Evaluation of an Algorithm for the Automatic Detection of Salient Frequencies in Individual tracks of Multi-track Musical Recording

This paper evaluates the performance of a salient frequency detection algorithm. The algorithm calculates each FFT bin maximum as the maximum value of that bin across an audio region and identifies the FFT bin maximum peaks with the highest five deemed to be the most salient frequencies. To determine the algorithm’s efficacy test subjects were asked to identify the salient frequencies in eighteen audio tracks. These results were compared against the algorithm’s results. The algorithm was successful with electric guitars but struggled with other instruments and in detecting secondary salient frequencies. In a second experiment subjects equalised the same audio tracks using the detected peaks as fixed centre frequencies. Subjects were more satisfied than expected when using these frequencie

An investigation into the efficacy of methods commonly employed by mix engineers to reduce frequency masking in the mixing of multitrack musical recordings

Studio engineers use a variety of techniques to reduce frequency masking between instruments when mixing multi-track musical recordings. This study evaluates the efficacy of three techniques, namely mirrored equalization, frequency spectrum sharing and stereo panning, against their variations to confirm the veracity of accepted practice. Mirrored equalisation involves boosting one instrument and cutting the other at the same frequency. Frequency spectrum sharing involves low pass filtering one instrument and high pass filtering the other. Panning involves placing two competing instruments at different pan positions. Test subjects used eight tools comprising a single unlabeled slider to reduce frequency masking in several two instrument scenarios. Satisfaction values were recorded. Results indicate subjects preferred using tools that panned both audio tracks

Audio interfaces should be designed based on data visualisation first principles

Audio mixing interfaces (AMIs) commonly conform to a small number of paradigms. These paradigms have significant shortcomings. Data visualisation first principles should be employed to consider alternatives. Existing AMI paradigms are discussed and concepts of image theory and elementary perceptual elements outlined. AMIs should be evaluated by usability experiments however performing these properly is time-consuming. There are many data visualisation options and combinations. Collaboration with others would enable a greater range to be explored. Better understanding data visualisation will benefit audio and music interface development in general

Novel Designs for the Audio Mixing Interface Based on Data Visualisation First Principles

Given the shortcomings of current audio mixing interfaces (AMIs) this study focuses on the development of alternative AMIs based on data visualisation first principles. The elementary perceptual tasks defined by Cleveland informed the design process. Two design ideas were considered for pan: using the elementary perceptual tasks ‘scale’ to display pan on either a single or multiple horizontal lines. Four design ideas were considered for level: using ‘length’, ‘area’, ‘saturation’ or ‘scalable icon’ for visualisation. Each level idea was prototyped with each pan idea, totalling eight novel interfaces. Seven subjects undertook a usability evaluation, replicating a 16 channel reference mix with each interface. Results showed that ‘scalable icons’, especially on multiple horizontal lines appear to show potential

Formal usability evaluation of audio track widget graphical representation for two-dimensional stage audio mixing interface

The two-dimensional stage paradigm (2DSP) has been suggested as an alternative audio mixing interface (AMI). This study seeks to refine the 2DSP by formally evaluating graphical track visualisation styles. Track visualisations considered were text only, circles containing text, individually coloured circles containing text, circles colour coded by instrument type with text, icons with text superimposed, circles with RMS related dynamic opacity and a traditional AMI. The usability evaluation focused on track selection efficiency and included user visualisation preference for this micro-task. Test subjects were instructed to click five randomly selected tracks for a six, sixteen and thirty-two track mix for each visualisation. The results indicate text only visualisation is best for efficiency however test subjects preferred icons and traditional AMI

Hybrid Multiresolution Analysis Of ‘Punch’ In Musical Signals

This paper presents a hybrid multi-resolution technique for the extraction and measurement of attributes contained within a musical signal. Decomposing music into simpler percussive, harmonic and noise components is useful when detailed extraction of signal attributes is required. The key parameter of interest in this paper is that of punch. A methodology is explored that decomposes the musical signal using a critically sampled constant-Q filterbank of quadrature mirror filters (QMF) before adaptive windowed short term Fourier transforms (STFT). The proposed hybrid method offers accuracy in both the time and frequency domains. Following the decomposition transform process, attributes are analyzed. It is shown that analysis of these components may yield parameters that would be of use in both mixing/mastering and also audio transcription and retrieval

LAMI: A gesturally controlled three-dimensional stage Leap (Motion-based) Audio Mixing Interface

Interface designers are increasingly exploring alternative approaches to user input/control. LAMI is a Leap (Motion-based) AMI which takes user’s hand gestures and maps these to a three-dimensional stage displayed on a computer monitor. Audio channels are visualised as spheres whose Y coordinate is spectral centroid and X and Z coordinates are controlled by hand position and represent pan and level respectively. Auxiliary send levels are controlled via wrist rotation and vertical hand position and visually represented as dial-like arcs. Channel EQ curve is controlled by manipulating a lathed column visualisation. Design of LAMI followed an iterative design cycle with candidate interfaces rapidly prototyped, evaluated and refined. LAMI was evaluated against Logic Pro X in a defined audio mixing task

Evaluation of a Perceptually-Based Model of "Punch" with Music Material

This paper evaluates a perceptually motivated objective model for the measurement of “punch” in musical signals. Punch is a perceptual attribute that is often used to characterize music that conveys a sense of dynamic power or weight. A methodology is employed that combines signal separation, onset detection, and low level parameter measurement to produce a perceptually weighted “punch” score. The model is evaluated against subjective scores derived through a forced pairwise comparison listening test using a wide variety of musical stimuli. The model output indicates a high degree of correlation with the subjective scores. Correlation results are also compared to other objective models such as Crest Factor, Inter-Band-Ratio (IBR), Peak-to-Loudness Ratio (PLR), and Loudness Dynamic Range (LDR)

An Investigation into the Sonic Signature of Three Classic Dynamic Range Compressors

Dynamic range compression (DRC) is a much-used process in music production. Traditionally the process was implemented in order to control the dynamic range of program material to minimize the potential of overloading recording devices. However, over time DRC became a process that was applied more as a creative effect and less as a preventative measure. In a professional recording environment it is not uncommon for engineers to have access to several different types of DRC unit, each with their own purportedly unique sonic signature. This paper investigates the differences between three popular vintage dynamic range compressors by conducting a number of measurements on the devices. The compressors were tested using: THD measurements, tone bursts, and objective analysis of music-based material using spectrum analysis and audio feature extracti

Intelligent Equalisation Principles and Techniques for Minimising Masking when Mixing the Extreme Modern Metal Genre.

The intensity, complexity and energy of performance, combined with the power and density of the tones involved are characteristics of the extreme metal genre. These characteristics present numerous problems when striving to achieve the clarity, definition and hyper-realism of performance required for this genres production. Avoiding masking in a mix is a fundamental aspect of clarity, definition, intelligibility and perceived loudness and due to the fact that masking especially occurs in a dense mix, and is more pronounced in low frequencies, is particularly applicable to mixing the downtuned extreme metal genre. Masking in simple terms is the ability of frequencies of one sound to obscure or inhibit (i.e. mask) the frequencies of another sound. This paper will draw upon the first author’s eight years of experience producing within the metal genre, including releases through Sony and Universal and working with the likes of Colin Richardson and Andy Sneap