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 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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Download SoundMeter Pro

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

RoomScope 2.1 validates reverberation time measurements

In version 2.1, RoomScope now presents a nonlinearity parameter to offer additional guidance on the validity of each acoustic decay parameter (T20, T30, T60, EDT). Values of greater than 10 ‰ (per mille, or parts per thousand) indicate that the estimated reverberation or decay time may be suspect, or that integration limits may need to be adjusted manually to obtain a more accurate result.

RoomScope 2.1 is now available for download on the App Store.

RoomScope Screenshot iPhone 5

Download RoomScope 2.1

SoundMeter 4.1 offers percentile-exceeded sound levels

SoundMeter 4.1, which is now available for download on the App Store, offers percentile-exceeded sound levels (Lx) via in-app purchase.

With the new upgrade, SoundMeter can display L10, L50, L90, or any percentile between 1 and 99. Percentile exceeded sound levels are also available in the Octave Analyzer tool (sold separately).

Also new in SoundMeter is the ability to set the meter to automatically stop after an arbitrary amount of elapsed time from 1 second to two weeks.

The Dosimeter and Octave Analyzer tools (sold separately) can also be set to automatically stop after a user-defined period of time.

Lx IAP Upgrade screenshot

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RoomScope Updated for iOS 7

RoomScope version 2.0 now fully supports iOS 7 with a refreshed look and feel that is consistent with recent updates to SignalScope Pro and IOScope. Although RoomScope still supports iOS 6, its appearance remains largely the same as before on the older iOS.

What’s new in RoomScope 2.0?

– RoomScope’s appearance has been completely revamped for iOS 7. RoomScope supports both iOS 6 and iOS 7, but looks largely the same on iOS 6 as the previous version.
– Audio data handling is more efficient.
– When entering a preferred sample rate, “48k” can be entered in the text box, as an alternative to typing out “48000.”
– Default input sensitivities have been updated, based on measurements of the iPhone 5S and 5C microphones and headset inputs. Nominal input sensitivities have also been updated for iPad Air and iPad mini with Retina display.
– Cursor info text now uses a larger font.
– 2Ch IR works properly when the internal excitation signal is selected for the X input and pan is set to 100%.
– A bug in the HTTP file server has been fixed.

RoomScope is a universal app designed for iPad, iPhone, and iPod touch.

 

RoomScope Screenshot iPhone 1

RoomScope Screenshot iPhone 2

RoomScope Screenshot iPhone 3

RoomScope Screenshot iPhone 4

 

Download RoomScope from the App Store.

 

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.

 

IMG_0046

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

IMG_0047

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

IMG_2286

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.

IMG_2287

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.

Download SoundMeter

Download dB

 

SignalScope Pro and SignalScope for iOS updated for iPad Air and new iPad mini

SignalScope Pro 3.0.1 and SignalScope 4.0.1 for iOS include updated nominal input sensitivities for iPad Air and iPad mini with Retina display.

Also new in SignalScope Pro:

  • Toolbars are now a dark blue in the black color scheme to make it easier to view the app in dark environments.
  • The HTTP file server configuration screen now scrolls to reveal the web URL on 3.5-inch iPhone screens (in SignalScope, the file server is available for in-app purchase as part of the data acquisition upgrade).

 

SignalScope Pro Screenshot iPhone 6

 

SignalScope Pro 3.0.1 and SignalScope 4.0.1 are now available for download on the App Store.

Download SignalScope Pro

Download SignalScope

 

IOScope 3.0 Updated for iOS 7

As in recent updates to SignalScope Pro and SoundMeter, IOScope’s appearance has been completely revamped for iOS 7. IOScope supports both iOS 6 and iOS 7, but looks largely the same on iOS 6 as the previous version.

Also new in version 3:

– Audio data handling is more efficient.

– For devices that support input gain adjustment on the built-in or headset microphone, the input gain is stored with exported data.

– When entering a preferred sample rate, “48k” can be entered in the text box, as an alternative to typing out “48000.”

– Default input sensitivities have been updated, based on measurements of the iPhone 5S and 5C microphones and headset inputs.

– Cursor info text now uses a larger font.

 

IOScope Screenshot iPhone 1 IOScope Screenshot iPhone 2 IOScope Screenshot iPhone 3

IOScope Screenshot iPhone 4 IOScope Screenshot iPhone 5

 

Download IOScope 3.0

 

 

SignalScope Pro 3.0 for iOS 7

In the new version 3, SignalScope Pro’s appearance has been completely revamped for iOS 7. SignalScope Pro supports both iOS 6 and iOS 7, but looks largely the same on iOS 6 as the previous version.

Also new in version 3:

– Audio data handling is more efficient.

– Image overlays created in the Level Meter tool now use the full resolution of the original image (whether the image comes from the photo library or straight from the camera).

– For devices that support input gain adjustment on the built-in or headset microphone, the input gain is stored with data exported from the FFT, Octave, or Oscope tools.

– When entering a preferred sample rate, “48k” can be entered in the text box, as an alternative to typing out “48000.”

– Default input sensitivities have been updated, based on measurements of the iPhone 5S and 5C microphones and headset inputs.

– Cursor info text now uses a larger font.

 

SignalScope Pro Screenshot iPhone 1 SignalScope Pro Screenshot iPhone 4 SignalScope Pro Screenshot iPhone 5

SignalScope Pro Screenshot iPhone 2 SignalScope Pro Screenshot iPhone 3

 

Download SignalScope Pro

SignalScope, SoundMeter, and dB have also received similar updates for iOS 7.

Download SignalScope

Download SoundMeter

Download dB

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