"Try new trophy range" is a myth
"I have been getting lucky at Gold II yesterday"
"Seems pretty good at Crystal III today"
"Try climbing in trophies, you might find better loot at xxxx"
"Loads of inactive in Gold I at the moment, you should try it out"
These are some of the general feedback on the forums. Myths.
There is no "perfect" trophy range in terms of inactive bases hunting. You are best of fishing at a range, with people around your own town hall level. So if you are TH9, find an area where you won't bump into any TH7s or below (or at least very few). Obviously if you go relatively high, like Masters, the amount of inactive bases will decrease. But it's my experience, that there are just as many inactive bases in Crystal II, III as in Gold II and III.
The only factor that plays in, the amount of inactive bases "released" by Supercell. We know they're holding them back, placing them at the end of the queue, and released when the pool gets too dry. There are good days - bad days - lucky days - but no trophy range is generally better for picking of inactive bases in the typical farming zone (Gold-Crystal). People spend WAY too much time trying new ranges. As long as you haven't pushed too far beyond or dropped too low, it' doesn't matter at what range you're farming.