A NEW LYRIC INTELLIGIBILITY TEST FOR EVALUATING REAL ACOUSTIC LIMEN (LITERAL)

摘要

Most professionals working with live sound have experienced the paradox that, as the sound level is increased, clarity - particularly of information in lyrics and the sense of instrument articulation - is ultimately lost. This is as true in sound control mixing rooms where a confused mix is often the end result as it is for the performers and audience of live sound. A poor recorded and mastered sound may simply lead to low consumer uptake - after all they do not have to buy what does not sound good. It is different for live sound because there is no chance for a second take for the audience, each of whom may typically be paying many times the cost of a premium recorded medium. There are good physiological models as to why this should be the case and there is a number of common physical reasons why venues and the details of their sound system placement and alignment may fail to deliver. The understanding of these limitations seems either to be often outside the structured experience of many sound engineers or simply abandoned in the heat of the moment. However the authors conjecture that more of the principles for success can be taked into account by sound practitioners and architects alike and will lead to greater audience satisfaction and better, more profitable, relations with the performers, the audience and the operators of the venues. Nearly all work in assessing intelligibility has taken place either within a focus of speech transmission within challenging environments or to determine clinical aspects in audiology. Challenging environments in which the reliable transmission of speech information is a requirement have reverberation or environmental noise characteristics which, once a satisfactory compromise for system settings has been determined, are largely fixed. Characteristically effort is put into reducing the impact of the acoustic environment, in controlling the propagation of unwanted noise and in trying to optimise the sound system design within budget and architectural constraints. The difference with performance spaces is that each instance of a performance is accompanied by its own set of such characteristics. The fresh set of variables includes reverberation formed within the sound system and excited by loudspeaker placement and by the demands of performers. Articulation and intelligibility is required, but in a situation where the propagation of interfering noise - in the sense of a musical accompaniment - is intentional. The authors propose an approach to evaluating the impact of problems in performance spaces on achieving good quality sound. The hypothesis held by the authors is that a basic understanding of the hearing process and architectural acoustics can be used to guide the optimum sound system installation and operation. To assist this, the authors propose a lyric intelligibility test -^sLIT. The test recognises the work which has been carried out for speech transmission and, particularly, the modified rhyme test (MRT). If the conjecture of the authors is in the right direction, then further development of the approach may lead to a widespread use of the LIT in establishing sound systems and in training their operators and performing users. The results of early work will be reported on in a future paper.