Pease help me with a sentence.

[Unregistered]

Active voice: I often hear him sing in his room.

To make a passive voice sentence:

He is often heard to sing in his room. or He is often heard singing in his room.

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I want to know which is correct or both are acceptable?

[bhaisahab]

Active voice: I often hear him sing in his room.

To make a passive voice sentence:

He is often heard to sing in his room. or He is often heard singing in his room.

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I want to know which is correct or both are acceptable?

He is often heard singing.