Onkyo HTX-22hdx sound problem

[Carper]

hi, i got the onkyo htx-22hdx the other day and seem to have a problem with the sound. I have connected the speakers via hdmi and in the tv's arc slot. I can get sound from the speakers but i have a problem with the sound stopping for a second then coming back on it does this at random times and has got seriously annoying. I have recorded a video of the problem if anyone wants to see it. Thanks for any help given