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AKG K 840 KL

Wireless on-ear headphones

Item #: 039K840KL

3 Reviews

This item is no longer available.

Original Price: $249.99

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Free yourself from the tyranny of the cable
Take AKG's K 840 KL lightweight wireless headphones with you everywhere to enjoy your favorite music without the hassle of being tethered by a cord. They include a small wireless transmitter that simply plugs into the headphone jack of your iPod®, iPhone®, laptop or other music player, and streams high-quality sound to the headset's built-in receiver. The included elastic band and Velcro strip makes it easy to attach the transmitter to your music source. A handy volume control on the earcup lets you adjust listening levels to suit your taste without ever taking your iPod or iPhone out of your pocket.

Lose the cable — not the sound quality
The K 840 KLs use Kleer® wireless technology to deliver uncompressed stereo sound. Unlike other wireless technologies, Kleer delivers lossless, CD-quality digital audio, which means you won't be able to tell the difference between these headphones and your wired ones. Multi-receiver mode allows up to four people using Kleer AKG headphones to listen to the same audio source, so you can easily share music with your friends and family. With a range of more than 60 feet and a battery life of up to 28 hours, the K 840 KLs will go farther and play longer than most other portable wireless headphones. And just in case you need it, AKG includes a cable plus an airline adapter for a direct wired connection in situations where you'd rather just plug in, or when you want to make use of an in-flight entertainment system.

From the review AKG K 840 Wireless Headphones: Travel 'phones that are at home in the office

"Everything about the packaging and presentation of the AKG K 840 headphones are about travel. And they would be great to have on a trip. You could keep your iPod (or other portable player) in your pocket with the attached transmitter, and go for hours just listening through the wireless headphones. But I really found the AKG K 840 KL wireless headphones a plus in the office. Not only did I enjoy great sound, but being untethered from my computer and free to roam around... was the real benefit for me. "

— Ralph, Crutchfield Blog Editor and A/V Writer

Product Highlights:

  • portable, on-the-ear design
  • 3D-Axis2 padded folding headband for convenient storage in supplied carrying case
  • padded, closed earcups for passive noise attenuation
  • Kleer® wireless technology delivers uncompressed stereo transmission over 2.4 GHz wireless frequency range
  • integrated volume control on earcup
  • built-in USB rechargeable headphone battery
  • USB rechargeable wireless transmitter with headphone mini plug audio connection
  • transmitter can be coupled with up to four headsets at a time
  • battery life (headphones/transmitter): up to 28 hours
  • elastic band and velcro strip included to attach transmitter to portable player
  • transmitter range: up to 65 feet
  • frequency response 10.5-31,000 Hz
  • impedance: 32 ohms
  • 47" detachable standard headphone cord with stereo mini plug for wired listening
  • airline adapter, full-size headphone adapter, USB charging cable, multi-country wall charging adapter, and carrying case included
  • weight (without cable): 5.1 oz.
  • warranty: 1 year
  • Our 60-day money-back guarantee

AKG K 840 KL Reviews

Average Customer Review:

3 Reviews

Nice Set

Written by: bb from Elk Grove, CA on August 6, 2012

Crutchfield Customer Review (What's this?)

  • "Coolness Factor"
  • Build Quality
  • Comfort
  • Noise Reduction
  • Sound Quality

Nice set. Use these while doing elliptical and work flawlessly. Great sound, comfortable, and noise reduction works.

Pros: Lightweight, comfortable, great sound. So far sweat proof.

Cons: None


Written by: BIG LEO from SUNSHINE STATE on October 19, 2011

Crutchfield Customer Review (What's this?)




Great to Have

Written by: DadE from Florida on July 7, 2011

Crutchfield Customer Review (What's this?)

Absolutely Wonderful !!! The sound clarity, range and definition are amazing. The fit is great, the ear cups are the perfect size, so you can wear these things for hours in total comfort. The transmitting range is 3X the stated 5 meters if you are in an open space. Last but not least, 55-60 hours on a full charge. There is NOTHING these wireless headphones lack.



Hands-on research

What's in the box?

Download owner's manual

  • Wireless headset
  • K840TX wireless transmitter
  • 57" USB charging cable (USB type-A connector on one end/ male 2.5mm mini-plug and female 3.5mm mini-jack on other)
  • AC adapter (5 volt/1 amp USB output)
  • 3 AC plug inserts (Europe/ UK/ Australia)
  • 47" Bypass cable (2.5mm connector on headset end and 3.5mm connector on source end)
  • 3.5mm to 1/4" Adapter
  • 3.5mm to 2.5mm Adapter
  • 3.5mm to 3.5mm Adapter
  • Airline adapter
  • 2 Rubber bands
  • Adhesive backed hook and loop fastener
  • Storage case
  • Owners manual (English/ French/ German/ Spanish and 12 other languages)
  • Warranty information
  • Attention booklet

Features and Specs

Fit Style On-ear
Earcup Type Closed
Noise-canceling No
Bluetooth No
Frequency Response 10.5-31k Hz
Sensitivity 120 dB
Impedance 32 Ohms
Weight 5.1 ounces
Cord Length 47"
Airline Adapter Included Yes
iPod Control No
Volume Control Yes
Built-in Microphone No
Parts Warranty 1 Year
Labor Warranty 1 Year

Product Research


Overview: The AKG K840 KL includes a headset with a built-in wireless receiver and a wireless transmitter that plugs into your source device, streaming your favorite music without the hassle of wires.

Transmitter: The included K840TX transmitter is shipped paired with the headset; it can also be paired with up to three additional K840 KL headsets simultaneously. The transmitter has a 2-1/2" cable attached, terminated with a 3.5mm mini-plug, used for signal input and charging.

Kleer Wireless Transmission Technology: The K840 KL headphone system features digital wireless audio transmission technology from Kleer, with a range up to 20 meters. Kleer technology transmits uncompressed, 16-bit CD-quality audio over a robust 2.4 GHz digital link (2.4 GHz-2.8 GHz), enabling you to enjoy your music without cables.

Note: Kleer technology will not interfere with wireless networks or other 2.4 GHz devices.

Charger: The AC adapter has a standard USB type-A output (5 volts/1 amp) and will charge the headset and transmitter at the same time using the included cable. In addition to the US style plug, three adapters are included for use in Europe, the UK, and Australia (the adapter accepts input of 100-240 volts at 50-60 Hz).

Bypass: When using wireless is not convenient, the 47" bypass cable can be used to wire the headset to the source.

Comfortable Fit: The headset features a lightweight design, leatherette padded ear-cups, and adjustable headband to provide a comfortable fit.

On-Ear Controls: Volume up/down and mute controls are on the left earcup (press volume up and volume down simultaneously to mute).

3D-Axis Folding Design: The headset features a unique 3D-Axis folding mechanism for ease of handling, storing, and transporting.

Auto Off: Whenever the transmitter is turned off, the headset turns off automatically. When the headset is turned off, the transmitter will search for it for three minutes, then turn off automatically. If no signal is available at the transmitter input for 10 minutes, it will turn off automatically.

Group Mode: Up to four K840 KL headsets can be paired to one transmitter simultaneously.

Rechargeable Battery: The headphones and transmitter are equipped with integrated rechargeable batteries that can last up to 24 hours. An AC adapter is included, or they can be recharged using a computer's USB port. The AC adapter charges the battery in 1.5 hours.

Storage Case: The AKG K840 KL comes with a zippered carrying case for the headphones, transmitter, AC adapter, and cables.


  • Wireless Frequency Range: 2.4 GHz-2.8 GHz
  • Transmission Power: <10 mW
  • Audio Frequency Range: 10.5 Hz-31 kHz
  • Impedance: 32Ω (when bypass cable is used)
  • Sensitivity: 120 dB (when bypass cable is used)
  • Maximum Input Power: 25 mW (when bypass cable is used)

Our Product Research Team

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