Across:
   7. He played 15 across during better Rajasthan over (7)
   8. see 27 across
  10. Why ants not moving into poor neighbourhood (10)
  11. Type of 18 which could turn bad? (4)
  12. Make your part important! (3)
  13. Improvises around 12 with five sharps in parts of Doors (5)
  15. Instrument that's not your forte? (5)
  17,20,22,24. (in no particular order) "Consumption" right addendum title! (2 2 2 2)
  21. Belts single out, most popular (4-7)
  25. Ultimately, incorrect 12 tap, so errors! (5)
  26. Performs polka? Yes, regularly! (5)
  27,4dn,8ac. Check tone not varying about left and right in 21 11 30 15 9 (3 4 7)
  29. Masses of people getting right to the front for some electric 15 (6)
  31. Cover of lame Blur composition (8)
  33. Son duly beaten thoroughly (7)
  34. Don't indulge sailor Mark! (7)
Down:
   1. He handles the money, and his care is amazing (7)
   2. see 32
   3. Not right to wander, so don't! (4)
   4. see 27 across
   5. Call in for quiet call on ... spring onions? Spring onions! (9)
   6. Stop launch of ad campaign perhaps (7)
   9. Mostly question 31 arrangement with no hint of rain for substantial 16 (6 5)
  12. Commercial venue's backing track with 'MC' switch (5)
  14. Unusual tray, creative (4)
  16. Fat starts to ooze bubbles on 112.5 degrees (5)
  18. Dig corner allotment for logging (9)
  19. Friend in backstreet dropping ecky (4)
  23. 60% of 25 put down to speed on roads in heavy weather (7)
  24. In cenotaph, all iconography symbolic of male part (7)
  28. Make it hard to present Mr 7 across (5)
  30. So lonely, missing other half? (4)
  32,2. By appearing in strange garb and sort of 15, 28 7 played in 27 4 8 (4 5)
Solution:
=C=G=S===K=S=P=|
JARRETT=CONCERT|
=S=A=A=D=L=A=E=|
SHANTYTOWN=LIVE|
=I=D===U===L=E=|
KEY=JAMBS=PIANO|
MR=R=R=L=A=O=TB|
A=BESTSELLING=E|
RT=C=Y=A=L=S=PS|
TYPOS=PLAYS=THE|
=P=R===B===K=A=|
RHODES=UMBRELLA|
=O=I=O=M=A=I=L=|
SOUNDLY=ABSTAIN|
=N=G=O===Y=H=C=|
Name: Puzzle 834 - Belted Single
Author: by BenDR