SPL meter corrections?

[masterp2]

Are there corrections for the "digital" RS meter somewhere? I don't have an analog meter.

 

[officeboy]

http://www.gti.net/wallin/audio/rsmeter/33-2055/33-2055.html

 

[masterp2]

Tanks for that link, which describes how to mod the meter. I won't be doing that. I don't see any corrections. Are they the same as the analog meter?

 

[officeboy]

hmmm, how else would you correct it? if not to physically correct it.. or are you looking for a calibration file?

 

[masterp2]

yep, sorry. Is the calibration the same as the analog

 

[masterp2]

Correction factors?

 

[officeboy]

Try this thread on the speaker workshop forums.
http://www.speakerworkshop.com/forum/viewtopic.php?t=143&highlight=332055

 

[Ron E]

These are what I measured on-axis for my analog model from the RCA output (not the meter movement). I doubt the digital model is much different. A positive number means the meter response is too high and vice versa. This is a comparison to a Behringer ECM8000 rather than an actual calibration, but the ECM8000 is said to be +/- 0.5dB up to 10kHz and perhaps -3 at 20kHz.....

FWIW, this curve is quite close to one published by ETF acoustic, and also to the curve enclosed with the meter instructions.

200 0.1
214 0.3
230 0.3
246 0.3
264 0.2
283 0.2
303 0.3
325 0.4
348 0.4
373 0.5
400 0.5
429 0.5
459 0.5
492 0.4
528 0.3
566 0.1
606 0.0
650 0.0
696 0.1
746 0.2
800 0.3
857 0.5
919 0.5
985 0.4
1056 0.6
1131 1.0
1213 1.1
1300 0.7
1393 0.6
1493 0.6
1600 0.3
1715 0.2
1838 0.6
1970 1.6
2111 2.4
2263 3.1
2425 3.2
2599 2.6
2786 1.5
2986 1.4
3200 1.9
3430 2.5
3676 2.1
3940 2.1
4222 2.4
4525 3.1
4850 3.0
5198 3.3
5572 3.8
5971 4.6
6400 4.6
6859 4.2
7352 3.3
7879 2.6
8445 2.5
9051 2.0
9701 1.1
10397 -0.7
11143 -2.4
11943 -3.4
12800 -3.7
13719 -4.2
14703 -5.9
15759 -7.0
16890 -7.8
18102 -10.1
19401 -12.2
20794 -12.8
22286 -13.0

 

[mikee12345]

just keep searching online-ive seen it.

its something like 1db at 50hz and 5db at 20hz...only worrysome if ur into subs...also rolls off after 10khz like ron E shows

get a wm-60
Cheers

 

[Salas]

A or C?

Is that on IEC A or C compensation switch position? slow or fast?

 

[Ron E]

Is that on IEC A or C compensation switch position? slow or fast?

If your question is related to my post, this is C weighted. The slow or fast reading does not affect the RCA output, it merely damps the meter response...

 

[Salas]

my RadioShack

Hello,

This is what I use as a mic compensation file in WinMLS 2000. It shows much positive bass output deviation. Its a fact though, cause I have compared to a friend's well calibrated mic (professional loudspeaker designer) with the same program taking alternate measuements on the same setup. Also in RTA programs I get much bass on the graph if I dont compensate that much. Setting is C. Analogue RS spl meter RCA out.

"Radio Shack low cost condenser mic (Salas)"
"Hz" "Data"
20.0, 35.0
40.0, 12.0
55.0, 11.0
80.0, 8.0
100.0, 6.0
120.0, 5.0
200.0, -0.5
300.0, -0.3
400.0, -1.0
1000.0, 1.0
1100.0, -1.0
1300.0, -1.0
2000.0, 0.5
3000.0, 1.5
4000.0, 4.3
5000.0, 2.0
6000.0, 4.7
7000.0, 3.0
8000.0, 3.4
9000.0, -2.0
9500.0, -2.5
10000.0, -3.0
12000.0, -2.5
13000.0, -4.0
15000.0, -6.0
18000.0, -5.5
20000.0, -6.0

 

[masterp2]

I have found the SPL corrections published in several places, all the same. Your bass corrections are grossly exagerated I think, 35Db at 20 HZ?. I don't know where you got these, what is the origin?

 

[Ron E]

Interesting, what is the model #? Mine is 33-2050 - purchased a long time ago (in 1990?)

I don't think the Behringer is out that much, so there must be substantial variation in the RS SPL meters...

I haven't checked mine in the bass.

 

[Salas]

here's a pic

Hello,

As I wrote I got em compared in a friends calibrated professional setup. The reason I did that it was that I kept getting too much bass in the graphs in all programs when I used all those readings I found on the web.
I include I a pic I made just now. The top graph is my PC speaker left channel + sub (Cambridge Soundworks) without any compensation used. The bottom one is the same but compensated with the file I sent before. Radioshack analogue set to C. These thingies must variate wildly I guess.

 

[Salas]

to RON E

Yes cat. no. 33-2050 'CHINA'

 

[masterp2]

Salas,

Is your radio shack SPL meter, the anaolg or digital, how old is it?

 

[Salas]

relatively new

Its the analogue, roughly 3 years old, purchased in the USA

 

[masterp2]

I'm confused.

Your post says add 35 Db at 20HZ. But your "compensated" graph shows 15Db LESS at 20 HZ (goes from 5 to -10).

 

[Salas]

Nooo....

The upper one reads roughly - 8@20 when the bottom one dives under -30@20