slash marks though speakers on sound board

[ray keeney]

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I can't seem to get any sound from my Newsmy t3 4.0 ICS tablet. I watch video where people are talking but I can't hear any sound. I go to the volumn and they appear to be at high. But still no sound. I notice the speaker icons have a slash mark thru them. I can't seem to remove them. I need help, thanks