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Typical Applications of KLIPPEL QC SYSTEM

Driver test setup

Driver test setup

The basic setup for testing single drivers comprises the Production Analyzer hardware, power amplifier, microphone(s) and a computer. In most cases the DUT and the near field microphone is mounted into a test box providing some protection against ambient noise. However, complete noise immunity cannot be obtained by simple passive shielding.

 

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Passive System test setup

Passive System test setup

The Passive system test is almost identical to the coax driver test, with the tweeter mounted on top of a woofer in one housing, and it exploits the two channel capability of the Production Analyzer hardware. Internal switches allow for testing the system channels separately as well as in combination without using external hardware. A starting switch (robust footswitch) and temperature and humidity sensor are included as options in this setup. Note that access to the speaker terminals must be provided for individual testing. Crossovers can also be measured using KLIPPEL QC System if in- and output are accessible.

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Active 2.1 System with electrical and acoustical testing

Active 2.1 System with electrical and acoustical testing

Active systems having internal power amplifiers are connected directly to the XLR outputs. In this example the satellites are passive and hence can also be tested electrically (impedance, T/S and large signal parameters). The total acoustical output is assessed by using a near-field microphone. The second microphone located in the far field detects the ambient noise.

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5.1 System with electrical and acoustical testing. Analog or digital (USB) interface of DUT

5.1 System with electrical and acoustical testing. Analog or digital (USB) interface of DUT

The first speaker multiplexer (1 out of 8) is used for selecting one or two speaker channels from the amplifier output at the subwoofer. The selected channels are fed via the voltage and current sensors in the production analyzer via the second multiplexer to the speakers under test. All the remaining speakers are switched off. Both multiplexers are controlled by the same binary GPIO pins of the Production Analyzer. The third multiplexer is used for selecting the microphones using different GPIO pins. Thus the selection of the microphones is completely independent of the selection of the speakers. The ambient noise microphone always monitors the far field sound pressure. Although the 5.1 system in the application is connected to the analogue output of the PA, it can also be operated using a digital audio interface (e.g. USB).

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Microphone test setup

Microphone test setup

Testing microphones using a reference speaker and enclosure is also a straigthforward application for KLIPPEL QC. Microphones can be connected via IEPE or XLR line input to the Production Analyzer hardware. 

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Alternate test setup

Alternate test setup

This test setup provides a cost efficient solution. Two lines with identical DUTs can be tested by using one KLIPPEL QC System only. One DUT can be mounted / dismounted while the other is tested. Thanks to the complete two channel architecture of the Production Analyzer hardware, the test environments can be switched automatically (speaker, microphone). An optional ambient noise microphone can be used to ensure Production Noise Immunity. An additional license "Alternate Testing" will be required.

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Headphone Testing

The quality of headphones depends on many factors. Most important are the frequency response and the match between left and right channel. Furthermore, excessive harmonic distortion shall be reliably detected as well as any disturbing rattling and buzzing noises, even if operated at high level.

The tests shown in this video can be applied to any kind of headphone:
 - analog or digital,
 - wired or wireless,
 - hearing aids,
 - headsets: extend test for microphone check,
 - active noise cancellation headphones
   and hearing protection, ear muffs: extend to check noise attenuation.

The complete test is extremely fast. The cycle time for production is clearly dominated by handling of DUT change, which can be also automated. Complete testing ensures superiour quality of the tested products.

 

Related Information

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Leak detection for large subwoofer

Detecting air leaks in large speaker systems with only one microphone leads to physical problems due to shadowing of high frequency leak noise. Locating multiple microphones around the device under test solves this problem by measuring the speaker from different sides and thus covering the whole surface. The four test microphones are switched by a signal multiplexer for sequential measurement. An additional far-field microphone always monitors ambient noise in parallel while the measurement chamber guarantees proper ambient noise attenuation for maximal measurement sensitivity.

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