To create a whistle sound effect that is eerie and echoing using the Whistle Sound Effect Generator, adjust the following settings:

1. Sound Type: Choose a high-pitched whistle for an eerie quality.
2. Pitch: Set to a higher frequency (around 1000-1200 Hz).
3. Duration: Select a longer duration (around 3-5 seconds) to enhance the eerie feel.
4. Volume: Moderate volume to maintain a haunting effect.
5. Echo Effect: Apply a delay with a moderate feedback level to create an echoing effect.

This configuration will yield a whistle sound that is both eerie and echoing.