AES Berlin 2017
Paper Session P13
P13 - Audio Processing and Effects
Sunday, May 21, 15:00 — 18:00 (Salon 2+3 Rome)
Udo Zölzer (Chair)
P13-01 The Perceptual Effect of Vertical Interchannel Decorrelation on Vertical Image Spread at Different Azimuth Positions
Christopher Gribben (Presenting Author), Hyunkook Lee (Author)
Two subjective experiments have been conducted to investigate the effect of vertical interchannel decorrelation on the perception of vertical image spread (VIS). Pairs of vertically arranged loudspeakers, one at ear level and another elevated by 30°, were positioned at 0°, ±30°, and ±110° azimuth to the listener. The first experiment compared octave-band pink noise stimuli, consisting of two decorrelation methods with three levels of interchannel cross-correlation (ICC), a coherent sample and a monophonic sample. The effect of vertical ICC on VIS perception was found to be most effective for frequencies around 500 Hz and above, with little effect at lower frequencies. The second experiment judged the absolute lower and upper boundaries of perceived VIS, using stimuli from the first experiment, showing a potential association between VIS and vertical localization.
Convention Paper 9747
P13-02 Predictors for the Perception of “Wildness” and “Heaviness” in Distorted Guitar Timbre
Koji Tsumoto (Presenting Author), Toru Kamekawa (Author), Atsushi Marui (Author)
Predictors for the perception of wildness and heaviness in distorted guitar timbre were investigated. A pairwise comparison was conducted for the stimuli of five different amounts of distortion and three types of diodes. The result indicated that the perception of wildness and heaviness seemed to be compiled as one attribute associated with the “power” of the timbre. The ratings appeared to correspond to the threshold voltage of diodes and the amount of distortion. Also, the spectral kurtosis had a relatively high negative correlation with the ratings. The types of diodes, the amount of distortion, and the spectral kurtosis seemed to be appropriate predictors for the perception of wildness and heaviness.
Convention Paper 9748
P13-03 An Investigation into the Relationship between the Subjective Descriptor Aggressive and the Universal Audio of the 1176 FET Compressor
Austin Moore (Presenting Author), Jonathan Wakefield (Author)
In popular music productions, the lead vocal is often the main focus of the mix and engineers will work hard to impart creative coloration on this source. This paper conducts listening experiments to test if there is a correlation between perceived distortion and the descriptor “aggressive” which is often used to describe the sonic signature of the Universal Audio 1176. The results from this study show compression settings that impart audible distortion are perceived as aggressive by the listener and there is a strong correlation between the subjective scores for distortion and aggressive. It was also shown there is a strong correlation between compression settings rated to have high aggressive scores and the audio feature roughness.
Convention Paper 9749
P13-04 Investigations Towards Plausible Blind Upmixing of Applause Signals
Alexander Adami (Presenting Author), Lukas Brand (Author), Jürgen Herre (Author)
Blind upmix denotes the process of converting audio content into a higher number of output channels without the aid of any prior spatial information. This is often needed for upmixing legacy monophonic recordings into modern multichannel audio formats. Especially in live-recordings, applause plays a vital role. However, creating a convincing blind upmix of applause signals is a demanding task. Applause can be interpreted as a superposition of distinctive and individually perceivable foreground claps and a more noise-like background. While the background signal can be upmixed by applying decorrelation and distribution across channels, it is important that the foreground claps are spatially distributed in a perceptually meaningful and plausible manner. This paper investigates the effect of the spatial, temporal, and timbral structure of foreground claps on the perceived plausibility of applause signals. The assessment was done by means of two listening tests. Results show that especially for sparse applause, plausibility is significantly reduced if its natural timbral and temporal structure is corrupted.
Convention Paper 9750
P13-05 Joint Parameter Optimization of Differentiated Discretization Schemes for Audio Circuits
Francois Germain (Presenting Author), Kurt James Werner (Author)
We propose a new approach to discretizing audio circuits that involves applying differentiated discretization schemes among the elements of a linear circuit, or sub-circuit, rather than a single uniform scheme. The scheme coefficients are jointly optimized to minimize some frequency response error function for that linear circuit. We describe the mathematical framework for this optimization and apply it to the case of the parametric bilinear transform. Differentiated discretization coefficients are jointly optimized by minimizing the L2 -norm error between the discretized frequency response and the frequency response of the original system. To demonstrate the validity of our approach, we apply our method to several examples and show a systematic reduction of the frequency response error in each case.
Convention Paper 9751
P13-06 Virtual Analog Modeling of Dynamic Range Compression Systems
Felix Eichas (Presenting Author), Etienne Gerat (Author), Udo Zölzer (Author)
Dynamic range compression (DRC) systems reduce the dynamic range of an input signal by amplifying low amplitude levels and attenuating higher ones. This work describes a method to digitally model any analog dynamic range compression unit solely with the help of input/output measurements. For this purpose a generic dynamic range compression model is chosen and its structure is adapted to be able to recreate an analog reference device. The linear characteristic as well as the static curve of the reference device are extracted and directly used in the model. Afterwards the parameters of the digital model are adapted with an iterative optimization routine. Finally the output of the digital model and the analog reference system are compared to evaluate the quality of the emulation.
Convention Paper 9752