Help, does anyone know what bird is it according to its graceful calls?

Hi this seems a common bird near my suburb: Carlingford, Sydney.

Never saw them, but heard their calls all the time,

It's quite special and the pattern is like always, three calls in a row: low-high-low.

Here is my sound recording: Sorry not very clear, 

2nd file is the same one, but filterred 1k-2k sound.

raw:

https://drive.google.com/file/d/1p9hQSQYxKzefL0TGUjbPTLup9qr8rD7B/view?usp=sharing

filterred 1k-2k freq:

https://drive.google.com/file/d/1NNqqCAGmwUABVRl-jG319wmfI9bs82WL/view?usp=sharing

I went thru dozens of videos on Youtube, no find this calls.

Anyone can identify the name of the bird, that would be a great help! Thanks!