|KLIPPEL R&D System||KLIPPEL QC System|
|Complex Transfer function||TRF, LPM, DIS, MTON||SPL, SPL-IMP, IMP, MSC|
|Total phase (unwrapping, without constant time delay)||TRF, LPM, DIS||SPL, SPL-IMP, IMP|
|Minimal-phase, excess-phase response||TRF|
The transfer behaviour of a linear system between input and output can be described by a complex transfer function H(jω) in the frequency domain. The transfer function is independent of the spectral properties of the stimulus as long as the system behaves linearly and as long as the input and output signals are measured at sufficient SNR. The real and imaginary part of the transfer function H(jω) can be displayed as a Nyquist plot.
Alternatively, the complex transfer function can be represented as magnitude and phase response. Simultaneous acquisition of input and output signal is recommended for measuring phase responses. A linear system can be described as a combination of three subsystems (minimal-phase subsystem, an all-pass and a subsystem having a constant time delay). The minimal-phase response can be calculated from the amplitude response by using the Hilbert transform.
TRF is dedicated for the measurement of the complex transfer function by using a sinusoidal sweep (chirp) as stimulus and performing a two-channel data acquisition. In the small signal domain the transfer function (amplitude and phase response) is independent on the properties of the stimulus (spectral properties). A variety of tools for post-processing is provided (impulse response, windowing, smoothing, time-frequency transformation, …).
LPM uses a multi-tone complex as stimulus which is perfect for measuring the electrical impedance, the mechanical transfer function Hx(f)=X(f)/U(f) between displacement and voltage and the sound pressure response Hp(f) in the small signal domain.
DIS performs a steady-state measurement of phase and magnitude of the fundamental component referred to the internal stimulus. This module is perfect to investigate the dependency on the measurement amplitude.
SCN measures the mechanical transfer function between loudspeaker terminals and the laser displacement sensor using a sweep with amplitude profile (amplitude increases by 10db/octave to ensure high SNR at high frequencies).
|Near Field Scanner (NFS)|
The NFS offers a fully automated acoustic measurement of direct sound radiated from the source under test. The radiated sound is determined in any desired distance and angle in the 3D space outside the scanning surface.
|Multi-Tone Measurement (MTON)|
MTON measures the complex transfer function among other measurements using a steady state multi-tone stimulus. Moreover, the mechanical and thermal compression produced in the transfer function is calculated in MTON multiple measurements mode.
SPL measures the amplitude and phase response of the electrical or acoustical input signal using a sinusoidal sweep as stimulus. The sweep may vary versus frequency according to an amplitude profile or a user defined sweep speed to ensure sufficient SNR of the input signals and optimal resolution of the transfer function at particular frequencies.
IMP measures the electrical impedance and phase using a sinusoidal sweep or a multi-tone complex as stimulus.
|Motor+Suspension Check (MSC)|
MSC dispenses with an additional small signal measurement but measures the nonlinear parameters at the rest position x=0 while operating the transducer in the large signal domain using an ultra-short multi-tone stimulus. It measures the electrical impedance and phase using multi-tone complex as stimulus.
Name of the Template
TRF Scanning Cone Vibration
Manual scanning of cone vibration using a laser sensor with high cut-off frequency (>15 kHz)
TRF sensitivity (Mic 2)
Calibration of the microphone at IN2 using a pistonphone
TRF SPL + harmonics
Standard measurement for fundamental component (SPL) and harmonic distortion
TRF SPL + waterfall
Sound pressure level and cumulative decay spectrum
TRF true acoustical phase
Total phase without time delay
TRF cumulative decay
Cumulative spectral decay
DIS SPL, Harm protected
Harmonic distortion measurement with protection
DIS X Fundamental, DC
Fundamental and DC component of displacement
Diagnost. MIDRANGE Sp1
Comprehensive testing of midrange drivers with a resonance 30 Hz < fs < 200 Hz using standard current sensor 1
Diagnost. RUB&BUZZ Sp1
Batch of Rub & Buzz tests with increased voltage (applied to high power devices)
Diagnostics MICROSPEAKER Sp2
Comprehensive testing of microspeakers with a resonance 100 Hz < fs < 2 kHz using sensitive current sensor 2
Diagnostics TWEETER (Sp2)
Comprehensive testing of tweeters with a resonance 100 Hz < fs < 2 kHz using sensitive current sensor 2
Diagnostics VENTED BOX SP1
Comprehensive testing of vented box systems using standard current sensor 1
Diagnostics WOOFER (Sp1)
Comprehensive testing of subwoofers with a resonance 30 Hz < fs < 200 Hz using standard current sensor 1
Diagnostics WOOFER Sp1,2
Comprehensive testing of subwoofers with a resonance 30 Hz < fs < 200 Hz using current sensor 1 and 2
IEC 20.6 Mean SPL
Mean sound pressure level in a stated frequency band according IEC 60268-5 chapter 20.6
IEC 21.2 Frequency Range
Effective frequency range according IEC 60268-5 chapter 21.2
IEC 22.4 Mean Efficiency
Mean efficiency in a frequency band according IEC 60268-5 chapter 22.4
A. Farina, “Simultaneous Measurement of Impulse Response and Distortion with a Swept-Sine Technique,” presented at the 108th Convention of the Audio Eng. Soc., J. of Audio Eng. Soc. (Abstracts), Volume 48, p. 350 (2000 Apr.), Preprint 5093.
G. B. Stan, J. J. Embrechts and D. Archambeau, “Comparison of different impulse response measurement techniques,” J. of Audio Eng. Soc. 50 (2002), pp. 249–262.
E. Mommertz and S. Müller, “Measuring impulse responses with digitally pre-emphasized pseudorandom noise derived from maximum-length sequences,” Applied Acoustics 44 (1995), pp. 195–214.
S. Müller, P. Massarani, “Transfer-Function Measurement with Sweeps,” J. of Audio Eng. Soc. 2001, June, Volume 49, No. 6, pp. 443-471.
D. D. Rife and J. Vanderkooy, “Transfer-function measurement with maximum-length sequences,” J. of Audio Eng. Soc. 37 (1989), pp. 419–443.