New K&K P750 QC Analyzer for loudspeaker, micro speakers and headphones testing

August 22 2014, 14:00
K&K’s P750 is a computer-controlled analyzer. It operates with Windows 8.1/8 and Windows 7. It performs 250 different frequency-point measurements and tests frequency response, sensitivity, polarity, slope, Rub & Buzz, total harmonic distortion (THD), impedance, resonance, efficiency bandwidth production (EBP), QMS, QTS, F, and Bl-coil offset. Each test data set from the measurements can be saved for future statistics and post-processing.

The system consists of a 19” P750 rack-mount cabinet with a 14-W power amplifier and generates sufficient power with the internal power amplifier to energize all defects from air-gap problems, puffing sounds, loose particles, a constrained voice coil, cabinet rattling, litz wire clatter, glue problems, and more—which generally speaking are known as Rub & Buzz distortion. 

On the front of the system is a Phantom-powered XLR input for a microphone and a Neutrik speakON plug for internal power amplifier output. The Phantom power is controlled by software. On the rear of the system is a jack output for external power amplifier and an input as an alternative for signal or impedance if the internal power amplifier is disabled. A 25-pole plug for digital I/Os on the transistor-transistor logic (TTL) level is used for external control (automated test lines) and as an USB connector.

The P750 needs a USB 2.0 high-speed or faster computer connection. The sample rates are 48, 96, and 192 kHz at 24 bits. The software is arranged in four modes—an operator mode, a technician mode, a global set-up mode, and a utility mode—all of which are password protected.

The operator mode is for day-to-day production testing of parameters, which are set up in the technician mode. This mode is designed for non-skilled personnel or for fully automated operations. In the technician mode, all parameters such as frequency range, test level, reference curves limits, Rub & Buzz, and THD filters are customized to the specific requirements for each individual test. In the global setup, the graphical presentation, test control, paths for files, chain of tests, and statistics are defined.

For post-processing and stored data manipulation, there are several utility functions (e.g., export and import of data, statistical analysis, and graphical display of batch data, etc). The statistical analysis includes the calculation of various numbers of standard deviation and average curves to determine the test limits. The analysis enables users to find a best-matched measured unit against the average or another unit.

With a computer and a test box/chamber and a measuring microphone, the P750 is a complete workstation for measuring and testing of loudspeaker units and systems. Prices start from 2800 EUR (approximate $3,900). 
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