RoomScope and IOScope measure longer IRs and use 64-bit FFTs

RoomScope 1.2 and IOScope 2.3 arrived in the iOS App Store this week. Both apps now support impulse response measurements up to 16 seconds long and use double precision (64-bit) FFTs in their measurements. The maximum measurement length is dependent on the amount of memory available on the device, so 16-second measurements are currently only supported on the iPhone 5, iPad 3, and iPad 4. The previous generation of devices, including the iPod touch 5, supports 10-second measurements, and older devices are still limited to measurement durations of 5 seconds or less.

RoomScope 1.2 also offers the following additions:

  • Center time has been added to the list of calculated acoustic parameters.
  • All parameters are now calculated in low, mid, and high frequency bands, as defined by the ISO 3382 standard.
  • The calculation of the clarity and definition parameters (C and D) compensates for the delay of the whole and 1/3-octave band filters, as described in ISO 3382.
  • Raw IR data can now be excluded or included in CSV, MAT, and TXT file data exports.

RoomScope turns your iPad, iPhone, or iPod touch into a room acoustics measurement and analysis tool. With RoomScope, you can measure a room impulse response and then calculate reverberation time, early decay time, center time, clarity, and definition, as defined in the ISO 3382 standard. RoomScope also allows you to adjust the Schroeder decay curve integration limits with the touch of your finger and plot the calculated room parameters versus whole or 1/3-octave band center frequency.

RoomScope

 

Download RoomScope 1.2

IOScope brings true dual-channel transfer function and impulse response analysis to iOS. With IOScope, measure loudspeaker impedance, frequency response, and sensitivity. Measure a room impulse response. Tune a large sound reinforcement system, time-align a set of surround sound speakers, or optimize your home stereo. Determine the actual cutoff frequencies of your latest speaker crossover circuit, or teach your students the fundamentals of Fourier analysis of dynamic systems.

Measure frequency response magnitude and phase, coherence, and group delay. Time domain functions enable you to measure impulse response and auto/cross-correlation. IOScope includes a built-in signal generator for producing suitable excitation signals to analyze your system or device under test (DUT). See http://youtube.com/faberast for a video demo of loudspeaker impedance measurement.

 

Download IOScope 2.3

 

Frequency Response Measurement with SignalScope Pro 3 (Mac)

Measuring the Frequency Response of Your Audio Device

Although SignalScope Pro does not include the Dual FFT Analyzer tool, found in Electroacoustics Toolbox, it is still equipped to perform basic frequency response measurements. This tutorial focuses on using SignalScope Pro’s FFT Analyzer and Signal Generator tools to measure the frequency response of the audio device that you use as an analog interface to measure other systems and devices. If you want to measure the frequency response of a listening room for example, that measurement will be affected by the quality of the audio interface that you are using to make the measurement. Therefore, it is important to know how your measurements will be influenced by your audio interface.

When measuring the properties of some device, like its frequency response, that device is commonly referred to as the “device under test” or DUT. In this case, the DUT is actually the audio device that would normally be used as part of the complete measurement system you use to measure other DUT’s.

Measuring Your Audio Device

  1. Connect your device to your Mac (if necessary, you may want to consult your device’s user guide or owner’s manual).
  2. Using a patch cable that is appropriate for the device you are using, connect one or more outputs of the device to one or more inputs of the same device. Figure 1 demonstrates the connections using an Echo AudioFire4 FireWire interface. It is important to keep in mind that what will be measured in this tutorial is actually the combined frequency response of the input channel, the output channel, and even the patch cable between them.
    AF4
    Figure 1: 1/4″ plug patch cable

     

  3. Launch SignalScope Pro, if necessary.
  4. Create a new project, if one was not created automatically when the program launched.
  5. Click the Device IO button in the project window’s toolbar to open up the Device IO Setup window.
  6. In the Device IO Setup window, click on the name of the device you would like to measure in the Available Devices list. This will display the device’s properties in the lower portion of the window.
  7. Make sure the nominal sample rate is set high enough to capture the desired frequency range. For this tutorial, select 44100 or 48000 Hz.
  8. Select your device from both the Input Device and Output Device popup menus in the project window. If your device does not have both input and output channels, you will need to select one that does, or use the Aggregate Device Editor in the Audio MIDI Setup application to create one. (Audio MIDI Setup is included with Mac OS X in the /Applications/Utilities/ folder.)
  9. Create a new FFT Analyzer tool. This can be accomplished by clicking the “+” button in the FFT Analyzer row of the project toolbox, selecting FFT Analyzer from the Tools menu in the project window’s toolbar, or by selecting New FFT Analyzer from the Tools menu.
  10. Select the Live Inputs tab in the controls drawer at the bottom of the Dual FFT Analyzer window.
  11. In the analyzer table below the Input Device label, the first row will already be pre-filled for Analyzer 1. For Analyzer 1, change the channel in the Input column to match the physical input channel connected in step 2.
    • The name of each analyzer can be edited by double clicking on it within the Channel column of the table, either in the Display tab or in the Live Inputs tab.
  12. If you connected multiple physical input/output channel pairs in step 2, click the “+” button above the analyzer table to add an additional analyzer for each additional channel pair and configure the input channels as in the previous step.
  13. In the FFT tab of the FFT Analyzer’s controls drawer, set the number of spectral lines to a value that will provide the frequency resolution you need. For the purposes of this tutorial, select 4410 spectral lines if your DUT’s sample rate is 44100 Hz or 4800 lines if your sample rate is 48000 Hz.
    • The frequency resolution of your measurement can be determined by the selected frequency span (which is dependent on the sample rate) and the number of spectral lines. You can calculate the frequency resolution by dividing the frequency span by the number of lines (if guardbanding is turned off). For example, if the selected frequency span is 24000 Hz, and the number of lines is 4800, the frequency resolution will be 24000/4800 = 5 Hz. You can also view the current frequency resolution of the analyzer inside the analyzer’s info drawer, which slides out of the right-hand side of the analyzer’s window.
  14. Create a new Signal Generator tool.
  15. Select your DUT in the Output Device popup menu of the Signal Generator’s signal drawer (on the lefthand side of the Signal Generator window).
  16. Select the output channels corresponding to the physical output channels that you connected in step 2. Select the first output channel in the Left Output Channel box, and the second output channel in the Right Output Channel box. If you have connected more than two output channels for a multichannel measurement, you will need to create a new Signal Generator tool for each pair of output channels to be measured.
  17. Click on the Swept Sine (Chirp) tab in the Signal Generator window to display controls for establishing a frequency sweep excitation signal. Configure the swept sine generator as follows:
    • Frequency Sweep: Linear
    • Sweep Direction: Up
    • Lower Frequency: 0
    • Upper Frequency: 22050 or 24000 Hz (The Upper Frequency should be half the selected sample rate, which corresponds to the Nyquist frequency–22050 for 44.1 kHz sampling or 24000 for 48 kHz sampling.)
    • Duration: 8820 samples for 44.1 kHz sampling or 9600 samples for 48 kHz sampling
    • Repeat: Yes
  18. Click the “On” check box to enable the swept sine generator.
  19. Create a new Meter Bridge tool.
  20. Select your device in the Input Device popup menu of the Meter Bridge’s controls drawer (in the Live Inputs tab).
  21. Start the Meter Bridge.
  22. Make sure the Peak level type is selected in the Meter Bridge’s controls, then look to be sure none of the input channels are in danger of clipping (colored red at the top of the meter bar). If any of the input signal levels are too high, reduce the level in the Signal Generator.
  23. Select the FFT Analyzer window again.
  24. Start the FFT Analyzer, either by clicking the start icon in the window’s toolbar, or by selecting Start Analyzer from the Control menu (or by typing Command-R).
  25. Start the generator(s), either by clicking the start icon in the window’s toolbar, or by selecting Start Generator from the Control menu (or by typing Command-R). If you have one or more Signal Generator tools in your project, you can start all of them by selecting Start All Tools from the Control menu.
  26. After everything is running and the measurements have stabilized, you can stop the tools. (If you choose to stop the tools individually, rather than with the Stop All Tools command, it would be best to stop the FFT Analyzer tool(s) first.) Figure 2 shows a plot which shows the frequency response of the Echo AudioFire4. The frequency response of the AudioFire4 is quite flat between 20 Hz and 20 kHz.
    • For more advanced frequency response measurements, including phase response, coherence, group delay, and SNR, or to measure multiple audio devices simultaneously, please consider downloading Electroacoustics Toolbox.
  27. Capture your measurement, either by clicking the capture button in the FFT Analyzer’s toolbar, or by choosing Capture Data from the Control menu.
  28. Save your project so you can review your measurement or export the data at another time.
    Figure 2: Echo AudioFire4 Frequency Response

     

iPhone 5 compatibility with existing audio input accessories

Since the Lightning to 30-pin Adapter (0.2 meter cable) arrived yesterday, I have had the opportunity to test several audio accessories with the iPhone 5. The results are presented below. Only accessories that worked with the iPhone 4 were tested, since earlier audio input accessories couldn’t be expected to work with the new iPhone (they relied on the analog input pins that were not supported on 4th generation iOS devices).

30-pin audio input accessory compatibility

Accessory iPhone 5 iPhone 4/4S
Apogee Jam Yes Yes
Fostex AR-4i Yes (1) Yes
Line 6 Mobile In Yes Yes
Sonoma Wire Works GuitarJack 2 Yes Yes
Tascam iU2 No (2) Yes
  1. There were a few times that I couldn’t get the iPhone 5 to recognize the Fostex AR-4i, but once it did, the AR-4i worked well. Sometimes, the iPhone would give the same message as that for the Tascam iU2 (below).
  2. When connecting the iU2 without USB power, the iPhone 5 wouldn’t recognize it. When USB power was supplied to the iU2, the iPhone would present a message which said, “The connected USB device is not supported.”

Finally! iOS 6 kills the filter on headset and mic inputs!

So, iOS 6 has finally arrived and the biggest news for SoundMeter, SignalScope, and SignalScope Pro users may just be that the high-pass filter which used to plague the built-in microphone and headset microphone inputs now gets bypassed. This exciting improvement to iOS 6 will significantly improve the quality of acoustical measurements that can be made with the iPhone, iPad, or iPod touch, without requiring a dock connector accessory for audio input.

Below are 1/3-octave headset input frequency response comparisons for the various iOS devices that support iOS 6. More details regarding the headset input and built-in microphone will be presented in the days ahead.

Update (9/19/20120, 7:32 PM): It should be noted that these are electrical frequency response measurements. When making acoustical measurements, the overall frequency response will depend also on the microphone that is used.

iPhone 4S Before iOS 6/Now

iPhone 4S Headset Leq Pre-iOS 6  iPhone 4S Headset Leq iOS 6

iPhone 4 Before iOS 6/Now

iPhone 4 Headset Leq Pre-iOS 6  iPhone 4 Headset Leq iOS 6

iPhone 3GS Before iOS 6/Now

iPhone 3GS Headset Leq Pre-iOS 6  iPhone 3GS Headset Leq iOS 6

iPod touch 4 Before iOS 6/Now

iPod touch 4 Headset Leq Pre-iOS 6  iPod touch 4 Headset Leq iOS 6

iPad 3 Before iOS 6/Now

iPad 3 Headset Leq Pre-iOS 6  iPad 3 Headset Leq iOS 6

iPad 2 Before iOS 6/Now

iPad 2 Headset Leq Pre-iOS 6  iPad 2 Headset Leq iOS 6

 

iOS 6 is now highly recommended for all SoundMeter, SignalScope, and SignalScope Pro users.

 

 

IOScope 2.1 exports impulse responses to AIF, CAF, or WAV audio files

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

IOScope room impulse response measurement

IOScope room impulse response measurement

IOScope 2 can now export normalized impulse response data to AIF, CAF, or WAV audio files. On iOS 5, or later, audio files can be previewed with IOScope or opened with other apps on the same device that can open these file formats. Of course, IOScope also allows for audio files to be transferred to a Mac or PC via iTunes File Sharing, or downloaded with a web browser via the built-in HTTP file server.

With IOScope, measure loudspeaker impedance, frequency response, and sensitivity. Measure a room impulse response. Tune a large sound reinforcement system, time-align a set of surround sound speakers, or optimize your home stereo. Determine the actual cutoff frequencies of your latest speaker crossover circuit, or teach your students the fundamentals of Fourier analysis of dynamic systems.

Measure frequency response magnitude and phase, coherence, and group delay. Time domain functions enable you to measure impulse response and auto/cross-correlation. IOScope includes a built-in signal generator for producing suitable excitation signals to analyze your system or device under test (DUT). The reference signal can be taken from the internal signal generator or from an external source (when using an external reference, a stereo audio input device, connected to the dock connector, is required).

IOScope also turns your iOS device into a platform for data acquisition, storing acquired data in CSV or tab-delimited text files, MAT-files, or images, including high-resolution PDF files, for later retrieval from your device.

What’s new in version 2.1?

  • Impulse responses can now be exported to AIFF, CAF, or WAV audio files. On iOS 5, audio files can be previewed within IOScope, or opened in other apps that support these file formats.
  • Frequency and time domain data can now be exported to CSV files, in addition to MAT-files and tab-delimited text files. CSV files can be opened directly in Numbers, or other spreadsheet apps that support it, from within IOScope.
  • The Excitation (signal generator) tab now supports the same color schemes as the analysis tools.
  • Other cosmetic improvements have been made to the user interface.

IOScope 2.1 requires iOS 4 or later, and is now available for download on the App Store for $74.99 (USD) in the Utilities category.

Learn more or download IOScope on the App Store

IOScope audio file export

IOScope audio file export

Stereo 1/3-octave analysis now available in SignalScope Pro

With the release of version 2.2, the Octave tool in SignalScope Pro for iOS can now analyze two input channels simultaneously. This new capability is only available on devices running iOS 5 or later, and it requires a stereo or two-channel dock connector audio accessory.

     

The Octave tool offers whole and 1/3-octave real-time spectral analysis with A, C, or flat frequency weighting and fast, slow, or impulse time weighting. Time exponential averaged level (Lp) and equivalent level (Leq) measurements are both supported.

The Octave tool available via in-app purchase in SoundMeter 3.0 and SignalScope 3.2 also offers two-channel measurement capability on iOS 5 or later. SoundMeter 3.0, SignalScope 3.2 and SignalScope Pro 2.2 are all available for immediate download on the App Store.

Improvements in SignalScope 3.2 and SignalScope Pro 2.2 include:

  • For users running iOS 5, or later, the Octave analyzer tool can now be operated as a stereo RTA, analyzing two input channels simultaneously (with compatible input hardware). (The Octave tool is available within SignalScope via in-app purchase.)
  • Data can now be exported to CSV files from the FFT, Octave, and Oscope tools. CSV files can be opened directly in Numbers, or other spreadsheet apps that support it, from within SignalScope. Tab-delimited text files can still be created by giving the file name a .txt extension. (Data file export requires the data acquisition upgrade available within SignalScope via in-app purchase.)
  • Corrects a potential crash when accessing the image picker on iPad.
  • SignalScope uses less memory on iPhone and iPod touch.
  • Twitter support has been restored (in iOS 5) for tweeting level meter data. (The Level Meter tool is available within SignalScope via in-app purchase.)

SoundMeter 3.0 offers in-app upgrades

  SoundMeter 3.0 is now available for download on the App Store,

offering in-app purchases of the same tools found in SignalScope Pro. Available upgrades include dual-channel Octave RTA, Oscilloscope, and FFT Analyzer tools, as well as a data acquisition upgrade.

Dual-channel analysis in the Octave tool enables SoundMeter to be used as a stereo 1/3-octave RTA. This dual-channel capability requires iOS 5, and is also coming soon to the Octave tool in SignalScope and SignalScope Pro, but it is available now in SoundMeter. (In SignalScope, the Octave tool is also available via in-app purchase.)

SoundMeter’s new data acquisition upgrade enables the user to export Octave, Oscope, and FFT data to CSV, tab-delimited text, and MAT files, and to access those files from a web browser on another device. This upgrade also enables additional units, such as V, A, g, and ips to be assigned to input signals.

Download SoundMeter 2

SignalScope 3 and SignalSuite 4 Complete Mac App Store Transition

Both SignalScope 3.0 and SignalSuite 4.0 became available for download on the Mac App Store, today. The availability of these two apps marks the successful transition of all of Faber Acoustical’s Mac apps to the new App Store. Both apps feature an improved user interface and require Mac OS X, version 10.6. Use of the Mac App Store requires at least Mac OS 10.6.6.

SignalScope 3 builds on SignalScope’s tradition of award-winning design and precision measurement capabilities by building on advanced technology developed for Faber Acoustical’s flagship product, Electroacoustics Toolbox.

SignalScope is a modularized, multi-channel dynamic signal analyzer and data acquisition platform for Mac. It brings powerful tools to the Macintosh platform for multi-channel, audio-band data acquisition and real-time analysis of electrical, acoustical, and electroacoustic signals and systems. The software is designed to work with any Mac-compatible audio hardware and supports multiple channels of 8, 16, 24, or 32-bit data with sample rates as high as the hardware will support.

New functionality in SignalScope includes the option to perform arithmetic operations, such as addition, subtraction, and multiplication, on two arbitrary input channels of an audio input device. Users can also specify arbitrary FFT lengths and view live spectrogram data with a logarithmic frequency scale. Two of each type of analysis tool can be opened and operated simultaneously.

Learn more about SignalScope 3.0

Download SignalScope from the Mac App Store

Download SignalScope Trial from FaberAcoustical.com

Version 4 continues SignalSuite’s tradition of offering tremendous flexibility in an audio test signal generator. The new version adds support for up to two stereo signal generators to be operated simultaneously.

Audio Unit generator support opens up endless possibilities for additional signal types. This includes signals stored in standard audio files, which can be now played within SignalSuite by using the AUAudioFilePlayer plug-in included with Mac OS X. It also opens up the option to play back signals sent across a network from another computer, via the AUNetSend/AUNetReceive plug-ins, which are also included with Mac OS X.

Learn more about SignalSuite 4.0

Download SignalSuite from the Mac App Store

Download SignalSuite Trial from FaberAcoustical.com

 

SignalScope Pro 3.0 is in the Mac App Store

SignalScope Pro 3.0 for Mac OS 10.6 is now available for download on the Mac App Store.

Faber Acoustical has announced the release of SignalScope Pro 3.0. The latest release of Faber Acoustical’s most popular acoustical test and measurement toolset for Mac is now available for purchase in the Mac App Store. Version 3 of SignalScope Pro features an enhanced user interface, better control over audio device configurations, and more comprehensive user preferences.

SignalScope Pro offers a suite of tools on the Mac for dynamic and real-time signal analysis, data acquisition, and automated testing. SignalScope Pro was designed for researchers, educators, consultants, and advanced hobbyists. Despite its power and flexibility, SignalScope Pro provides an intuitive user interface that enables even complex measurements to be configured within a few minutes. Those measurement configurations can then be saved and reloaded when the need arises.

 

New functionality in SignalScope Pro includes the option to perform arithmetic operations, such as addition, subtraction, and multiplication, on two arbitrary input channels of an audio input device. Users can also specify arbitrary FFT lengths and view live spectrogram data in 3D with a logarithmic frequency scale. Two of each type of analysis tool can be opened and operated simultaneously.

Minimum Requirements:
* Intel-based Mac
* Requires Mac OS 10.6 or later

Pricing and Availability:
SignalScope Pro 3.0 is now available for download on the Mac App Store for $199.99 (USD) in the Utilities category. Those who wish to try SignalScope Pro before they buy are welcome to download a free 30-day trial. SignalScope Pro 2 users can upgrade to version 3 for $99 at our online store.

Learn more about SignalScope Pro 3.0

Download SignalScope Pro from the Mac App Store

Download SignalScope Pro 3 trial

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