Technical Note: Effects of different fuels on annoyance from diesel enginesounds

Annoyance judgments of engine sounds under six different fuel conditions we re investigated using forty subjects. An equal number of males and females participated in the listening test. Thirty stereophonic recorded sounds wer e randomly presented to the subjects through a pair of loudspeakers. All so unds were recorded in a hemi-anechoic room. The listening test was conducte d using a sequential rating method known as the method of successive Interv als. Tests for effects of the different fuels were made on the basis of non -parametric statistics. Engine sounds for an ethanol fuel with 9% Beraid we re rated as least annoying whereas engine sounds for a mixture of diesel an d ethanol fuels were rated as most annoying, The differences In annoyance j udgments for different fuels at the same engine running speed could not be predicted using the annoyance index developed in an earlier study based on loudness, sharpness and harmonic ratio. (C) 2000 Institute of Noise Control Engineering.