PROCEEDINGS of the
23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Parametric measurement of the effects of relative loudness on therelative weights
Alexander Fischenich1; Jan Hots2, Jesko Verhey2; Daniel Oberfeld1
1

Johannes Gutenberg-Universität Mainz, Germany
2

Otto von Guericke Universität Magdeburg, Germany

Keywords: Sound, Loudness, Temporal weights

ABSTRACTAs many experiments have shown (Namba, Kuwano, & Kato, 1976; Oberfeld, Heeren, Rennies, &Verhey, 2012; Oberfeld, Jung, Verhey, & Hots, 2018; Pedersen & Ellermeier, 2008), the beginning of asound is of greater importance for the judgement of loudness than later temporal parts. This pattern
known as the primacy effect is largely independent of the sound duration (Oberfeld, Hots, & Verhey,2018). Furthermore, it occurs both when the sound is presented in quiet and in the presence ofcontinuous background noise and is not altered by the average sound pressure level of the temporalsegments (Fischenich, Hots, Verhey, & Oberfeld, submitted). The primacy effect is well described by
an exponential decay function with a time-constant of about 200-300 ms (Oberfeld, Hots, et al., 2018;
Oberfeld, Jung, et al., 2018), where the temporal weight at the beginning of the sound is 4-5 times
higher than the asymptotic weight, and where the weight assigned to a temporal portion of a sound is
the integral of this function over the segment duration (Oberfeld, Jung, et al., 2018).
Another effect altering perceptual weights in loudness judgements is loudness dominance, which
describes the phenomenon that temporal components of a sound that are systematically louder relative
to other components within the stimulus receive increased weight and thus tend to dominate the global
loudness judgement of a sound (Berg, 1990; Lutfi & Jesteadt, 2006; Oberfeld, 2015; Oberfeld, Kuta, &Jesteadt, 2013; Oberfeld & Plank, 2011; Ponsot, Susini, Saint Pierre, & Meunier, 2013; Richards, Shen,& Chubb, 2013; Turner & Berg, 2007). The aim of the present study was to gain insight into theparameters that modulate the size of the loudness dominance effect . How does loudness dominanceinteract with the temporal weighting? Do effects of forward or backward masking on intensity
resolution (Oberfeld, 2008; Zeng, Turner, & Relkin, 1991) play an important role for the occurrence ofloudness dominance? And is the effect of relative component level symmetric in the sense that
amplifying the level of a stimulus component by, e.g., 15 dB relative to the remaining temporal
stimulus components increases the weight on the amplified segment by a given factor, while anattenuation by 15 dB decreases the weight on the attenuated segment by a comparable factor?
In two experiments, we measured temporal weights in loudness judgments for level fluctuating
sounds. All sounds consisted of 100-ms Gaussian wideband-noise-segments (20-20,000 Hz). In
Experiment 1, the sounds contained of four such segments which were separated by 500-ms silent gaps,
which should reduce the effect of non-simultaneous masking between adjacent segments (Zeng &Turner, 1992). In Experiment 2, the sounds consisted of either four or ten contiguous segments. Level
fluctuations were created by assigning each segment a sound pressure level drawn independently andat random from a normal distribution on each trial. The task of the listeners was to judge wh ether thesound presented on a given trial was “louder” or “softer” compared to the sounds they had encounteredon previous trials. To investigate the effect of relative segment level within a sound (loudnessdominance), in some experimental conditions the mean of the level distribution of certain segments
was attenuated or amplified relative to the remaining segments. In Experiment 1 (four-segment soundswith silent gaps), either segment 1 or segment 3 received an amplification of 5 or 15 or an attenuationof 5 or 15 dB SPL. In Experiment 2 (sounds with 4 or 10 contiguous segments), either segment 1 orsegment 7 in case of the ten-segment sounds or segment 1 or segment 3 in case of the four-segment
sounds received an amplification or attenuation of 15 dB SPL. The variation of the position of the6665

amplified or attenuated segment was realized in order to investigate whether the effect of relative
component level varies as a function of the temporal position of the amplified/attenuated component
within the sound. Such an effect would occur if the temporal weighting (primacy effect) and loudness
dominance interacted.
The temporal weights assigned to each segment were estimated using multiple logistic regression,
separately for each listener and each experimental condition. The sound pressure levels of thesegments served as the predictors and the response of the participants was the criterion variable.
For the sounds with segments separated by 500-ms silent gaps in Experiment 1, no primacy effectwas observed. This can be attributed to a "reset" of the primacy effect during the silent gap (Fischenich,Hots, Verhey, & Oberfeld, 2019; Hots, Verhey, & Oberfeld, 2018). As expected, the weights assigned
to amplified segments were increased and the weights assigned to attenuated segments were decreased,compatible with loudness dominance. Thus, the loudness dominance effect does occur even whennon-simultaneous masking between adjacent components is reduced by 500-ms silent gaps. For thesounds with contiguous segments in Experiment 2, a primacy effect as well as effects of relativesegment level (in the same direction as in Experiment 1) were found. The effects of relative level werestronger for the contiguous segments of Experiment 2, compared to those found in Experiment 1.
Additionally, segments next to the amplified segments received slightly lower weights compared to thecontrol condition where all segments had the same average level. A potential explanation of thispattern is that backward and forward masking of intensity processing played a role in the conditions
with contiguous segments (Oberfeld et al., 2013). The effects of relative level on the weights of theamplified segment did not differ substantially between an amplification of the first and the third or thefirst and the seventh segment. This indicates that there is no substantial interaction between loudness
dominance and the primacy effect. However, attenuation of the first segment resulted in a greater
decrease of the weight assigned to the attenuated segment, compared to an attenuation of the third orseventh segment.
The effects of amplification and attenuation were rather symmetric for the middle segments in bothexperiments in the sense that amplification increased the weight on the amplified segment by a given
factor and attenuation by the same amount decreased the weight on the attenuated segment by acomparable factor. As mentioned above, attenuation of the first segment had a stronger effect on theweight than amplification by the same factor.
Taken together, the data show that the loudness dominance effect cannot be attributed to forward or
backward masking, that there is no substantial interaction between loudness dominance and thetemporal weighting, and that in many conditions the effect of relative component level isapproximately symmetric for amplification and attenuation by the same factor. Additional data areneeded to confirm these findings and to gain insight into the exceptions from these rules and themechanisms underlying the loudness dominance effect.

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