He's basically a mix of the announcer  trumpet and himself. Tinky Winky is supposed to sound shy and scared, while the announcer  is supposed to sound happy and welcoming!

Tinky Winky's voice is not raspy like Laa-Laa, so don't worry about killin' your voice. 

!REMINDER THAT ATLEAST TWO PEOPLE ARE ABLE TO ADDITION FOR THIS, SINCE IT'S TWO CHARACTERS IN ONE (Announcer and Tinky Winky)!