SPL Meter Correction Tables - Page 7

You said your "my mixer does not use the RCA" but since the UB802 does have RCA in and out, it could be used, couldn't it?

I'm gonna get a ECM8000 and XLR cable into the mixer. Then use the RCA's into a laptop USB sound card inputs. Then the sound card rca outputs would feed into my pre-pro aux inputs >> amplifier >> speakers.

Does this sound correct?

Could be, but if you want to make sure, check out this hometheater shack. That forum supports REQW and has helpful information for getting it to work with the mic and the UB802 (amongst other things)

link I learned everything from that site, and found it very helpful. I haven't had to calibrate my system for a year and a half, so my memory is a little foggy. I just noticed that it has RCA Tape input and output. I happened to use the 1/4" though.

Is there anything new on this front that can be added to THIS thread?


Thanks In Advance.

Just in case anyone is interested, recently I "blew" my RS Digital SPL Meter via a static electricity discharge. I was going to toss it out, but I decided to "repair" it. The mike element went bad, so I replaced it.


Now, the interesting part. A few days after I repaired the SPL meter, I thought that with all the so called calibration files out there how much of the error is electronic and how much of it is mike related.


Here is the answer. I removed the mike, and swept the electronics via True RTA (1/24 octave no smoothing). Green is C scale, Red is A scale. This proves that the basic filters are pretty accurate A scale and C scale filters.


The accuracy of the mike used in the SPL meter determines SPL meter "accuracy" relative to the well known electronic A scale and C scale filters in the SPL meter.


http://hyperphysics.phy-astr.gsu.edu.../acont.html#c1

.

If you are measuring max SPL LFE peaks with the meter set to "C" and "fast" response, is the meter still off and needs to have the SPL Meter Correction Table value applied assuming you know the freq the bass peak you are measuring is at?

For example lets say I am taking a LFE peak measurment of a movie scene that the bass is centered about 40hz and I read 115db on the meter would this actualy be a 117.5db LFE peak since the meter is down 2.5db at 40hz and you would need to add this 2.5db to 115 to get your true measurement which would be 117.5 in this case?

This is apparently the accepted response for the radioshack 33-4050 analog meter (and the 33-2055 digital meter as well).
(Taken from Home Theater Shack forum / REW RADIOSHACK-33-2055_4050.cal file.) I am just posting this for quick and easy reference...

Hz dB (so, for example, add 16.91 dB to a meater reading taken at 10Hz to obtain the actual level)
7 -27
8 -22.55
9 -19.37
10 -16.91
11 -15.27
12 -13.74
13 -12.42
14 -11.33
15 -10.28
16 -9.28
17 -8.53
18 -7.86
19 -7.12
20 -6.56
21 -6.18
22 -5.77
23 -5.41
24 -5.1
25 -4.9
26 -4.54
27 -4.27
28 -4.03
29 -3.73
30 -3.53
31 -3.25
32 -3.04
33 -2.84
34 -2.61
35 -2.54
36 -2.44
37 -2.28
38 -2.13
39 -1.97
40 -1.8
41 -1.75
42 -1.6
43 -1.54
44 -1.51
45 -1.43
46 -1.34
47 -1.23
48 -1.12
49 -1.02
50 -0.9
51 -0.82
52 -0.68
53 -0.64
54 -0.58
55 -0.5
56 -0.46
57 -0.38
58 -0.37
59 -0.36
60 -0.35
61 -0.34
62 -0.33
63 -0.32
64 -0.31
65 -0.31
66 -0.31
67 -0.22
68 -0.22
69 -0.23
70 -0.23
71 -0.19
72 -0.19
73 -0.17
74 -0.1
75 -0.1
76 -0.07
77 -0.06
78 -0.03
79 -0.01
80 0.00

And from 80 Hz out to 200 Hz (in 1 Hz steps) the values are all listed as 0.00.

Man this thread gives me a headache the more I re-read it!

What are the currently accepted correction values for the Radio Shack RS-2055 digital SPL using the meter as a standalone unit? i.e. I am reading the values from the LCD display on the meter.

I think the values in my post just above are the corrections you are looking for, although I'm not sure what to do above 200 Hz yet.

Hai I am new to this site. I am unable to understand the topic on which the comverstion was going on.

ToTo Man, try these:

LF corrections for Radio Shack 33-2055 meter
These are for the current digital meter used as a microphone.

10 -5.66
11 -5.25
12 -4.66
13 -4.20
14 -3.80
15 -3.50
16 -3.30
17 -3.10
18 -2.90
19 -2.70
20 -2.50
21 -2.30
22 -2.10
23 -1.95
24 -1.80
25 -1.60
26 -1.40
27 -1.15
28 -1.00
29 -0.90
30 -0.75
31 -0.65
32 -0.55
33 -0.44
34 -0.33
35 -0.22
36 -0.11
37 0.00
38 0.08
39 0.15
40 0.22
41 0.34
42 0.36
43 0.41
44 0.45
45 0.49
46 0.52
47 0.55
48 0.59
49 0.60
50 0.62
51 0.64
52 0.64
53 0.64
54 0.63
55 0.62
56 0.60
57 0.59
58 0.56
59 0.53
60 0.50
61 0.48
62 0.44
63 0.41
64 0.39
65 0.37
66 0.36
67 0.34
68 0.30
69 0.28
70 0.27
71 0.30
72 0.32
73 0.34
74 0.34
75 0.35
76 0.36
77 0.37
78 0.38
79 0.39
80 0.42
81 0.42
82 0.43
83 0.43
84 0.43
85 0.43
86 0.43
87 0.44
88 0.45
89 0.45
90 0.46
91 0.46
92 0.47
93 0.48
94 0.48
95 0.49
96 0.49
97 0.50
98 0.50
99 0.50
100 0.50
101 0.50
102 0.50
103 0.50
104 0.50
105 0.50

Hi,
I am trying to get the most current correction table for the Digital RS SPL meter to be used as a standalone unit. i.e not in combination with REW or anything similar. I have looked and found conflicting info. Is there kind of a consensus as to which correction table is the best/most current? Any help will be appreciated.

Does it really matter? The unit to unit variations are large. The meters have been manufactured for a long, long time. All stages of the manufacturing process may have changed several times. It's difficult to keep tight tolerances on the mic capsule element (some of the higher priced calibration mic manufactures get lots of mic capsules and select the best ones). Also the mic elements drift with time, temperature and humidity.

Wow that far off for cheap Realistic Tandy analogue SPL metre. I’ll think I’ll use the RTA instead.

Im plan on getting a radioshack meter soon but im a little confused about how it works.

Why is the meter readings not accurate? how do i know what to add or subtract? i want to calibrate my speakers and if i understand correctly there all suppose to read 75db spl including the sub?
since the meter is not accurate how do i know if its the right number?

And what direction do i point the mic, i have a tripod should i use that?

Is it ok to the receives test tones?

I've been using the nifty little thing at the cinema for basic reference like the Empire Leicester Square because its so superior over six-million dollars!

I'm about to dive into the world of manual calibrations which means I have a dumb question. Uh....how do I know what hz the test tone on my denon 989 is for the sub (I don't need to correct anything for the speakers do I?). Or do you guys just use a CD containing different tones? And whats the consensus for analog vs digital meters?

I went to my local radio shack which is called the source now and was looking to buy a spl meter. The only one they had was a scosche boomstick spl1000 digital meter. Has anyone tried these and know how accurate they are?? I couldn't find an analog version. Which one should I get?? Thanks

Is there a correction table for the Galaxy CM-140 or am I good to go out of the box?

There are files based on other user's units, but you should understand that there are within model variances that limit the usefulness of such data.

If you want references, you need to buy a calibrated mic or have a mic or meter calibrated or profiled so that the data is valid for your unit.

Which correction table is one to use? I just looked at several for the same RS Meter, and the correction values are all very different on each link.

anyone know what to compensate for above 100hz? with the newer spl meters

I have a digital Radioshack meter.

It must be at least ten years old and it's model number is 33-2055.

What correction values do i use for this particular model ?

Ignore the above post if these are the correct values ( i need to read more of the posts )

I have the old SPL model from radio shack and have a few questions.

I have no test CD's and have always used the test tones from my Denon 4800 AVR.

I have set all speakers to 75db and the HSU sub at 80db.
What frequency is my sub putting out during this test tone so I can adjust db according to the SPL correction table?

Just assuming the HSU test tone is 25hz and wanted 5db above the other speakers, I would add around 5db which is really 75 on the meter to give me the 80db I'm looking for?

I don't think anyone except someone who owns the same receiver, could answer you the question on the frequency of the test tones it provides. You can, however, generate your own. Audacity (free) can do it, so make your tones, save to WAVs, then burn as audio CD with your favorite burning program. There, you got a test tone CD.

There is Noway that my treo ssi 10" sub goes above 126 db ( that is where my radio shack meter stops at) that's measured in a 12'X 16' room playing 30hz

Let's say I want to do a simple level match of my speakers to 75db using the internal test tones on my receiver. The rumble tone for the sub causes the analog RS meter to dip and peak. Should I be setting the volume on the sub so that the rumble tone peaks at 75db?

Set it to SLOW and take an average of the range it bounces around in. The less "flat" your bass response is, the more it will bounce around.

I don't know what frequencies your receiver plays at, but the Avia disc is pretty much 38Hz-80Hz. And my Sony 5300ES receiver's bass test tone is much louder than the other tones, and if I used it to calibrate the sub, my sub level would be much too low. That's why I prefer to use a test disc like Avia.

After reading this thread several times, I have a question concerning the "newer" correction values. I have the older analog RS meter, are the larger values to be used ONLY when using software such as REW because the output line DOESN'T have C weighting applied (even though switch is set to C)? If I am manually measuring (reading the needle with switch on C-weighted) are the "older" values still to be used or not?

I also have some question I hope someone can answer. I have the newer RadioShack digital SPL meter. What correction table applies, when I am reading off the display? When its says "-10 dB" in the correction table, does that mean I add or subtract 10 dB from the actual reading? What weighting do I need to use, A or C, and what weighting was used for the correction data?

Thanks in advance.