Tag Archive for: soundcheck

Virtual Instruments Enhancements in SoundCheck

Virtual Instruments Enhancements are available in SoundCheck version 22 and later.
The multi-instrument, which includes both an RTA and FFT analyzer, now includes additional display and calculation options. A single multi-instrument can have multiple simultaneous display windows. These are now detached from the control panel, and can be re-sized and re-positioned for unlimited desktop layout flexibility. Multi-instrument windows can now also be used in a sequence step to offer a clear readout of results while the sequence is running. Real time calculation can be implemented on a combination of live and stored (active and static) curves simultaneously which enables clear display of the difference between live results and a reference curve. Finally, a new dB addition option expands its calculation capabilities.

Watch the video demo of Virtual Instruments Enhancements

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Powerful New Post-Processing Tools in SoundCheck

Powerful New Post-Processing Tools are available in SoundCheck version 22 and later.

New powerful post-processing tools expand SoundCheck’s calculation capabilities and simplify complex applications. These include:

  • Logarithm and Exponent calculation using base 2, 10, or custom values, in addition to the existing base e.
  • Leq (equivalent continuous sound level) versus Time option for use in noise monitoring, communications applications, and many standards.
  •  A new ‘Intersection Modes’ option for greater specificity in the choice of finding intersection points.
  • An option to ignore units in arithmetic and constant post-processing. This facilitates simple mathematical calculations, for example, quickly subtracting a fixed number of dB to correct sound level from the near field to the far field.
  • A ‘Cosine Taper’ custom window in post-processing FFT which allows leading and trailing taper widths to be customized. This is useful for time-windowed measurements.

Watch the video demo of Powerful New Post-Processing Tools

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New Statistics Module in SoundCheck

A New Statistics Module is available in SoundCheck version 22 and later.
SoundCheck’s statistics module is completely overhauled to make it more powerful and intuitive. A new layout makes data selection easier, and curves, values, and results can now simply be dragged and dropped from the memory list into the statistics editor. A new ‘Reset Statistics’ step allows statistics to be reset during a sequence. This is useful when applying statistical analysis to data from a sequence loop or a fixed number of measurements, as the statistics data and sample count can be automatically cleared, ready for the next measurement once the desired settings have been reached. Enhanced searching, including meta-data, makes it easy to select groups of curves from the memory list, and it is now even possible to specify a frequency range within which to run statistics.

Watch the video demo of the New Statistics Module

 

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Crest Factor Analysis in SoundCheck

Crest Factor Analysis is available in SoundCheck version 22 and later.
Distortion options now include crest factor analysis,  a technique that measures peak-to-RMS ratio to evaluate impulsive distortion and analyze the dynamic range of real signals. It complements SoundCheck’s unique enhanced Loose Particle algorithm for transient distortion measurement.

Watch the video demo of Crest Factor Analysis

 

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Sequence Protection in SoundCheck

Sequence Protection is available in SoundCheck version 21 and later.

Sequence protection guards your intellectual property and adds an additional level of assurance that your tests are run as-intended by your production facility or contract manufacturer. Any test sequence can now be locked and password-protected before distribution. Once in a locked state, it can be run, but sequence steps and limits cannot be edited without the password. Furthermore, the sequence steps cannot even be viewed, protecting the intellectual property in your sequences.

Sequences can also be configured to only run on a particular SoundCheck system, or block of systems. This further protects against unauthorized use and helps ensure the end-to-end integrity of your tests when working with contract manufacturers, guaranteeing that your products are tested exactly as you planned.

Watch the video demo of Sequence Protection in SoundCheck

 

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Sequence Versioning in SoundCheck

Sequence Versioning is available in SoundCheck version 22 and later.
Sequence versioning makes it easy to track changes made to a sequence to ensure that colleagues and contract manufacturers are using the correct version. Comment fields make it easy to document changes, and the sequence history view provides a log of historical changes. Archiving functionality allows the sequence to be backed up while it is being developed, so changes can easily be rolled back while retaining the versioning information.

Watch the video demo of Sequence Versioning

 

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Soundbar Measurement over HDMI Connection

Soundbar Measurement - screenshot of final displaySoundbar measurement over HDMI is simple in  SoundCheck as the WASAPI driver option allows easy connection to the device under test via HDMI.  This test sequence is not exclusive to soundbars; it can be used to make audio measurements on any audio device that accepts audio over HDMI (e.g. TV, computer monitor, home theater speakers, etc.)

The sequence itself is quite simple, containing 4 steps: Stimulus, Acquisition, Analysis and Display. Frequency response, THD, Rub & Buzz and ePRB are shown on the final display. More important are the instructions for configuring your SoundCheck system’s Hardware and Calibration to support the HDMI connected device.

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100 Things #99: Calibrate Signal Paths with Any Interface

Calibrating signal paths is a critical part of any audio measurement, and SoundCheck offers the ultimate flexibility for calibrating audio interfaces. Whether you need two channels or sixty-four, analog or digital, each has its own unique configuration and there is no limit on the number of channels that can be calibrated. For example, its possible to have some channels calibrated with a 6-mic array for recording a response, while others are configured to measure motor vibration and RPM speed. Not only can you mix different devices, but each channel can be calibrated using different audio drivers so it’s no problem to combine something like a Bluetooth headset with analog ear simulators and a digital wav file. Learn more in this short video.

Calibrating Audio Signal Paths

 

Learn More About Calibrating Signal Paths in SoundCheck

Check out our calibration tutorials (section 2)

Read more about recommended audio interfaces to use with SoundCheck.

Learn more about AmpConnect 621 and AudioConnect 2, Listen’s self-calibrating audio interfaces

 

Video Script: Calibrate your Signal Paths with any audio interface

In any audio test and measurement system, your signal path begins and ends with your audio interface. Whatever software system and interface you’re using, it’s important to correctly calibrate all input and output channels to get accurate results

SoundCheck offers the ultimate flexibility for calibrating audio interfaces. Any number of channels can be calibrated, so whether you need two channels or sixty-four, each channel has its own unique configuration. This means it’s possible to have some channels calibrated with a 6-mic array for recording a response, while others are configured to measure motor vibration and RPM speed.

Not only can you mix different devices, but each channel can be calibrated using different audio drivers so it’s no big deal if you are combining something like a Bluetooth headset with analog ear simulators and a digital wav file.

This flexibility ensures your test system is future-proofed and can even calibrate hardware that doesn’t exist yet, so long as it conforms to digital audio standards. Over the years we’ve calibrated USB, Bluetooth, Dante, AVB, A2B and more, as well as the more standard types such as WDM, ASIO, Core Audio and WASAPI.

To calibrate an audio device, you need to measure both the Vp in and Vp out values as well as the latency at all the sample rates you will be using.

You can do this directly from the hardware editor itself. You’ll need an AC multimeter that’s accurate to at least 250Hz, and an adapter to insert it in the input / output chain of the audio interface during the calibration process. Should the need arise for field calibration, that can also be done using this method.

To avoid this step, when you purchase a 3rd party interface directly from Listen, we’ll determine the Vp values and the latency before it leaves our facility. All you need to do is enter the device values from the provided calibration sheet into the hardware editor, and you’re ready to start measuring.

Our own all-in-one audio test hardware takes this one step further with self-calibration. With both the 2-channel AudioConnect 2 and the 6-in, 2-out AmpConnect 621, hardware editor  values are measured during manufacture and stored on the device. These values are auto-populated in the hardware editor when it’s connected via USB, so you never need to manually calibrate these devices. If you swap hardware, the calibration is automatically updated.

To learn more about calibrating signal paths in SoundCheck, check out our online knowledgebase and user manual.

 

 

100 Things #98: MEMS Speaker Measurements

MEMS speakers are one of the biggest innovations in speaker technology in recent years. Offering full range performance with compact size and low power, they are rapidly being adopted for use in devices such as earbuds, hearing aids, smart glasses and more. With SoundCheck you can make exactly the same MEMs speaker measurements as you can with conventional mechanical speakers. Watch this short video where we demonstrate frequency response, impedance, and distortion measurements on the xMEMS Montara MEMS speaker.

MEMS Speaker Measurements

 

We’d like to thank Michael Ricci, Sr. Director of Electroacoustic Engineering at xMEMS for the technical guidance on Piezo-MEMS transduction.

You can also learn more about the techniques demonstrated in this video in our June 2024 AudioXpress article on Measuring MEMS Microspeakers.

Learn More About SoundCheck’s Advanced Features

Read more about more measurement features in SoundCheck.

Learn more about the Normalized Distortion Measurement technique mentioned in the video – we have a short video explaining this, or a longer (but rather old) technical paper.

More information is also available in the  SoundCheck Manual.

 

Video Script: MEMS Speaker Measurements

SoundCheck is one of the most widely used loudspeaker and microspeaker measurement systems in the world, but did you know that it can also measure MEMS micro-speakers? MEMS micro-speakers are rapidly becoming popular for devices such as hearing aids, earbuds, smart glasses and more as they offer full range performance with compact size and low power, and they are also SMT reflowable. They’re constructed in an entirely different way to conventional miniature speakers – rather than using inductive coils and magnets, they use a voltage driven capacitive actuator to provide full range performance.

I’m going to demonstrate a MEMS micro-speaker test using the xMEMS ‘Montara Plus’ full-range Piezo-MEMS microspeaker, that uses a monolithic solid state fabrication. These devices are entirely manufactured with MEMS processes in a semiconductor wafer foundry. When you’re testing these devices, the xMEMS provided driver circuit delivers Voltage bias and boost converter to step up the voltage as piezo-MEMS devices have a very high input impedance and draw very low current.

Here, I’m going to use xMEMS’ own charge amplifier. You’re also going to need to build the speaker into an earbud or make your own test jig in order to test it. I’m going to demonstrate using this test jig, which is actually the one that xMEMS uses for their own measurements, and we’re going to put an ear simulator coupler on it to simulate an in-ear measurement. Aside from that, the test setup’s very similar to what we would use for any other speaker. We have an AudioConnect 2 interface which will power the coupler, and that’s connected to SoundCheck for analysis.

So we have a test sequence that will play the stimulus and analyze the response. You won’t hear it as it’s all in the coupler. And here we can see the results.

Let’s start with the frequency response. You can see it has a very flat response at low frequencies, and then in the higher frequencies you have a resonance due to the piezoelectric material and the resonance of the coupler.

We can also look at the impedance. You can see here that it’s a very different shape from a conventional loudspeaker impedance. The values are much higher but it’s very linear, which makes it easy to compensate for.

We can also look at distortion. The total harmonic distortion is also very linear right up to where we get into the ear canal response.

And while we’re on the subject of distortion, I just want to use the measurements on this device to highlight the importance of using frequency normalized distortion measurement.

With this conventional distortion measurement, you can see the second and third harmonics plotted at their actual measured frequencies, along with the fundamental.

Frequency Normalized distortion measurement compares the harmonic levels to the fundamental level at their measured frequency before their ratio is plotted, rather than the fundamental level at the excitation frequency. This removes the effect of the non-flat frequency response from the distortion and makes it easier to see the peaks in the distortion response independent of the peaks and dips in the fundamental response. Here, you can see both regular THD, the orange line, and normalized THD, the blue line. And as you can see, you have a high Q here at resonance, but apart from that there is very little distortion, so you can focus your efforts on planning around this peak. If you were going by conventional distortion, you could be wasting your time trying to solve resonances you don’t have with this second bump on the graph here.

So that’s piezo-MEMS speaker measurements in a nutshell. Check out our website for more information on testing MEMS speakers, or if you want to learn more about normalized distortion measurement.

 

 

100 Things #97: Zwicker Loudness Measurement

Zwicker Loudness Measurement, an indication of overall perceived loudness level, is calculated in SoundCheck using the Zwicker Loudness post processing step. Instead of just measuring the absolute sound pressure level in dB SPL relative to 20uPa, the Zwicker Loudness algorithm takes into account how humans hear sound level using  the PEAQ international standard. This is an ITU-developed standardized algorithm for objectively measuring perceived audio quality as subjects would in a listening test.

Zwicker Loudness Measurement

Learn More About SoundCheck’s Advanced Features

Read more about more measurement features in SoundCheck.

More information is also available in the  SoundCheck Manual.

 

Video Script: Zwicker Loudness Measurement

Did you know that SoundCheck can calculate the overall perceived loudness level using a Zwicker Loudness post processing step ? Instead of just measuring the absolute sound pressure level in dB SPL relative to 20uPa, the Zwicker Loudness algorithm takes into account how humans hear sound level using  the PEAQ international standard. This is an ITU-developed standardized algorithm for objectively measuring perceived audio quality as subjects would in a listening test.

The input to this post processing step must be a spectrum of a complex signal in pascals or dBSPL. We can easily capture this in SoundCheck using an FFT or RTA broadband measurement using a calibrated Reference Mic signal path. To simulate the non-linearity of the ear, the Zwicker Loudness algorithm then filters these frequencies into auditory bands according to the bark scale – a frequency scale where equal distances correspond with perception. Once the spectrum is plotted on a bark scale, a frequency weighting is applied that correlates to human hearing. Finally, a level compression is applied and the loudness is output in Phons and Sones. The loudness spectrum can optionally be shown with the X axis either in Hertz or Bark.

Knowing the actual perceived loudness of a signal is extremely important for certain applications. For example, listeners that are trying to subjectively compare different headphones will be biased towards the louder one. If I want users to subjectively compare two different headphones, I need to make sure they are played back at the same level to avoid this bias. Looking at the 1kHz sensitivity of each headphone doesn’t take into account the difference in frequency response across the two devices. Often A-weighting is used to correlate measurements to human hearing, but a simple A-weighting curve makes a lot of assumptions such as what level of playback that will be used. Zwicker Loudness gives us a much more accurate perceived loudness, and enables us to precisely match the loudness, in phons, between the two devices regardless of level..

Zwicker Loudness is also widely used in communication testing for measuring loudness of both speech transmission, and ringtones. Check out our website to learn more.