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How to Export SoundCheck Sequences

This short video, “How to Export SoundCheck Sequences”, is a must-watch for those who need to share their sequences with their colleagues and contract manufacturers around the world.

Exporting a sequence from SoundCheck instead of saving it packages all dependent files with the sequence. This prevents any errors caused by hard-coded file paths for stimulus files or signal paths that might not exist on a different SoundCheck installation.

Additional Resources for Exporting SoundCheck Sequences

Detailed explanations of how to export SoundCheck sequences can be found in the SoundCheck manual.

Read more about SoundCheck test sequences.

Video Script: How to Export SoundCheck Sequences

When you’re sharing sequences with colleagues or contract manufacturers, or even just making your own self contained backup, you should use the sequence export function rather than simply saving it. ‘Save’ or ‘save as’ works well if you want to make a new version based on a sequence you already have, or want to make a local backup, but if your sequence has hard-coded links to other files, you’ll have problems if you send it to a different computer. Exporting instead of saving packages all dependent files with the sequence, and prevents any errors caused by hard-coded file paths for stimulus files or signal paths that might not exist on a different SoundCheck installation. Let me show you how to do that. Before we start, just remember that the person you are sending the sequence to must have the same version of SoundCheck that the sequence was created in or higher – sequences are not backwards compatible!

With the file export option I can point to the sequence I want to share and export it to a new location. I’ll create a new folder called exported sequence and you can see that all dependent files in my sequence are now copied into the same directory. If I’m recalling different dat files, if I have an autosave template for Excel or if I’m using a wave file as a stimulus all of these dependent files are carried along with the export. Even the calibrated input and output signal paths that I’m using will be added into this directory.

Now, I can simply zip up this folder, share it with my colleagues or contract manufacturers in another location, and when they open up this sequence all of the signal paths will automatically use the files in the folder. In addition, all absolute file paths used in the sequence will be changed to relative file paths looking inside of my exported folder. They won’t need to re-link or reconfigure any of the steps.

Remember to use this export feature to make sure everyone is running your sequence exactly as you intended.

Audio Test Stimuli: 8 Audio Test Signals and When to Use Them

Electroacoustic measurements rely on many different audio test stimuli. This brief summary of the various options guides you towards the best stimulus for your measurements.

Stepped Sine Sweep
A stepped sine sweep plays a sine wave, one frequency step at a time with a user-defined frequency range and resolution. SoundCheck’s stepped sine sweep, the ‘Stweep’ is optimized with an integer number of cycles at each frequency step and continuous phase between steps for a smooth transition from frequency to frequency. This minimizes transient ringing in the device under test for faster and more repeatable measurements. Stepped sine waves can be configured with different resolutions and averaging times at high and low frequencies to optimize the trade-off between stimulus duration, background noise and therefore, test time and accuracy. The stepped sine sweep is one of the most widely used audio test stimuli for basic electroacoustic testing because it offers good noise immunity and provides acoustic (e.g. frequency response, phase, THD), perceptual distortion, and electrical (e.g. impedance) measurements with a single sweep.

Graph of Stepped Sine Sweep (Stweep) Audio Test Stimulus

Stepped Sine Sweep (Stweep) Audio Test Stimulus

 

Log Sine Sweep (AKA Frequency Log Sweep, Log Chirp or Farina Sweep)
A continuous log sine sweep from low to high covers every frequency in the chosen range. The same time and energy in each octave achieves a good signal-to-noise ratio at all frequencies. The sweep rate is slow at low frequencies for accurate measurement, but increases with frequency for a fast overall test speed. SoundCheck was the first test system to implement simultaneous simulated free field measurements of harmonics using  the Log chirp stimulus, just months after Angelo Farina’s landmark AES paper on the subject in 2000.

The log sine sweep is a good alternative to a stepped sine sweep for production line loudspeaker measurements, and is also common for fast time-selective measurements of fundamental response and distortion. Used with a Time Selective Response algorithm it provides simulated free-field measurements for free-field analysis of a loudspeaker without an anechoic chamber.

Graph of Log Sine Sweep (AKA Frequency Log Sweep, Log Chirp or Farina Sweep)Audio Test Stimulus

Log Sine Sweep (AKA Frequency Log Sweep, Log Chirp or Farina Sweep)Audio Test Stimulus

 

Log Amplitude Sweep
A Log amplitude sweep is similar to a stepped sine sweep except a single frequency is chosen and swept logarithmically through various levels.

It is useful for evaluating how a device performs at different stimulus levels (linearity tests) and for testing devices with compressors, limiters or automatic gain control (AGC). It can also be used with advanced analysis algorithms to evaluate characteristics like THD vs. stimulus level.

 

Graph of Log Amplitude Sweep Audio Test Stimulus

Log Amplitude Sweep Audio Test Stimulus

 

Noise
Both pink and white noise can be used for audio testing. Pink noise has a continuous frequency spectrum and equal power per constant percentage bandwidth, e.g. equal power in any one-third octave band. It is used with constant percentage bandwidth filters such as the RTA. White noise has a continuous frequency spectrum and with equal power per unit bandwidth, for example, equal power in any band of 100-Hz width. It is generally used with FFT analysis.

Noise test stimuli are often used where sine waves cannot be used, such as devices with on-board signal processing e.g. codecs.

Graph of Pink Noise Audio Test Stimulus

Pink Noise Audio Test Stimulus

Graph Of White Noise Audio Test Stimulus

White Noise Audio Test Stimulus

 

Multitone
A multitone stimulus consists of multiple sine tones at discrete frequencies played simultaneously with equal amplitudes and random phase. All the frequencies are present at the same time, in contrast to the stepped sine sweep where the frequencies are present sequentially. All frequencies are covered in a very short stimulus, providing very fast measurements. Multitone is good for measuring frequency response, but the number of simultaneous frequencies in the stimulus makes it impractical for measuring other characteristics such as harmonic distortion, limiting its use.

Multitone test signals have applications in simple, rapid production line tests, for example measuring the frequency response of microphones.

 

Two Tone Stimulus

A two tone stimulus plays two simultaneous tones. In a non-linear system, these generate intermodulation distortion, output frequencies that are not part of the stimulus and have no harmonic relationship to the original signal. There are two commonly-used types of two-tone stimulus. An intermodulation (IM) two-tone stimulus is a stepped sine sweep superimposed on top of a fixed frequency tone. The fixed tone is usually at a low frequency, and the sweeping frequency is generally  five times greater than the fixed tone frequency. A difference frequency (DF) two tone stimulus is composed of two simultaneous sweeping tones separated by a specified frequency interval which may be a fixed difference or a fixed ratio.

Measuring distortion using a two-tone stimulus presents an alternative to harmonic distortion measurement in which the distortion products are kept close to the stimulus frequency and typically fall outside of the masking curve. This makes artifacts more clearly audible and avoids the under/over estimation that can sometimes occur with higher order harmonic distortion methods. IM distortion is generally used for broadband devices such as full range drivers and microphones. DF distortion is used for measuring band-limited devices such as hearing aids.

 

Graph of Two Tone Intermodulation Audio Test Stimulus

Two Tone Intermodulation Audio Test Stimulus

Graph of Two Tone Difference Frequency Audio Test Stimulus

Two Tone Difference Frequency Audio Test Stimulus

 

Speech and Music Based Signals
Speech and music based stimuli enable devices to be tested with real-world test signals. This is particularly important for audio devices with built-in non-linear signal processing. In SoundCheck, any WAV file can be used as the stimulus, making it simple to use music, real speech, or artificial speech. Additional software features such as active speech level control enable these signals to be used for a variety of different purposes including communications testing to industry standards.

Applications include phones, codecs, hearing aid compressors and more. Additionally, these test signals are valuable for creating calibrated background noise for testing smart devices, headphones and wearables.

Graph of Speech (wav file) Audio Test Stimulus

Speech (wav file) Audio Test Stimulus

 

Composite Stimulus Signal
Composite stimuli allow a conditioning signal to warm up the device or open up an activity detector before playing the stimulus signal. They are essential for testing smart devices, where it can be necessary to create a stimulus that consists of a wake word plus a command, or to prepend a stimulus with a trigger tone to enable precise alignment of stimulus and response. SoundCheck offers total flexibility to create customized composite stimuli, and also permits the user to precisely select which sections of the stimulus should be analyzed.

Graph of Compound Audio Test Stimulus consisting of voice activation followed by a test tone

Compound Audio Test Stimulus consisting of voice activation followed by a test tone

All these stimuli are available in SoundCheck. Learn more about SoundCheck’s features and functionality.

Standardizing the Immersive Audio Playback Chain

Immersive Audio Listening Room at Genelec: Customized room for listening to spatial audio

Immersive Audio Listening Room at Genelec

If you follow my posts, you’ll know that spatial audio measurement is a big research area for us right now. As immersive audio takes off, it’s important that designers of spatial audio systems have the tools they need to accurately measure spatial sound characteristics such as localization and envelopment. This will enable consistency in playback so that artists and mixers know that the effects that they are creating sound as they intended, no matter what the consumer’s playback equipment.

To complicate the issue, having designed the playback system, manufacturers also need to take into account the myriad ways in which their customer may configure their speakers to ensure consistent reproduction. This is no simple task when room acoustics also comes into it and few consumers have a perfect listening space.

While we are some way from having universal measurement techniques and standards, I witnessed an interesting insight into how Genelec is addressing the issue of customer configuration at the AES/ASA/BAS Boston chapter meeting at their facility in Natick earlier this week.

First we received a demonstration in their newly-configured immersive room where they demonstrated several soundtracks. This included correlated and uncorrelated pink noise at low frequencies to illustrate bass reproduction. They also played a couple of musical pieces including the musical score from a video game (which was surprisingly impressive) and a piece of Indian music. These were both very immersive, with sound coming from multiple directions. What I found interesting about this was that in the 9-seater listening room, there was really only one sweet spot or seat where you received the full impact of the immersive experience. The effect in the other seats was not uniform and depended on the seat’s position relative to the center spot. This will certainly present challenges to sound designers!

In a separate room, we saw how Genelec helps their customers ensure that their equipment is correctly configured. This was impressive too! Their bespoke software uses a microphone and network adaptor to make measurements in the room and upload them to a server. The speaker-room interactions are diagnosed, and their software returns a comprehensive report including frequency response, time response and time-frequency analysis including wavelet analysis. It also provides an electronic file that equalizes and time-aligns the speakers to compensate for the room characteristics and exact speaker placement. This ensures that Genelec’s customers are hearing the sound as they intended, regardless of their room configuration.

This is a great start, and it’s encouraging to see spatial audio playback system vendors following through to ensure the end user’s experience is as intended. However, this is only one part of the puzzle. There is still a need for the industry to agree on useful metrics that allow manufacturers to design and evaluate their systems to Dolby Atmos and other spatial audio specifications. This will allow the creative effects of spatial audio to transcend individual manufacturers and allow consumers hear exactly what the recording engineer intended, regardless of their chosen brand of playback equipment. If you make spatial audio playback equipment, what metrics do you think show the most potential for evaluating spatial sound effects? We’d love to hear from you.

AudioConnect 2 Audio Measurement Interface Demonstration

What makes an audio measurement interface different from any other audio interface? This is a good question. As you probably know, SoundCheck works with most audio interfaces – this is advantageous as our customers can use hardware they already own, keeping the overall system cost down.

However, if you don’t have an audio interface and need to get one at the same time as your test system, there are many advantages to purchasing dedicated test hardware such as the AudioConnect 2, or for multi-channel applications, the AmpConnect 621. They include many features specifically designed for audio test, such as microphone power and internal switching. This saves money on other components. They are designed for production and field measurements so they are ruggedly constructed, and unnecessary features such as front panel controls are eliminated to avoid accidental adjustment. Perhaps more importantly, Listen’s audio interfaces are configured for full plug’n’play automated setup that hugely simplifies the setup process and virtually eliminates the possibility of incorrect configuration.

Watch this short 5 minute video to learn more.

 AudioConnect 2 Audio Measurement Interface Demonstration Video

Learn more about the AudioConnect 2 Interface

Check out our product information page, and another short video that we made explaining the philosophy around offering our latest generation audio interfaces.

More Information?

Curious? Contact our sales team for more information and pricing.

Audio Measurement Troubleshooting: 10 Time-Saving Tips

Audio Measurement TroubleshootingAudio measurement troubleshooting can be challenging. All too often we plug and unplug things, tweak settings and re-test, often changing several variables at once. A consistent and logical approach greatly accelerates the process.  Here, we share the process that our experienced team of support engineers has developed to assist customers. Follow these 10 audio measurement troubleshooting tips to quickly get to the root of your problems.

  1. Check your cables. Cables are the single biggest cause of setup problems! Make sure all your cables are properly connected and in the right place. Next substitute alternate cables one at a time – cables often get broken inside or damaged, even though they pass visual inspection. Make sure you understand the different types of cables and when you should use each – particularly where they look similar, e.g. single-ended and balanced cables. It’s a good idea to label your cables to make it quick and easy for anyone to replicate your measurement setup and quickly fix things if anything becomes unplugged.
  2. Check everything is plugged in! It sounds obvious, but if there is no output signal or not what you expect (e.g. it just looks like noise), check that everything is plugged in and turned on – not just the computer, but all audio interfaces, amplifiers, hardware, microphone power supplies etc.
  3. Run a self-test. Always run a self-test before making measurements to confirm that your measurement system and cables are working correctly. This facility is usually built into your measurement system and confirms that all components are working as expected.
  4. Make one change at a time and document everything. Don’t move cables, tweak the sequence and change the microphone position all at once – you won’t know what the cause of the problem was! Change one thing at a time, and keep a checklist of what you have done (this will be useful if you need to call customer support).
  5. Check your audio interface configuration. If your audio interface is incorrectly configured, nothing else will work. Ensure sound monitoring is switched off to prevent feedback, and make sure you are using the full dynamic range. Try making a loopback (output to input) measurement on the audio interface using the appropriate SoundCheck self-test. It should have a flat frequency response.  If your frequency response looks noisy it is likely that you have insufficient gain. You should have unity (0dB) gain when looped back on itself and very low THD. Latency should be consistent and repeatable and must be ≥ 0 Record Delay. There are many places where audio interface settings can be incorrectly configured  – check your hardware setup, ASIO control panel and mixer (if applicable), device front panel (if applicable) and Windows audio device settings.
  6. Calibrate your signal paths. Calibrating your signal paths is critical to accurate measurements and you should always have a multimeter and an acoustic calibrator handy! Calibration should be carried out at regular intervals as well as when you first run the test, particularly if there is a change in atmospheric conditions. Good measurement microphones and electronics are typically very stable but loudspeakers e.g. mouth simulators are generally very non-linear and their performance changes with temperature. It’s  always a good idea to warm up a loudspeaker before testing it by playing pink noise for example at a reasonable level. Factories should re-calibrate every day or at the beginning of every shift.
  7. Measure twice. Always measure something at least twice on the first measurement to make sure that you get the same result. This helps identify problems with the setup or background noise. It’s far better to discover this on the first measurement than at the end of a day of data collection! A golden unit, e.g. a demo speaker that you have measured many times, is a good sanity-check if measurements appear unexpected. A golden unit is advantageous over calibration as it also takes into account the fixturing and test environment.
  8. Check your units and your resolution. Make sure you are measuring in your intended units. For example the difference between dB Pa and db SPL is 94dB. If you are not careful you could blow something up. It’s also important to check your resolution. Lower resolutions provide faster measurements, but it’s important to ensure that you are using enough. If you keep increasing the resolution until the curve doesn’t change, you can easily identify the lowest acceptable resolution to test at.
  9. When in doubt, look at your recorded time waveform. Use your software’s oscilloscope function to see if your recorded waveform looks noisy, has drop outs, or gets cut-off too soon.  Look at the peaks of the recorded waveform and Max FSD in the memory list to see if it looks unexpectedly flat – it may be overloaded and clipping. These problems are very difficult to see in the frequency domain.
  10. Minimize background noise. Background noise is the biggest cause of unrepeatable measurements, so minimizing this improves your test environment. Easy ways to minimize background noise impact include positioning the microphone closer to the source, increasing the test level, increasing the duration of the test signal, and using repeated averages of the test signal. Doubling the averages or signal duration should increase the signal to noise ratio by 3 dB.

We hope you found these audio measurement troubleshooting tips useful. Follow our blog for more handy hints for audio measurement.

Directional Audio Measurements with the MDT-4000 Turntable

Have you ever wondered about the thought process that goes into designing a new audio test product? Our sales and support teams worked closely with Portland Tool & Die during the design of the MDT-4000 turntable for directional audio measurements to ensure it addressed all the pain-points that our customers had with other brands – speed, accuracy, portability, control and more. In this short video, designer Kris Hett demonstrates these features and you can see how seamless integration is with SoundCheck.

 Directional Audio Measurements with the MDT-4000 Turntable

Learn more about the MDT-4000 Turntable

Check out our product information page, and our comparison of the MDT-4000 specifications with other popular turntables

Free polar plot test sequence for use with the MDT-4000 Turntable. This gets you up and running quickly with polar plots, and can be used as a base for creating your own measurement sequences.

More Information?

Curious? Contact our sales team for more information and pricing.

Does audio test feel like Groundhog day?

It doesn’t with SoundCheck. Advanced test automation enables repetitive and time-consuming  tests on speakers, headphones, microphones, smart devices, communications devices and more to be run automatically.

Let’s take a look at an example. The AES75 standard for measuring Max SPL takes considerable time and operator involvement to run – there are multiple iterations of running a test at different levels, examining results, adjusting levels and repeating. Then again for the next speaker. Groundhog Day, right?

In SoundCheck, the entire sequence is automated! It makes measurements, objectively compares them, increases the levels, and repeats the measurements to the failure point. It then automatically reduces the level and repeats measurements repeated until the Max SPL value is determined. This leaves you free to kick back, listen to some tunes or work on something else!

 

Check out this short video for a demonstration of the sequence in action:

 

This is made possible by the advanced sequence writing options in SoundCheck, including looping. This short video demonstrates how to automate measurements with sequence looping to free up your time for more exciting tasks.

Want to know more? Request a demo and one of our engineers will be in touch.

The Missing Measurements – Challenges of Measuring Immersive Audio

The University Atrium and Presentation Space that was Simulated in the Immersive Listening Room (Photo courtesy of Acentech)

Earlier this week I attended the AES Boston section meeting at Acentech’s state-of-the art facility, lured by the promise of a demonstration of their 3D acoustic listening simulation. I was not disappointed! After some drinks and conversation with other attendees, we broke into smaller groups to experience their immersive listening room. Although only the size of a large conference room, this room simulates much larger spaces such as lecture halls, restaurants and offices.

We listened to a simulation of a University atrium and presentation space. There was a dining space on a balcony above it, and offices and classrooms above and behind that. We heard how it would sound both with and without diners during a presentation, and if you closed your eyes it was easy to believe that you were actually there. This impressive auralization was created by first recording a presenter in an anechoic environment, then applying sophisticated predictive models to apply reflections, reverberations and background noise to account for the room configuration and construction materials. It was then reproduced in the immersive room on an Ambisonic playback system. This model permits not only evaluation of  architectural features, but also experimentation with different materials for walls, windows, furniture etc. Architects, designers and sound consultants can evaluate and adjust the acoustics of a room at the design stage, ensuring acoustic perfection in the finished product.

What I found surprising was the lack of feedback to the model based on real measurements. It seems that there’s a prime opportunity to make actual measurements in the room once it is built, and compare this real-life data to the model. This was also apparent when I spoke to another attendee, a recording engineer, about mixing in Dolby Atmos. We discussed how he could master something until it was perfect on his Dolby Atmos system, but there was no way of knowing whether other listener’s Dolby Atmos systems would reproduce the sound in the same way he intended.

Spatial audio measurements are still in their infancy, and they are a complex combination of perceptual measurements such as localization, intertwined with room acoustics. Until we devise reliable and accurate ways of measuring spatial audio, we have no way of measuring room simulations to compare them to actual measurements, and no way of comparing the fidelity of various Dolby Atmos playback systems. This is a source of frustration for many product design engineers who are accustomed to having good measurement data to drive their product development.

Recently, I’ve been investigating how a binaural head perceives virtual source location and envelopment, and we’ve developed some rudimentary ways to measure sound localization and envelopment using interaural level difference and interaural cross-correlation measurements with a head and torso simulator. What are your thoughts on spatial audio measurement and what measurement techniques and metrics you are working on? Let me know in the comments and please reach out for me if you’d prefer an offline discussion.

Learn more about Acentech.

Learn more about stereo soundfield measurements for quantifying sound localization and envelopment.

100 Things #100: Production Line Audio Measurement With SoundCheck

Everyone knows SoundCheck is a versatile and flexible R&D audio test system. But did you know it’s also fast and cost-effective for production line audio measurement, and offers unrivaled integration with larger factory test environments?

End of line testing is nothing new to us. We started the global trend from human listeners and expensive hardware analyzers to software-based test systems back in 1995. Many of the measurements we introduced in the 1990s are still used today. Besides introducing newer and better measurement methods like perceptual algorithms, we’re driving the integration of audio testing within a larger factory test environment. Let’s take a look at some of the things that make SoundCheck great for end-of-line tests.

Production Line Audio Measurement with SoundCheck

 

Learn More About SoundCheck’s Production Line Features

Seminar Recording: External Control of SoundCheck. Detailed information about controlling SoundCheck as part of a large factory automation system.

Video: 100 Things #85: Integrate SoundCheck with your Database.

Video: 100 Things #11: External Control Using TCP/IP

Transitioning Audio Tests from R&D to the Production Line. An article by Steve Temme, reprinted from the March 2023 edition of AudioXpress.

 

Video Script: Production Line Audio Measurement

Everyone knows SoundCheck is a versatile and flexible R&D audio test system. But did you know it’s also fast and cost-effective for production line testing, and offers unrivaled integration with larger factory test environments?

End of line testing is nothing new to us. We started the global trend from human listeners and expensive hardware analyzers to software-based test systems back in 1995. Many of the measurements we introduced in the 1990s are still used today. Besides introducing newer and better measurement methods like perceptual algorithms, we’re driving the integration of audio testing within a larger factory test environment. Let’s take a look at some of the things that make SoundCheck great for end-of-line tests.

Most importantly, SoundCheck’s fast and reliable. Every test algorithm we’ve designed has speed and noise immunity at the forefront, from our unique stepped sine wave stimulus, Stweep, and Harmonictrak analysis back in 1995 to the second generation of perceptual distortion measurements in more recent years. And all our production line measurements, use the same stimulus to ensure fast throughput with simultaneous measurement of all parameters.

Soundcheck is hardware-agnostic, and compatible with many audio interfaces from our own custom designed all-in-one hardware to off the shelf soundcards. It even supports audio over IP with Dante. It works with any brand of amplifiers, microphones, couplers and test jigs. It’s also easy to control footswitches, PLCs, barcode readers and other production line equipment through a custom step in a test sequence. This gives you total flexibility, whether you are re-using existing hardware or building a system from scratch.

Both hardware and software are modular, so you can get the production functionality you need, without paying for anything that you don’t. Although a production system is significantly cheaper than an R&D SoundCheck system, it’s still fully compatible – you can create tests on an R&D system and send them to your production systems, or bring results from your production system back into an R&D system for detailed analysis.

However, it’s the seamless integration with custom factory test systems that really differentiates SoundCheck.

Full TCP/IP control lets SoundCheck communicate on any operating system, via any TCP/IP-supportive language including python, c-sharp and Labview. TCP/IP commands can trigger a test, pass the output back to an external program, or even pull in externally stored sequence parameters such as limits and stimuli. This allows the same test sequence to be used for many different products, reducing the sequence maintenance burden.

SoundCheck is just as flexible for saving data. Standard data formats include text, csv, Excel, TDMS, Matlab and SoundCheck’s open source binary file format. There’s also a plugin for WATS Test Data Management software. You can use an autosave step in your sequence to write curves, values, results, or waveforms directly to an SQL database each time a sequence is run, and industry standard tools can then be harnessed to run analytics over large data sets. If these options aren’t enough, all the data, curves, and other  items saved in SoundCheck’s memory list, can always be accessed directly via TCP/IP, so you can write your own customized program to collect exactly the SoundCheck data you need.

SoundCheck’s built-in security features provide peace of mind if you share your tests with manufacturing partners. Sequence protection locks and hides all the information in a sequence so that it can be run, but not viewed or altered. So you have confidence that your products are tested exactly how you intended. No-one can adjust the limits to achieve higher yield, and it removes the risk of  your tests being modified and re-purposed for use on other product lines. To add further security and measurement confidence, a sequence can even be configured to only run on a particular SoundCheck system, or block of system hardware keys.

These features let you bring the power of SoundCheck into pretty much any large automated test platform, no matter what software and operating system it is running on. Talk to your sales engineer to learn more.

 

 

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.