NodeMCU PlayMP3FromSPIFFS pin for output

[k-str50]

I've been looking for a solution for a few days. The goal is that I insert an mp3 file into the SPIFFS and then output it to a loudspeaker.
I can compile the PlayMP3FromSPIFFS sketch and upload it to the NODEMPU, but I don't know which IO pin to connect the speaker to.
I think that the RX pin is used as an output and the GND is connected to a ground on the NodeMCU. I connected the speaker (0.5w, 8Ω) directly. See picture below.
But there's no sound coming out.
Can someone help me?
Thanks very much!

[k-str50]

I am afraid that there are no answers to be expected. That is why I am closing this discussion.