Tonality perception of stationary and transient signals
Invited paper
Carl v. Ossietzky University Oldenburg
Wednesday 3 june, 2015, 09:00 - 09:20
0.6 Madrid (49)
Abstract:
For environmental noise, especially for machine noise, annoyance tends to increase with increasing tonality. Tonality also represents an important feature in the overall sound character sensation. A psychoacoustical experiment was set up for determining the degree of perceived tonality for various masker types. For this purpose points of equal tonality were measured with an adaptive procedure adapting the level of a pink noise masking a fixed tonal signal. The results for pure tones with several SNRs in different masker situations showed that the perceived tonality does not depend on individual detection thresholds for normal-hearing listeners. Instead it was found that, in line with DIN45681 (2005), the tonality strongly depends on the SNR within a critical band around the tonal component but tonality might also be dependent of the intensity of the Tone. The performance of the DIN45681 decreases for tonal components rapidly varying in frequency. As a result tonality analysis of many may become problematic when very fast frequency changes of tonal components occur, such as for example for combustion engines equipped with turbochargers. As a first approach to investigating the tonal perception of time-variant sounds, detection thresholds of sinusoidal logarithmic sweeps masked with pink noise were determined in dependence of sweep duration and frequency range. Results show that listeners can detect sinusoidal sweeps, but that thresholds increase significantly with increasing sweep rate. To conclude a new algorithm for tonality detection based on an auditory filter bank approach is introduced. This algorithm is capable of detecting fast frequency changes as they might occur in many natural sounds.