## 30 iPad Sound Measurement Apps Reviewed

30 iPad Sound Measurement Apps Reviewed

How good are those “inexpensive”  iPad sound measurement apps?  Are any of them as accurate as a properly calibrated \$2,000 type 2 sound level meter?

In this study, we reviewed and tested 30 different  low cost iPad sound measurement apps on iPad tablets (version 4).  These iPad sound measurement apps ranged in cost from free to \$3.99.  We wanted to see which of these apps were the best, and determine if any could be used to effectively measure workplace noise levels.

Evaluation Methods

The type 2 sound level meter that we used to compare the app’s results to was a 3M/Quest Model 2200 SLM .  We would like to acknowledge and thank Sentry Insurance in Stevens Point Wisconsin for kindly loaning us this modern sound level meter.  The 3M/Quest sound level meter was calibrated both before and after testing. The sounds we measured were generated by on-line tone generators.  The unit of measurement in all cases were decibels (A scale).

The following is a description of  our four tests –

Test 1 (T1) was a steady state low frequency tone (1,000 hertz)

Test 2 (T2) was a steady state higher frequency tone (8,000 hertz)

Test 3 (T3) was a 30-second sound recording that had significant extremes of noise frequency and volume that was used to measure the average noise level over time

Test 4 (T4)  was a loud prerecorded explosion that used to test peak noise capabilities

All of the apps we tested had readouts showing: current noise level, average noise level, peak noise, and peak hold.  Even though some of the apps allowed for the use of external microphones, all app testing was done using our iPad 4’s built in microphone.

None of the apps had a proper built-in calibrator so we used the factory default calibration settings in all cases.

Please note that we are not a testing laboratory, and our findings should not be considered infallible.  We encourage others to carry on from where we left off.  Similar studies using iPhones and Android devices would be interesting.   Also, we love to see evaluations of  the “higher priced” sound measurement apps; with and without external microphones, and with and without calibration.

Conclusions

The following apps were found to be totally inadequate: Decibel Pro II, dB, Sound Meter, Noise Alarm, iSPL, Audio Tool, Noise Meter, Decibel Ultra, dB Meter Pro, Decibel 10th, Decibel Meter, Sound Level Meter and Noise Sniffer.  They lacked key features and were extremely inaccurate. We thought it would be a waste of time to even publish their test results.  These apps should only be used as “toys” with the children.

Our highest rated app is the SPLnFFT app.  It received our highest possible rating – five out of five ♥♥♥♥.  It costs only \$3.99.  During the four tests we conducted, this was the only app to absolutely nail the results each and every time.  It passed all four tests with flying colors.  In fact, this app’s results were so close to the results obtained using the \$2,000 noise meter that the tiny differences between the two are probably due to sampling error.

The developer of SPLnFFT  has an other sound measurement app called logSPL.   It is basically the little brother of SPLnFFT.   LogSPL is simpler to use, and it is  \$2.00 cheaper then it’s big brother.  We tested logSPL against SPLnFFT and found the results to be nearly as good.  We rate logSPL  ♥♥♥♥ (second place overall).

The SoundMeter+ app for \$1.99 is our third highest rated app (passed three tests).  It’s not as accurate on the higher frequencies as the SPLnFFT app is.  Also, this app offers the most features.

The SPL Meter app came in at fourth place (passed two tests).  We found it difficult to reset, lacking some features, and it also had trouble with the higher frequencies.

While the remaining apps shown below all had the key features we like to see in a sound measurement app, none of these apps came close on even a single test to the results attained with the 3M/Quest Model 2200 sound level meter.  We would have no use for any of these apps. Please keep in mind that our testing was done using an iPad-4.  Results may be different if either another iPad model or an iPhone were used.

Test Results (the more accurate results are highlighted)

3M/Quest 2200 type 2 SLM –    T1= 88.5   T2=94.3    T3=82.2   T4=87.6

SPLnFFT (app) – ♥♥♥♥♥        T1=88.9    T2=93.9     T3=82.4   T4=87.7

SoundMeter+ (app) – ♥♥♥       T1= 91.3   T2=102.3   T3=82.5   T4=90.7

SPL Meter (app) –  ♥♥             T1= 88.3   T2=101.1   T3=n.a.    T4=87.7

dB Meter (app) –   T1=66.8   T2=150  T3=61   T4=150

Audio DB Meter (app) –  T1= 68   T2=120  T3=61   T4=120

How Loud is it (app) –  T1= 66.6   T2=120  T3=59   T4=120

SPL Volume Meter (app) –    T1= 66.8   T2=120  T3=60.6   T4=71.3

Sound Meter Pro (app) –    T1= 67.5   T2=150  T3=57.3   T4=150

Graphic Meter (app) –   T1=67   T2=120  T3=57.1   T4=120

dB Volume Meter (app) –    T1= 67.3   T2=120  T3=60.1   T4=70.3

Professional DB Tester (app) –    T1= 67   T2=120  T3=60.2   T4=120.0

Volume Meter (app) –    T1= 66.8   T2=150  T3=60.9   T4=150.0

Decibel Meter (app) –   T1= 67.2   T2=150  T3=60.4   T4=150

Advanced Decibel Meter (app) –    T1= 67.1   T2=120  T3=60.3   T4=120.0

Pro Volume Meter (app) –    T1= 67.2   T2=120  T3=60.5   T4=120

Decibel Graph (app) –    T1= 66.8   T2=120  T3=60.4   T4=120

Using Apps For OSHA Workplace Noise Surveys

In the USA, OSHA standard 1910.95 (Occupational Noise Exposure) states that sound level meters that are used for OSHA compliance surveys should meet the ANSI S1.4-1971 (R1976) standard. The more expensive sound measurement apps actually say in their descriptions that they do not meet this ANSI standard. While the cheaper apps are silent on this subject, we assume that none of them meet the standard either.

As of this writing, we know of no apps that meet ANSI S1.4-1971 (R1976).  Therefore, for OSHA compliance purposes, one should not use any of the current crop of sound measurement apps to measure workplace noise. However, there are other reasons one might want to measure noise (e.g. engineering purposes, noise pollution, frequency analysis, noise comfort surveys, screening surveys, noise abatement, noise complaints etc.).  For such non-OSHA compliance applications, we would see nothing wrong with using one of our higher rated apps for measuring noise levels.

Update – NIOSH reviewed 192 sound measurement apps.  Click here to review this study.
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