To play the qín [instrument] to a cow
To try to use reason or logic with someone who understands neither; to use jargon with someone who won't understand it. Often used to mock or satirize.
Negative
To preach to deaf ears
Talk over someone's head
对牛鼓簧 (duì niú gǔ huáng)
In some dictionaries, 琴 (qín) is translated as "lute," but in reality, it refers to an ancient string instrument called the 古琴 (gǔ qín). I think "lute" is used in translations because many non-Chinese speakers wouldn't understand what a 古琴 was.
《理惑论》(Lǐ Huò Lún) by 牟子 (Móu Zǐ), a Hàn Dynasty (汉, 206 BC - 220 AD) court official
In the Warring States Period (475 - 221 BC), there was a musician named 公明仪 (Gōng Míng Yí) whose skills were second to none.
One day, he was carrying his 琴 (qín, an instrument with 7 strings similar to the zither) while he was out on a walk. The fresh grass smelled fragrant on the blowing wind, and he felt so exceedingly happy that he couldn't help but play a few notes on his 琴. However, he felt a little strange without an audience. He looked all around and saw that there was a bull grazing not far from him. Delighted, he went over to the cow, stretched out his fingers, and started playing the animal an elegant and refined song.
Despite the beauty of the song, however, the cow was utterly unmoved, and he kept munching on grass. 公明仪 tried another few songs, but again, the cow didn't so much as look in his direction. This frustrated 公明仪, but after a while, he came up with an idea. He plucked the strings of the 琴, this time producing a sound similar to that of a lost calf. This time, the bull stopped chewing on the grass immediately, and he waved his tail, pricked his ears, and started listening intently.