Measuring Audio Devices

London – Copenhagen – Frankfurt

Join Axiometrix Solution’s Dan Knighten and James Kelly for this two-day, in-person workshop where we will explain everything you have ever wanted to know about measuring audio devices. 

We will cover the basics of sound and fundamental measurements to automation and advanced measurement techniques. This workshop is ideal for both new and experienced users of AP and GRAS equipment.

This will be a hands-on workshop. Measurement techniques will be demonstrated by the instructor, and you will be able to follow along and complete simulated exercises using APx500 software. To facilitate this, please make sure that you have downloaded and installed the latest version of APx500 on your computer and bring it.

The latest software version is here:


CityDateLocationEstimated Cost*
October 6 and 7
Time: 9:00 -17:00
Renaissance London Heathrow Hotel
Bath Road, Hounslow, United Kingdom, TW6 2AQ
Room: Waterloo Suite
£220 Per Day
£47 Day 1 Dinner (Optional)
October 10 and 11
Time: 9:00 -17:00
Clarion Hotel, Copenhagen Airport
Ellehammersvej 20, 2770 Kastrup, Denmark
Room: Tyr
1926.05 Kr. Per Day
408 Kr. Day 1 Dinner (Optional)
October 13 and 14
Time: 9:00 -17:00
Sheraton Offenbach Hotel
Berliner Strasse 111, 63065 Offenbach, Germany
Room: Isenburg
€260 Per Day
€55 Day 1 Dinner (Optional)
*The workshop fee does not include travel expenses. Travel expenses incurred to attend are at the workshop attendee’s own cost.


Introduction to Audio MeasurementWhat is sound?
What’s special about audio measurement?
Units of measure
Introduction to the basics acoustics, sound pressure, the speed of sound and wavelength, basic ear anatomy, and psychoacoustics.
Developed from
Explanation of electrical, digital, and acoustic units, dB, etc…
Overview of APx based audio analyzers
Review all analyzers from APx555 to Flex as well as DIO options, switchers, and accessories
Introduction to APx500High-level tour of the UI
Signal Path Setup
Sequence Mode Basics
Bench Mode Basics
The standard tour of the APx500 layout, user-interface, and design philosophy
Explain input and output configuration, verifying connections, and references. Basic test setup
The measurement setup pane, results, limits, graph properties, and derived results
Overview of the usage concep, meters, and custom sweeps
Fundamental MeasurementsLevel & Gain
Distortion & Noise
Frequency Response
Spectrum Analysis
Sweeps vs Frequency, Level, Time
Everything you wanted to know but where afraid to ask about the most fundamental measurement in audio, RMS vs Peak and don’t forget about DC
THD vs THD+N, all about noise, dynamic range, SINAD, and Q-Peak noise
Frequency Response and basic introduction to sweeps
Phase – Interchannel vs absolute and group delay
All the ways we can look and channel leakage
Introduction to the Fourier analysis
Introduction to Frequency Sweeps, Level Sweeps, and the Measurement Recorder
Open Loop MeasurementsTesting playback only devices, record only devices, record then playback devices, and file analysis
Electro-AcousticsOverview of measurement peripherals (mics, ear simulators, KEMAR, etc…)
Acoustic Response, Loudspeaker Production Test, Impedance
Measurement microphone basics, ear simulators, mouth simulators, fixtures, and KEMAR
Review the fundamental transducer measurements in APx500
Why do we (almost) always use sine wavesMultitone & Transfer Function – Then explain practical uses of Multitone And Transfer Function analysis
Beyond THDIMD, TD (+N), CoherenceCharacterizing the non-linear performance of a device with tests beyond harmonic distortion.
Voice Communication MetricsPESQ, POLQA, STI, & ABC-MRTMaking speech intelligibilty tests on communication devices with a variety of methods.
High Speed MeasurementsChirp, Multitone, & FastSweepWhen time matters: Different techniques for the fastest possible audio test.
Sequence Mode AutomationMeasurement Steps, ReportingDeep dive into automating test sequences, especially the many advanced features we have hidden in SPS properties and sequence sub-steps.
Advanced Bench ModeTime vs Frequency Domain Explanation, SweepsA more in-depth approach to bench mode, explaining the tradeoffs in frequency vs time-domain analysis, bench mode settling, transfer function for continuously updating frequency response, recorder for high-reading rate charting. a
Digital I/O InterfacesBluetooth
Jitter generation & measurement
Configuration of the Bluetooth interface especially discovery and pairing, roles/profiles, CODEC priority, optimization for production test
Connecting directly to DACs/ADCs/DSPs and other chips directly. Basics of I2S, cable length limitations, and troubleshooting
An explanation of Pulse Density Modulation and configuration of PDM inputs and outputs.
Configuration of the HDMI, compare bitstream, and the metadata recorder
SPDIF, AES3, and Toslink will never die
Using AMC to measure jitter residuals and tolerance
Advanced Measurement TopicsSettling & Input RangingPoorly understood topic which is often the key to fast AND accurate measurements.
Hands-on WorkshopsElectro-Acoustic (Speakers, Headphones, Microphones)
Analog Electronics (consumer music player, power amplifier, small mixing deck)
Digital Audio (Bluetooth speaker, I2S DAC, PDM mic, HDMI soundbar or TV)
Hands-on, real-word test of actual devices.
Additional ResourcesGetting Help – Technical Support
Whitepapers, technical notes, Youtube, & the blog
Add-in’s, Plug-in’s, & Utilities
Resources for Programmers
Tour of the many, many additional resources that are available online.