Rat Shack Digital SPL meter

grub · « **on:** 21 Sep 2005, 07:30 pm »

Hey guys, I've been measuring my subs the past couple of days and I have a question about the correction values for the SPL meter. Do the correction values apply to both the analog and digital meters? The digital meter I have says it's "Radio Shack" brand (I didn't see Tandy anywhere on it).

One final aside, are the correction values meant to compensate for a poor mic, or is it to counter the "C" weighting?
Thanks fellas,
-->grub

mgalusha · « **Reply #1 on:** 22 Sep 2005, 03:46 am »

grub,

There used to be a lot of information on this posted by Eric Wallin. This is the gentleman who posted all the modding instructions for the meter. His take was this:

Quote

In many ways the analog RS meter is better than the digital meter RS offers: The resolution of the readout is higher (fractions of a dB, while the digital meter only reads to the nearest dB), the analog meter movement provides more information when analyzing dynamic signals, and finally it is less expensive than the digital meter. If the digital meter dispensed with the range selector switch and read fractional dBs, I would consider purchasing one, but with it, I consider the analog meter more useful and the better value.

The correction values compensate for the electronics in the bass region. I don't know if they apply to both digital and analog models. The mic is pretty good down low but the electronics need help. It's pretty useless above about 10KHz or so. If you are into a little DIY, it's pretty easy to mod the analog meters for a flat low frequency response. If you're interested I can send you the info. At the time I did mine, I archived the web pages. Turns out it was a good idea.

RS doesn't sell the analog models any more. You can find the analog models on eBay pretty easily if you really want one that's accurate down low.

grub · « **Reply #2 on:** 22 Sep 2005, 03:56 am »

Thanks for the info Mike.
I'll see if I can get a hold of an analog RS meter sometime. I'm following the BFD Comprehensive setup guide, and using the spreadsheet to measure my room (to see what sort of trouble I'm in bass-wise). The bass measurements seem a little weak, especially considering that my subs will move the floor if I feed them. This leads me to believe that the SPL meter is inaccurate in the low bass region. How inaccurate I can't say for sure, but if I use the analog correction values, the graph begins to even out nicely. I think the cheapest way to know for sure is to get my hands on an analog meter.
Thanks for pointing me in the right direction Mike.
-->grub

Sonnie Parker · « **Reply #3 on:** 7 Oct 2005, 10:09 pm »

grub...

There was a fellow on one of the forums who actually tested both the analog and digital and they were different. He never gave me the differences although I asked for them. If you do get your hands on an analog meter and test both of them with the mics as close to each other as possible (they absolutely have to be literally within a half inch of each other)... I would greatly appreciate the differnces so I could calculate correction values for the digital meter and add those to the guide and/or an Excel Workbook.

bacobits1 · « **Reply #4 on:** 8 Oct 2005, 04:28 pm »

Interesting SVS Subs carries the Analog Rat Shack Meter.
http://www.svsubwoofers.com/parts.htm

Den

Sonnie Parker · « **Reply #5 on:** 21 Oct 2005, 02:48 am »

Had a fellow tell me just this past week that he went to his local Radio Shack and picked up an analog meter. Might have been a left over, but it doesn't hurt to call your local ratshack and ask if they have one or if they can get you one.

Russell Dawkins · « **Reply #6 on:** 21 Oct 2005, 06:07 am »

I have an analog rad shack meter and am interested in doing the mods. Could you post links to his posts or the web pages you referred to, please, mgalusha.
Thanks,
Russell