SPL meter corrections? - Page 2

Ron E · 8th February 2004, 02:49 PM

Quote:

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 · 8th February 2004, 04:16 PM

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 · 8th February 2004, 04:26 PM

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 · 8th February 2004, 04:36 PM

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 · 8th February 2004, 04:46 PM

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 · 8th February 2004, 04:52 PM

Yes cat. no. 33-2050 'CHINA'

masterp2 · 8th February 2004, 04:52 PM

Salas,

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

Salas · 8th February 2004, 04:57 PM

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

masterp2 · 8th February 2004, 05:06 PM

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 · 8th February 2004, 05:10 PM

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

8th February 2004, 04:16 PM	#12
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	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

8th February 2004, 04:26 PM	#13
masterp2 diyAudio Member Join Date: Feb 2002 Location: Arizona	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? __________________ Michael

8th February 2004, 04:36 PM	#14
Ron E diyAudio Member Join Date: Jun 2002 Location: USA, MN	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. __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. —Aldous Huxley

8th February 2004, 04:52 PM	#16
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	to RON E Yes cat. no. 33-2050 'CHINA'

8th February 2004, 04:52 PM	#17
masterp2 diyAudio Member Join Date: Feb 2002 Location: Arizona	Salas, Is your radio shack SPL meter, the anaolg or digital, how old is it? __________________ Michael


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8th February 2004, 04:57 PM	#18
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	relatively new Its the analogue, roughly 3 years old, purchased in the USA

8th February 2004, 05:06 PM	#19
masterp2 diyAudio Member Join Date: Feb 2002 Location: Arizona	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). __________________ Michael

8th February 2004, 05:10 PM	#20
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Nooo.... The upper one reads roughly - 8@20 when the bottom one dives under -30@20

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