What is comparative and superlative of the word tinny?

The word "tinny" is already in the superlative form. It describes something that is most like tin, meaning it has a thin, metallic, and often unpleasant sound.

There is no comparative or positive form of "tinny."

If you want to express a lesser degree of the quality described by "tinny", you could use terms like:

* Slightly metallic

* Somewhat hollow

* Thin-sounding

* Resonant (in a negative context)