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· 3 min read
Alinka Greasley
Scott Bannister
Bruno Fazenda
Michael Akeroyd
William Whitmer

We are now reaching the end of our sensory evaluation study, where a panel of twelve listeners who use hearing aids have worked across online music listening tasks and three focus groups, to reach a consensus on the important perceptual attributes of music audio quality.

Starting from 373 unique terms used by participants to describe music audio quality, a discussion process was completed as outlined in the image below:

Figure 1, Objectives of each Focus Group session.
At this stage in the work, we wanted to share the current state of these perceptual attributes and short definitions:
AttributeShort Definition
Overall Audio QualityPerceived audio quality results from judgments of the sound of the music, in relation to a person’s expectations of how the music should ideally sound to them.
ClarityClarity refers to how well you can hear and distinguish between the different instruments and elements within the music.
HarshnessHarshness refers to an uncomfortable overemphasis of certain parts of the sound. It is most often heard in the treble resulting in a piercing, screechy or sharp sounds.
DistortionDistortion can be caused by artefacts that shouldn’t be present e.g., noise, hiss, pops or crackles. It can also be caused by the pitches sounding wrong. Music with No distortion sounds like an authentic version of what was performed.
SpaciousnessSpaciousness refers to how much you feel the music is ‘coloured’ by the performance space, and how much you can hear the reverberations and sense of space.
Treble StrengthTreble strength refers to the perceived strength or prominence of sound qualities that are characterised by higher frequencies in the treble range, or similarly, sounds, instruments or voices with higher pitches.
Middle StrengthMiddle strength refers to the perceived strength or prominence of sound qualities that are characterised by middle frequencies found between bass and treble ranges, or similarly, sounds, instruments, or voices that pitches perceived as being between lower and higher pitches.
Bass StrengthBass strength refers to the perceived strength or prominence of sound qualities that are characterised by lower frequencies in the bass range, or similarly, sounds, instruments or voices with lower pitches.
Frequency BalanceFrequency balance refers to the perceived balance between treble (or higher pitch) and bass (or lower pitch) sounds.

Our next steps in the perceptual research will involve further data collection and testing of these attributes, to understand which are the strongest predictors of overall audio quality. This is an important process as enhanced music signals submitted by challenge entrants will be scored on these attributes by a listening panel, and so the necessity of these attributes requires some initial testing.

As always, we would like to express our sincere gratitude and thanks to our sensory panel group for their incredible commitment, motivation, and contribution to this research!

· 2 min read
Alinka Greasley
Scott Bannister
Bruno Fazenda
Michael Akeroyd
William Whitmer

Here at Cadenza our sensory evaluation work to define audio quality for hearing impaired listeners is underway. We want to understand better how hearing-impaired listeners perceive audio quality in music and develop quality metrics that will subsequently be used by our listener panel to rate the systems submitted by challenge entrants. Through careful listening tasks and group discussion, the sensory panel will arrive at a consensus about important sound quality attributes and how these should be measured. You can find out more about this process on the Sensory Evaluation page.

The first task was an individual elicitation task in which we asked twelve listeners with hearing impairment to provide single-word perceptual terms to describe various music excerpts provided to them. This resulted in hundreds of unique attributes used to describe sound quality, of which 89 were used more than four times (see Fig. 1) and 87 were used two or three times (see Fig. 2). This provided the starting point for the first Focus group which sought to identify the most important attributes and to identify ways of grouping the attributes into perceptual dimensions that could be captured in the quality metric.

The outcome of Focus group one was a spatial mapping of the ways in which the panel grouped attributes together which was used as a starting point for Focus group two (see Fig. 3). The panel then discussed further the meaning and grouping of different terms to reach consensus about important dimensions. In February, we will carry out a third Focus group to arrive at final dimensions, how these can be defined, and how they can be rated or scored in the challenges.

We would like to thank our Sensory panel group for their ongoing motivation and commitment with this challenging task!

Figure 1, 89 terms that were used four or more times to describe the musical excerpts.
Figure 2, 87 terms that were used twice or three times to describe the musical excerpts.
Figure 3, starting point for focus group two, discussing the further meaning and grouping of different terms.

· One min read
Trevor Cox
Jon Barker

Welcome to the new Cadenza webpage. We will be using this page to post the latest news about our forthcoming machine learning challenges and workshops, as well as posts discussing the tools and techniques that we are using in our baseline systems.