Sensory evaluation study update

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:

Attribute	Short Definition
Overall Audio Quality	Perceived 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.
Clarity	Clarity refers to how well you can hear and distinguish between the different instruments and elements within the music.
Harshness	Harshness 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.
Distortion	Distortion 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.
Spaciousness	Spaciousness 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 Strength	Treble 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 Strength	Middle 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 Strength	Bass 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 Balance	Frequency 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!