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  1. Home
  2. Headphones
  3. Compare
  1. Table of Contents
  2. Top
  3. Main Differences
  4. Sound
    1. Sound Profile
    2. Frequency Response Consistency
    3. Raw Frequency Response
    4. Bass Profile: Target Compliance
    5. Mid-Range Profile: Target Compliance
    6. Treble Profile: Target Compliance
    7. Peaks/Dips
    8. Stereo Mismatch
    9. Group Delay
    10. Cumulative Spectral Decay
    11. PRTF
    12. Harmonic Distortion
    13. Electrical Aspects
    14. Virtual Soundstage
    15. Test Settings
    16. Imaging
    17. Weighted Harmonic Distortion
  5. Design
    1. Style
    2. Comfort
    3. Controls
    4. Breathability
    5. Portability
    6. Case
    7. Build Quality
    8. Stability
    9. Headshots 1
    10. Headshots 2
    11. Top
    12. In The Box
  6. Isolation
    1. Noise Isolation - Full Range
    2. Noise Isolation - Common Scenarios
    3. Noise Isolation - Voice Handling
    4. ANC Wind Handling
    5. Leakage
  7. Microphone
    1. Microphone Style
    2. Recording Quality
    3. Noise Handling
  8. Active Features
    1. Battery
    2. App Support
  9. Connectivity
    1. Wired Connection
    2. Bluetooth Connection
    3. Wireless Connection (Dongle)
    4. PC Compatibility
    5. PlayStation Compatibility
    6. Xbox Compatibility
    7. Base/Dock
  10. Comments

Sennheiser HD 6XX vs HiFiMan Sundara 2020

Side-by-Side Comparison

Products

Sennheiser HD 6XX
HiFiMan Sundara 2020

Tested using Methodology v1.6

Updated Jun 09, 2025 09:07 PM

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Amazon.com

Tested using Methodology v2.0

Updated Apr 24, 2025 06:41 PM

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Amazon.com
Sennheiser HD 6XX Picture
HiFiMan Sundara 2020 Picture
TypeOver-ear
Noise CancellingNo
EnclosureOpen-Back
WirelessNo
TransducerDynamic
MicNo
TypeOver-Ear
Noise CancellingNo
EnclosureOpen-Back
Bass Amount
Slightly Underemphasized (-3 dB)
WirelessNo
TransducerPlanar Magnetic
Treble Amount
Slightly Underemphasized (-2 dB)
MicNo
Sound Signature
Flat
  1. Recommended in 3 articles:
  2. Music
  3. Critical Listening
  4. Open-Back

Variants

  • HD 6XX (Midnight Blue)
  • Sundara 2020 (Black)

Review

See Sennheiser HD 6XX Review
See HiFiMan Sundara 2020 Review
0 
7 

Our Verdict

Sennheiser HD 6XX

HiFiMan Sundara 2020

The HiFiMan Sundara 2020 and the Sennheiser HD 6XX are both open-backs with flat sound profiles, but the HiFiMan are able to reproduce treble a bit more evenly, and they're a bit less plasticky. They're also more comfortable, and don't need an amp. However, you may prefer the Sennheiser's tuning and slightly more stable fit.

0 

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Midnight Blue
HD 6XX
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Sundara 2020
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HD 6XX
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Main Differences for
Neutral Sound

Threshold 

0.10

Neutral Sound 

8.3
No major differences between these headphones for neutral sound. See full list of tests below.

Full Comparison

Sound

Sound Profile 
 

Sound Profile  

See details on graph tool
See details on graph tool

Normalization Frequency 
 

650 Hz

Bass Amount 
 

Slightly Underemphasized (-3 dB)

Bass Amount 
 

-3.21 dB

Treble Amount 
 

-1.74 dB

Treble Amount 
 

Slightly Underemphasized (-2 dB)

Sound Signature 
 

Flat
Show Text 

Frequency Response Consistency 
 

8.4
7.9

Consistency L  

See details on graph tool
See details on graph tool

Consistency R  

See details on graph tool
See details on graph tool

Avg. Std. Deviation 
 

0.32 dB
0.88 dB
Show Text 

Raw Frequency Response 
 

Raw FR L  

See details on graph tool
See details on graph tool

Raw FR R  

See details on graph tool
See details on graph tool

Bass Profile: Target Compliance 
 

7.7
8.0

Bass Profile: Target Compliance  

See details on graph tool
See details on graph tool

RMS Deviation From Target 
 

3.08 dB
4.3 dB

Low-Frequency Extension 
 

60.8 Hz
22.68 Hz

Low Bass 
 

-6.09 dB
-6 dB

Mid Bass 
 

-1.34 dB
-2.37 dB

High Bass 
 

1.4 dB
0.06 dB
Show Text 

Mid-Range Profile: Target Compliance 
 

9.4
9.0

Mid-Range Profile: Target Compliance  

See details on graph tool
See details on graph tool

RMS Deviation From Target 
 

0.86 dB
1.4 dB

Low Mid 
 

-0.33 dB
0.56 dB

Mid-Mid 
 

-1.21 dB
0.04 dB

High Mid 
 

0 dB
-1.86 dB
Show Text 

Treble Profile: Target Compliance 
 

8.0
9.3

Treble Profile: Target Compliance  

See details on graph tool
See details on graph tool

RMS Deviation From Target 
 

2.99 dB
2.19 dB

Low Treble 
 

0.29 dB
-2.53 dB

Mid Treble 
 

-2.82 dB
-0.82 dB

High Treble 
 

-8.59 dB
-4.67 dB
Show Text 

Peaks/Dips 
 

7.9
7.9

Peaks/Dips Graph 
 

See details on graph tool
See details on graph tool

Peaks 
 

1.35 dB
1.1 dB

Dips 
 

0.92 dB
1.85 dB
Show Text 

Stereo Mismatch 
 

8.0

Frequency Response Mismatch  

See details on graph tool

Phase Response Mismatch  

See details on graph tool
See details on graph tool

Weighted Amplitude Mismatch 
 

0.83
0.2 dB

Weighted Frequency Response Mismatch 
 

1.1
1.2 dB

Weighted Phase Mismatch 
 

5.67
2.1°
Show Text 

Group Delay 
 

6.8

Group Delay  

See details on graph tool

Weighted Group Delay 
 

1.2 ms
Show Text 

Cumulative Spectral Decay 
 

CSD  

HiFiMan Sundara 2020 CSD

PRTF 
 

7.2
7.2

PRTF  

See details on graph tool
See details on graph tool

PRTF Accuracy (RMS Deviation) 
 

2.24 dB
2.36 dB

PRTF Size (Avg.) 
 

3.3 dB
4.77 dB

PRTF Distance 
 

5.37 dB
9.84 dB

Openness 
 

9.5

Acoustic Space Excitation 
 

8.1
Show Text 

Harmonic Distortion 
 

9.5

Harmonics Levels  

See details on graph tool

THD Ratio  

See details on graph tool
See details on graph tool

WHD @ 94 dB SPL 
 

0.127
0.04%

WHD @ 104 dB SPL 
 

0.120
0.09%
Show Text 

Electrical Aspects 
 

Impedance  

See details on graph tool

Sensitivity @1kHz-1V 
 

105.0 dB SPL

Bluetooth Max SPL 
 

N/A
Show Text 

Virtual Soundstage 
 

0.0
0.0

Virtual Soundstage  

Sennheiser HD 6XX Virtual Soundstage
HiFiMan Sundara 2020 Virtual Soundstage

Head Modeling 
 

No
No

Speaker Modeling 
 

No
No

Room Ambience 
 

No
No

Head Tracking 
 

No
No

Virtual Surround 
 

No App
No App
Show Text 

Test Settings 
 

Firmware 
 

No Firmware
No Firmware

Power 
 

Passive
Passive

Connection 
 

Wired
Wired

Codec 
 

PCM, 24-bit, 48kHz
PCM, 24-bit, 48kHz

Test Instrument  

Audio Precision APx517B

EQ 
 

No EQ
No EQ

ANC 
 

No ANC
No ANC

Tip/Pad 
 

Default
Default

Microphone 
 

No Microphone
No Microphone
Show Text 

Imaging 
 

8.8

Group Delay  

See details on graph tool

Phase Response Mismatch  

See details on graph tool
See details on graph tool

Weighted Group Delay 
 

0.15

Weighted Phase Mismatch 
 

5.67
2.1°

Weighted Amplitude Mismatch 
 

0.83
0.2 dB

Weighted Frequency Mismatch 
 

1.1
1.2 dB
Show Text 

Weighted Harmonic Distortion 
 

8.2

Weighted Harmonic Distortion  

See details on graph tool
See details on graph tool

WHD @ 90 
 

0.127
0.04%

WHD @ 100 
 

0.120
0.09%
Show Text 
Design

Style  

Design Picture 2  

Sennheiser HD 6XX Design Picture 2
HiFiMan Sundara 2020 Design Picture 2

Type  

Over-ear
Over-Ear

Enclosure  

Open-Back
Open-Back

Wireless  

No
No

Transducer  

Dynamic
Planar Magnetic
Show Text 

Comfort 
 

7.0
8.0

Comfort Picture  

Sennheiser HD 6XX Comfort Picture
HiFiMan Sundara 2020 Comfort Picture

Weight  

0.69 lbs
0.87 lbs

Clamping Force 
 

1.6 lbs
1.6 lbs
Show Text 

Controls 
 

0.0
0.0

Controls Picture  

Sennheiser HD 6XX Controls Picture
HiFiMan Sundara 2020 Controls Picture

OS Compatibility 
 

No Controls
No Controls

Ease Of Use  

No Controls
No Controls

Feedback  

No Controls
No Controls

Call/Music Control  

No
No

Volume Control  

No
No

Microphone Control  

No
No

Channel Mixing 
 

No
No

Noise Cancelling Control  

No
No

Talk-Through 
 

No
No

Additional Controls  

No
No
Show Text 

Breathability 
 

Breathability After Picture  

Avg.Temp.Difference  

Portability 
 

5.4
5.3

Portability Picture  

Sennheiser HD 6XX Portability Picture
HiFiMan Sundara 2020 Portability Picture

L  

7.4" (18.8 cm)
8.3" (21.1 cm)

W  

7.0" (17.8 cm)
5.8" (14.7 cm)

H  

3.7" (9.4 cm)
4.6" (11.7 cm)

Volume  

192.00 in³ (3,146.30 cm³)
221.00 in³ (3,621.53 cm³)

Transmitter Required  

No
No
Show Text 

Case 
 

0.0
0.0

Case Picture  

Sennheiser HD 6XX Case Picture
HiFiMan Sundara 2020 Case Picture

Type  

No case
No case

L  

N/A
N/A

W  

N/A
N/A

H  

N/A
N/A

Volume  

N/A
N/A
Show Text 

Build Quality 
 

7.5
7.5

Build Quality Picture  

Sennheiser HD 6XX Build Quality Picture
HiFiMan Sundara 2020 Build Quality Picture
Show Text 

Stability 
 

7.0
6.5

Stability Picture  

Sennheiser HD 6XX Stability Picture
HiFiMan Sundara 2020 Stability Picture
Show Text 

Headshots 1  

Angled Picture  

Sennheiser HD 6XX Angled Picture
HiFiMan Sundara 2020 Angled Picture

Side Picture  

Sennheiser HD 6XX Side Picture
HiFiMan Sundara 2020 Side Picture

Headshots 2  

Front Picture  

Sennheiser HD 6XX Front Picture
HiFiMan Sundara 2020 Front Picture

Rear Picture  

Sennheiser HD 6XX Rear Picture
HiFiMan Sundara 2020 Rear Picture

Top  

Top Picture  

Sennheiser HD 6XX Top Picture
HiFiMan Sundara 2020 Top Picture

In The Box  

In The Box Picture  

Sennheiser HD 6XX In The Box Picture
HiFiMan Sundara 2020 In The Box Picture
Show Text 
Isolation

Noise Isolation - Full Range 
 

1.2
0.6

Noise Isolation - Full Range Graph  

See details on graph tool
See details on graph tool

Noise Cancelling  

No
No

Overall Attenuation 
 

-3.1 dB
-1.46 dB

Isolation Audio 
 

Bass 
 

-0.17 dB
1.05 dB

Mid 
 

1.06 dB
-0.31 dB

Treble 
 

-9.87 dB
-5.78 dB
Show Text 

Noise Isolation - Common Scenarios 
 

0.7

Noise Isolation - Common Scenarios Graph  

See details on graph tool

Airplane Noise Attenuation 
 

-2.06 dB

Airplane Noise Isolation Audio 
 

Office Noise Attenuation 
 

-1.14 dB

Office Noise Isolation Audio 
 

Street Noise Attenuation 
 

-1.01 dB

Street Noise Isolation Audio 
 

Show Text 

Noise Isolation - Voice Handling 
 

Female Voice 1 
 

Male Voice 1 
 

Female Voice 2 
 

Male Voice 2 
 

ANC Wind Handling 
 

ANC Wind Handling Graph  

HiFiMan Sundara 2020 ANC Wind Handling Graph

ANC Wind Noise 
 

N/A

Leakage 
 

2.5
0.9

Leakage  

See details on graph tool
See details on graph tool

Leakage Audio 
 

Overall Leakage @ 1ft 
 

60.09 dB
66.5 dB
Show Text 
Microphone

Microphone Style 
 

Integrated 
 

No
No

In-Line 
 

No
No

Boom 
 

No
No

Detachable Boom 
 

No
No

Mic  

No
No
Show Text 

Recording Quality 
 

0.0
0.0

Microphone Frequency Response  

Sennheiser HD 6XX Microphone Frequency Response
HiFiMan Sundara 2020 Microphone Frequency Response

Recorded Speech 
 

N/A
N/A

LFE 
 

N/A
N/A

FR Std. Dev. 
 

N/A
N/A

HFE 
 

N/A
N/A

Weighted THD 
 

N/A
N/A

Gain 
 

N/A
N/A
Show Text 

Noise Handling 
 

0.0
0.0

SpNR  

Sennheiser HD 6XX SpNR
HiFiMan Sundara 2020 SpNR

SpNR 
 

N/A
N/A

Noise Gate 
 

No
No

Speech + Pink Noise Handling 
 

N/A
N/A

Speech + Pink Noise Audio Sample  

N/A
N/A

Speech + Subway Noise Handling 
 

N/A
N/A

Speech + Subway Noise Audio Sample  

N/A
N/A
Show Text 
Active Features

Battery 
 

0.0
0.0

Battery Type 
 

No Battery
No Battery

Continuous Battery Life 
 

N/A
N/A

Additional Charges 
 

N/A
N/A

Total Battery Life 
 

N/A
N/A

Charge Time 
 

N/A
N/A

Power-Saving Feature 
 

No
No

Audio While Charging 
 

No
No

Passive Playback 
 

Passive Headphone
Passive Headphone

Charging Port  

None
None
Show Text 

App Support 
 

0.0
0.0

App Picture  

Sennheiser HD 6XX App Picture
HiFiMan Sundara 2020 App Picture

App Name  

No App
No App

iOS  

No
No

Android  

No
No

macOS  

No
No

Windows  

No
No

Equalizer 
 

No
No

ANC Control 
 

No
No

Mic Control  

No
No

Room Effects 
 

No
No

Playback Control 
 

No
No

Button Mapping  

No
No

Surround Support 
 

No
No
Show Text 
Connectivity

Wired Connection 
 

9.9
9.9

Cable Picture  

Sennheiser HD 6XX Cable Picture
HiFiMan Sundara 2020 Cable Picture

Analog Audio 
 

Yes
Yes

USB Audio 
 

No
No

Detachable 
 

Yes
Yes

Length 
 

5.80 ft (1.77 m)
4.80 ft (1.46 m)

Connector 
 

1/8" TRS
1/8" TRS

Latency - Analog 
 

0.2 ms
0.2 ms

Latency - USB 
 

N/A
N/A

Recorded Latency 
 

Recorded Latency Connection  

Analog
Analog
Show Text 

Bluetooth Connection 
 

0.0
0.0

Bluetooth Version 
 

No Bluetooth
No Bluetooth

Multi-Device Pairing 
 

No
No

Quick Pair (Android) 
 

No
No

Quick Pair (iOS) 
 

No
No

Line Of Sight Range 
 

N/A
N/A

Latency - SBC 
 

N/A
N/A

Latency - aptX 
 

N/A
N/A

Latency - aptX Adaptive (High Quality) 
 

N/A
N/A

Latency - aptX Adaptive (Low Latency) 
 

N/A
N/A

Latency - LDAC 
 

N/A
N/A

Recorded Latency 
 

N/A
N/A

Recorded Latency Codec  

No Bluetooth Audio
No Bluetooth Audio

AAC Support 
 

No
No
Show Text 

Wireless Connection (Dongle) 
 

0.0
0.0

Line Of Sight Range 
 

N/A
N/A

Latency - Dongle 
 

N/A
N/A

Recorded Latency 
 

N/A
N/A
Show Text 

PC Compatibility 
 

Analog 
 

Audio Only
Audio Only

Wired USB 
 

No
No

Non-BT Wireless 
 

No
No
Show Text 

PlayStation Compatibility 
 

PS4 Analog 
 

Audio Only
Audio Only

PS4 Wired USB 
 

No
No

PS4 Non-BT Wireless 
 

No
No

PS5 Analog 
 

Audio Only
Audio Only

PS5 Wired USB 
 

No
No

PS5 Non-BT Wireless 
 

No
No
Show Text 

Xbox Compatibility 
 

Xbox One Analog 
 

Audio Only
Audio Only

Xbox One Wired USB 
 

No
No

Xbox One Non-BT Wireless 
 

No
No

Xbox Series X|S Analog 
 

Audio Only
Audio Only

Xbox Series X|S Wired USB 
 

No
No

Xbox Series X|S Non-BT Wireless 
 

No
No
Show Text 

Base/Dock 
 

0.0
0.0

Type 
 

No Base/Dock
No Base/Dock

USB Input 
 

No
No

Line In 
 

No
No

Line Out 
 

No
No

Optical Input 
 

No
No

RCA Input 
 

No
No

Dock Charging 
 

No
No

Power Supply 
 

No Base/Dock
No Base/Dock
Show Text 

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Midnight Blue
HD 6XX
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Black
Sundara 2020
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Midnight Blue
HD 6XX
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Sundara 2020
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HD 6XX
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Sundara 2020
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HD 6XX
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Sennheiser HD 6XX

HiFiMan Sundara 2020

Comments

  1. Comparison
 • Posted 1 year ago

Sennheiser HD 6XX vs HiFiMan Sundara 2020: Main Discussion

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