Samsung Mhl to HDMI no sound

I can't get my sound to come out of the tv only the phones speakers. I tried to make sure this was going to work by getting the Samsung SIII adapter. The picture works fine, but no sound. I've tried it on a LG and Sony Bravia. Also, I used the factory USB charger and cable. I also tried one of the apps but can't remember what it was.

Plug everything to the TV first. Then plug your phone up. This worked for me.
 
Re: Samsung Tab 3 (8") MHL to HDMI no sound

Hi all - having read this thread I looked through the options on my Galaxy Tab 3 (8") and found that I cound get sound via my HML lead by ticking the box in Settings>System>Accessories>Dock>Audio Output Mode "Use external speakers when device is docked". I haven't seen this specific tip before so I hope it helps.