K&K Development 


PC platform: Windows 10, Windows 7.

With its fast test time and high performance the P750 are very cost-effective in a fully automated environment. It performs measurement of 500 different frequency points and tests parameters as frequency response, sensitivity, polarity, slope, Rub & Buzz, THD, impedance, resonance, EBP, Qms, Qts, F (Fres/Q) and Bl-coil offset. Each test data from the measurements are saved for future statistics and post-processing. As new the P750 can test wireless speakers by using a sync burst pulse to compensate delays in signal chain.

P750  The P750 generates sufficient power with the internal power amplifier to energize all defects from air-gap problems, puffing sounds, loose particles, constrained voice coil, cabinet rattling, litze wire clatter, glue problems etc., which generally speaking are known as Rub & Buzz distortion.

The system consists of a 19" P750 cabinet with a 14 volt power amplifier. The power amplifier has a 50 VA core as standard or as option a 120 VA core.
On the front a phantom powered XLR input for microphone, the phantom power is controlled by software, and a speakon plug for internal power amplifier output. 
As an option a 2. input can be added with a Lemo connection used for B&K, Grass, ACO etc. microphones including microphone psu with 28V and 200V.
As an option a 2. or 3. BNC input can be added for CCP powered microphones. Constant current is 4 mA.
On rear a jack output for external power amplifier and a input for alternative input as for signal or impedance if interbnal power amplifier is disabled. A 25 plole plug for digital in & outputs on ttl level used for external control (automated test lines) and a USB connector.
The P750 need a least USB 2.0 high speed connection (480 Mhz). Sample rate 48 / 96 / 192 KHz and 24 bit.

The software is arranged in four modes, an operator mode, a technician mode, a global set-up mode, and a utility mode, which all are protected by passwords.

The operator mode is for day-to-day production testing of parameters aready set-up in the technician mode. This mode is specially designed for non skilled personnel or for fully automated operations.
In the technician mode all parameters as frequency range, test level, reference curves limits, Rub & Buzz and THD filters etc. are customized to the specific requirements for each individual test.
In the global set-up the graphical presentation, test control, paths for files, chain of tests, statistics etc. are defined in the global set-up the graphical presentation, test control, paths for files, chain of tests, statistics etc. are defined.
For post-processing and manipulation of stored data there are a number of Utility functions as Export and Import of data, Statistical analysis and graphical display of batch data etc. The statistical analysis including calculation of various numbers of standard deviation and average curves to determine the test limits. The analysis is able to find a best matched measured unit against the average or another unit.

P750 can do following test parameters: 

Frequency response against upper / lower limits Sensitivity against upper / lower limits with move option  Impedance against upper / lower limits 
Frequency response against 2. upper / 2. lower limits  Sensitivity test point 1  Resonance  
Frequency response against 3. upper / 3. lower limits  Sensitivity test point 2  Qms 
Average of Frequency  Sensitivity test point 3  Qts  
Average of Frequency in groups  Sensitivity test point 4  F (Fres./Q)  
Average1 of sensitivity point 1-5  Sensitivity test point 5  Voice Coil offset, BL
Average2 of sensitivity point 1-5  Rub & Buzz channel B against upper / lower limits  EBP  
Polarity  Rub & Buzz channel D against upper / lower limits  T/S parameters
Slope of frequency  THD  Cpk / Ppk 

Basic specifications:

Analyzing channels: 4 primary, 2 secondary Test points:      500
Sweep frequency: 10 Hz – 30 KHz Sweep time:    0.1 – 32 sec.
Filters: 3 Filter frequency range: 20 Hz – 45 KHz
Filter types: TRK-HP, FIX-HP Detector modes: Lin, Log & Spl
Input level: 3.16 mV – 20 V Input impedance XLR: > 8 Kohm
Output Jack: Typ. 1.0 V rms Input impedance JACK: > 20 Kohm
PA output type 1: 14 volt @ 8 ohm PA output type 2: 14 volt @ 8 ohm
PA output type 1: 12 volt @ 4 ohm PA output type 2: 13.5 volt @ 4 ohm
PA output type 1: 9.5 volt @ 2 ohm PA output type 2: 11.5 volt @ 2 ohm
Phantom on XLR: +48 Volt, by software I/O functions TTL level: 8 inputs, 8 outputs
Optional Input Lemo plug: +28 & +200 Volt for B&K,Grass, ACO etc. Optional  Input BNC: CCP Typical 4 mA