Fast as a flash
High-speed measurement at physical limits
- Stimulus adjusted to transducer dynamics
- Maximal excitation of Rub & Buzz and other speaker defects
- Sinusoidal sweep with speed profile
- High spectral resolution
- Alternating testing – one instrument works for two
Measurements at the physical limits require optimal test stimuli to excite the device under test (DUT) at the particular frequencies where defects produce reliable symptoms. Chirps with variable sweep speed profile are optimally adjusted to the transient behavior of the loudspeaker. Such a stimulus sounds like the crack of a whip starting slowly at low frequencies but having ten times higher sweep speed at high frequencies as shown in the waveform below. A 200 ms stimulus is sufficient for comprehensive measurement of a 5 inch woofer.
The figure above illustrates the measurement of loudspeakers using a sinusoidal sweep (chirp) with a speed profile which is optimal for loudspeaker measurements. 90 % of the available measurement time (180 ms) is used to measure the loudspeaker below 200 Hz, but only a very short measurement time (20 ms) is required to measure the loudspeaker at higher frequencies. The chirp with speed profile excites the loudspeaker at all frequencies and provides sufficient energy to activate Rub & Buzz defects.
A complete acoustical and electrical test can be accomplished in far less than 1 s. Ultra fast testing saves measurement time which can be used for repeating the test to gain ambient noise immunity.
The Motor + Suspension Check (MSC) measures the voice coil offset and other large signal parameters in less than 1 s compared to 5 min in the R&D System.
