Maximum SPL
Characteristics: | KLIPPEL R&D System | KLIPPEL QC System |
|---|---|---|
| Total harmonic distortion (THD, THD+N) | TRF, DIS, TBM | SPL, SPL-IMP |
| Nth-order component versus frequency and/or amplitude | TRF, DIS, TBM | SPL, SPL-IMP |
| Hi-2 distortion (weighted low order harmonics) | DIS | Hi-2 |
| Equivalent input distortion | TRF | |
| Intermodulation Distortion | DIS, SIM | |
| Multi-tone distortion (*deprecated) | MTON, (LPM*) | |
| Impulsive Distortion (Rub & Buzz) | TRF-Pro, TFA | SPL, SPL-IMP, ALD, MHT, 3DL |
| Higher Order Harmonic Distortion (HOHD) | SPL, SPL-IMP | |
| Incoherence | LAA | SAN |
| Compression of fundamental components | DIS, SIM, MTON, LSI3, LAA | |
| Maximum mechanical excursion of the voice coil | LSI3, MTON, DIS | MSC, DCX |
| Increase of voice coil temperature |
Achieving the maximum SPL (Sound Pressure Level) under various conditions is one of the main challenges during the development of transducers and sound systems. To reach this SPL value, several standards and good engineering practice define procedures and thresholds of measurements and parameters:
- Harmonic Distortion (THD, 2nd, 3rd)
- Intermodulation Distortion
- Impulsive / Higher Order Harmonic Distortion (Rub & Buzz symptoms)
- Compression of fundamental components
- Mechanical excursion of the voice coil
- Increase of coil temperature
Since several kind of DUTs (Devices Under Tests) and usages may be covered, diverse standards using different test signals, conditions and measurements are available.
KLIPPEL R&D SYSTEM (development)
Module | Comment |
|---|---|
TRF provides a fast harmonic distortion analysis (THD and higher-order distortion components) based on Farina Technique for log sine sweeps. | |
DIS module performs a steady-state harmonics and intermodulation distortion measurement based on single or two tones versus level and frequency. | |
| Tone Burst Measurement (TBM) | TBM is based on extremely short, narrow band tone bursts measuring harmonic distortion versus level until a harmonic distortion threshold is reached. |
| Multi-Tone Measurement (MTON) | MTON is based on multitone excitation and provides multitone distortion, compression and voice coil temperature increase versus level. |
| Linear Parameter Measurement (LPM) | LPM is based on multitone excitation and provides multitone distortion. MTON replaces this functionality in LPM. |
| Time Frequency Analysis (TFA) | TFA visualizes the characteristics of an audio signal over time and frequency. Based on wave files it reveals detailed distortion signatures (harmonics, intermodulation, impulsive…). |
| Live Audio Analyzer (LAA) | Using arbitrary audio signals LAA separates linear from nonlinear responses. A detailed distortion analysis reveals critical conditions and applications. |
| Simulation (SIM) | SIM module performs a steady-state harmonics and intermodulation distortion simulation based on single or two tones versus level and frequency. It is the simulation twin of DIS. |
| Large Signal Identification (LSI, LSI3) | LSI modules identify non-linear parameters that may limit the working range (Xmax) and therfore SPLmax. It provides voice coil temperature, input power and distortion analysis based ona band limited noise stimulus versus level. |
KLIPPEL QC SYSTEM (end-of-line testing)
Module | Comment |
|---|---|
Sound Pressure Task (SPL)
| The Tasks measures 2nd-5th harmonics, THD and Rub & Buzz using a sinusoidal chirp with sweep speed and amplitude profile which excites the loudspeaker persistently in the critical frequency range while performing an ultra-short measurement. |
| Hi-2 Weighted Harmonic Distortion (Hi-2) | The Hi-2 Feature is based on specially weighted harmonics of 2nd to 10th order. It is mainly used in automotive industry for woofers and subwoofers. |
| Air Leakage Detection (ALD) | The ALD task detects air noise modulated by the air pressure below dust cap or in the test box. The measurement is immune to other noise which is not modulated or modulated with a frequency different than the stimulus. The task also identifies random impulses generated by loose particles and deterministic distortion generated by wire beating, bottoming and buzzing. Measurements corrupted by ambient noise are detected and repeated automatically. |
| Meta Hearing Technology (MHT) | The regular motor and suspension distortion masks the symptoms of Rub & Buzz at higher amplitude levels. The MHT compensates actively for regular distortion by adaptive modelling and generates the isolated defect distortion. This increases the sensitivity for symptoms of irregular defects, simplifies the limit setting and gives more robustness. |
| Spectrogram 3D Limits (3DL) | 3DL performs a time-frequency analysis with a high time resolution by applying a filter bank based on an auditory model. The resulting spectrograms make it possible to identify the spectral fingerprint of a defective unit as well as the excitation frequency that activates it. |
| Spectrum Analysis (SAN) | SAN is a versatile tool for the QC framework of the KLIPPEL Analyzer System dedicated to testing loudspeakers, audio systems or any sound emitting devices with no signal input. A white or pink noise generator is provided to measure characteristics like sound pressure spectrum, frequency response, A-weighted level and incoherence. |
| Motor + Suspension Check (MSC) | MSC is a unique tool for high-speed identification of nonlinear driver parameters on the production line. Effective linear and nonlinear parameters (Bl(x) and Kms(x)) are identified to derive meaningful single value parameters like voice coil offset and suspension asymmetry. |
Templates of KLIPPEL products
Name of the Template | Application |
|---|---|
TRF SPL + Harmonics | Standard measurement for fundamental component (SPL) and harmonic distortion |
| TRF Rubb+Buzz w/o Golden Unit | Rub & Buzz detection without "Golden Unit" according Application Note AN 22 |
DIS Amplitude Compression AN12 | Displays output amplitude versus input amplitude |
DIS Harmonics vs. Voltage | Harmonic distortion measurement versus amplitude |
DIS HI-2 | Weighted harmonic distortion (blat distortion) used for Application Note AN 7 |
DIS SPL, Harm protected | Harmonic distortion measurement with protection |
| MTON Max SPL fixed level; IEC 60268-21 | Rated maximum sound pressure according IEC 60268-21 |
| MTON Max SPL increased level; IEC 60268-21 | Rated maximum sound pressure according IEC 60268-21 with increase stimulus level to determine SPL max |
| MTON Short term max SPL fixed level; IEC 60268-21 | Rated maximum short-term sound pressure according IEC 60268-21 |
| MTON Short term max SPL increased level; IEC 60268-21 | Rated maximum short-term sound pressure according IEC 60268-21 with increase stimulus level |
| MTON Long term max SPL fixed level; IEC 60268-21 | Rated maximum long-term sound pressure according IEC 60268-21 |
| MTON Long term max SPL increased level; IEC 60268-21 | Rated maximum long-term sound pressure according IEC 60268-21 with increase stimulus level |
| MTON Max. Usable SPL - cont @ SP1; ANSI/CEA-2010-B | Maximum sound pressure level related to ANSI/CEA-2010-B |
| PWT IEC Short Term Voltage | Power test to determine short term maximal voltage according IEC 60268-5 paragraph 17.2 without parameter measurement applied to 1 DUT monitoring temperature, power and resistance. |
| PWT IEC Long Term Voltage | Power test to determine long-term maximal voltage according IEC 60268-5 paragraph 17.3 without parameter measurement for one device monitoring voltage, resistance, temperature and power. |
| TBM ANSI/CEA2010A | Maximum SPL measurement according to Standard ANSI/CEA-2010-A. |
| TBM ANSI/CEA2010B | Maximum usable Sound Pressure Level - Peak measurement according to Standard ANSI/CEA-2010-B. |
| TBM ANSI/CEA2034 | On-Axis Maximum Sound Pressure Level - Peak measurement according to Standard ANSI/CEA-2034. |
| QC Motor and Suspension Check (MSC) | Xmax analysis based on nonlinear parameter measurement |
| QC Sound Pressure Level | Harmonics, impulsive, HOHD distortion analysis |
| QC SPL HI-2 (SPL+HI2) | HI-2 distortion analysis added to SPL task |
| QC SPL Bluetooth (EXD+SPL+SYN) | SPLmax analysis for Bluetooth bases DUTs |
Application Notes
AN 4 Measurement of Peak Displacement Xmax (performance-based method)
AN 5 Displacement Limits due to Driver Nonlinearities
AN 6 Measurement of Amplitude Modulation
AN 7 Measurement of Weighted Harmonic Distortion HI-2
AN 8 3D Intermodulation Distortion Measurement
AN 9 3D Harmonic Distortion Measurement
AN 10 AM and FM Distortion in Speakers
AN 12 Causes for Amplitude Compression
AN 16 Multi-tone Distortion Measurement
AN 20 Measurement of Equivalent Input Distortion
AN 22 Rub & Buzz Detection
AN 29 Long Term Monitoring
AN 36 Characteristic Harmonic Distortion
AN 37 Characteristic Modulation Distortion
AN 59 Power Test with bypassed stimulus from CD
AN 67 Auralization of Signal Differences
AN 72 Testing wireless Audio devices with Klippel R&D System
AN 76 QC Testing of Wireless Audio Devices
Standards
International Electrotechnical Commission
IEC 60268-5 Sound system equipment - Part 5: Loudspeakers
IEC 60268-21 Sound system equipment - Part 21: Acoustical (output-based) measurements
Consumer Technology Association
CEA-2010-A (ANSI) Standard Method of Measurement for Powered Subwoofers
CEA-2010-B (ANSI) Standard Method of Measurement for Subwoofers
CEA-2034 (ANSI) Standard Method of Measurement for In-Home Loudspeakers
EIA-426-B Loudspeakers, Optimum Amplifier Power
Other Related Test
Typical Test Objects
Papers and Preprints
Klippel, Wolfgang. "Assessment of voice-coil peak displacement Xmax." Journal of the Audio Engineering Society 51.5 (2003): 307-324.