Recorded, first-hand impressions of Pitt’s voice will be the subject of several future blog posts, but I find this one from The Farington Diary (Vol 2: 283) particularly illustrative. The diarist Joseph Farington relates an instance in 1804 when Edridge (the artist) stayed at Lord Essex’s house at the same time as Mr. Pitt. Edridge noticed “the deep, bell-toned, voice of Mr. Pitt which, with his emphasis, made common things said by him to have a great effect. He [Pitt] was occasionally jocose…and at being offered some cowslip wine at first declined it, but immediately after said he would drink success to Sir Francis Burdett (who was in the political contest for Middlesex at the time) in Cowslip - Every day the numbers on the poll were brought to him.”
I suppose I don’t need to mention that Pitt wasn’t overly fond of Burdett (they were political opponents).
Farington, J. (ed. by James Greig) (1923) The Farington Diary, Volume 2. London: Hutchinson, pg. 283.