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- Table of Contents
- Top
- Main Differences
- Design
- Sound
- Isolation
- Microphone
- Active Features
- Connectivity
- Comments
Superlux HD 668B vs Audio-Technica ATH-M40x
Side-by-Side Comparison
Products
Superlux HD 668B
Audio-Technica ATH-M40x
Tested using Methodology v1.5
Updated Apr 26, 2022 08:51 PM
SEE PRICE
Amazon.comTested using Methodology v1.5
Updated May 28, 2025 01:43 PM
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Amazon.com
TypeOver-ear
EnclosureSemi-Open
WirelessNo
TransducerDynamic
Noise CancellingNo
MicNo
TypeOver-ear
EnclosureClosed-Back
WirelessNo
TransducerDynamic
Noise CancellingNo
MicNo
Variants
- HD 668B
- ATH-M40x (Black)
Our Verdict
Superlux HD 668B
Audio-Technica ATH-M40x
Full comparison details regarding individual product score sets can be found in the section below
Check Price
Standard
HD 668B
SEE PRICE
Amazon.comBlack
ATH-M40x
SEE PRICE
Amazon.comStandard
HD 668B
SEE PRICE
BestBuy.comBlack
ATH-M40x
SEE PRICE
Walmart.comStandard
HD 668B
SEE PRICE
Walmart.comBlack
ATH-M40x
SEARCH
B&HStandard
HD 668B
SEARCH
B&HBlack
ATH-M40x
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BestBuy.comBlack
ATH-M40x
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Samsung.comMain Differences for-
-
Threshold
Full Comparison
Design
Style
Design Picture 2
Type
Over-ear
Over-ear
Enclosure
Semi-Open
Closed-Back
Wireless
No
No
Transducer
Dynamic
Dynamic
Comfort
6.0
7.5
Comfort Picture
Weight
0.51 lbs
0.55 lbs
Clamping Force
1.2 lbs
1.1 lbs
Controls
0.0
0.0
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
Breathability
6.8
6.2
Breathability After Picture
Avg.Temp.Difference
4.8 °C
6.5 °C
Portability
5.2
5.9
Portability Picture
L
9.0" (22.9 cm)
5.1" (13.0 cm)
W
7.1" (18.0 cm)
6.5" (16.5 cm)
H
4.1" (10.4 cm)
3.5" (9.0 cm)
Volume
262.00 in³ (4,293.39 cm³)
111.20 in³ (1,822.23 cm³)
Transmitter Required
No
No
Case
5.5
6.5
Case Picture
Type
Pouch
Pouch
L
N/A
N/A
W
N/A
N/A
H
N/A
N/A
Volume
N/A
N/A
Build Quality
5.5
7.0
Build Quality Picture
Stability
6.5
6.5
Stability Picture
Headshots 1
Angled Picture
Side Picture
Headshots 2
Front Picture
Rear Picture
Top
Top Picture
In The Box
In The Box Picture
Sound
Sound Profile
Frequency Response
Bass Amount
-1.62 dB
0.33 dB
Treble Amount
0.34 dB
-0.15 dB
Frequency Response Consistency
7.5
7.0
Consistency L
Consistency R
Avg. Std. Deviation
0.49 dB
0.62 dB
Raw Frequency Response
Bass Accuracy
7.9
7.2
Std. Err.
2.86 dB
4.35 dB
Low-Frequency Extension
32.68 Hz
16.82 Hz
Low-Bass
-2.72 dB
1.61 dB
Mid-Bass
3 dB
4.54 dB
High-Bass
3.17 dB
6.09 dB
Mid Accuracy
9.1
8.4
Std. Err.
1.25 dB
2.15 dB
Low-Mid
1.47 dB
0.4 dB
Mid-Mid
0 dB
0.69 dB
High-Mid
0.74 dB
3.13 dB
Treble Accuracy
7.4
8.0
Std. Err.
3.93 dB
2.97 dB
Low-Treble
0.37 dB
1.42 dB
Mid-Treble
5.18 dB
2.67 dB
High-Treble
-0.9 dB
0.32 dB
Peaks/Dips
7.4
7.3
Peaks/Dips Graph
Peaks
1.62 dB
1.67 dB
Dips
1.41 dB
1.44 dB
Imaging
8.5
7.9
Phase Response Mismatch
Weighted Group Delay
0.33
0.33
Weighted Phase Mismatch
9.13
4.27
Weighted Amplitude Mismatch
0.31
1.76
Weighted Frequency Mismatch
1.75
2.17
Passive Soundstage
7.6
6.0
PRTF Accuracy (Std. Dev.)
1.64 dB
1.56 dB
PRTF Size (Avg.)
7.04 dB
4.72 dB
PRTF Distance
11.79 dB
7.21 dB
Openness
9.1
5.6
Acoustic Space Excitation
6.4
4.2
Virtual Soundstage
0.0
0.0
Virtual Soundstage
Head Modeling
No
No
Speaker Modeling
No
No
Room Ambience
No
No
Head Tracking
No
No
Virtual Surround
No App
No App
Weighted Harmonic Distortion
8.0
6.9
Weighted Harmonic Distortion
WHD @ 90
0.100
0.300
WHD @ 100
0.189
0.542
Test Settings
Firmware
No Firmware
No Firmware
Power
Passive
Passive
Connection
Wired
Wired
Codec
PCM, 24-bit, 48kHz
PCM, 24-bit, 48kHz
EQ
No EQ
No EQ
ANC
No ANC
No ANC
Tip/Pad
Default
Default
Microphone
No Microphone
No Microphone
Isolation
Noise Isolation
2.0
4.2
Noise Isolation
Isolation Audio
Overall Attenuation
-6.69 dB
-11.21 dB
Noise Cancelling
No
No
Bass
0.16 dB
-0.09 dB
Mid
-0.23 dB
-9.09 dB
Treble
-19.73 dB
-25.22 dB
Leakage
4.5
6.4
Leakage Audio
Overall Leakage @ 1ft
51.95 dB
43.12 dB
Microphone
Microphone Style
Integrated
No
No
In-Line
No
No
Boom
No
No
Detachable Boom
No
No
Mic
No
No
Recording Quality
0.0
0.0
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
Noise Handling
0.0
0.0
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
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
App Support
0.0
0.0
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
Connectivity
Bluetooth
0.0
0.0
Bluetooth Version
No Bluetooth
No Bluetooth
Multi-Device Pairing
No
No
NFC Pairing
No
No
Line Of Sight Range
N/A
N/A
PC Latency (SBC)
N/A
N/A
PC Latency (aptX)
N/A
N/A
PC Latency (aptX HD)
N/A
N/A
PC Latency (aptX-LL)
N/A
N/A
iOS Latency
N/A
N/A
Android Latency
N/A
N/A
Non-Bluetooth Wireless
0.0
0.0
Non-BT Line Of Sight Range
N/A
N/A
Non-BT Latency
N/A
N/A
Wired
9.5
9.5
Cable Picture
Analog Audio
Yes
Yes
USB Audio
No
No
Detachable
Yes
Yes
Length
10.00 ft (3.05 m)
10.11 ft (3.08 m)
Connection
1/8" TRS
1/8" TRS
Analog/USB Audio Latency
0 ms
0 ms
PC Compatibility
Analog
Audio Only
Audio Only
Wired USB
No
No
Non-BT Wireless
No
No
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
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
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
Check Price
Standard
HD 668B
SEE PRICE
Amazon.comBlack
ATH-M40x
SEE PRICE
Amazon.comStandard
HD 668B
SEE PRICE
BestBuy.comBlack
ATH-M40x
SEE PRICE
Walmart.comStandard
HD 668B
SEE PRICE
Walmart.comBlack
ATH-M40x
SEARCH
B&HStandard
HD 668B
SEARCH
B&HBlack
ATH-M40x
SEARCH
BestBuy.comBlack
ATH-M40x
SEARCH
Samsung.com
Superlux HD 668B
Audio-Technica ATH-M40x
Comments
Superlux HD 668B vs Audio-Technica ATH-M40x: Main Discussion
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