4.375 1 5 0

In particular, Radio Frequency (RF) transmission sends the signals between the transmitter and the headphones.

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stylish design, seem like a high-end piece of stereo equipment

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plenty of bass support, good for sound effects and dynamic basslines

1 agrees

fairly light weight, don't feel like they're pressing down on you

1 agrees

enough volume output for the hearing impaired

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excellent range, don't have to stay in one spot while listening

1 agrees

easy to install and have set up in a minute

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sound quality is above average for wireless headphones, good coverage of the sound spectrum

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need to be a bit careful with them, can be damaged if they're dropped

1 agrees
  • Only 3 words are allowed.


The Sony MDR-RF4000K is a pair of digital wireless headphones that uses 2.4GHz wireless technology to transmit a signal from the transmitter up to 100 ft. In particular, Radio Frequency (RF) transmission sends the signals between the transmitter and the headphones. These signals allow for high-fidelity audio reproduction. Featured are high-powered, 40mm closed Neodymium drivers that keep ambient noise out while outputting quality audio along a wide 10Hz-22,000Hz frequency range. Plus the unit comes with a rechargeable NiMH battery that lasts up to eight hours on a single 15-hour charge. In case the battery ever dies, it can be replaced with either a regular or rechargeable AAA battery. Ultimately, the Sony MDR-RF4000K is a midgrade wireless unit. There are models with greater power handling, larger drivers, and improved frequency, but their prices tend to range over $200 or even $300.

  • Closed, Dynamic Earbud Headphones
  • Aluminum Body
  • No Redundant Vibration
  • Smooth Bass Response
  • Clear Mid-High Range
  • Large Neodymium Magnets
  • Low Power Handling
  • Extra-Wide Frequency Range
  • No Ambient Noise
  • High-Resolution Diaphragm
  • High-Quality Audio
  • Distortion: 1% or less
  • Driver Unit: 40mm, Closed
  • Frequency: 10Hz-22,000Hz
  • Infrared Carrier Frequencies: 2.404 Ghz – 2.476
  • Range: Approximately 100 ft
  • RF Modulation: GFSK
  • Input Jack: Phono Jacks (L/R), Stereo Mini Jack
  • Weight: 300 g
Battery Details
  • Charging: 15 Hours
  • Life: 8 Hours
  • Type: AAA Ni-mH x2
  • Voltage: DC 5.2 V (AC)
  • AC Power Adaptor
  • Connecting Cable
  • Rechargeable Battery
  • Unimatch Plug Adaptor
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