Q: MacBookPro / TV no sound

Hello,

I would like to launch a diaporama of pictures with sound on my HDMI TV.

I bought an HDMI adaptator and I have the pictures but no sound.

I have a macbookpro bought in 1999 / os Yosemite 10.10.5

Is there a way to have the sound sent to the TV ? Actually sound gets out of my computer.

excuse my english...

kind regards Albine