Here's the message.
1 seconds sound clip from Superman (1948) - Superman At Bay (Chapter 14).
You can hear this line at 00:11:13.123 in the Blu-ray version of the episode.
Quote context
[...]
- No, you stay here. White wants one of us to cover the jail.
- You get back here in a hurry, or you'll hear from me.
- All right, beat it. You've been paid off. Come on.
- Third tier. Cell on the southeast corner.
- Good. I'll contact the Spider Lady.
- Message received. Our two friends are together.
- Third tier. Cell on the southeast corner.
[...]