Darth Sidious, born Sheev Palpatine and commonly known simply as the Emperor, was a Force-sensitive human male who became a Dark Lord of the Sith and Galactic Emperor of the Galactic Empire, shaping history and ruling the galaxy throughout most of the Imperial Era. Rising to power in the Galactic Senate as the senator of Naboo, the manipulative Dark Lord cultivated two identities, which he used to his advantage by orchestrating the Clone Wars and playing both sides of the war, in order to accumulate political authority during the final years of the Galactic Republic, culminating in a reign that lasted from his ascension to absolute power in 19 BBY to his demise in 4 ABY. Death was not the end for Sidious, however, as the dark side of the Force was a pathway to abilities that made his return possible. 

Palpatine's false personality was one of a kind-hearted grandfather figure. He was a master of manipulation. His TRUE personality, one of great cruelty and sadism, would occasionally shine through in ways that were obvious even to the most sycophantic of his servants. This caused many of those who worked closely with him, such as Senator Orn Free Taa and some of the Empire's intelligence chiefs, to greatly fear him. Sidious was also known to loath ostentation and luxury. Sidious's most defining trait was his deeply manipulative nature, seducing many parties with promises of power, prize, even salvation to further his agenda. He attempted to sweet talk Ezra Bridger with being able to reunite with his deceased parents by altering fate.

Palpatine should sound like his voice actor, Ian McDiarmid.

Example:  https://www.youtube.com/watch?v=GiMiWes-hXk   and  https://www.youtube.com/watch?v=64-6BZvSlQg