Loudspeaker Measurements
SoundCheck measures:
- Frequency response
- Phase & polarity
- Distortion: harmonic, IM, multitone & non-coherent
- Rub & Buzz (inc. Perceptual Rub & Buzz)
- Impedance
- Directivity (including polar plots)
- Max SPL
- Power rating tests
- Simulated free field measurements
- Thiele-Small parameters
- Time-frequency analysis
The SoundCheck System
SoundCheck’s modular combination of hardware and software is cost-effective, flexible and expandable.
At the heart of the system is the SoundCheck software. Powerful, fast and accurate, it measures every audio parameter from the R&D laboratory to the production line. Complete flexibility in stimulus choice enables the use of a continuous log sweep (Farina sweep) for simulated free field measurements including harmonics, and permits any test signal, even music, to be used. Virtual instruments offer the functionality of stand-alone hardware on your laptop. Advanced analysis and powerful post-processing options allow all types
of analysis and mathematical operations – for example, estimated resonance for finding the true resonant frequency (f0), quality factor (Q) and impedance (Zmax) of a loudspeaker.
Display options range from comprehensive Microsoft Word or Excel reports to simple pass/fail output or writing to a database.
Repeatable, automated tests are quickly and easily created, modified and saved using the simple point-and-click interface. Several easy to modify sample loudspeaker sequences are provided for measurements such as Thiele-Small parameters, simulated free field measurements, polar plots, etc. and more complex sequences are available for specific test standards such as IEC 60268-5 and ALMA and AES standards.
The software also controls the audio measurement hardware – an audio interface, measurement microphone, power supplies, amplifiers and optional turntable.
Loudspeaker test sequence with nearfield and farfield response
Listen’s loudspeaker test hardware includes:
AmpConnect™: Listen’s all-in-one hardware includes an audio interface, amplifier, power and gain for up to 2 SCM or IEPE microphones, digital I/O, and integrated impedance circuit for all loudspeaker tests.
SCM™ Measurement Microphones: SCM measurement microphones are robust, accurate, low noise and stable.
SoundConnect 2™: A 2-channel microphone power supply (SCM, IEPE, 200V polarization) ideal for applications where polarization and high and low pass filtering are required. It also provides autoranging when used with SoundCheck to maximize the dynamic range of a measurement.
AudioConnect™: A compact audio interface with power supply and gain for up to 2 SCM™ microphones. This is a very cost-effective approach for basic loudspeaker testing.
SC Amp™: Listen’s audio test amplifier offers a patented integrated impedance circuit, fixed gain to reduce calibration errors and DC voltage offset support, along with low distortion and a low noise floor.
BTC-4148 and BQC-4148 Bluetooth Interfaces: Designed for R&D and production respectively, these connect Bluetooth speakers to SoundCheck, offering full control over all Bluetooth protocol settings and explicit control over the CODEC choice and transmitter power.
Also available for more complex test requirements: multichannel audio interfaces, MEMS interfaces, amplifiers, current monitors, and 3rd party hardware.
In the R&D lab, SoundCheck measures loudspeaker design characteristics such as Thiele-Small parameters, voicecoil offset, polar response, spliced nearfield-farfield sequences and more. SoundCheck’s sequence editor makes it simple to re-run tests and compare results as designs are modified. Powerful test capabilities, with many stimuli, analysis, post-processing and statistics options allow you to make all the measurements you need, plus offer unrivalled flexibility to calculate any parameters arising from these without leaving the system.
SoundCheck is the ideal tool for R&D loudspeaker testing because it offers unlimited test development flexibility yet it is quick and easy to develop tests. Features include:
- Unlimited test flexibility – although SoundCheck is pre-programmed with all common loudspeaker tests, it is so flexible that any test that you can conceive can be implemented. Simple point and click sequence development enables complex tests to be developed with no need for programming.
- Virtual instruments – a virtual real time analyzer, multimeter, signal generator, spectrum analyzer and oscilloscope offer the same functionality within the SoundCheck software as their conventional hardware counterparts.
- Advanced stimulus, analysis, post-processing and even statistical options allow you to not only make all the measurements you need but also calculate any parameters arising from these without leaving the system.
- Sophisticated report writing functionality enables comprehensive reports to be automatically generated, ensuring consistency and saving time.
- SoundCheck is simple to calibrate, and measures to all loudspeaker industry standards such as AES, ALMA, IEC and more.
On the production line, SoundCheck offers extremely fast and accurate testing of microspeakers, drivers and speaker systems. This results in better quality and higher yields, as faults are immediately identified, enabling production lines to be halted before too much product is wasted.
It is simple to operate, offers high immunity to background noise, and can carry out a complete production test including frequency response, Rub & Buzz (or perceptual Rub & Buzz), THD, loose particles, polarity and phase in as little as one second. Results can be compared to pre-set limits or a reference standard, and can be presented as a simple audible or visual pass/fail indication, a detailed failure mode analysis, or automatically written to a database. SoundCheck interfaces with barcode systems, footswitches and PLCs, and can be controlled via National Instruments Test Stand or LabVIEW for full integration with automatic production lines and large-scale test systems.
A production line loudspeaker test system is considerably less expensive than an R&D system, yet contains all the functionality needed for production line loudspeaker test.
- Fast – a complete production test, including frequency response, Rub & Buzz (or perceptual Rub & Buzz), THD, Loose particles polarity and phase can be executed in just one second
- Accurate – unique test signals and measurement algorithms ensure that measurements are fast and accurate, even in noisy environments
- Results can be compared to pre-set limits or a reference standard
- Results can be presented as a simple audible or visual pass/fail indication, a detailed failure mode analysis, or automatically written to a database
- Simple, error-free operation – SoundCheck can be configured for one-click operation, and various levels of operator control prevent modification of the test sequence. A Chinese language option is also available
- SoundCheck fully integrates with automatic production lines and large-scale test systems. It interfaces with barcode systems, footswitches, and PLCs, and can be controlled via Test Stand or LabVIEW
Examples: How do our Customers use SoundCheck for Measuring Speakers?
These are just some of the loudspeaker measurements that our customers are making:
- Environmental testing of loudspeakers (heat, humidity, vibration, etc.) using SoundCheck to automatically calculate of pre and post test differences
- Using SoundCheck to automatically incrementally increase the stimulus voltage level to identify the voltage level at which a speaker reaches a certain % distortion
- Complete production test measuring frequency, distortion, Rub & Buzz, loose particles and polarity. Control and barcode scanning are automated, measurement data is saved to a database and failed units are removed from the assembly line
More information? See the right sidebar to view detailed information about relevant test sequences, white papers, webinars and more about loudspeaker testing.