The phrase "audio line" is correct and usable in written English.
It can be used to refer to a connection or pathway for transmitting audio signals, often in the context of audio equipment or technology.
Example: "Make sure to connect the microphone to the audio line before starting the recording."
Alternatives: "audio channel" or "sound line".
Ms. Branch, a specialist in Sony's personal audio line, assured me that the DEJ01 was a fine model.
His studio — a man-cave-style haunt slathered floor to ceiling with Nixon memorabilia and conspiracy books — has been stocked with professional lighting and a broadcast-quality audio line by Stone's 19-year-old grandson, Nick.
This fall, the company will introduce an audio line of turntables, speakers and, most important, audiophile-quality headphones, rendered in leather and brushed stainless steel, which it intends to sell for $450 to $650.
The film's effective climax depicts how, in the middle of chaos, CNN manages to keep its audio line open, describing the bombardment from the inside, as the network's staff members, including the reporters Peter Arnett (Bruce McGill and John Holliman John Carroll Lynchch), risk their lives.
The dock itself offers no revelations, with the familiar vertical stance and audio line out.
The Apple TV does offer an Ethernet port, though, as well as an optical audio line out.
All of these filters receive input from the audio line-in (blue phone jack) and send output to audio line-out (green phone jack).
Soundfreaq Sound Step - This $139 dock supports audio line-in and Bluetooth and includes both a standard iPod/iPad port as well as a separate USB port for charging other devices.
MIT students could listen via ordinary radios connected to direct audio lines that served just the dorms, which meant that the station didnt need a radio license.
There's even an audio line-out built in.
A separate phone-to-phone cable, which connects your computer's audio line-out and your TV's audio input, will be necessary.
