The FFT-based spectrum analyzer in SignalScope Pro 6.2 allows arbitrary upper and lower frequency bounds (Fmax and Fmin) to be specified for the spectrum display. The cursor peak track function will operate only within the specified frequency bounds. The hardware sample rate may optionally be automatically adjusted to best match the specified value for Fmax.
A typical minimum sample rate of iOS hardware is 8 kHz. If a frequency resolution of 1 Hz is used for the spectrum, and values of 10 and 400 are specified for Fmin and Fmax, respectively, the data between 10 and 400 Hz will be plotted and the plot will be scaled to extend only from 10 and 400 Hz. If the cursor peak track function is enabled, the cursor will find the frequency of the highest magnitude between 10 and 400 Hz.
If the option to automatically adjust the sample rate based on Fmax has been selected, the hardware sample rate (Fs) will automatically be reduced to the minimum rate required to acquire data up to 400 Hz. In the case of typical iOS or USB audio input hardware, this rate would be 8 kHz. Since FFT data would then include values between 0 and 4 kHz, an additional option allows either all data (0 to 4 kHz) or only data from 10 to 400 Hz to be exported when saving FFT data to a CSV, TXT, or MAT file. Note that the DC term may be omitted from exported data when FFT data is displayed on a logarithmic frequency scale.
Also new in SignalScope Pro 6.2:
When “cpm” is selected for units of frequency, exported data files will include frequencies specified in cpm.
The nominal microphone sensitivity is properly set on the new iPhones.
Other bug fixes/stability enhancements, including iOS 9 compatibility.
Similar improvements have been added to version 7.2 of SignalScope. Specifying values for Fmin and Fmax in SignalScope require the Data Acquisition Upgrade, which is available via in-app purchase.
SoundMeter 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.
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”).
SignalScope Pro 6.1 and SignalScope 7.1 have been released for sale on the App Store with some important enhancements, including the ability to mix audio output with other apps. Audio mixing means that it is possible to play music from the Music app while performing signal analysis with SignalScope or SignalScope Pro. It is also possible to mix the output of the signal generator* with the audio output from another app.
The SignalScope apps include other important enhancements:
The FFT analyzer tool now supports frequency resolution as fine as 0.1 Hz for audio input signals.
When working with 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
When analyzing two input channels in the Octave tool, both spectra are displayed in a single line plot.
Although Faber Mac and iOS apps have offered excellent sound and vibration analysis tools from the start, the introduction of the Digiducer 333D01 USB Digital Accelerometer makes vibration measurement easier and more portable. When the 333D01 is connected to a Mac, iPhone, or iPad, it will be immediately recognized by our apps and ready for calibrated measurements.
For example, SignalScope Pro will recognize the connected 333D01 as an accelerometer and set the measurement units accordingly. SignalScope Pro will also automatically read calibration information from the 333D01 and establish the appropriate sensitivity so calibrated measurements can be made immediately. This works with both the Mac and iOS versions of SignalScope Pro.
The 333D01 communicates with Mac OS or iOS via the standard USB Audio Class driver. Connecting to a Mac is as simple as plugging the 333D01’s cable into an available USB port. For iOS, Apple’s Lightning to USB Camera Adapter is required.* When connecting to iOS, no additional power source is required, which makes Faber apps and the 333D01 part of an ultraportable vibration measurement system.
Version 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.
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.
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.
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
The UCA202 from Behringer offers very inexpensive and portable stereo input for iOS.
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
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.
Faber Acoustical is pleased to announce that a live Spectrogram tool is now available for purchase within SignalScope and SignalScope Pro. The Spectrogram tool is offered in both 2D and 3D versions. The 3D Spectrogram includes all the functionality of the 2D version and adds powerful hardware-accelerated 3D plotting capabilities including a live 3D surface plot. A 3D upgrade is available to those who opt to purchase the 2D version.
The real-time Spectrogram plots FFT-based spectral data versus time in a colorful surface plot. Signal magnitude at each time and frequency is represented by color. Use single-finger tap and drag to place a data cursor within the plot. When the cursor is visible, details regarding time, frequency, and magnitude will be displayed above the plot.
Main Features (available in both versions of the Spectrogram tool:
Frequency resolutions between 1 Hz and 50 Hz, depending on sample rate, may be specified for audio input (between 1 Hz and 10 Hz for the built-in accelerometer).
Input data can be windowed with one of 7 different FFT data window types.
Spectrogram data can be captured over time periods ranging from 2 to 20 seconds.
Lin, log, and dB magnitude scales with Up, Down, or Full auto-scaling.
Lin and log frequency scales.
Fractional-octave band frequency smoothing in 1/6, 1/12, and 1/24-octave bands.
Cursor peak track can track peaks in time, frequency, or both.
Color scale bar graph enables manual adjustment of magnitude scale and offset. The color scale can also be hidden.
Data may be exported to CVS, MAT, or TXT files for post processing or plotting. Optionally, include GPS location information with exported data. (The data export option is included in SignalScope Pro. It requires the Data Acquisition upgrade, sold separately, in the standard version of SignalScope.)
Optionally save a high-resolution PDF file of the spectrogram plot, or save an image to your Photos library.
3D Spectrogram Features:
Choose between 2D and 3D surface plots. Each plot can be drawn live (in real time).
Trackball-style 3D rotation of the 3D surface plot, just by dragging a single finger across the plot.
Tap with a single finger to place a cursor within the 3D plot.
In 3D, the cursor outlines the time and frequency slice associated with its current location.
Optional grid planes for each axis (magnitude vs. frequency, magnitude vs. time, and frequency vs. time) are drawn at the bounds of the 3D plotting region.
By default, the 3D spectrogram is drawn as a surface and magnitude values are represented by both position and color. The surface can be turned off, which allows data to be drawn only as a mesh.
The 3D spectrogram data can be seen as a solid-colored mesh (the mesh draws nothing between its lines or points). The mesh can be overlaid on the surface or drawn alone.
The mesh can be drawn as lines in time, lines in frequency, or lines across both time and frequency. It can alternatively be drawn as a series of dots, each one representing a single spectrogram data point.
When only viewing the 3D spectrogram data as a mesh, the time and frequency slices outlined by the cursor show through the mesh, making it very easy to see them in the midst of the rest of the data.
Also new in SignalScope and SignalScope Pro:
GPS coordinates, altitude, and accuracy may now optionally be saved with FFT, Spectrogram, or Oscope data when exporting to a data file (Data Acquisition Upgrade required in SignalScope).
Downloaded frequency response data for connected microphones will automatically be saved in a file in the Frequency_Response_Data folder to make it easier to access at a later time.
Smarter selection of the maximum frequency when FFT data smoothing is enabled.
Fixed an issue with Full Autoscale in the FFT analyzer.
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
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.”
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.
This SoundMeter update will require you to restore your in-app purchases (you will not be charged again for upgrades you have already purchased).
Apple Watch compatibility requires iOS 8.2 and iPhone 5 or later.