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  1. Home
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LG SP9YA vs Vizio M Series M51ax-J6

Which Soundbar Is Better?

    Top
    Main Differences
    Design
      Style - BarStyle - SubwooferStyle - SatellitesDimensions - BarDimensions - SubwooferDimensions - SatellitesMountingBuild QualityIn The Box
    Sound
      Stereo Frequency ResponseStereo Frequency Response With Preliminary CalibrationStereo SoundstageStereo DynamicsStereo Total Harmonic DistortionCenterSurround 5.1Height (Atmos)Sound Enhancement Features
    Connectivity
      Inputs/Outputs - BarAudio Format Support: ARC/eARCAudio Format Support: HDMI InAudio Format Support: OpticalAudio Latency: ARCAudio Latency: HDMI InAudio Latency: OpticalVideo Passthrough To TVWireless Playback
    Additional Features
      InterfaceBar ControlsRemoteVoice Assistants Support
    Comments

Products

LG SP9YA
Vizio M Series M51ax-J6

Tested using Methodology v1.1

Updated Aug 22, 2025 08:54 PM

SEE PRICE
Amazon.com

Tested using Methodology v1.3

Updated Jan 06, 2026 09:22 PM

SEE PRICE
Amazon.com
LG SP9YA Picture
Vizio M Series M51ax-J6 Picture
Channels
Locked
Channels
Locked

Our Verdict

LG SP9YA

Vizio M Series M51ax-J6

Depending on your listening habits, you may prefer either the LG SP9YA or the Vizio M Series M51ax-J6. The LG is a 5.1.2 setup with a better soundstage and more sound enhancement features, including room correction. The Vizio has a better surround performance thanks to the included satellites. While you can purchase satellites for the LG separately, the Vizio offers a better value overall.

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Variants

  • SP9YA (Black)
  • M Series M51ax-J6 (Dark Charcoal)

Review

See LG SP9YA Review
See Vizio M Series M51ax-J6 Review
0 
8 

Check Price

Black
SP9YA
SEE PRICE
Amazon.com
Dark Charcoal
M Series M51ax-J6
SEE PRICE
Amazon.com
Black
SP9YA
SEE PRICE
BestBuy.com
Dark Charcoal
M Series M51ax-J6
SEARCH
B&H
Black
SP9YA
SEE PRICE
Walmart.com
Dark Charcoal
M Series M51ax-J6
SEARCH
BestBuy.com
Black
SP9YA
SEARCH
B&H
Dark Charcoal
M Series M51ax-J6
SEARCH
Vizio
Black
SP9YA
SEARCH
LG.com
Dark Charcoal
M Series M51ax-J6
SEARCH
Walmart.com
Read more

Main Differences for
Mixed Usage

Threshold 

0.10

Mixed Usage 
 

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0.0
GET INSIDER ACCESS  to see main differences

Full Comparison

Design

Style - Bar  

Style photo - bar 
 

LG SP9YA Style photo - bar Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Style photo - bar Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Show Text 

Style - Subwoofer  

Style photo - sub 
 

LG SP9YA Style photo - sub Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Style photo - sub Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Sub Wireless 
 

Locked
Locked

Enclosure 
 

Locked
Locked
Show Text 

Style - Satellites  

Style photo - satellites 
 

LG SP9YA Style photo - satellites Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Style photo - satellites Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Satellite Wireless 
 

Locked
Locked
Show Text 

Dimensions - Bar  

Dimensions photo - bar 
 

LG SP9YA Dimensions photo - bar Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Dimensions photo - bar Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Width  

Lock" (Lock cm)
Lock" (Lock cm)

Height  

Lock" (Lock cm)
Lock" (Lock cm)

Depth  

Lock" (Lock cm)
Lock" (Lock cm)
Show Text 

Dimensions - Subwoofer  

Dimensions photo - sub 
 

LG SP9YA Dimensions photo - sub Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Dimensions photo - sub Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Width  

Lock" (Lock cm)
Lock" (Lock cm)

Height  

Lock" (Lock cm)
Lock" (Lock cm)

Depth  

Lock" (Lock cm)
Lock" (Lock cm)
Show Text 

Dimensions - Satellites  

Dimensions photo - satellites 
 

LG SP9YA Dimensions photo - satellites Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Dimensions photo - satellites Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Width  

N/A
Lock" (Lock cm)

Height  

N/A
Lock" (Lock cm)

Depth  

N/A
Lock" (Lock cm)
Show Text 

Mounting 
 

Bar Mounting Holes 
 

LG SP9YA Bar Mounting Holes Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Bar Mounting Holes Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Satellite Mounting Holes 
 

LG SP9YA Satellite Mounting Holes Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Satellite Mounting Holes Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Mountable Bar 
 

Locked
Locked

Bar Brackets Included 
 

Locked
Locked

Mountable Satellites 
 

Locked
Locked

Satellite Brackets Included 
 

Locked
Locked

Build Quality 
 

N/A
N/A

Build quality photo 
 

LG SP9YA Build quality photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Build quality photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Show Text 

In The Box 
 

In The Box photo  
 

LG SP9YA In The Box photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 In The Box photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Show Text 
Sound

Stereo Frequency Response 
 

N/A
N/A

Stereo Setup 
 

LG SP9YA Stereo Setup Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Stereo Setup Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Raw Frequency Response  

LG SP9YA Raw Frequency Response Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Raw Frequency Response Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Frequency Response Small  

LG SP9YA Frequency Response Small Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Frequency Response Small Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Channels 
 

Locked
Locked

Tested Preset 
 

Locked
Locked

Slope 
 

Lock
Lock

Standard Error 
 

Lock dB
Lock dB

Low-Frequency Extension 
 

Lock Hz
Lock Hz

High-Frequency Extension 
 

Lock kHz
Lock kHz
Show Text 

Stereo Frequency Response With Preliminary Calibration 
 

N/A
N/A

Frequency Response Calibrated  

LG SP9YA Frequency Response Calibrated Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Frequency Response Calibrated Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Suggested Preset 
 

Locked
Locked

Suggested Bass Setting 
 

Lock
Lock

Suggested Treble Setting 
 

Lock
Lock

Slope 
 

Lock
Lock

Standard Error 
 

Lock dB
Lock dB

Low-Frequency Extension 
 

Lock Hz
Lock Hz

High-Frequency Extension 
 

Lock kHz
Lock kHz
Show Text 

Stereo Soundstage 
 

N/A
N/A

Crosstalk  

LG SP9YA Crosstalk Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Crosstalk Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Crosstalk Error 
 

Lock dB
Lock dB
Show Text 

Stereo Dynamics 
 

N/A
N/A

Dynamic Range Compression  

LG SP9YA Dynamic Range Compression Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Dynamic Range Compression Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

SPL @ Max Volume 
 

Lock dB SPL
Lock dB SPL

DRC @ 90dB 
 

Lock dB

DRC @ Max Volume 
 

Lock dB
Lock dB
Show Text 

Stereo Total Harmonic Distortion 
 

N/A
N/A

THD  

LG SP9YA THD Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 THD Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Weighted THD @ 80dB 
 

Lock

Weighted THD @ Max Volume 
 

Lock
Show Text 

Center 
 

N/A
N/A

Center Setup 
 

LG SP9YA Center Setup Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Center Setup Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Frequency Response  

LG SP9YA Frequency Response Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Frequency Response Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Localization 
 

Locked
Locked

Slope 
 

Lock
Lock

Std. Err. 
 

Lock dB
Lock dB

SPL @ Max Volume 
 

Lock dB SPL
Lock dB SPL

Weighted THD @ 80dB 
 

Lock
Lock

Weighted THD @ Max Volume 
 

Lock
Lock
Show Text 

Surround 5.1 
 

N/A
N/A

Surround Setup 
 

LG SP9YA Surround Setup Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Surround Setup Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Frequency Response  

LG SP9YA Frequency Response Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Frequency Response Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Localization 
 

Locked
Locked

Slope 
 

Lock
Lock

Std. Err. 
 

Lock dB
Lock dB

SPL @ Max Volume 
 

Lock dB SPL
Lock dB SPL

Weighted THD @ 80dB 
 

Lock
Lock

Weighted THD @ Max Volume 
 

Lock
Lock

7.1 Rears 
 

Locked
Locked
Show Text 

Height (Atmos) 
 

N/A
N/A

Height Setup 
 

LG SP9YA Height Setup Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Height Setup Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

H Frequency Response  

LG SP9YA H Frequency Response Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 H Frequency Response Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Localization 
 

Locked
Locked

Slope 
 

Lock
Lock

Std. Err. 
 

Lock dB
Lock dB

SPL @ Max Volume 
 

Lock dB SPL
Lock dB SPL

Weighted THD @ 80dB 
 

Lock
Lock

Weighted THD @ Max Volume 
 

Lock
Lock
Show Text 

Sound Enhancement Features 
 

N/A
N/A

Room Correction 
 

Locked
Locked

Dialogue Enhancement 
 

Locked
Locked

Auto-Volume/Night Mode 
 

Locked
Locked

Subwoofer Level Adjustment 
 

Locked
Locked

Bass Adjustment 
 

Locked
Locked

Treble Adjustment 
 

Locked
Locked

EQ 
 

Locked
Locked

Surround Level Adjustment 
 

Locked
Locked

Rear Level Adjustment 
 

Locked
Locked

Height Level Adjustment 
 

Locked
Locked

Virtual Surround 
 

Locked
Locked
Show Text 
Connectivity

Inputs/Outputs - Bar 
 

Physical Connections Bar Photo 1 
 

LG SP9YA Physical Connections Bar Photo 1 Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Physical Connections Bar Photo 1 Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Physical Connections Bar Photo 2 
 

LG SP9YA Physical Connections Bar Photo 2 Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Physical Connections Bar Photo 2 Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Optical Audio In 
 

Locked
Locked

HDMI ARC 
 

Locked

HDMI Out 
 

Locked
Locked

HDMI 2.1 Class Bandwidth 
 

Locked

Full HDMI In 
 

Locked
Locked

Analog Audio In 3.5mm (Aux) 
 

Locked
Locked

RCA In 
 

Locked
Locked

USB for Files 
 

Locked
Locked

Ethernet 
 

Locked
Locked

Subwoofer Output 
 

Locked
Locked
Show Text 

Audio Format Support: ARC/eARC 
 

N/A
N/A

Dolby Atmos 
 

Locked
Locked

Dolby Digital 
 

Locked
Locked

Dolby Digital Plus 
 

Locked
Locked

Dolby TrueHD 
 

Locked
Locked

DTS 
 

Locked
Locked

DTS:X 
 

Locked
Locked

eARC 
 

Locked

DTS-HD MA 
 

Locked
Locked

PCM Channels 
 

Locked

5.1 PCM (eARC only) 
 

Locked
Show Text 

Audio Format Support: HDMI In 
 

N/A
N/A

Dolby Atmos 
 

Locked
Locked

Dolby Digital 
 

Locked
Locked

Dolby Digital Plus 
 

Locked
Locked

Dolby TrueHD 
 

Locked
Locked

DTS 
 

Locked
Locked

DTS:X 
 

Locked
Locked

DTS-HD MA 
 

Locked
Locked

PCM Channels 
 

Locked

5.1 PCM 
 

Locked
Show Text 

Audio Format Support: Optical 
 

N/A
N/A

Dolby Digital 
 

Locked
Locked

DTS 
 

Locked
Locked

PCM Channels 
 

Locked
Show Text 

Audio Latency: ARC 
 

N/A
N/A

ARC Latency Video  

LG SP9YA ARC Latency Video Sample

SAMPLE

GET INSIDER ACCESS

To see product videos

Vizio M Series M51ax-J6 ARC Latency Video Sample

SAMPLE

GET INSIDER ACCESS

To see product videos

PCM-2.0 ch 
 

Lock ms

PCM-5.1 ch 
 

Lock ms

Dolby MAT (PCM) Atmos 
 

Lock ms

Dolby Digital 
 

Lock ms

Dolby Digital Plus 
 

Lock ms

Dolby Digital Plus Atmos 
 

Lock ms
Show Text 

Audio Latency: HDMI In 
 

N/A
N/A

HDMI Latency Video  

LG SP9YA HDMI Latency Video Sample

SAMPLE

GET INSIDER ACCESS

To see product videos

Vizio M Series M51ax-J6 HDMI Latency Video Sample

SAMPLE

GET INSIDER ACCESS

To see product videos

Latency Video  

LG SP9YA Latency Video Sample

SAMPLE

GET INSIDER ACCESS

To see product videos

Vizio M Series M51ax-J6 Latency Video Sample

SAMPLE

GET INSIDER ACCESS

To see product videos

PCM-2.0 ch 
 

Lock ms

PCM-5.1 ch 
 

Lock ms

Dolby MAT (PCM) Atmos 
 

Lock ms

Dolby Digital 
 

Lock ms

Dolby Digital Plus 
 

Lock ms

Dolby Digital Plus Atmos 
 

Lock ms

ARC 
 

Lock ms

Optical 
 

Lock ms

Full HDMI In 
 

Lock ms
Show Text 

Audio Latency: Optical 
 

N/A
N/A

Optical Latency Video  

LG SP9YA Optical Latency Video Sample

SAMPLE

GET INSIDER ACCESS

To see product videos

Vizio M Series M51ax-J6 Optical Latency Video Sample

SAMPLE

GET INSIDER ACCESS

To see product videos

PCM-2.0 ch 
 

Lock ms

Dolby Digital 
 

Lock ms
Show Text 

Video Passthrough To TV 
 

N/A
N/A

1080p Max Refresh Rate 
 

Locked

1080p @ 4:4:4 Max Refresh Rate 
 

Locked

4k Max Refresh Rate 
 

Locked

4k @ 120Hz @ 10-Bit 
 

Locked

4k @ 4:4:4 Max Refresh Rate 
 

Locked

8k Max Refresh Rate 
 

Locked

HDR10 Passthrough 
 

Locked
Locked

HDR10+ Passthrough 
 

Locked

Dolby Vision Passthrough 
 

Locked

HDMI Forum VRR Passthrough 
 

Locked

4k @ 60 Hz Passthrough 
 

Locked

FreeSync Passthrough 
 

Locked

G-SYNC Passthrough 
 

Locked

ALLM Passthrough 
 

Locked

4k @ 60 Hz @ 10 bit Passthrough 
 

Locked

4k @ 60 Hz @ 4:4:4 Passthrough 
 

Locked
Show Text 

Wireless Playback 
 

N/A
N/A

Bluetooth 
 

Locked
Locked

Wi-Fi Playback 
 

Locked
Locked

Chromecast built-in 
 

Locked
Locked

Apple AirPlay 
 

Locked
Locked

Spotify Connect 
 

Locked
Locked
Show Text 
Additional Features

Interface 
 

Interface photo 
 

LG SP9YA Interface photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Interface photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Display 
 

Locked
Locked
Show Text 

Bar Controls 
 

Controls photo 
 

LG SP9YA Controls photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Controls photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Show Text 

Remote  

Remote photo 
 

LG SP9YA Remote photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Vizio M Series M51ax-J6 Remote photo Sample

SAMPLE

GET INSIDER ACCESS

To see pictures and test results

Show Text 

Voice Assistants Support 
 

Amazon Alexa 
 

Locked
Locked

Google Assistant 
 

Locked
Locked

Apple Siri 
 

Locked
Locked

Microphone Mute 
 

Locked
Locked
Show Text 

Check Price

Black
SP9YA
SEE PRICE
Amazon.com
Dark Charcoal
M Series M51ax-J6
SEE PRICE
Amazon.com
Black
SP9YA
SEE PRICE
BestBuy.com
Dark Charcoal
M Series M51ax-J6
SEARCH
B&H
Black
SP9YA
SEE PRICE
Walmart.com
Dark Charcoal
M Series M51ax-J6
SEARCH
BestBuy.com
Black
SP9YA
SEARCH
B&H
Dark Charcoal
M Series M51ax-J6
SEARCH
Vizio
Black
SP9YA
SEARCH
LG.com
Dark Charcoal
M Series M51ax-J6
SEARCH
Walmart.com
Back to Top

LG SP9YA

Vizio M Series M51ax-J6

Comments

  1. Comparison
 • Posted 1 year ago

LG SP9YA vs Vizio M Series M51ax-J6: Main Discussion

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