yes, your first example looked as though each set had only one pair of brackets.
Then it is a different thing.
Try an action of the type "Replace with regular expression" for ALBUMARTIST
Search string: \(tracks.*?\)
Replace string:
(leave empty)
becomes
Double Bass – Lisle Ellis , Drums – Donald Robinson (2) , Electric Guitar – J.R. Routhier* , Engineer – Oliver DeCicco*
Example:
From:
Glenn Spearman - tenor saxophone, Marco Eneidi - alto saxophone, J.R. Routhier - electric guitar (1,3,5,6,8)
Lisle Ellis - double bass (1,2,3,6,7,8)
Raphe Malik - trumpet (1,3,6,8)
Donald Robinson - drums (1,2,3,5,6,7,8)
Paul Plimley - piano (2,7)
Shafqat Ali Khan - voice (4)
To:
Glenn Spearman - tenor saxophone, Marco Eneidi - alto saxophone, J.R. Routhier - electric guitar
Lisle Ellis - double bass
Raphe Malik - trumpet
Donald Robinson - drums
Paul Plimley - piano
Shafqat Ali Khan - voice