SoundMeter updated for iPhone 6S and iOS 9

SoundMeterProIcon76@2xSoundMeter 8.2 and SoundMeter Pro 4.2 are now available for download on the App Store. Each new version includes proper handling of the built-in microphone on iPhone 6S and iPhone 6S Plus devices and minor changes in iOS 9.

Unfortunately, the new iPhones do not support analog input gain selection for the built-in microphones as previous iPhone models did. The fixed input gain of the iPhone 6S/Plus matches the “Mid” input gain setting in the iPhone 5C, 5S, and 6 models. This means that the peak sound level that can be measured using the built-in microphone of the new iPhones is nominally 116.5 dB. Previous iPhones, on their lowest input gain setting, could measure nominal peak levels of 136 dB.Screen Shot 2015-10-20 at 2.56.19 PM

The SoundMeter apps now allow mixing audio with other apps. This means that it is possible to play music from the Music app while performing measurements with SoundMeter or SoundMeter Pro. It is also possible to mix the output of the signal generator with the audio output from another app.

Also new in each app, when using an iPhone or iPad that has multiple built-in microphones, the unique name of the selected microphone is displayed (e.g. “Bottom Microphone” or “Right Microphone”).

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SignalSuite for iOS now sports a fresh UI and support for larger iPhone screens

SignalSuiteAppIcon120Version 1.5 of SignalSuite, the original stereo audio signal generator for iPhone, finally supports larger iPhone screens, including those of the new iPhone 6S and 6S Plus, with a fresh new look. Functionally, the new version of SignalSuite is equivalent to previous releases, although it is now possible to manually select from a list of available audio output routes (e.g. the iPhone speaker or an Apple TV on the local network). The user interface elements have been updated to be consistent with the changes made to the appearance of iOS since version 7.

SignalSuite047ScreenShot1 SignalSuite047ScreenShot2 SignalSuite047ScreenShot3 SignalSuite047ScreenShot4 SignalSuite047ScreenShot5

SignalSuite supports 3.5, 4.0, 4.7, and 5.5-inch iPhone screens and requires iOS 7 or later. SignalSuite 1.5 is available now on the App Store.

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SoundMeter now offers Octave data logging on iPhone and iPad

For some time, SoundMeter has offered an optional in-app upgrade that would allow users to log sound level and noise dose measurements for up to two weeks. Version 8.1 adds an upgrade to allow whole and 1/3 octave sound levels to be logged for similar durations. The Octave Data Logging Upgrade will be made available within SoundMeter to users who have already purchased the Octave Analyzer Upgrade.


When Octave data logging is enabled, logged levels are displayed in a 2D color surface plot below the standard Octave spectrum graph. The color scale is defined by the vertical scale of the spectrum graph. A data cursor may be placed within the log plot to identify specific levels associated with date,  time, and frequency band.

Octave data can be logged as often as every 0.1 seconds for up to 1 hour, every second for up to 10 hours, or every 10 seconds for up to two weeks. Larger intervals can also be specified in each case.

When data logging is enabled, logged levels will also be included when saving data to a CSV, TXT, or MAT
file. (Saving data in SoundMeter requires the Data Acquisition Upgrade, sold separately.)

SoundMeter Pro includes all the functionality of SoundMeter plus that of SoundMeter’s in-app upgrades. Current SoundMeter Pro users get the additional Octave data logging functionality for free.

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iOS Audio Hardware: Stereo input via USB

If you’re looking for a way to acquire stereo input signals in apps like SignalScope Pro or IOScope, you’ll be pleased to know that you can connect a USB audio device to your iPhone, iPad, or iPod touch via Apple’s Lightning to USB Camera Adapter. Built-in USB audio support in iOS opens up a vast array of options for getting audio signals into, and out of, your iOS device. (USB audio support on iPhone and iPod touch requires iOS 7 or later.)


The trick is to find a device that conforms to the USB Audio Device Class specification, which essentially means that no special drivers are required when connecting the device to a host, like a Mac or an iPhone. Some device manufacturers clearly state that their product works with iOS and some do not. In general, if you find a USB audio device that does not require special drivers to work with Mac OS, then it will work with iOS as well.


One thing to consider when selecting a USB audio device to connect to your iPhone or iPad is power. Some USB audio devices require an external power source, which means portability will be somewhat limited due to the need to have an A/C power outlet nearby. Other devices support USB bus power, which means they’ll draw their power from the host device (e.g. the iPhone). For portability, this would be the ideal situation since the iPhone and input device could be completely portable and operate for the life of the iPhone’s battery. However, only low-power devices can be directly powered by an iPhone or iPad, which means that a lot of otherwise compatible USB audio devices cannot be connected to iOS without some other source of power. For bus-powered USB devices that require more power, it is possible to maintain some portability with a USB battery power supply and an additional adapter cable.

A Few Examples (portable and inexpensive)

Stereo USB Audio Devices
Behringer UCA202
The UCA202 from Behringer offers very inexpensive and portable stereo input for iOS.

It features:

  • 16-bit/48 kHz sampling
  • 2 inputs and 2 outputs with RCA jacks
  • Headphone output with volume control (1/8″ jack)
  • Low power operation so it can be powered directly by an iPhone or iPad
  • S/PDIF optical digital output
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Behringer UFO202
The Behringer UFO202 is similar to the UCA202. Instead of a digital output, it offers the option to select between line-level and phono preamp input.
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ART USB Dual Pre
Another inexpensive option, which also adds mic preamps with switchable 48V phantom power, is the USB Dual Pre from ART.

It features:

  • 16-bit/48 kHz sampling
  • 2 inputs with XLR / 1/4″ combo jacks for mic preamp or line-level input
  • 2 outputs with 1/4″ jacks
  • Headphone output with volume control
  • Low power operation so it can be powered directly by an iPhone or iPad
  • Switchable 48V phantom power, powered from a 9V battery
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Apple Lightning to USB Camera Adapter
This adapter is all that’s needed to connect a compatible USB audio device to an iPhone, iPad or iPod touch with a Lightning connector. As indicated above, if your USB device needs additional power, additional components will be needed. That will be discussed in a separate article.
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Apple iPad Camera Connection Kit
If you have an older iPhone or iPad with a 30-pin dock connector, you can connect a USB audio device with the USB adapter included in this kit. Remember that iOS 7 is required for USB audio on iPhone.
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SoundMeter 8 includes companion app for Apple Watch

SoundMeter 8.0 and SoundMeter Pro 4.0, which are both now available for download on the App Store, each include a companion app for Apple Watch. With the Watch app, you can monitor the current sound level, spectrum, and/or noise dose from your wrist (requires iOS 8.2 and iPhone 5 or later). These new versions of SoundMeter add other significant features, as well, including background sound level measurements and notifications of exceeded levels. The original sound level meter app for iPhone has now become the original sound level meter app for Apple Watch.

SoundMeter’s companion app for Apple Watch includes a separate screen for each of SoundMeter’s available tools running on the iPhone (new tools added to SoundMeter via in-app purchase are also supported in the companion app). Each tool can be started or stopped from the watch and current measurement values are updated on the watch display each second. The new notifications feature in SoundMeter allows the user to be notified on the Apple Watch when certain events occur. Notifications can be triggered when measurements stop (using the Auto-Stop feature) or when certain user-defined levels are exceeded. These notifications are supported in each of the Meter, Octave, and Dosimeter tools.

SoundMeter’s new ability to run in the background allows it to continue to run long-term measurements while other (non-audio) apps are in use. A complimentary new feature also allows the individual tools in SoundMeter to run independently. This means that users can run measurements in the Meter, Octave, and Dosimeter tools simultaneously. Users no longer need to worry about resetting the current measurement by switching to another tool (whether intentionally or accidentally). This makes SoundMeter more robust in terms of its ability to preserve acquired data until it can be saved more permanently in an image or data file.

Watch App Screenshots

SoundMeter Pro Screen Shot - Apple Watch  SoundMeter Pro Screen Shot - Apple Watch

SoundMeter Pro Screen Shot - Apple Watch  SoundMeter Pro Screen Shot - Apple Watch

The new versions of SoundMeter also include the following improvements:

  • Lx (percentile-exceeded sound level) measurements now use the same time and frequency weighting as the Lp measurement, instead of automatically switching to Fast and A weighting.
  • Frequency weighting may now be set to Flat, A, or C in the Dosimeter options menu (previously, the Dosimeter only allowed A weighting).
  • Meter, Octave, and Dosimeter tools now use local notifications to alert you when a measurement has finished or when selected levels have exceeded user-defined thresholds.
  • This release corrects a bug that could cause the device sensitivity for the built-in mic or the headset input to get corrupted when changing input gain selection with device units set to “FS.”


  1. Octave and Dosimeter tools, Lx measurement and data file export capability are sold separately within SoundMeter via in-app purchase. These capabilities are all included with SoundMeter Pro.
  2. This SoundMeter update will require you to restore your in-app purchases (you will not be charged again for upgrades you have already purchased).
  3. Apple Watch compatibility requires iOS 8.2 and iPhone 5 or later.


Download SoundMeter 8.0

Download SoundMeter Pro 4.0


SignalScope Pro 4 for iOS uniquely identifies USB audio devices

SignalScope Pro version 4 can uniquely identify USB audio devices attached to iPhone, iPod touch, or iPad, and remember user settings for each device the next time it is connected. Direct support has been added for The Modal Shop’s model 333D01 USB digital accelerometer and miniDSP’s UMIK-1 USB measurement microphone. With the 333D01, SignalScope Pro automatically loads serial number and sensitivity calibration information directly from the device as soon as it is connected. When the UMIK-1 is connected, SignalScope Pro recognizes it and prompts the user for its serial number. Sensitivity calibration and frequency response data for the UMIK-1 can then be downloaded automatically, just by entering the UMIK-1’s serial number.

Another major new feature in version 4 is SignalScope Pro’s ability to load microphone frequency response data (FRD) and apply frequency response correction (FRC) to FFT spectrum measurements. FRD can be loaded for any input channel, for any kind of transducer (i.e. it’s not just for microphones). Sophisticated interpolation techniques are employed to generate a smooth frequency response
correction curve that matches the loaded data. This correction curve can then be applied to an FFT spectrum
of arbitrary length or frequency resolution.

SSP4 Accel and Mic

Also new in version 4:

– SignalScope Pro directly supports The Modal Shop’s model 333D01 USB digital accelerometer, and can automatically load serial number and sensitivity calibration information directly from the device. Making calibrated acceleration measurements is as easy as plugging in the 333D01. Factory calibration information is embedded in exported audio files (from the Oscope tool) when data is acquired with the 333D01.

– SignalScope Pro directly supports the miniDSP UMIK-1 USB measurement microphone. Sensitivity calibration and frequency response data for the UMIK-1 can be downloaded automatically, just by entering the UMIK-1’s serial number. Making calibrated sound level measurements is as easy as plugging in the UMIK-1 and typing in its serial number (the serial number only needs to be entered once, after which SignalScope Pro will remember the microphone sensitivity).

– Additional dB scales of 3, 6, 12, 15, and 18 dB per div are now supported by the FFT analyzer. Also, when adjusting the dB scale manually, the dB offset will always be set as a multiple of the scale so that 0 dB is always available in the vertical axis labels.

– Minor bug fixes and cosmetic enhancements.

– Apple’s Lightning to USB Camera Adapter or iPad Camera Connection Kit is required for connecting USB Audio devices to your iPhone, iPod touch, or iPad.

– SignalScope Pro 4 requires iOS 7 or later.

Similar features have been added to SignalScope 5.0, although select in-app upgrades may be required (available via in-app purchase).

Download SignalScope Pro

Looking for the best sound level meter app

Last year, researchers at NIOSH (the National Institute for Occupational Safety and Health) began looking at mobile sound level meter apps, hoping to find that such apps could be suitable for occupational noise measurements. After defining specific criteria to qualify sound level meter apps as suitable for their tests, they set out to find matching apps for  iOS, Android, and Windows-based mobile devices. Ten iOS apps, out of over 130 available, were examined as part of their research. Of 62 Android apps downloaded for examination, only 4 apps partially met their criteria. No Windows-based apps qualified.

The results of the study were recently published in the (peer-reviewed) Journal of the Acoustical Society of America (JASA). According to the published article, “The evidence suggests that for A-weighted data, SoundMeter is the app best suited for occupational and general purpose noise measurements. In addition to having the smallest mean difference for the A-weighted data, SoundMeter had the narrowest distribution of differences…”

SoundMeter Screenshot iPhone 5

The article concludes, “This study showed that certain sound measurement apps for Apple smartphones and tablets may be considered accurate and reliable to be used to assess occupational noise exposures. Android and Windows developers do not offer apps that meet the functionality needed for occupational noise assessments.”

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Noted at the end of the article: “The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Mention of any company or product does not constitute endorsement by NIOSH.”

JASA Article

NIOSH Blog Article (with images and video)


Faber Acoustical announces SoundMeter Pro for iOS

Building on the success of SoundMeter, which debuted on the iPhone App Store in August of 2008, Faber Acoustical has announced the release of SoundMeter Pro. SoundMeter Pro turns your iPad, iPhone, or iPod touch into a handheld data-logging sound level meter (SLM), data-logging noise dosimeter, and real-time analyzer (RTA).

SoundMeter Pro works with built-in or external measurement microphones to deliver reliable sound level measurements, including time-weighted and equivalent sound levels in addition to percentile-exceeded sound levels and noise dose. Measured levels can be logged at intervals as small as 0.1 seconds for durations of up to two weeks (longer measurement durations may require larger logging intervals). The built-in Octave tool performs sound level measurements in whole or 1/3-octave frequency bands.

In a recent article published in the Journal of the Acoustical Society of America, NIOSH researchers found that, out of over 130 sound measurement apps for iOS, “SoundMeter is the app best suited for occupational and general purpose noise measurements.” SoundMeter Pro builds on everything SoundMeter has to offer.

With the built-in or headset microphone, SoundMeter Pro can measure peak sound levels of up to approximately 130 dB. Results may vary between iOS devices and headset microphones. External microphones may enable the measurement of much higher sound levels.

SoundMeter Pro also includes various features that users have come to expect from Faber apps, including the ability to save measurement data to CSV, TXT, or MAT files, save measurement displays to high resolution PDF files, switch between three different color schemes, and calibrate microphone input sensitivity. Exported data files may be retrieved from the iOS device via iTunes File Sharing or by enabling the app’s built-in file server and downloading the files to another device or computer via a standard web browser. The built-in signal generator tool further extends SoundMeter Pro’s utility by producing any of various test signals, including white noise, pink noise, frequency sweeps, and periodic waveforms.

Faber Acoustical has simultaneously announced the availability of SoundMeter 5.0. The new version of SoundMeter adds support for a new Data Logging Upgrade, which is available via in-app purchase. SoundMeter Pro includes all the functionality of SoundMeter 5 with all its available in-app purchase upgrades. Although both apps run on iOS 6, each also features a user interface tailored for iOS 7.

NOTE: Although it has been designed to do so, SoundMeter Pro is not guaranteed to meet ANSI or IEC standards for sound level meters. These standards require conformance of the entire measurement system, including software, hardware and microphones.

The built-in and headset microphones are suitable for certain, basic sound level measurements, but high precision external microphones may also be used with appropriate audio accessory hardware. Even though default sensitivity values are included for the built-in and headset microphones, for best results, SoundMeter Pro should be calibrated before use. Sound levels may be off by a few dB when using the default microphone sensitivity.

   SoundMeter Pro Screenshot iPhone 1 SoundMeter Pro Screenshot iPhone 2

   SoundMeter Pro Screenshot iPhone 3 SoundMeter Pro Screenshot iPhone 4


Minimum Requirements:
* iOS 6.0 or later
* iPhone, iPod touch, or iPad
* 4.12 MB

Pricing and Availability:
SoundMeter Pro is now available for download on the App Store for $99.99 (USD). External hardware may be required for analog input capability. More information on SoundMeter Pro can be found at Faber Acoustical online. More information regarding suitable input devices for specific iOS devices can be found on the Faber Acoustical blog.

Download SoundMeter Pro

Download SoundMeter 5.0

iOS 7 Brings USB Audio Support to iPhone and iPod touch

I’m not sure how I missed it, but I discovered this week that USB audio devices can now be used with iPhones that support iOS 7 as well as the 5th generation iPod touch (I have personally confirmed that it works with iPhones as old as the iPhone 4S and the 5G iPod touch–iOS 7 is required in order for this to work). This is great news for anyone looking to perform multi-channel or high-quality audio or acoustic analysis with something smaller than an iPad.

The iPad has supported USB audio input and output, via the iPad Camera Connection Kit, from the beginning. Until the advent of iOS 7, however, this functionality was not supported on iPhone or iPod touch. Now, a whole host of devices, ranging from inexpensive stereo USB audio interfaces to higher end multichannel interfaces, can be used with the iPhone or iPod touch you carry in your pocket. Smaller, simpler USB interfaces will draw their power directly from the iOS device. More sophisticated hardware will require some kind of additional power supply. In any case, it is important to note that the USB audio interface must support the standard USB Audio Class driver (if it works with Core Audio on your Mac, without the need to install special drivers, then it should work with your iPhone).

In order to connect a USB audio interface to an iPhone, either the 30-pin USB adapter of the old iPad Camera Connection Kit or a Lightning to USB adapter is required (depending on whether your iPhone has a 30-pin or Lightning connector on the bottom). The screenshots below demonstrate success with a Behringer UFO-202 connected to a 5th generation iPod touch and a Tascam US-800 connected to an iPhone 5S. The UFO-202 runs completely off of power from the iPod (or iPhone), so it is a completely portable solution. The US-800 requires external power.



Measuring the inexpensive, bus-powered Behringer UFO-202 with SignalScope Pro running on the 5th generation iPod touch.


Measuring the inexpensive, bus-powered Behringer UFO-202 with SignalScope Pro running on the 5th generation iPod touch.


Analyzing 6 input channels simultaneously with SignalScope Pro running on the iPhone 5S. The input device is a Tascam US-800 sampling at 96 kHz.


Analyzing 6 input channels simultaneously with SignalScope Pro running on the iPhone 5S. The input device is a Tascam US-800 sampling at 96 kHz.


If you have had any experience connecting USB audio devices to your iPhone or iPod, I would love to hear about it in the comments. What have you found that works? What doesn’t?


Download SignalScope Pro from the App Store.


SoundMeter and dB support new iPads

Nominal microphone sensitivities for the iPad Air and iPad mini with Retina display have been added to SoundMeter 4.0.1 and dB 3.0.1.

Both apps also display dark blue toolbars in the black color scheme to make it easier to view the screen in dark environments.

SoundMeter additionally corrects the HTTP file server configuration screen, which now scrolls to reveal the web URL on 3.5-inch iPhone screens (the file server is available for in-app purchase as part of the data acquisition upgrade).

SoundMeter Screenshot iPhone 5


SoundMeter 4.0.1 and dB 3.0.1 are both available for download on the App Store.

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