Denis - I can help you with your very specific problem regarding your device, sorry.
However, a solution for recordings may be to use headphones. When plugged in to my tv, I can have the sound as loud as I like without affecting the external volume of the television - visitors can set the volume to their own comfort level.
If you do consider this option, make sure your television doesn't automatically mute external sound when headphones are plugged in - many televisions do.