Abstract
The just-noticeable (sinusoidal) amplitude modulation (JNAM) and the just-noticeable (sinusoidal) frequency modulation (JNFM) were measured by four subjects at 250 Hz and 60 dB SPL using the method of adjustment. For JNFM, two types of stimuli—monaural and binaural with unmodulated tone at the right ear—were presented through a matched pair of TDH-39 earphones driven in phase. The rate of modulation was either 1, 2, 4, 8, 16, 32, or 64 Hz. The results are plotted as a function of modulation rate and are expressed in terms of a modulation index which is similarly related to the amplitude of the first spectral side tones for both types of modulation. A comparison of the data allows the following conclusions: JNAM, JNFM (mon), and JNFM (bin) diverge strongly at low modulation rates but are indistinguishable at 32 Hz, in agreement with earlier monaural AM/FM data describing the limit of validity of Ohm's acoustical law. In the binaural situation, sensitivity to FM (which produces interaural time-delay modulation) remains high, up to unexpectedly large modulation rates (32 Hz). Individual differences in just-noticeable interaural time delay produce BMLD's of different magnitude which, however, still exist at modulation rates as large as 16 Hz; BMLD's appear to show temporal characteristics similar to those of normal thresholds.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
