Back to the OP.
The distinguishing factor with your example is the Audience expectation. What are they coming to do? Are they coming as educated computor based DJ's looking to their 'Hero' for inspiration, or a crowd that is gonna be half cut and ready for a good time? Is the music in the first instance simply a vehicle for a 'good time' or is the performance and the artist actually
meant to be critiqued? This same situation exists for 'traditional' musicians as well. Knowing who the
majority of your audience is and their
intention can change the way you approach your 'performance.' The reality is that there is always someone out there ready to pass judgement on your performance irrespective of the success of your show. For Angstrom, the customer is always right, despite what the compitition has to say.
Now for the compitition. It seems that it's not Joe average who gets on a forum straight after a night clubing and points fingers at DJwotnot and rips to shreds his show. Its people in the know! People who aspire to be 'The Man'. In the OP's scinareo, your the minority. Most people in the audience fundamentally don't give a rats ass.
Now to the slightly off topic comments in this thread. Some have talked about the uneasyness they feel finding a point somewhere along the spectrum of totally canned to totally improvised. These are fantastic feelings that show people are examining who they are and what they do and how they want to be seen by the public and their peers. Each to their own in the end. It's good to look at others and measure yourself as an artist. But the only valid purpose should be to improve your own game, not simply to shit on someone.
As a side note, consider that most audiences are programed NOT to see a computor as an instrument in the traditional sense. When you are hunched over a guitar, even if all you are playing is the 4 chords mentioned in an earlier post, the general population
understands what you are doing. When you are hunched over a computor... well... guess what, you look like you are sending an email. Its not uniformly understood that there is a very highly skilled and highly practised person behind the screen or assorted boxes, who has to engage in a certain type of synchronistic thinking along with sensing 'vibe'. You DJ types have an up hill battle. I raise my hat to you.
A lot of your skill base actually can go unseen to the average person. Shame. This to me is the issue that strikes at the core of the topic of 'What is a valid performance or performer?'. PERCEPTION. The fine and very personal line between who you are and what you portray.
Now, back to practising the tambourine...

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