Why are our loudspeakers and acoustic systems different in sound character from others? What is the reason and outcome of our design approach?
There are two fundamental principals we believe in:
- Musical and vocal signals have nothing in common with stationary sine wave signals
- Impulse signal (Dirac function) and a speaker's acoustic impulse response are the signals that should be used for measurements. The analysis of these signals paints a complete picture of subjective results of the listening and objectively measured electro-acoustic characteristics.
How did we arrive at this conclusion?
Because we are not attempting to build the theoretical model of a loudspeaker and create a new one to simplify the analysis. We are not trying to invent new interpretations of laws of physics through simplifying electro-mechanical models.
We are trying to understand the features of single impulse’s radiation into the compressible medium.
Traditional methods of electro-acoustic measurements, such as frequency response, phase response and total harmonic distortion, etc. are based on sweep tone and stationary noise and showed that they consider spectral balance only. But the other sound parameters, such as slew rate, attenuation time, power responce, non-liner displacements on real signal, still need further research.
For our own usage we created proprietary methods of electro-acoustic measurements and tests allowing us to effectively develop new product and solutions in short period of time in all applied areas:
- Measuring and analyzing of the electro-acoustic transducer’s impulse response in the surrounding field and defining its main parameters
- Measuring of the environment’s attached mass and evaluating its effect on a speaker's efficiency
- Measuring of non-linear displacements (total harmonic distortions) on real signals
- Measuring of the musical and vocal signal’s real crest-factor and comparing its acoustic image with its electric image with visualization and evaluation
- Measuring and visualization of musical signal parameters of reproduction in real time using different signal sources and different digital formats; also the later comparison of obtained results with the results of the subjective examinations
- Measuring and visualization of the positions of sound images in front of a pair of speakers; determination of displacements of the virtual sound images in depth and height, with measurements of correlation parameters between the channels
These methods and results of our research helped us to make the following conclusions:
- Thielle-Small Parameters have very limited applications in loudspeaker and acoustic system design for musical and vocal content reproduction
- Any acoustic enclosure, besides the unlimited baffle and a baffle of limited size, has a negative effect on correct low frequency envelope reproduction of the musical signal. It’s related to resonance fluctuations in a closed or ported box. The incorrect reproduction of the low frequency envelope brings an almost complete loss of area information, stability and localization of virtual sources
- With multiple driver systems, the diversity of electro-acoustic transducer centers in space and frequencies causes the complete destruction of the musical signal image integrity and the stability of virtual sources in the front, depth and height of the soundstage
- Any naturally sounding musical instrument has higher front impulse and exceeding capacities compared to any perfect sound recording or sound reproduction equipment by many times. The reason for this is excitation speed of the string, horn and drum instruments’ elements compared to the speed of electro-acoustic transducer's impact on its cone
- The weight of the driver’s moving system should be many times less than the weight of the joined co-fluctuating air. Only then the active radiation of the acoustic energy will grow dramatically.
These are just a few differences in our approach to research, development and design of electro-acoustic transducers and reproduction systems that allowed us to achieve spectacular results.