Audi's recent announcement about its very comprehensive Sound Identity seems to have set a new standard for our industry. You can see a rather self-congratulatory 'making of' documentary here on YouTube, and several of my friends in the industry have blogged about it (for example Ruth Simmons and Karhelinz Illner. What captures my attention is the commitment of the client. Sound is being treated as an essential component of the Audi brand, not the icing on the cake, and resources been made available to work that through into consistent and on-brand audio in all Audi's marketing communication. This is a huge step forward, and creates a benchmark for all major brands to aim at.
But is it enoufh? I'm not on the inside of this project, but so far I have seen Audi covering five of the eight expressions of a brand in sound we differentiate at The Sound Agency - as shown in the BrandSound™ graphic. 
Audi have defined Brand Music (including the approach of creating a library for all future uses, which is excellent); Sonic Logo (the heartbeat); Advertising Sound (now consistent and derived from brand values); Product Sound (pretty well-defined in general in the car industry); and Brand Voice (including recorded on-brand and standardised voicemail announcements). This is a far more comprehensive approach than many, which is why there is so much excitement about this case study in the industry.
But I wonder if they are also tackling Branded Audio (podcasts, apps and other high-value sound given or sold to customers or other stakeholders); Telephone Sound (have they looked at their IVR system's structure and live voice interactions on the phone?); and most of all Soundscapes (are they redesigning the aural experience of being in their showrooms? For example I know that the huge flagship Audi showroom in West London is very challenged in that way, with plenty of unpleasant noise and challenging acoustics). The research is clear and comprehensive on the importance of retail soundscapes in terms of their effect on sales - but in my experience most car showrooms have predominantly hard surfaces causing unsuitably long reverberation times, and the sound sources tend to be uncontrolled - for example SkyTVNews on plasma screens or commercial radio playing on ceiling loudspeakers, or even both at the same time. That kind of set up pipes in negative messages (such as bad news) and inappropriate sound (such as fast-paced music) and even allows competing brands to advertise into your own branded space, which is obviously undesirable. The far better alternative is branded, generative soundscapes designed to create an appropriate ambience and to enhance the desired state in visitors, which for showrooms is relaxed, unhurried and alert.
A truly comprehensive approach to BrandSound™ will cover all auditory interactions. Audi's commitment is a welcome inspiration to its peers, but it seems there is still potential for them to explore.