Overview
Signal and System Analysis
Waveform and Spectrum
- Time domain analysis
- Statistical analysis
- Spectral analysis
- Signal to noise ratio SNR
Magnitude and Phase Response
- Magnitude and phase response
- Complex transfer function
- Total phase (unwrapping, without constant time delay)
- Minimal-phase, excess-phase response
- Polarity
- Nyquist plot
Impulse Response
- Time windowed impulse response
- Step response
- Energy time curve
- Group delay response
- Excess time delay response
- Constant time delay detection
Time-frequency Analysis
- Wigner-distribution
- Cumulative decay spectrum
- Sonagraph
- Wavelet transform
Sound Radiation and Propagation
Far Field Sound Pressure On-axis
- SPL sensitivity at 1W and 1m on-axis
- Mean level in frequency band
- Effective frequency range
Directional Radiation Characteristics
- Off-axis far field SPL response
- Directional response pattern
- Polar and balloon plots
- Coverage and radiation angle
- Directivity index
- Sound power response
Near Field Measurement
- Extrapolated far-field SPL response
- Low frequency measurements without anechoic condition
- Splicing near-field/ far-field measurement
- Merging multiple sound sources
- Distortion measurements at high SNR
Area of Radiation
- Effective radiation area Sd
Radiation Analysis
- Far field SPL-response generated in a half space
- Directivity index, sound power response
- Polar and balloon plot
- In-phase component (constructive contribution to SPL)
- Anti-phase component (destructive contribution to SPL)
- Quadrature component (no contribution to SPL)
Mechanical Vibration
Voice Coil Displacement
- Transfer-function Hx(f)=X(f)/U(f) between voltage and displacement
- Linear parameters (Thiele-Small)
- Nonlinear parameters
- Peak, rms and dc displacement
- Rub & Buzz analysis
Scanning Mechanical Vibration
- Complex transfer function Hx(r, f) at point r on the radiator’s surface
- Magnitude and phase plot
- Animated vibration pattern
- Distributed mechanical parameters
Vibration Analysis
- Accumulated acceleration level AAL
- Modal analysis (natural frequencies, modal loss factor, mode shape)
- Radial and circumferential modes
- Rocking modes
Scanning Geometry
- Geometry of the surface in cylindrical coordinates
- Export in dxf, stl and other format
Material Parameters of Loudspeaker Parts
- Young’s E modulus
- Modal loss factor
Transducer Parameters
Small Signal Lumped Parameters
- Resonance frequency fs
- Mechanical quality factor Qms
- Electrical quality factor Qes
- DC resistance Re
- Force factor Bl(x=0)
- Mechanical resistance Rms(v=0)
- Stiffness Kms(x=0) and compliance Cms(x=0)
- Additional Thiele-Small parameters (e.g. Vas)
- Visco-elastic parameter (creep factor λ)
- Lossy inductance parameters (Wright, Leach, LR2 model)
Transducer Nonlinearities (Curve Shape)
- Force factor Bl(x) versus displacement x
- Mechanical compliance Cms(x) versus displacement x
- Mechanical stiffness Kms(x) versus displacement x
- Incremental stiffness Kinc(x) versus displacement x
- Inductance L(x,i) versus displacement x and current i
- Mechanical resistance Rms(v) versus velocity v
- Force-deflection curve F(x)
Single-valued Nonlinear Parameters
- Voice coil offset Xoffset
- Suspension asymmetry Ak
- Maximal peak displacement Xmax
- Force factor limited peak displacement Xbi
- Suspension limited peak displacement Xc
- Inductance limited peak displacement XL
- Stiffness Kms(x=0) at the voice rest position
- Force factor Bl(x=0) at the voice coil rest position
- Effective stiffness related to effective resonance frequency
- Symmetry point xsym in force factor curve
Electrical Impedance
- Amplitude and phase response
- Nominal electrical impedance Zn
- Impedance measured by using a large signal model
Parameters of the Enclosure
- Port resonance fb
- Quality factor Qlb of vented enclosure
Nonlinear Distortion
Harmonic Distortion
- Total harmonic distortion (THD, THD+N)
- Nth-order component versus frequency and amplitude
- Hi-2 distortion (weighted low order harmonics)
- Equivalent input distortion
Intermodulation Distortion
- Nth-order difference-tone and summed-tone intermodulation
- Total intermodulation distortion (absolute and relative)
- Amplitude modulation distortion
Multi-tone Distortion
- Relative multi-tone distortion
- Distortion-noise-ratio
Separated Loudspeaker Distortion
- Total distortion in a reproduced audio signal
- Distortion generated by force factor Bl(x)
- Distortion generated by stiffness Kmx(x)
- Distortion generated by inductance Le(x)
- Distortion generated by inductance Le(i)
Compression of Fundamental Components
- Output amplitude versus input amplitude
- Thermal power compression
- Nonlinear amplitude compression
DC Displacement – Dynamic Offset the Voice Coil
- DC displacement versus frequency
- DC displacement versus amplitude
- Asymmetrical probability function pdf
- Peak-bottom value
Rub & Buzz and Impulsive Distortion
- Peak value of higher-order harmonics
- Rms value of higher-order harmonics
- Crest-factor of higher-order harmonics
- Crest-factor versus voice coil displacement
- Peak value of deterministic component
- Peak value of random component
- Isolated defect distortion
- Noise immunity
Air Leakage Noise
- Absolute envelope of modulated noise MOD
- Relative envelope of modulated noise RMOD
- Peak value of random distortion RAND
- Peak value of deterministic distortion DET
- Crest factor of deterministic distortion CREST
- Inter-channel delay time
- Incident angle
- Mechanical loss factor Qms
- Port resonance frequency fp
- Quality factor representing box leakage
Auralization
- Distortion generated by force factor Bl(x)
- Distortion generated by stiffness Kmx(x)
- Distortion generated by inductance Le(x)
- Distortion generated by inductance Le(i)
- Voice coil displacement
- Voice coil temperature
- Voltage, current and input power
Maximum SPL
- Tone burst measurement according to ANSI CEA-2010
Power Handling and Heat Dissipation
Accelerated Life and Power Testing
- Input power versus time
- Displacement versus time
- Voice coil temperature
- Durability, endurance, reliability
- Parameter variation over time (aging)
Voice Coil Temperature
- Variation of dc resistance Re versus time
- Increase of voice coil temperature δTv
- Heating and cooling curves
Thermal Parameter Measurements
- Thermal resistances of voice coil and magnet
- Thermal capacities of voice coil and magnet
- Air convection cooling coefficient
- Eddy current heating factor
Thermal Analysis and Heat Transfer
- Increase of voice coil temperature δTv
- Increase of magnet temperature δTm
- Bypass factor
- Power Pcoil transferred to coil
- Power Pcon transferred by convection cooling
- Power Peg transferred by eddy currents
Voltage and Current
- Rated noise voltage
- Short term maximum voltage
- Long term maximum voltage
- Peak and rms value, crest factor
- Probability density function
Electrical Input Power
- Real input power Preal
- Power PRe dissipated on Re
- Pn nominal impedance Zn
- Short term maximum input power
- Long term maximum power