Could be another clue for us, all right. Let's go inside.
3 seconds sound clip from Scooby-Doo, Where Are You! - The Backstage Rag (S1E9).
You can hear this line at 00:06:28.744 in the Blu-ray version of the episode.
Quote context
[...]
- The thing to do is to get into the Strand Theater and look around, but how?
- How about getting an audition for a trained dog act?
- Don't look now, fans, but I think a star is about to be born.
- A watchman or a doorman, most likely.
- Look. He's working a puppet.
- Could be another clue for us, all right. Let's go inside.
- Hello.
- Well, hello. What can I do for you?
- We would like to inquire about arranging an audition for our trained dog.
- He's a great talent. Do a bit, Scooby.
- Well, that was pretty good. What do you say, Johnny?
- No. Sorry, chum, but you can't work this show unless you're a puppet.
[...]