** Shares of voice AI platform SoundHound AI SOUN.O slump 16.8% to $6.29; set for its worst day since March

** Co reports Q3 adj. gross margin of 59.7%, down from 73.7% last year

** Brokerage Wedbush says co saw a negative impact from the business mix change following its Amelia acquisition, that weighed on near-term margins

** Ladenburg downgrades SoundHound to "neutral" from "buy", as per thefly.com

** Says near-term absorption of losses around the Amelia acquisition as well as "rapid share price appreciation" prompted downgrade

** SOUN, in which AI bellwether Nvidia NVDA.O is an investor, however, beat Q3 revenue and profit

** Wedbush, still, raises PT to $10 from $9, citing a growing demand for SOUN's voice-enabled ecosystem and business expansion

** Average rating of seven brokerages is a "buy"; median PT $7

** Stock has more than doubled in value YTD

(Reporting by Ragini Mathur in Bengaluru)

((Ragini.Mathur@thomsonreuters.com))