AKG K391-NC  Headphones Review

Reviewed Feb 26, 2016 at 12:00am
Test bench update Aug 10, 2017 at 11:33am
Tested using Methodology v1.0 
AKG K391-NC
7.0
Mixed Usage 
6.7
Critical Listening 
7.1
Commute/Travel 
7.0
Sports/Fitness 
7.0
Office 
6.8
Home Theater 
 0

The AKG K391-NC are a good set of in-ear buds that sound great and isolate the listener really well. Their outstanding noise cancellation and leakage performance are recommended for noisy commutes. The sound profile works well for most music genres, but their in-ear design might not be for everyone.

Our Verdict

7.0
Mixed Usage 

Above-average as everyday headphones. They're compact and have a good sound. They can also handle loud environments well, thanks to their great noise cancelling. This makes them versatile enough to use in most situations.

Pros
  • Outstanding noise isolation.
  • Accurate audio reproduction.
  • Very little sound leakage.
Cons
  • Unexciting design.
  • Uncomfortable "in ear" fit.
6.7
Critical Listening 

Average for critical listening. Above-average sound quality but the small in-ear buds aren't optimized to produce a good soundstage, which isn't ideal for pure critical listening.

7.1
Commute/Travel 

The AKG K391-NC have a great isolation performance, which makes them easy to recommend to anyone who travels a lot or has very noisy daily commutes. They'll reduce a significant amount of ambient noise, and they're easy to carry around.

7.0
Sports/Fitness 

Above-average for sports. The AKG K391-NC will easily fit into most pockets, and they're stable enough to run with. As long as are comfortable with the in-ear fit.

7.0
Office 

Above-average for studio use. Leakage is barely audible and won't disturb anyone around you even at higher volumes.

6.8
Home Theater 

Above-average for home theater use. The AKG K391-NC have no latency but they also have a short audio cable. They have the range to watch TV from your couch unless you have an extension cord for the audio cable.

  • 7.0
    Mixed Usage
  • 6.7
    Critical Listening
  • 7.1
    Commute/Travel
  • 7.0
    Sports/Fitness
  • 7.0
    Office
  • 6.8
    Home Theater
  • Changelog

    1.  Updated Aug 10, 2017: Converted to Test Bench 1.0.
    2.  Updated Feb 26, 2016: Review published.

    Check Price

    Overhauling Our Audio Measurements And A New Multi-Curve Graphing Tool

    We've upgraded our Headphones Test Bench to 2.0! This update brings several key changes to our tests and usages, making it easier than ever to interpret our sound results based on your personal preferences. You'll also find a brand-new interactive graph tool featuring multiple targets (including our own!) for you to explore and compare.

    For a full breakdown, check out our changelog, which includes detailed commentary from our test designer explaining the rationale behind our update.

    We'd also love to hear your thoughts: your feedback helps us keep improving, so join us in the comments!

    Test Results

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    RATINGS
    Category:
    All
    Design
    Style
    TypeIn-ear
    EnclosureClosed-Back
    WirelessNo
    TransducerDynamic
    MicYes

    The AKG K391-NC's design is very simple. They look good but are a little unexciting. The control module has a brushed metal finish that's also noticeable on the earbuds. The cable is black and the rest of the accents are a deep gray, matching the AKG branding.

    6.5
    Comfort
    Weight0.2 lbs
    Clamping Force
    0 lbs

    The AKG K391-NC are as comfortable as you would expect in-ear earbuds to be. The sleeves come in three sizes, so unless your ear canals are unusually narrow or wide, you should be able to get a comfortable fit.

    4.9
    Controls
    Ease of useAverage
    FeedbackMediocre
    Call/Music ControlYes
    Volume ControlNo
    Noise Canceling ControlNo
    Talk-ThroughNo
    Additional ButtonsNo

    The buttons are in the right place, and the Control Module is small enough to fit any pocket. The in-line remote has a mic and call/music control. No volume up/down.

    7.0
    Stability

    The AKG K391-NC are decently stable headphones. Their in-ear design fits deeply into the ear canal making it hard for them to fall out during moderate physical activity. However, they won't be sufficiently stable for high-intensity exercises, and the control module and long cable can easily get hooked on something and pull the headphone out of your ears.

    8.3
    Portability
    L4.72"
    W1.18"
    H1.57"
    Volume8.83 in³
    Stand requiredN/A

    The AKG 491 are highly portable headphones. The in-ear design is compact and doesn't take too much space which makes it easy to transport in a bag or purse. The control module adds a little more bulk than basic passive in-ear headphones but doesn't reduce their portability as they will still comfortably fit into most pants or jacket pockets.

    5.5
    Case
    TypePouch

    The AKG K391-NC come with a soft fabric pouch that will protect the headphones from scratches and doesn't add much bulk. However, the soft fabric isn't waterproof and won't protect the headphones from hard falls or water damage.

    7.0
    Build Quality

    Except for the in-line remote, which feels a bit flimsy, the rest of the headphone has an even and decent build quality.

    9.2
    Breathability
    Avg.Temp.Difference0.8 °C
    Cable
    DetachableYes
    Length5.42 ft
    Connection1/8" TRRS

    The AKG K391-NC come with three cables (in addition to the non-detachable part): one USB for charging, and two 1/8" TRRS-TRRS with different plug colors.

    Front
    Angled
    Side
    Rear
    Top
    In The Box

    • AKG K391NC headphones
    • Silicone sleeves in three sizes
    • Flight adapter
    • Two cables for different smartphones
    • USB cable
    • Carrying pouch
    • AKG warranty card
    Sound
    9.3
    Bass
    See details on graph tool
    Std. Err.
    1.08 dB
    Low-Frequency Extension
    13.94 Hz
    Low-Bass
    -0.83 dB
    Bass
    -0.76 dB
    High-Bass
    1.38 dB
    7.8
    Mid
    See details on graph tool
    Std. Err.
    2.88 dB
    Low-Mid
    4.29 dB
    Mid
    0.96 dB
    High-Mid
    -0.53 dB
    7.5
    Treble
    See details on graph tool
    Std. Err.
    3.87 dB
    Low-Treble
    -0.19 dB
    Treble
    -0.5 dB
    High-Treble
    -3.3 dB
    9.5
    Frequency Response Consistency
    See details on graph tool
    See details on graph tool
    Avg. Std. Deviation
    0.1 dB
    1.4
    Soundstage
    PRTF Error
    12 dB
    Openness
    2.4
    Acoustic Space Excitation
    1.6
    Correlated Crosstalk
    -0.06 dB
    6.5
    Imaging
    See details on graph tool
    Phase Error
    161.07°
    Driver Mismatch (Amplitude)
    0.61 dB
    Driver Mismatch (Frequency)
    1.52 dB
    Driver Mismatch (Phase)
    9.45°
    6.7
    Total Harmonic Distortion
    See details on graph tool
    Weighted THD @ 90
    2.271
    Weighted THD @ 100
    20.972
    Isolation
    8.4
    Noise Isolation
    See details on graph tool
    Overall Attenuation
    -22.95 dB
    Noise-CancellingYes
    Bass
    -17.79 dB
    Mid
    -18.85 dB
    Treble
    -33.54 dB
    Self-Noise
    15.82 dB

    They have excellent noise isolation, especially at higher frequencies. Passive noise isolation is very good down to 500Hz. Below that, ANC kicks in, which maintains excellent isolation performance. The only point where they seem to struggle is around 400Hz.

    8.4
    Leakage
    See details on graph tool
    Overall Leakage @ 1ft
    31.14 dB

    Very good leakage performance. The AKG K391-NC leak more around 4kHz, which means higher notes will escape.

    Active Features
    0.0
    Wireless
    Type
    N/A
    Obstructed Range
    N/A
    Line of Sight Range
    N/A
    NFC
    No
    10
    Latency
    Base Latency
    0 ms
    aptX Latency
    N/A
    aptX(LL) Latency
    N/A
    6.2
    Battery
    Battery Type
    Rechargable
    Battery Life
    37.5 hrs
    Charge Time
    5.5 hrs
    Auto-off
    No
    Audio while charging
    Yes
    Passive Playback
    Yes

    The AKG 491-NC have a long battery life but take considerably longer than average to charge. This may be because they use an older mini-USB charging port. Unfortunately, this means you have to charge your headphones overnight which is not always practical. On the upside, they deliver above a day worth's of battery life, and you can use them while charging so they are decent headphones to use at the office or if you have access to a power source while on the bus, train, or plane.

    0.0
    App Support

    No compatible app.