Acoustic output apparatus, earphone and ultra-linear multi-magnetic double-diaphragm loudspeaker

An earphone, comprising an acoustic output apparatus, wherein the acoustic output apparatus comprising:

• an electroacoustic transducer comprising a first diaphragm and a driving component, wherein the first diaphragm is provided on a side of the driving component and is connected to the driving component;
• a second diaphragm provided at a side of the driving component away from the first diaphragm, the second diaphragm being spaced apart from the electroacoustic transducer;
• and
• a housing structure configured to carry the electroacoustic transducer and the second diaphragm, wherein a space between a side of the second diaphragm close to the driving component and a side of the first diaphragm close to the driving component forms a first cavity with the housing structure, and a space between a side of the electroacoustic transducer close to the second diaphragm and the second diaphragm forms a second cavity with the housing structure;
• wherein
• in a working state, the driving component drives the first diaphragm to vibrate, the first diaphragm pushes an air spring sealed in the first cavity to vibrate and causes the second diaphragm to passively vibrate with the air spring, and a volume of the second cavity is not greater than ⅕ of an equivalent volume of the electroacoustic transducer.