Tag Archive for: sequence

100 Things #79: Lock and Password Protect Your Test Sequences with Sequence Protection

With sequence protection in SoundCheck, sequences can be password protected, preventing unauthorized modification and viewing of sequence steps and data. This feature is perfect for distributing developed sequences to third parties, where you can rest assured that sequence parameters like limits cannot be changed to alter results. Sequences can even be locked to a specific set of SoundCheck hardware keys, so only authorized systems can access the sequence. All protected SoundCheck sequences are encrypted for maximum security.

Lock and Password Protect Your Test Sequences

Check out even more SoundCheck features and functionality like sequence protection

SoundCheck is built from the ground up to be the most flexible, reliable test system. Read on about all of SoundCheck’s capabilities like sequence protection and more.

Video Script:

It’s always been easy to share SoundCheck test sequences with your colleagues and manufacturing partners, but did you know that sequences can be locked to prevent modification, and conceal your test details? This stops your colleagues from altering them without your knowledge, and also prevents them from being copied and misappropriated if they are shared outside your organization.

Locking a sequence and password protecting it is simple. You can run the sequence as normal, but once it’s in the locked state, it cannot be modified without the password – steps, limits and other sequence parameters cannot be changed. Furthermore, the sequence details cannot even be viewed, protecting the intellectual property in your sequence.

This means that if you’re sharing your test sequences with 3rd parties –  for example, contract manufacturers – you can be confident that your products are tested exactly how you intended. No-one can adjust the limits to achieve higher yield! It also removes any risk of  your tests being modified and re-purposed for use on other product lines. 

You can even go one step further and configure a sequence to only run on a particular SoundCheck system, or block of system hardware keys. This is also simple to configure – either by entering the hardware key laser IDs, or importing a list from a CSV file. Locking a sequence to your particular systems adds another layer of security, and gives you additional confidence in your test set-up, as you know your measurements are being made on a genuine SoundCheck system with all the capabilities needed to successfully run the sequence.

And, just one final word of caution… all sequence protection data is encrypted for maximum security, so make sure you have that password in a safe place! 

This feature is available in SoundCheck 21 and higher. Check out the user manual or ask your sales engineer for additional information.

VR Headset Leakage Measurement Sequence

VR Headset Leakage measurement screenshotVR headset leakage measurement is a useful parameter for VR headset characterization. While they are sometimes connected to headphones, most VR headsets also contain built-in speakers, often on the strap close to the ear. These small speakers often have considerable audio leakage due to their positioning on the band, where there is some transmission through air before reaching the ear. This is annoying to others in the room, so efforts are made to minimize this. 

For this measurement, the headset is positioned on a head and torso simulator mounted on a turntable, and a log sweep played from 20Hz-20kHz at user-defined level and distance. The sequence measures leakage and frequency response for one ear in 10° increments from 0 to 180°, and mirrors it to provide a complete 360° polar plot. The final display produces a polar plot for four frequencies, and all eighteen measurements are shown on a frequency response graph.


100 Things #70: Make Smarter Tests with Sequence Logic

SoundCheck has sequence logic integration through every step. The ability to use If/Then logic with sequence steps means sequences expand beyond a linear path. Loops are easily created, perfect for using turntables to create polar plots. Incrementing and measuring level increases means it’s easy to automate testing devices to specific SPL, distortion, and perceptual distortion levels. Conditional branching can also help production line efficiency, where operators can be guided through calibration procedures if DUTs change.

Make Smarter Tests with Sequence Logic

Learn more about sequence logic in SoundCheck

If you want to see sequence logic in action, check out conditional branching in our pre-written M-Noise sequence.

Video Script:

Conditional branching is a powerful tool that lets you alter the order of step execution in the sequence based on the pass or fail status of a particular step. Using sequence logic in this way offers unrivaled flexibility in complex sequences.

If we right click on any step in our sequence, we can see a variety of options within the configuration window. These two options, Jump on Pass and Jump on Fail, let us use conditional branching and looping within our sequence. From the dropdown, we can select any other step for the current step to jump on pass or fail to. This can be used to skip particular sections of the sequence, or even to create loops.

For example, if I am measuring the frequency response of a loudspeaker, I can configure the Analysis step to “jump on pass” back to our stimulus step. I can then define the loop to last for a certain amount of repetitions and then end the loop. So here I could say after 4 repetitions, jump to my final display. This will give us a total of 5 runs through our stimulus and acquisition.

Every time the loop occurs, our index will increment. This can be used to simply track the number of times the sequence has looped. It will start at 0, then increase by 1. But we can reference this value in other steps in the sequence. I could define a starting level, and then increment that level by 3dB on each one of our loops. I’ll point to this value in the stimulus step, and now when I run my sequence I play the signal out 5 times, each time increasing the level by 3dB.

Conditional branching can also be used to jump around entire sections of sequences. For example, the sequence could ask the operator if they need to run a pre-conditioning test and jump accordingly. Another application would be to check for a signal near the beginning of a long sequence and if it fails then jump to a message step that warns the user that no signal was detected instead of running the entire sequence.. This way, the operator doesn’t waste time testing a bad device, and different autosave steps can be used to mark the data as a failure.

In-Car Audio Measurements

Screenshot showing in-car audio measurement sequence final display showing frequency response, distortion and Max SPL

Final display of in-car audio measurement sequence showing frequency response, distortion and Max SPL

This in-car audio test sequence measures the transient distortion (also known as buzz, squeak, and rattle, Rub & Buzz, or impulsive distortion), frequency response, and maximum sound pressure level of a vehicle infotainment system to the methods outlined in the Audio Engineering Society Technical Committee on Automotive Audio (TC-AA) in-vehicle measurements draft white paper.  The three measurements are incorporated into one overall test sequence, making it fast and simple to run the entire suite of tests. This sequence facilitates evaluation of the committee’s proposals, and also serves as a basis for any similar in-house measurements. The white paper (linked above) outlines both measurement methods and physical configuration such as microphone and seat positioning in an effort to simplify comparison between vehicles. This test sequence may, of course, be used with your own in-house physical configuration if adherence to the TC-AA guidelines is not essential.


Polar Plot (MDT-4000 Turntable) Sequence

This sequence measures the polar response of a loudspeaker in both the vertical and horizontal dimensions. It is designed to work with the Portland Tool & Die MDT-4000 turntable, and has all the necessary commands to automatically rotate it via RS-232. The sequence uses a log sweep stimulus with the Time Selective Response algorithm so that the measurements can be run in a non-anechoic environment. Note that the time window needs to be adapted to the user’s measurement space.

The sequence plays the stimulus and measures at 10 degree increments from 0 to 180 degrees. This process is repeated with the speaker positioned horizontally. The two results are mirrored to display full 360 degree polar plots for each axis. A directivity index curve is also calculated for each axis and is displayed at the end of the test.


Receive Loudness Rating with ITU Real Speech Test Sequence

The purpose of this sequence is to measure the Receive Loudness Rating (RLR) following the ITU-T P.79 standard using a Head and Torso Simulator (HATS). First, real speech from the ITU-T P.501 standard is sent to the Device Under Test (DUT) speaker by an electrical interface. The HATS right ear captures the DUT‟s speaker response. SoundCheck calculates the frequency response and then RLR based on that recording.


Send Loudness Rating with ITU Real Speech Test Sequence

The purpose of this sequence is to measure the Send Loudness Rating (SLR) following the ITU-T P.79 standard. This sequence can be used with handsets, headsets, and conference call devices. First, real speech from the ITU-T P.501 standard is played out of a mouth simulator. The Device Under Test (DUT) microphone then captures the signal and transmits this back to SoundCheck. SoundCheck calculates the frequency response function in 1/3 octaves and calculates SLR based on that frequency response.


Loose Particles Sequence

This sequence demonstrates how to use SoundCheck to detect loose particle defects in loudspeakers. Loose particles typically reveal themselves as randomly spaced impulses, so they may not be detected when performing frequency based measurements such as THD, even though they can be clearly heard as undesirable artifacts. The loose particle algorithm, which is an available function in all analysis algorithms, analyzes a time waveform to detect these impulses. The user sets a customized threshold level for detection.


Complete Test Sequence

The purpose of this sequence is to perform a full suite of basic measurements for a loudspeaker. A 500 mV stepped sine sweep from 20 kHz to 50 Hz is played through the speaker and measured via two channels of the audio interface. A calibrated reference microphone is connected to one of the channels, and an impedance reference is connected to the other.

A HarmonicTrak™ analysis step analyzes the recorded waveform from the reference microphone, and outputs frequency response, THD, Rub & Buzz, and various harmonic curves. A second analysis step analyzes the waveform from the impedance reference and outputs a curve of impedance versus frequency. A post processing step is used to estimate the characteristics of the impedance curve and calculates the max impedance, resonance frequency, and the Q of the resonance peak.


Bluetooth Headset Test Sequence

The purpose of this sequence is to test a Bluetooth headset using a mixture of analog and digital channels. First, a Multitone stimulus is created with SoundCheck, played back over the Bluetooth headset (at 8 kHz) and recorded by a head and torso simulator’s ear (at 44.1 kHz). Then the same Multitone stimulus is played back through the head and torso’s mouth simulator (at 44.1 kHz) and recorded via the Bluetooth headset (at 8 kHz).

Due to inaccuracies of clock frequency, the Bluetooth device playback sampling rate is often slightly different than it is specified. Therefore, in SoundCheck, the Recorded Time Waveforms are frequency shifted to correct for the inaccurate sampling rate. The exact device playback sampling rate is displayed.