Samsung UN46ES7500FXZA E-Manual page 431

If you want to use the TV's
microphone, turn on the preference in
System settings.
Motion Control
N
When using the microphone on
your Smart Touch Control, speak a
voice command using your normal
speaking voice into the microphone
on your Smart Touch Control. The
optimum distance from your face
should be approximately 0.3 — 0.4
(System
→ Voice
→ Voice and
Control)