According to the signal theory vocal speech presents a non-stationary random process due to time variation of its main characteristics. A special emotional impact is gained during ensemble and choir performances. The article provides the correlation analysis results and the autocorrelation function of ensemble singing calculated, taking into account the non-stationary nature of acoustic signals. The studies have shown that there is a certain visual resemblance between correlation portraits of a non-professional student ensemble and a non-professional solo singer. At the same time the correlation portrait of student and professional co-performance tends to a professional singer correlation portrait. This helps to make a quantitative assessment of an ensemble’s professionalism which, alongside with a vocal teacher’s subjective assessment, can provide an objective view on singers’ voices condition to optimize the academic voice training process in an ensemble, which is important when using this voice assessing method in music schools, colleges and universities.

Keywords: Vocal speech, acoustic signal, ensemble singing, choir performance, non-stationary random process, autocorrelation function, quantitative assessment

Vocal speech is a random process. Taking into account the fact that the main characteristics of a singing voice vary with time, in the article vocal speech is studied as an acoustic nonstationary random process. To describe this process we should calculate one of its informative parameters – the autocorrelation function. The findings show that there are some differences between the autocorrelation functions for professional and nonprofessional singers. This helps to make a quantitative assessment of a singer’s professionalism which, alongside with a vocal teacher’s subjective assessment, can present an objective view on a singer’s voice and provide a good basis for optimization of academic voice training. Moreover a teacher does not have to be technically educated because this quantitative assessment is presented in diagrams which are quite easy to assess visually. It is especially important to consider when we use the given voice assessing method in music schools, colleges and universities.

Keywords: Vocal speech, acoustic signal, nonstationary random process, autocorrelation function, the maximum autocorrelation interval, quantitative assessment

Strengthening of processes of eutrophication and toxification reservoirs examined in the aspect of emergency. Shows the negative effects of "bloom" of blue-green mikrvodorosley and proposed approaches to localization and liquidation of emergency situations caused by their massive development.

Keywords: emergencies, water, cyanobacteria, "bloom" of blue-green algae, toxification, eutrophication