Sound output delay

[Thorpy]

I've noticed recently that when I start playing music (Spotify, iTunes etc.) or start watching a YouTube video the first 1-2 seconds of audio are cut then the audio comes on (perfectly in sync). But if i pause the music for a couple of second then resume playback the sound play immediately. Its really annoying when I'm watching online tutorials having to wait for the audio to come back.

My PC is connected to my display via my Onkyo TXNR-717 AV amp.

Any thoughts on where to begin?

TIA