Vpliv hrupa ozadja na govorno razumljivost v visokošolskih predavalnicah : magistrsko delo št.: 57/II.ST

Pirnat, Denis (author), Dovjak, Mateja (mentor), Prislan, Rok (comentor)

V okviru magistrske naloge smo izvedli študijo vpliva hrupa na govorno razumljivost v visokošolskih predavalnicah. Govorno razumljivost smo določili s pomočjo indeksa prenosa govora STI (orig. Speech Transmission Index) in ankete, kjer so anketiranci (N = 80) na podlagi zvočnih posnetkov ocenili govorno razumljivost ter zapisali slišan govor. Delo je potekalo tako, da smo v izbrani predavalnici visokošolske ustanove pri različnih robnih pogojih določili vrednosti STI ter pri istih robnih pogojih posneli zvočne posnetke umetnega govorca (v studiu predhodno posnete brane števke). Dodatno smo v izbrani predavalnici izmerili tudi odmevni čas RT60. Različne robne pogoje smo dosegli s spreminjanjem pozicije mikrofona (postavitev na sredini prve oziroma zadnje vrste) ter z uvedbo vira dodatnega hrupa (po spektralni sestavi je ta ustrezal hrupu prezračevalne naprave, za proizvajanje pa smo uporabili neusmerjen zvočni vir), ki smo mu spreminjali raven hrupa in pozicijo v prostoru. Na ta način smo dosegli 26 različnih robnih pogojev. Poleg posameznih rezultatov STI in anket nas je zanimala tudi primerjava obojega, iz katere lahko ugotovimo, kako STI odraža dejansko govorno razumljivost v prostoru. Ugotovili smo, da na oba pokazatelja razumljivosti (tako na STI kot na subjektivno oceno) najbolj vpliva raven dodatnega hrupa; saj so se vrednosti obeh nižale z višanjem ravni dodatnega hrupa. Prav tako na oba pokazatelja vpliva tudi pozicija mikrofona, kjer se je, izkazalo, da je za govorno razumljivost v izbranem prostoru celo nekoliko boljša pozicija v zadnji vrsti. Primerjava pokazateljev razumljivosti glede na različne pozicije vira dodatnega hrupa je pokazala, da ta na parameter STI nima vpliva, nasprotno pa vpliva na subjektivno oceno razumljivosti, kjer se kot najslabša izkaže pozicija vira hrupa v zadnjem delu prostora (za poslušalcem). Izkazalo se je, da je pri nizkih ravneh hrupa (vključno z najvišjo zakonsko dovoljeno ravnjo) najbolj ugodno, če je vir hrupa čimbolj odmaknjen od govorca, pir visokih ravneh hrupa pa je bolje, če je vir čimbolj odmaknjen od poslušalca.

• Language: Slovenian
• Keywords: gradbeništvo, magistrska dela, govorna razumljivost, STI, hrup, akustika
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [D. Pirnat]
• Year: 2022
• Number of pages: XVI, 72 str., [5] str. pril.
• PID: 20.500.12556/RUL-141490-d4e59e16-6bd5-13ca-75fb-46fc10eca889
• UDC: 534.84:727(497.4)(043.3)
• COBISS.SI-ID: 132271363
• Publication date in RUL: 30.09.2022

Secondary language

• Language: English
• Title: The effect of background noise on speech intelligibility in higher education lecture rooms : master thesis no.: 57/II. ST

Abstract

As part of the master’s thesis, we conducted a study of the impact of noise on speech intelligibillity in higher education lecture rooms. Speech intelligibillity was determined using the speech transmission index (STI) and surveys where respondents (N=80) assessed speech intelligibillity based on audio recordings and recorded audible speech. The work was carried out by setting the values of the STI in the selected lecture room of the higher education institution under different boundary conditions and recording audio recordings of an artificial speaker (pre-recorded reading of digits in the studio) under the same boundary conditions. In addition, we also measured the RT60 reverberation time in the selected lecture room. Different boundary conditions were achieved by changing the position of the microphone (positioning in the middle of the first or last row) and by introducing a source of additional noise (according to the spectral composition, this corresponded to the noise of the ventilation device, and to produce noise, we used an undirected sound source), to which we changed the level of noise and position in the room. This way, we obtained 26 different boundary conditions. Next to individual results of the STI and the surveys, we were also interested in comparing both, from which we can find out how the actual speech intelligibillity in the room is reflected with STI. We established that both indicators of intelligibillity (both the STI and the subjective assessment) are most affected by the level of additional noise; the values of both were lowered by increasing the level of additional noise. Both indicators are also affected by the position of the microphone, where it turned out that in order for the speech to be intelligible in a given room, the position in the last row is slightly better. A comparison of the indicators of intelligibillity with regard to different positions of the source of additional noise showed that this has no influence on the STI parameter, but on the contrary, it affects the subjective assessment of intelligibillity, whereby the position of the source of noise in the back of the room (behind the listener) is the worst. It turned out that for low levels of noise (including the maximum legally permissible level), it is the most favourable if the source of the noise is as far away from the speaker as possible, and it is preferable to keep the source of noise away from the listener for high levels of noise.

• Keywords: civil engineering, speech intelligibility, STI, noise, acoustics