# Re: Faulty spl meter



## gperkins_1973 (Aug 25, 2008)

*Re: Faulty spl meter*

Hi all

I have an analogue Radioshack spl meter which seems to be going faulty.

I have noticed that the last couple of days I keep getting in consistant REW sweeps and low levels.
I have also noticed that when I flick it from 80db to 70db it creates alot of noise through the subs.

Would this be down to the spl meter or would it still be reading correct even though it is doing some strange things.

I spent 4 hours yesterday going back and forth with doing sweeps.

I have bought some new phono to 3mm jack leads which were cheap but would presume they would do the job. Could it be those.

cheers

Graham


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## JohnM (Apr 11, 2006)

*Re: Faulty spl meter*



gperkins_1973 said:


> I have also noticed that when I flick it from 80db to 70db it creates alot of noise through the subs.


Nothing you do on the SPL meter should have an effect on the signal going to the subs, if it does there must be a monitoring path active, which is sending the signal picked up on the input the meter is connected to back to the output. That might be a selection on the soundcard, or having "listen to this device" ticked in the properties for the input, for example.


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## gperkins_1973 (Aug 25, 2008)

*Re: Faulty spl meter*

HI John,

I have checked the input window and 'listen to this device' is unchecked.

Playback through this device is set to 'default playback device'

In this I have various selection in which two of them are my soundcard. One being speakers and one being digital.

I am running windows 7 through my Imac 27" and to be honest when I was running my PC laptop with everything set up I had no issues at all.

Since getting the Imac I can run REW on the mac and on the windows side it is a nightmare.

I used be able to select 'speakers audio ARM' and get sound. Now I have to select 'Digital output audio ARM' to get any sound out of my turtle beach ARM soundcard.

Im at a loss to be honest.

cheers


Graham


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## EarlK (Jan 1, 2010)

*Re: Faulty spl meter*



> <<<<<snip>>>>>
> 
> I am running windows 7 through my Imac 27" and to be honest when I was running my PC laptop with everything set up *I had no issues at all*.
> 
> <<<<<snip>>>>>


Obviously, running REW through a Win7 emulation ( on a Mac ) isn't quite as straightforward as one assumes .

Considering the above quote, I would recommend that you go back to using REW on your Win7 laptop ( until you figure out your current monitoring problems ) .



:sn:


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## gperkins_1973 (Aug 25, 2008)

Lol I wish I could as I sold that laptop.


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## EarlK (Jan 1, 2010)

*Re: Faulty spl meter*

Get yourself one of these ( at least until you determine if your Turtle Beach Card will work with your current hardware ) .

Use the generic ( builtin ) USB drivers ( with either the Win7 or the Mac OS ) , that way there's no pesky ( extra ) software to learn .










Keep the monitor switch in the "off" position to avoid ( input-to-output ) "feedback" .

:sn:


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## gperkins_1973 (Aug 25, 2008)

*Re: Faulty spl meter*

Thanks for this. These are only £25 here in the UK so I will get one of those.

Do you have to install any software for one of these and what do you select in REW for the input/output?

cheers again

Graham


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## EarlK (Jan 1, 2010)

*Re: Faulty spl meter*

The Behringer UCA 202 ( or 222 ) come with their own device drivers ( if one wants to use them ) but they're unnecessary for typical day-to-day use . 
I now use the generic, USB system drivers (after "uninstalling" the Behringer drivers ) .

This is a screen-shot ( of an older version of REW ) that shows the selection of the system's own generic USB drivers .










This is a screen-shot showing the selection of Behringer's dedicated USB drivers .










:sn:


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## EarlK (Jan 1, 2010)

*Re: Faulty spl meter*



> I have an analogue Radioshack spl meter which seems to be going faulty.
> 
> <<<<<SNIP>>>>>


If you still think that you have a problem with either your SLM or your cables, then here's a small app that can help you trouble-shoot .

The idea is to setup a "wiggle-test" and then listen for problems ( from within a recording ) .

Simply play back a constant 1K tone ( generated by REW ) through your speakers while you record that tone into the audiorecorder software . 
- All the while the tone is playing ( & being recorded ) , wiggle the cables connecting your computer to your SLM . 

Playback the recording ( via Windows Media Player ) & listen for interruptions & severe crackling ( which would indicate a cable problem .
- Keep the SLMs meter from "pinning" the needle or you'll hear the distortion ( on second thought, as an experiment over-drive the meter on one test, so that you get an idea of why it's a bad idea to subject REW to that type of distortion )

The software is easy to use & can be setup to stop recording at any user-defined length of time ( I choose either 30 sec or 60 sec ) . You can record as a Mp3 , Wav or OGG ( I use Wave since my file lengths are short ) .
- Be aware that file recording starts immediately* after one hits "Save"* ( which is sort of backwards to how most software works ) .

Here's the website  *( for the software )* and here's the download link itself 

:sn:


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## AlexF (Sep 30, 2012)

*Re: Faulty spl meter*

Hello everyone!

I have practically the same problem with my Radioshack 33-2055 SPL meter and the input/mic in on my laptop. That's why I decided to reply here and not to duplicate the topic, if it is OK.

Today I finally received my RadioShack, callibrated the sound card. While SPL calibration procedure I've got the warning message about "low level -60db signal". First I checked the cable from SPL meter to my laptop's mic in, used several different cable and I've got the same very low level of input signal. I thought that the SPL meter's output port might be broken. I plugged the additional external mic instead that one and got low level again. I turned up mic's volume to max and it did not help. 

5 days ago I made the measurements with REV and my Denon Audissey mic. I had to turn up volume level on my AV reciever very hight to get the lowest acceptable level to do the measurements. And with all these I got about 64db level. That time I didn't pay much attention to this detail. 

As I understand correctly it is probably the problem with my laptop's mic input. How can I fix this problem? What I have to do?


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## EarlK (Jan 1, 2010)

*Re: Faulty spl meter*

Hi Alex,

I'm currently very busy with work , therefore I won't be able to help sort out your problems ( for a few days ) .

In the meantime, be aware that it's not likely a problem with your meter but more likely a problem with the cable interface to your computer ( ie; wrong adapter, etc. etc. ) .

All in all, it's simpler to use an external soundcard ( if you don't understand the connection requirements of your on-board soundcard ). 

:sn:

ps : In the meantime you might better explain your connection philosophy ( pictures work well ) .


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## AlexF (Sep 30, 2012)

*Re: Faulty spl meter*

Yesterday all day long I was experimented with different cables and laptops. Here is what I did.

*1. Equipment*

** 3 laptops*

- Acer Aspire 1551 - soundcard Realtek HD
- Dell Vostro - soundcard Realtek HD
- my syster's HP Presario - - soundcard Conax Audio

** SPL meter Radio Shack 33-2055*

** cables*

- jack 3.5 mm stereo - 2 RCA = laptop's headphones/speakers OUT to front input on AV reciver Denon AVR-1909
- jack 3.5 mm stereo - jack 3.5 mm stereo = laptop's Mic IN to output on SPL meter 
or
- jack 3.5 mm mono - jack 3.5 mm mono = laptop's Mic IN to output on SPL meter 

*NO ADAPTERS used*

*2. Calibrating the Soundcard*

1. All system sounds are turned off, slected Asio driver, input and output









2. selected Mic, cleared SPL meter correction file









3. All output devices are turned off, only speakers OUTPUT are left ON - left panel 3.5 jack

















All affects are off









4. Only Mic INPUT is left ON - left panel 3.5 jack

















All affects are off

5. Made loop connection with jack 3.5 mm stereo - jack 3.5 mm stereo cable

6. Started sweep -12. On Dell and HP laptops reached easily the desires level between output and input. On my Acer I tried to reach -6db difference in the levels between the out and the in, but got only -8/-9db









In the Mic panel on the Levels page the *change in volume has no effect on the input results*

















*Input level can be adjusted only on the Speakers' panel* on the Levels page









7. I made the measurement with difference in -8 db and got very good results of the soundcards response









8. I saved it as a cards calibration file









9. Loaded calibration file for the SPL meter Radio Shack 33-2055









10. Connected SPL meter with jack 3.5 mm stereo cable (output on Radio Shack to laptop's mic input). Checked Levels with my AV receiver

11. Stared Calibrating the SPL readings. Input the data as described in Help section 









and *received this message!!!* - *The input level is very low (-80 db)*









Tried different cable and different laptops. I do not understand - *why is that???* 

*Do I need a special cable to connect SLP meter or I have to turn somehow the output out jack on my SLP meter????*

*How can I test the SPL meter's output jack in order to know exactly it is OK????*

If I proceed with the calibration of SPL meter I receive the message 









18. *I made another calibration file with JAVA driver*. On Dell and HP got fine results, on my Acer another big difference in levels, but good frequency response.

























but good frequency response.









*3. Check Levels with SPL meter Radio Shack 33-2055*

1. SPL meter Radio Shack 33-2055 is connected from OUTPUT jack to laptops MIC INPUT with different cables

- jack 3.5 mm stereo - jack 3.5 mm stereo = 2 m or 5 m
or
- jack 3.5 mm mono - jack 3.5 mm mono = laptop's Mic IN to output on SPL meter 

Connected to different laptops and when I'm *trying to check the Levels* I *receive NO INPUT SIGNAL*. Why??? I do not understand... I *turned the volume on my AV receiver, came close to speakers with SLP meter *(on its display the level in db is changing), changing the volume level on laptop but I have *no input signal in the REV window*.

*On Dell laptop*

























*On Acer laptop*

















It seems the signal from SLP meter is not transmitted to the laptop (changed 3 different cables). 

*How can I test the OUTPUT jack on my Radio Shack 33-2055???? Or mayby I need to turn On somehow the Mic In on my laptop????*

I hope some could help me what I'm doing wrong. I need to setup REW with this SPL meter badly.

Any advise would be very appreciated.


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## JohnM (Apr 11, 2006)

*Re: Faulty spl meter*



AlexF said:


> - jack 3.5 mm stereo - jack 3.5 mm stereo = laptop's Mic IN to output on SPL meter


The radio shack SPL meter output connector is RCA, not 3.5mm.


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## AlexF (Sep 30, 2012)

*Re: Faulty spl meter*



JohnM said:


> The radio shack SPL meter output connector is RCA, not 3.5mm.


Ooooppss It's my gaffe :dontknow: Thanks, JohnM for the tip. I used my Denon's mic with 3,5 jack for the first measurements and supposed I need the same one for RadioShack :devil:

I'm a newbie with all this. Please help me to understand some points.

*1. Volume level*

- *in the "Checking Levels"* help section it is advised to reach *a level of around 75dB* *on SPL meter* (usually *ear height *at your main listening position).

- *during SPL Calibration Procedure* to set the meter range to suit the measurement level *used in the check levels process* (*the 80dB range* is recommended *for the Radio Shack meter*)

- other says *the volume level at the listening position* should be the one I'm feeling comfortable for me \ *usually used for the listening* (music or movies)

*At what volume level should I make the measurements? *

When I set 75 db during level check & SPL Calibration, I cannot make any measurements because the level is low.

When I set 84-85 db (this is my usually used volume level for the listening, the level is shown as OK and I can make the measurements.

*2. SPL meter pointing*

When setting the SPL meter at my listening position, *where should I direct it*:

*- to the ceiling ???
- to the floor ???
- or to the speakers and at what angle???*

Thank you very much for all your advises in advance.


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## EarlK (Jan 1, 2010)

*Re: Faulty spl meter*



> Ooooppss It's my gaffe Thanks, JohnM for the tip. <<<<<<SNIP>>>>>>


Glad to see that John sorted you out ( with your cable challenge ) .

:sn:


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