With my current small collection of 'nice' notes, I can run through most of the hymn tunes and ballad type melodies I know by heart and be happy with the sound of most of them. There's a sort of envelope of speed, range, dynamic and endurance which if I stay within it, the sound is generally 'nice'; if I stray outside, some of the notes will be 'nasty'.
One of my standard practice pieces (Intermezzo from Cavalleria Rusticana) is within the envelope save for one run of four (slow) quavers (eighth notes) G - low A - F - low G. If I play it in minims (half notes), the notes are nice, but at speed, I've not yet gained the necessary flexibility to centre the low notes and they sound nasty. Should I:
1) Continue to practise the piece, tolerating the squirrels in the hope that eventually they'll straighten out.
2) Stop playing the piece and religiously practise slow minor seventh lip slurs until I develop the flexibility to control the low notes at faster speeds.
Is there a danger that in tolerating the squirrels, we actually reinforce them by repetition and embed them into muscle memory?
Should we ONLY play the notes we can play nicely and patiently wait for the envelope to expand in its own good time?