SIG_BAUMGARTNER2017looming
flattens magnitude spectra of HRTFs

Usage:

Obj = sig_baumgartner2017looming(Obj,C,flow,fhigh)
stim = sig_baumgartner2017looming(exp)

Input parameters:

`Obj`	reference SOFA object
`C`	spectral contrast. 1 refers to reference (default), 0 to flat, -1 to flipped spectral magnitude
`flow`	lower cut-off frequency in Hz. Default is 1 kHz.
`fhigh`	higher cut-off frequency in Hz. Default is 18 kHz.
`Nfft`	FFT length. Default is 1024.
`Ntrans`	number of frequency bins used to softly transition the magnitude spectrum. Default is 10.
`delay`	additional delay in ms to allow temporal dispersion in obtained impulse responses. Default is 0.

Output parameters:

`Obj`	modified SOFA object
`stim`	stimulus structure containing - subject ID (`ID`) - sampling rate (`fs`) - impulse responses (`IR` referring to contrasts `C_IR`) - selected azimuths (`azi`), and - stimuli of the selected experiment (`cont` for Exp. I; `cont` and `discont` for Exp. II; both referring to contrasts specified in `C_pair`).

Description:

The exp flag may be used to get stimuli and impulse responses: 'exp1 Stimuli from Exp. I. 'exp2 Stimuli from Exp. II.''

Optional flags: 'soft soft magnitude transition option for use with broadband stimuli'

sig_baumgartner2017looming either generates spectrally flattened HRTF representations as used by Baumgartner et al. (2017) in order to induce various degrees of sound externalization, or generates the signals presented to the listeners in one of the two experiments from Baumgartner et al. (2017) as specified by the exp flag.

References:

R. Baumgartner, D. K. Reed, B. Tóth, V. Best, P. Majdak, H. S. Colburn, and B. Shinn-Cunningham. Asymmetries in behavioral and neural responses to spectral cues demonstrate the generality of auditory looming bias. Proceedings of the National Academy of Sciences, 2017. [ DOI ]