Dichotic, diotic, and monaural summation of loudness: A comprehensive analysis of composition and psychophysical functions

Abstract

In a series of six experiments, the method of magnitude estimation, constrained by a multivariate model, was used to assess the rules that govern the summation of the loudness of two-tone complexes. This methodology enabled us to specify the amounts of summation and simultaneously to construct the corresponding loudness scales.\The components had different frequency separations and in the different experiments were presented (1) dichotically, a different frequency to each ear; (2) diotically, to both ears; and (3) monaurally. Results replicated and in some condi· tions extended known features of multiple signal processing by the auditory system. Thus, qualitatively different rules of loudness integration appeared. For monaural and diotic modes of stimulation, overall loudness depended on total sound energy within the critical band, but on the simple sum of component loudnesses beyond the critical band. For dichotic presentations, a fully additive rule of loudness summation appeared, regardless of frequency spacing. For the latter (but not the former), loudness summation was perfect, with the underlying loudness scales closely approximating Stevens's sone scale.In the present set of experiments, we measured the loudness of two tones as a function of (1) their frequency separation (narrow spacing within a critical band vs. wide spacing across a critical band) and (2) their mode of presentation (dichotic, diotic, or monaural). Although the various conditions thus generated have all come under the name of auditory summation, there are substantial differences among them in both the nature of the subjective experience and the objective, measurable outcome. For one, they can be classified as analytic or synthetic, depending on whether or not the components of stimulus mixtures are perceptually separable. More importantly, the rules of integration may differ across conditions. Indeed, the major purpose of this study is to uncover systematically the rules that govern summation under specific conditions of stimulation. Both of the variables tested within the framework of the present investigation are shown to affect the way the auditory system deals with the effects of concurrent multiple stimulation.Preparation of this paper was supported by Nlli Grant NS21326 to Lawrence Marks. His support and suggestions are gratefully acknowledged, as is Robert Melara's useful criticism. We also thank Edward Carterette and two anonymous reviewers for helpful comments on an earlier version of this manuscript. Barbara Faulkner and Elise Low provided skillful assistance at various stages of the completion of the manuscript. Address correspondence to Daniel Algom, Department of Psychology, Bar nan University, Ramat Gan 52100, Israel.Many of the basic findings on loudness summation have been reported by earlier researchers (e.g., Algom & Marks, 1984;Irwin, 1965;Marks, 1978a Marks, , 1978b Marks, , 1979a Marks, , 1979bMarks, , 1980Porsolt & Irwin, 1967;Reynolds & Stevens, 1960;Scharf, 1969Scharf, , 1970Scharf, , 1978Scharf & Fishken, 19...

Development and Current Status of the “Cambridge” Loudness Models

“…Some early data suggested that the LDEL was approximately 10 dB (Hellman & Zwislocki, 1963); the monaural sound had to be 10-dB higher in level than the diotic sound for the loudness to be matched. Because a 10-dB change in level corresponds approximately to a twofold change in loudness, an LDEL of 10 dB is consistent with the idea that loudness (in sones) simply sums across ears (Algom, Ben-Aharon, & Cohen-Raz, 1989; Fletcher & Munson, 1933, 1937; Hellman & Zwislocki, 1963; Levelt, Riemersma, & Bunt, 1972; Marks, 1978). The 1997 model and the 2006 model were both based on the assumption that this was the case.…”

“…The 2007 model accurately predicts a wide variety of data on the binaural perception of loudness, including the data of Scharf (1969), Keen (1972), Algom, Ben-Aharon, et al. (1989), Zwicker and Zwicker (1991), Sivonen and Ellermeier (2006), and Glasberg and Moore (2010).…”

Measurement and modeling of binaural loudness summation for hearing-impaired listeners

“…Some early data suggested that the LDEL was $10 dB (Hellman and Zwislocki, 1963). Since a 10-dB change in level corresponds approximately to a twofold change in loudness (Stevens, 1957;Hellman, 1976), an LDEL of 10 dB is consistent with the idea that the loudness evoked by presenting a sound to both ears is the sum of the loudness (in sones) evoked by the sound at each ear separately Munson, 1933, 1937;Hellman and Zwislocki, 1963;Levelt et al, 1972;Marks, 1978;Algom et al, 1989).…”

Binaural perception of the modulation depth of AM signals

“…Some authors have shown that the amount of binaural summation of loudness depends on the mode of presentation (diotic or dichotic), interaural level differences, spectral and temporal distribution, etc. (Algom et al, 1989;Zwicker and Zwicker, 1991). These data show that the mechanism of the binaural loudness summation is still uncertain and its explanation needs further study.…”