Improvement Example 1: Advancing the Quality of the Sound Experience

Whilst company A moved into headphone design and manufacturing in 1958, it was 1968 before company A presented their first headphone design improvement, the open headphone design, to the market. This improvement played a major role in improving the personal sound experience of the user.

Company A wanted to improve the quality of the sound experienced by the user and focused their attention on the design of the earpiece as it directly channelled the sound into the user’s ear.

“It was 1968, so naturally I wasn’t involved in this development project. But it was the first innovative development milestone of the company. A legacy of the company’s

innovative headphone development ethos. It features as part of induction for every engineer involved in development projects. It is even displayed on walls around the site as a reminder of its contribution to the headphone division’s success”. LMC1

It was 1968 and headphone development was in its infancy. The company’s engineers felt that the sound output from the standard earpiece’s design of that time was “trapped in the user’s head”. It was believed that sound could be improved and made to feel more life-like, as if they were in the room type of experience; this was defined later as a “wider soundstage feel”.

“The open principle of the x headphone liberated the sound that was up to that point stuck inside the user’s head.” AEC1

The earpiece reflected the focus of this first improvement cycle within company A. The outcome of this improvement project became a universally accepted contribution to the standard design of a headphone, not just in Company A but across headphone manufacturing organisations.

An improvement team, comprised of mechanical and audio engineers, was formed and the earpiece identified as the focus of investigation. The internal configuration of sound reproduction parts were examined and deemed adequate at the point in time. Exploration moved to the earpiece’s form. The opportunity to improve the quality of the sound reproduced was deemed dependent on allowing controlled amounts of ambient sound (external noise) to enter the earpiece and interface with the sound reproduced within the earpiece to facilitate the wider soundstage feel.

The earpiece’s back had a hard enclosure. The hard enclosure prevented reproduced sound from escaping out the back of the earpiece. Making a change to the external enclosure of the earpiece, within which the sound reproduction parts were located, represented an opportunity to realise improvements in the personal sound experience. Referred to as the open principle, engineers realised that positioning openings at the back of the earpiece, allowing outside noise and the reproduced sound to meet, would achieve a wider soundstage feel.

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“The opening at the back of an earpiece lets some sound out, lessening the impact of music beamed into your head, leading to a personal sound experience that feels more like listening to music in a room. In other words, it sounds more realistic.”

AEC1

Initially applied to a supra-aural earpiece form, as visualised in the left of figure 14, company A released a headphone offering with an open back to the earpieces.

Figure 14 Closed vs Open Earpiece form

These openings leaked more sound out of the headphone but also let more ambient sounds into the headphone, resulting in a more natural or speaker-like sound and a more spacious "soundstage" giving the perception of distance from the source. 100,000 sets of this open back headphone were sold by the end of 1969, deeming it a success. Additionally, company A patented their open principle technology, but licensed it to Sony for use in its first-generation Walkman headphones.

“We licensed the Open principle technology to Sony for use in its first-generation Walkman headphones.” PAC1

The open principle introduced a new feature for consideration during the development of future high-end headphone ear pieces. Whilst the change was made to the back of the earpiece’s external form, this change refined the quality of the sound experience delivered. The open back was added, as visualised in table 15, as an alternative earpiece attribute within the library stock for earpiece parts.

Open vs Closed Back Earpieces

Table 15 Inclusion of the New Open Back as a Detail in Library Stock of Subsystem Parts

However, the core competence of company A was driver technology. Refinements to the driver part reflected the more commonly adopted focus of headphone improvements in company A.

“Over the years, the focus of our development projects and established competence has evolved to driver technology” LMC1

In stark contrast to the simple example of the refinement to the external form of the earpiece, refinements focused on improving the driver’s conversion capability were more complicated. Improvement team members needed to consider the potential knock-on effect of changes applied to any internal part on the ability of related parts to maintain compatibility with the working principles of audio source devices and the physiology of the human ear.

Improvement example 2 reveals the complex management challenge of ensuring that refinements to the standard design of any part of the driver’s configurations did not compromise the ability of related internal and/or external parts of the headphone to deliver the personal sound experience.