Radio Shack SPL meter with DCX2496?

[mazeroth]

I was going to purchase a Radio Shack analog SPL meter in the near future to measure my room's bass and was wondering if this guy could be used to measure my recently completed line arrays? These are a budget set of arrays using (10) 4.5" Vifa TC11 woofers and a single Fountek JP-2.0 ribbon. I have them hooked up to my Behringer DCX2496 and after a quick set up I'm BLOWN AWAY! I'd like to be able to measure them and tweak their output with the DCX2496's built-in EQ system. Being they're only 4.5" drivers I have the boxes tuned to 65hz. While they sound very good, they are lacking a little in the low end so I'd like to make that as flat as possible.

For $39, do you think the analog Radio Shack is the way to go? Should I step up to the $49 digital one they offer? Or is there a better solution (like to keep it under $100) that will provide me with better results?

Lastly, how high will the Radio Shack meters go? I doubt they'll do 20khz but I could be wrong.

Thanks!

I'm also attaching a pic of the unfinished cabs so you guys can see what I've built! Not too shabby for a first time woodworker, eh?

 

[tiroth]

Check the part numbers, but here are the correction factors for the analog SPL meter. I don't see any need to go with the digital one. I would think the VU meter would be more valuable to have anyway.

http://www.anidian.com/audio/misc/spl.shtml

Oh, and great looking work!

 

[mazeroth]

The one used in the article is the 33-2050, while the one Radio Shack sells now is the 33-4050, and is $5 more than the one listed in the article. Can anyone confirm these are the same? I sure hope so! Also, the digital one they list on their site is the 33-2055, which probably has the same "guts" as the 33-2050, and I'm sure it's the same one the guy who wrote that article has.

http://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=33-4050

http://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=33-2055

As far as the 1/3 octave pink noise goes, can I just use my computer with WinISD to generate a frequency?

Thanks!

 

[Grahamt]

You can use the RS meter and Speaker Workshop to measure your speakers. I would say it is accurate enough for us amateurs up to 5-7 kHz. There are calibration files for SW.

I like the digital meter better myself.

 

[Mentero]

Hi,

You will find a very useful set of mods to the RS SPL in this page

Eric Wallin

Look under RS SPL Mods.

I am using an old RS analog with Eric's modification with very good results.

Miguel mentero

 

[Cordraconis]

SPL meter from Germany?

Well, I'll be starting my very first loudspeaker project shortly by ordering the drivers, but I'd like something to measure the final result. (I'll burn a test-cd with sweep tones etc ... myself)

Hence I want to buy an SPL meter, preferrably a digital one for ease of use.

Now, I looked at the radio shack one and it is the most documented one (correction curves! yeey!), but if you add the shipping costs and if the customs department of Belgium wants their share too, then it is better to look at SPLmeters available in Europe, me thinks.

I found for 99€ (shipping included!) this one in Germany:
http://www.earplugs.de/Cont/Plugs/SoundLevelMeter.htm

It looks like the Radio Shack one, but with another name on it.

It is also the cheapest digital SPLmeter I could find on the net, with others (Class 2 - domestic use, NOT for law enforcements and thus cheaper) prices starting from 175€ exl VAT and shipping.

Is there anyone who knows better or even cheaper alternatives in Europe? Or if someone has this SonicShop SPLmeter and can give me a 'go ahead' nod, I'd greatly appreciate it.

thx,

Joris

 

[planet10]

I know that when i got mine, the analog meter was considered superior to the digital one, alas only the digital one is available in canada anymore.... hold that, looks like none may be available... radio shack canada has just been sucked up by circuit city.

dave

 

[Cordraconis]

errrm ... so are you saying I should go for an analog one?


I remember something vaguely about a shop in Ghent who could get those, but i don't know the brand ...

 

[planet10]

errrm ... so are you saying I should go for an analog one?

The models aren't the same anymore, so who knows... just don't assume that the digital one is better

dave

 

[thomas997]

Hi,

You will find a very useful set of mods to the RS SPL in this page

Eric Wallin

Look under RS SPL Mods.

Yeah I did those and they really extended the low end measurement..

I think its even too much for me.. If for example, I wave my hand infront of the meter, or close a door, the thing goes crazy from the ultra low frequency.. heh

Its fine if you mount on a tripod though.

btw if you want the analog one, check ebay.

 

[oblong]

The one used in the article is the 33-2050, while the one Radio Shack sells now is the 33-4050, and is $5 more than the one listed in the article. Can anyone confirm these are the same?

I just purchased a 33-4050 model (7 scale selector switch, Tandy catalog Q1461 here in Australia), and I have not seen any other models. I opened it up, and just from the description of the component values, I'd say it is different from the models described on Eric Wallin's site. The original values I see are:

C1, C2, C3: 1 uF
C4, C5, C14, C15: 100uF
C7, C12, C13, C16: 22uF
C17: 220uF

C6, 8, 9, 10, 11, 18, 19 are surface mounted tiny capacitors on the rear side of the board.

So it would be good to know if anyone has information on the calibration of this model. It does have a trim-pot called "cal" (VR1) for calibration, but no instructions other than to take it to an expert for that.

Bob Long

 

[Cordraconis]

It does have a trim-pot called "cal" (VR1) for calibration, but no instructions other than to take it to an expert for that.

My Sonicshop SPLmeter arrived a few days ago (see previous posts of me in this thread), and it also has a calibration trimpot and the instruction to take it to an expert if nessesairly.

Since you mentioned the capacitors, I assume you want to calibrate it for maximally flat frequency response.
I believe the trimpot is for setting the gain factor(sensitivity) and not for the freq resp.

Maybe you know someone who has access to much better equipment and you can use that to create a correction curve?
I have a friend who still studies for civil engineer at university of Ghent, and he knows of a lab in his faculty that tests material with soundwaves. When I go to Ghent in a few days, I'll start harassing some assistents

 

[Salas]

RadioShack RCA out cal. data

Here you are, this is the RCA out (C curve switch setting) calibration file for the stock RadioShack

"Radio Shack low cost condenser mic (Salas)"
"Hz" "Data"
20.0, 25
40.0, -2.5
50.0, -1.5
63.0, -1.5
80.0, -1.5
100.0, -2.0
110.0, -2.0
200.0, -1.5
1500.0, -1.5
1800.0, -1.0
2000.0, -1.0
2700.0, 3.5
2900.0, 3.5
3500.0, 4.0
4000.0, 3.5
5000.0, 3.5
6000.0, 3.5
7500.0, 1.8
8000.0, 1.3
9000.0, 0.5
10000.0, -0.3
11000.0, -1.5
12000.0, -2.5
13000.0, -4.0
14000.0, -6.5
15000.0, -7.5
17000.0, -5.5
19000.0 -8
20000.0 -12

 

[Josephjcole]

I just got myself an 33-4050 radio shack test meter to use with this test CD:
http://www.rivesaudio.com/software/TestCD.html
The CD has 3rd Octave test tones already calibrated for the Radio Shack meter. Pretty handy really.
Joe

 

[Salas]

soft RTA

Using some RTA windows based application (even freeware), you can drive your computer soundcard input using the correction values I gave and have much more resolution and faster checks than using a cd and a paper chart. Mind, the values I give are only for RCA out and differ from the needle or digit readouts on the RS (analog or digital they are the same device). Each value you see in my data can be entered and counteracted by the mic calibration function of measuring software.

 

[Josephjcole]

Yeah the test Cd and some graph paper are a bit of a pain in the a**. But it is certainly the simplest to get started testing right away. I'm using a Mac so there is no freeware RTA measuring software that I'm aware of.
Joe