# Inexpensive replacement for the old RS SPL meter



## bigbwb (Jan 7, 2009)

Hey guys,

The old RS Analog SPL meter is acting up and I need to replace it for just basic level matching. I already own a Dayton mic etc for full REW measurements etc. I know the Galaxy 140 gets mentioned a lot but its over $100. anything a bit cheaper that fits the bill?

Thanks,
Brandon


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## NBPk402 (Feb 21, 2012)

Why not just get another RS meter?


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## andy_c (Aug 8, 2006)

When I needed an SPL meter for REW cal, I originally thought I could get away with a cheapie, so I bought a Triplett SoniCheck for a little over 30 bucks. When I first tried it, I was really pleased, as its residual C-weighted SPL in a quiet room seemed to be around 30dB. But then, after about an hour of use on its battery, its residual C-weighted SPL jumped up to around 72dB. I went into a closet and closed the door to make a measurement, just to make sure there weren't any noise sources I wasn't aware of disturbing the readings. No difference. So I replaced the battery, and lo and behold, I got back my 30 dB residual. At first I thought it must have come with a faulty battery, but the backlight still lit up well. Then, after about an hour of use on the second battery, the residual jumped back up to around 72 dB again - completely useless for the REW 75dB SPL calibration.

I have heard that batteries get more noisy when they run down, so maybe its internal mic preamp has poor power supply rejection.

I ended up buying a Galaxy CM-130, which is available for 60 bucks. It's completely reliable. On the down side, it does not have a backlight, but its battery life is claimed to be 100 hours. It picks up peaks much better than the Triplett did, and has both A- and C-weighting. I am very happy with it, and wished I had just gotten it in the first place.


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## bigbwb (Jan 7, 2009)

ellisr63 said:


> Why not just get another RS meter?


The analog display has always jumped around on me and I have not had the best of luck with it.


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## bigbwb (Jan 7, 2009)

andy_c said:


> When I needed an SPL meter for REW cal, I originally thought I could get away with a cheapie, so I bought a Triplett SoniCheck for a little over 30 bucks. When I first tried it, I was really pleased, as its residual C-weighted SPL in a quiet room seemed to be around 30dB. But then, after about an hour of use on its battery, its residual C-weighted SPL jumped up to around 72dB. I went into a closet and closed the door to make a measurement, just to make sure there weren't any noise sources I wasn't aware of disturbing the readings. No difference. So I replaced the battery, and lo and behold, I got back my 30 dB residual. At first I thought it must have come with a faulty battery, but the backlight still lit up well. Then, after about an hour of use on the second battery, the residual jumped back up to around 72 dB again - completely useless for the REW 75dB SPL calibration.
> 
> I have heard that batteries get more noisy when they run down, so maybe its internal mic preamp has poor power supply rejection.
> 
> I ended up buying a Galaxy CM-130, which is available for 60 bucks. It's completely reliable. On the down side, it does not have a backlight, but its battery life is claimed to be 100 hours. It picks up peaks much better than the Triplett did, and has both A- and C-weighting. I am very happy with it, and wished I had just gotten it in the first place.



The 130 seems decent! Thanks! It says it only measures down to 125hz, would that be an issue?


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## andy_c (Aug 8, 2006)

bigbwb said:


> The 130 seems decent! Thanks! It says it only measures down to 125hz, would that be an issue?


Good catch. I guess that means the SPL cal must be done with the mains only, not the SW in REW. That might be a concern for some setups. So if you're doing an SW-only measurement, it looks like an SPL cal using the mains would be done first before deactivating the mains.

Edit: Looks like RS have changed their digital meter. This post shows the old and new. It's not clear to me what those two graph traces represent (which is the old one and which is the new one), but it looks like the RS meter might be a better choice than the Galaxy 130, due to low-frequency response issues.


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## cavchameleon (Jan 7, 2008)

Hi, I have used this SPL meter with good results. You can also purchase their more expensive one that can data log.

http://www.mcmelectronics.com/product/72-942
http://www.mcmelectronics.com/product/72-945
http://www.mcmelectronics.com/product/72-947










Product Description

Compact Size
A and C weighting
Selectable fast / slow response time
Selectable MAX hold and data hold function
Two measurement ranges
Large ¾" digit LCD backlit display
Threaded insert which accepts standard tripod mount
Auto power off
1999 count display with 0.1dB resolution
Removable windscreen
Includes manual and 9V battery

Specifications:
Frequency range: 31.5Hz ~ 8KHz
Measurement range:
30 ~ 100dB (low)
60 ~ 130dB (high)
Microphone element: ½" electret condenser
Sample rate: 0.5 seconds
Time weighting: 125mS (fast), 1 Sec. (slow)
Accuracy: ±1.4dB @ 1KHz, 94dB
Dimensions: 8¼" (L) x 2¼" (W) x 1¼" (D)


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## informel (Jun 21, 2011)

andy_c;547551
I have heard that batteries get more noisy when they run down said:


> Ab atterry may get weak, but not noisy. They supply DC and can only get weak. The electronic is probably acting up when the voltage drop, but the backlit will probably stay on until the battery is almost dead


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## Wayne A. Pflughaupt (Apr 13, 2006)

bigbwb said:


> ellisr63 said:
> 
> 
> > Why not just get another RS meter?
> ...


If you’ve primarily been using the meter for low frequency measurements, that’s perfectly normal, especially with pink noise signals and to a lesser extent single-frequency sine wave signals. It has more to do with the test signal than the meter, and probably any meter is going to react the same way. I just note the values at the upper and lower end of the meter swing and use the half-way point as the relevant dB figure. If you’re looking for a cheap replacement, no reason not to ebay one.

Regards,
Wayne A. Pflughaupt


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## tonyvdb (Sep 5, 2007)

Just a note: The Galaxy CM130 does not have a line out so if you plan to use it as a mic with REW you must step up to the CM140.


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