0 0.00

[brucek]

Yes, there are many calibration files for the Radio Shack meters floating around. Quite a few are simply comparisons against calibrated mics. They may or may not be accurate.
Our Radio Shack calibration files have been professionally created by Cross Spectrum Labs. They are tested as frontal incidence employing the pressure method. They're quite accurate for the meters they were created for, but you take the risk of them not being accurate for your own meter.

So, which ones does one use?

Use the ones from our download site.

brucek

[stc4life]

Hi,
Sorry for the noobish question, but where can I download the spl correction table? Also, I thought I read that there are excel tables that automatically apply the corrections. Can someone point me in the right direction?
Thanks!

[brucek]

See the Download Page.

I would suggest using REW instead of the manual method. Read the REW HELP files and the REW Cabling and Connections Basics.

Also note the REW information Index.

brucek