IOScope 5 brings data overlays, spectrum smoothing, new hardware support

IOScope 5, which is now available for download on the App Store, employs a new plotting framework for real-time data graphs and high resolution image export. The new plotting capability also enables live frequency response data to be overlaid on up to 7 frequency response curves loaded from existing data files (CSV, MAT, or text data files exported from the Frequency tab in IOScope). An additional benefit is IOScope’s ability to smooth frequency response data into fractional octave bands (1/6, 1/12, and 1/24 octave bandwidths).

Screen Shot 2015-01-07 at 11.14.38 AM copy

Other additions to the new version of IOScope include:

– Built in support for iTestMic and iAudioInterface2 from Studio Six Digital.

– Built-in support for automatic downloading of sensitivity data for the Dayton UMM-6 USB measurement microphone.

– Support for drawing directly to an external screen (from iPad) has been removed in favor of screen mirroring, which is handled by iOS.

– Audio hardware input and output options are now presented from a separate toolbar button, which looks like a microphone, on iPad, iPhone 6 and iPhone 6 Plus.

– It is possible to adjust the line thickness of live and loaded frequency response data. The opacity of loaded data can also be adjusted in order to make the live data stand out in the graph.

Screen Shot 2015-01-07 at 11.15.09 AM copy

IOScope brings two-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). The reference signal can be taken from the internal signal generator or from an external source (when using an external reference, a stereo or multi-channel audio input device, connected to the dock connector, is required).

Download IOScope 5 on the App Store.

Faber Mac Apps Updated for Mavericks

All Faber apps for Mac have been updated for Mac OS 10.9, Mavericks. These are minor updates, which include the following improvements:

– This update addresses plot freezing issues on Mac OS 10.9 (Mavericks).

– SLM and Octave Analyzer tools operate more efficiently.

– A potential crash has been addressed in the Signal Generator tool.

Electroacoustics Toolbox 3 Screenshot Electroacoustics Toolbox Screenshot 2

 

Download a free trial from FaberAcoustical.com:

Download Electroacoustics Toolbox 3.4.1

Download SignalScope Pro 3.1.5

Download SignalScope 3.1.5

Download SignalSuite 4.1.5

 

Download from the Mac App Store:

Download Electroacoustics Toolbox 3.4.1

Download SignalScope Pro 3.1.5

Download SignalScope 3.1.5

Download SignalSuite 4.1.5

 

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

 

 

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

 

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

IOScope 2 adds native support for iPad and new, lower price

IOScope 2.0 is now available for download on the App Store.

IOScope room impulse response measurement

IOScope room impulse response measurement

IOScope 2 comes with a new, lower price and offers some of the same new features which were recently added to SignalScope, SignalScope Pro and SoundMeter for 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). 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 tab-delimited text files, MAT-files, or images, including high-resolution PDF files, for later retrieval from your device.

What’s new in version 2.0?

  • IOScope now runs natively on iPad, as well as on iPhone and iPod touch devices.
  • iPad retina display resolution is fully supported.
  • Analyzer plots can be saved to PDF files in addition to jpeg image files.
  • Data files are accessible via iTunes file sharing, in addition to the app’s built-in web server.
  • Data files, including text and PDF files, can be previewed or printed within the app or optionally opened in another compatible app.
  • Three color schemes are supported, offering black, blue, and white background colors (white may be preferred for printing results stored in PDF or jpeg images).
  • In landscape orientation, the new full-screen mode hides the toolbar and tab bar to maximize the size of the analyzer displays.
  • IOScope offers enhanced support for audio accessories, connected via the 30-pin dock connector.
  • Input gain adjustment is available for any audio input hardware that supports it.
  • Software-selectable options for the GuitarJack and GuitarJack model 2, from Sonoma Wire Works, may be adjusted directly from within IOScope.
  • IOScope now supports multi-channel USB audio devices, connected to any iPad model via the iPad Camera Connection Kit.
  • External displays are supported on iPad (up to 1920×1200 resolution on iPad 2 or 3; up to 720p on the original iPad). External display resolution is dependent on the screen resolution as well as the video output adapter connected to the iOS device.

IOScope 2.0 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 impedance measurement

IOScope impedance measurement

Measuring Loudspeaker Impedance with IOScope

Today, a new video, Measuring Loudspeaker Impedance with IOScope, was published on this site, as well as on the Faber Acoustical YouTube channel. The video is both a demonstration of IOScope, as well as a simple tutorial on measuring loudspeaker impedance. Although the video is largely self-explanatory, I thought it would be beneficial to include some further explanation and tips for those who are interested. The movie is essentially broken into four chapters and a similar format will be followed here.

What is impedance? How is it measured?

By a generalized version of Ohm’s law, we understand that voltage is equal to the product of electrical current and impedance. This means that electrical impedance is equal to the ratio of voltage and current, or:

Z = V/I

where Z represents impedance, V represents voltage, and I represents current. This means that we can calculate impedance as long as we can measure voltage and current. Voltage is easily measured from the iPhone’s audio inputs, but how do we measure current? By returning to Ohm’s law, we see that if we measure the voltage across a resistor (a known impedance), we can compute the current by I=V/Z. So, as long as we have a known resistance and a means to measure the voltage on both sides of it, we can effectively measure current.

Voltage calibration

Although audio signals come into the iPhone as voltages, those voltages get converted to digital values. In order to measure voltage correctly within IOScope, we need to perform some type of calibration that will define the relationship between the digital values and the actual voltage reaching the iPhone audio input jack.

As is demonstrated in the video, voltage calibration in IOScope can be easily achieved by measuring the voltage going into the iPhone with an rms voltmeter. Once the rms voltage has been measured with the voltmeter, that measured quantity should be entered into the Ref Input Level text box of IOScope’s calibration screen. All that’s left is to press the Calibrate button and confirm the action–IOScope will automatically compute the audio input device’s voltage sensitivity.

  • The accuracy of the calibration will largely depend on the accuracy of the voltmeter.
  • In the video, IOScope’s built-in signal generator is used to produce a single tone with a frequency of 1 kHz. As long as the tone is turned on in the Excitation tab of IOScope’s main screen, the signal will be output when the calibration screen appears.
  • When entering values into a text box in IOScope, you can enter unit magnitude prefixes, like m for milli, or u for micro. For example, in the video, “618m” is entered into the text box for 618 millivolts. Alternatively, “.618” could have been entered for the same value.
  • When performing a voltage calibration, you need to be sure that the input device or input channel units are set to V (for volts).

Current calibration

When working with a stereo input device, like the Belkin TuneTalk Stereo that was used in the video, IOScope adds a special third channel to the device. That channel is the difference between input channel 2 and input channel 1. Such a channel enables convenient measurement of current by measuring the voltage difference across a resistor. Since the previous voltage calibration was performed at the device level, which means that the calibrated voltage sensitivity applies to all input channels, calibrating the difference channel for accurate current measurement simply requires you to enter the value of the resistor you will be using. In this case, the resistor was measured to have a resistance of 999 ohms. Instead of using the Calibrate button on the channel calibration screen, the known sensitivity of 999 Volts per Amp can be entered directly into the Input Sensitivity text box.

How do we know the sensitivity of the Ch2-Ch1 difference channel should be 999 V/A? Again, Ohm’s law gives us the answer. Since V=IZ (or, in this case V=IR, where R is resistance), if we put 1 amp of current through a 999 ohm resistor, we should read 999 volts, or 999 volts per amp.

  • When performing a current calibration, you need to be sure that the input channel units are set to A (for amps).

Setting up the loudspeaker measurement

As I indicated before, in order to measure the impedance of a loudspeaker, we need to measure the voltage across the loudspeaker’s terminals and the current flowing through them. Measuring the voltage across them is as simple as connecting one of our input channels to the terminals. However, we need a little help from Kirchoff’s current law to understand that if we put a resistor in series with the loudspeaker, the electrical current through the resistor and the loudspeaker will be identical. Since we’re already prepared to measure current across a resistor, we’re good to go.

  • IOScope’s Measurement Configuration screen provides a simple graphic representation of the measurement, which makes it easy to identify which input channel should be which. Since we’re measuring loudspeaker impedance, which is equal to V/I, we set the Y signal to Input Channel 1 and the X signal to Input 2 – Input 1.
  • The proper connections of the signals to the loudspeaker are shown in the video (at 3 minutes).
  • Again, the built-in excitation signal is employed, although this time it is in the form of a logarithmic frequency sweep. The length of the sweep corresponds to the length of the FFT used by IOScope, which allows excellent results to be obtained with little or no averaging (which is also evident in the video).

Making the measurement

Once things are configured, making the measurement just takes a tap of the start button in the toolbar of IOScope’s Frequency tab.

  • A double tap in the vertical axis label region of the display will toggle auto scaling on and off (it’s on by default).
  • Notice that the magnitude measurement is displayed in units of ohm’s (IOScope is smart enough to know that volts divided by amps means ohms).
  • The video also demonstrates saving the frequency domain data into a .mat file, which can be downloaded from IOScope onto a Mac or PC, via a web browser. Data contained in .mat files can be loaded in to MATLAB, Gnu Octave or FreeMat.