Good match for Quad 405

If it is the original 405 than it will have difficulty driving speakers with anything less than 8 Ohms which you must keep in mind.

Audition any speakers with 8 Ohm impedence or higher(very few speakers have higher than 8 Ohms imp nowadays)

I was a Quad dealer in the days when it was current and found that it worked well with most of the classic British monitors, Spendor, Rogers, etc. An ideal speaker should be the Castle Conway, which the Audio Advisor has on special for 50% off. If this is in your price range I would consider them as they have received excellent reviews. Stan

Try Sequerra or Shahinians. Both make nice music.