SPL is a professional-grade digital sound level meter (decibel meter) for your iPhone or iPod touch. It includes all of the modes, filters, and features that you would expect from a professional ANSI or IEC Sound Level Meter. All filters and averaging modes meet or exceed the criteria for ANSI Type 1 or better. SPL is created from the same team who brought you the Audio Toolbox and ATB Plus.
Do Not buy this app if you own AudioTools — buy it from WITHIN AudioTools.
If you are planning on buying iAudioInterface, you should instead buy our AudioTools suite of apps instead of this app, and buy this app from within AudioTools. It is priced lower in AudioTools.
*** Important Note for 3Gs Owners ****
The 3Gs has a much steeper low-frequency roll-off filter than previous models. This release detects the 3Gs model and corrects this as much as possible, given the extreme loss of low frequencies. See our web site for more information.
Graphics — There are three user-selectable options for the front panel. These include aluminum, dark metal, and plain. The dark metal option, with blue digits, is designed to work best in dark environments. Use aluminum or plain in daylight. To change the skin, just tap the small “i” icon in the bar on the top of the screen.
Store Result — We now have provided 9 memory slots for storing results. The dB SPL level, mode, weighting, time, date, and a description are all stored. Also, for non-Leq modes, the max and relative are stored, and for Leq, the Max and Leq time.
The iPhone 3G has the best microphone frequency response. SPL will work on the first generation iPhone, but without the same accuracy. You can also use SPL with our calibrated iPhone measurement mic, see below for details.
If you have an iPod Touch 2nd Generation, SPL will work, but you need to use an external mic, like the headphones / mic that is included with the iPhone.
The screen flips if you turn the phone upside down, so that you can point the built-in iPhone mic directly at the sound source.
*** Modes: Slow, Fast, Impulse, Peak, and Leq.
*** Filters: A and C weighting, and 10 octave band filters.
*** Includes a resettable Max field to track the highest reading.
*** Includes a reference field (except in Leq mode) so that you can set a reference level and do seat-to-seat comparisons.
The SPL meter can be fully calibrated. It comes preset with the calibration for a typical iPhone 3G. Most iPhone model 3G will be within a few dB of this reading. If you have access, even temporarily, to a calibrated sound level meter, just use the calibration field on the flipside to match the meter, and you will be accurately calibrated.
Also, see our other professional-grade audio apps: AudioTools, our premier suite of professional-caliber audio and acoustics test apps, Speaker Pop, to test speaker polarity, and RTA, a real-time analyzer for the iPhone.
And, we will soon be releasing a calibrated, accurate measurement microphone as part of our iAudioInterface system for the iPhone and iPod touch. This will allow measuring a range from approximately 30 dB SPL to 130 dB SPL. Each mic will include a calibration factor that you will enter into the SPL app for calibrated measurements. This mic will also work with Speaker Pop, our speaker polarity tester, FFT, RTA, ETC, and other acoustical measurement apps in our AudioTools app that we will be releasing soon.


NOTE: I have enabled the “buy for first gen Touch option”, but be advised that you have to arrange your own input via the dock connector. This model does not support the headset mic nor does it have an internal mic.
Now includes an iPhone internal mic compensation filter, to cancel out the low-frequency roll-off present in the iPhone.

Decibel Ultra

Ultra decibel measures the volume and helps you figure out how big the noise level compared to the same values. Ultra decibel measures the sound pressure level with built-in microphone in the iPhone 3G, 3GS, iPhone 4, iPad, iPod touch 4G. iPod Touch 2G and iPod Touch 3G users have to use an external microphone, since these devices have no built-in microphone.
Calibrate with Ultra decibels all the surround speakers on the same level.
Ultra Decibel measures the sound pressure level in the logarithmic unit of dB(c).
You want know how loud is your music or your TV? Or is the neighbor again too loud? With Decibel Ultra you know it! Noise can be a potential hazard to your health!
• Uses different graphics vor normal and retinal displays, optimal for the best Präsentation.
• Display of the average and peak value, and maximum memory for both.
• Really easy and intuitive operation.
• The offset can be set manually at any time.
• Relative measurements are possible any time.
• The sampling rate can be changed any time.
• Two analog display panels.
• histogram curve.
• Clean interface.
Additional features:
• Calibration menu
• Support for 180 degree rotation.
• Each setting is stored immediately.
• Internal and external microphone is supported.
• You can select a alternative analog panel.
• Long- term measurements are possible without sleep.
• Reset button to reset max. values, rate and offset.
• Calibrated values are separated for internal / external microphone saved.
• Calibrated values for the iPhone (3G, 3G, 4) and iPod Touch (2G, 3G, 4G) are integrated.
• REC button to record up to max. 1200 measured points. The measuring point of the record can then copy or send it by e-mail, including date and time format in ISO 8601.
• Help- and Information View in English, German, French and Italian.
-> Is continuously perfected <-


The Analyzer is a combination of a sound pressure level (SPL) meter and a full range multiple bands frequency analyzer. It is mainly designed for audio professionals who need to evaluate different working environments (e.g. studios, live stages)… that’s why it’s perfect for anyone who’s in need of acoustical analysis!! It is easy to use and comes with amazing features only known from professional acoustic tools. 
Use the Analyzer for measuring stages, testing speakers, evaluate sound mixing environments, analyzing your instrument… or the noise your neighbor makes with his new stereo!
Analyzer features:
– select your bandwidth in 7 steps (1/1 to 1/192 octave)
– choose between 5 different window functions
– select your FFT blocksize from 128 to 65536 samples
– automatic peak detection
– touch control scaling of frequency window
SPL Meter features:
– response time modes: impulse, slow, fast
– weighting functions: A B C
– hold function
– mute function

Sonic Scan

Displays sound pressure level [decibel] and frequency [Hertz] of sound in your environment.
Measure noise exposure in residential areas, at work, inside cars (compare cars), in bed- and livingrooms, near airports, discos, party noise, traffic noise, …
A-weighting for sound pressure level (the most commonly used weighting used to emphasize frequencies around 3–6 kHz where the human ear is most sensitive, while attenuating very high and very low frequencies to which the ear is insensitive).
Support for upside down device orientation (mic towards sound source).
Decibel meter calibration (shift and scale).
Sound pressure ranges from approx. 35 up to 105 decibels.
The real time frequency value displayed shows zero-crossings per second.
Even though Sonic Scan passed tests with professional equipment, Sonic Scan cannot replace professional equipment and should be used for entertainment purposes only.
Keywords: sound pressure level meter, SPL, decibel, hertz, frequency, loudness, dBA, dB, graph, measure, environment, scan, sonic, noise, dezibel, lärm, lärmmessung, lärmmesser, schalldruck 

dBMeter Pro

This application measures ambient noise in decibel using the built in microphone of the iPhone and iPhone 3G / 3GS and iPhone4. Apart from a modern and vintage look it also features a reference view showing typical noise producers in relation to the currently measured noise. It can record up to 500 samples, display them graphically and send them via eMail for further analysis.
Disclaimer: Even though the dBMeter Pro Software has been calibrated using professional grade equipment, do no use dBMeter Pro to carry out professional measurements. The author can not be held liable for any damage which might arise by using dBMeter Pro.