ML System No Rear Bass Speaker

[Caiya]

I purchased the gx550 Overtrail plus with ML system in it. The first impression of the ML system is not worth the 1000+ price. My previous car was a Volvo xc60 with B&W speaker, it sounded absolutely amazing, but this ML is just so so. After driving for 4000 miles and I realized there’s no bass sound at the back. I also found the video other people taking the rear door panel off and this is what the bass speaker looks like. Lexus come on.

 

[TexLex]

I wonder if we can swap out w a better speaker.

 

[Franz]

I also have no sound coming from the bottom set of speakers in the rear doors. I have the lux+.

 

[NoriGreen]

I purchased the gx550 Overtrail plus with ML system in it. The first impression of the ML system is not worth the 1000+ price. My previous car was a Volvo xc60 with B&W speaker, it sounded absolutely amazing, but this ML is just so so. After driving for 4000 miles and I realized there’s no bass sound at the back. I also found the video other people taking the rear door panel off and this is what the bass speaker looks like. Lexus come on.

What is that? It’s a speaker?

 

[Rkdgto]

No audio from rear hatch speaker. Very dissapointed in this 1k upgrade.

 

[ilumo]

I also have no sound coming from the bottom set of speakers in the rear doors. I have the lux+.

Interesting. How are you testing this? I might want to have a look as well.

 

[Franz]

Interesting. How are you testing this? I might want to have a look as well

I listened to the front and rear bottom set of speakers. I also faded the sound from front to rear.

Update from dealership.
They removed the rear door panels and showed me the "dummy" speakers and said that all ML's were like this. The speaker map another forum member posted indicates otherwise.

 

[NoriGreen]

I listened to the front and rear bottom set of speakers. I also faded the sound from front to rear.

Update from dealership.
They removed the rear door panels and showed me the "dummy" speakers and said that all ML's were like this. The speaker map another forum member posted indicates otherwise.

So strange they'd put dummy speakers in. A simple cost cutting thing? Or maybe the dummy speakers there for a potential sound upgrade option in the future?

 

[Mainelexus]

Actually the speaker map does show them empty.

 

[Mainelexus]

So strange they'd put dummy speakers in. A simple cost cutting thing? Or maybe the dummy speakers there for a potential sound upgrade option in the future?

Someone said those blanks are for the non ml system.

 

[Franz]

Actually the speaker map does show them empty.

Someone posted these on another thread

 

[FLGX550]

Lux+ owner here. There are blank plastic speaker hole fillers in the rear doors of the ML equipped GX550’s. Yes, the connector is plugged in, but has no power going to it, and the plastic piece appears to only serves as a place holder for the speaker, and perhaps to maintain some rigidity in the door. Interestingly, the two other door speakers are mounted to the actual door panel, and come off with it, when you remove it from the vehicle. I may attempt to splice into the larger of the two door speakers, to add a 6.5” speaker to the bottom of the door. Just not sure how or if the factory amp has that speaker’s lower frequencies tuned out…in that case, it wouldn’t help much to add another speaker back there.
And, the door panel just pulls straight off, once you remove one screw behind the door handle and two from behind the door pull. Pull straight off, no lifting up on the top of the panel. All secured with push in clips.

 

[moosemountain62]

This is probably moot point, we test drove an OT+ in May last year…. I adjusted the EQ ML system which made some difference, but did NOT help or boost low end, like previous Lexus vehicles. Sadly, my wife’s eight year old GX (even mother In laws RX), blows the ML sound system away in the new GX550! With that said, my friend has a $97,000 loaded Silverado, it’s nice, however it’s been towed in three times….at only 8,400 mile, it’s got a pretty rad sound system if GM can keep it running … Maybe Lexus has slipped a bit but might still be the best brand….

 

[JBHorne]

I know this is a GX forum, but this is relevant even though I own a TX 500h. The ML system in the TX is very similar to the GX and is terribly tuned, specifically as low to mid volume. I have been leading a forceful initiative with Lexus to get this addressed, and have created a group with lots of info. In fact, I have a meeting later today with representatives from Lexus and Mark Levinson who are flying in. We will see how that goes and I will be posting an update later. I invite those from this forum to join my group, which I may expand to more models as this action progresses. There are also instructions on how to submit an executive case, which helps demonstrate to Lexus that this is an issue they must resolve.

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[M2L2024]

I know this is a GX forum, but this is relevant even though I own a TX 500h. The ML system in the TX is very similar to the GX and is terribly tuned, specifically as low to mid volume. I have been leading a forceful initiative with Lexus to get this addressed, and have created a group with lots of info. In fact, I have a meeting later today with representatives from Lexus and Mark Levinson who are flying in. We will see how that goes and I will be posting an update later. I invite those from this forum to join my group, which I may expand to more models as this action progresses. There are also instructions on how to submit an executive case, which helps demonstrate to Lexus that this is an issue they must resolve.

Facebook

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Happy to jump on the train and have submitted a FB request. Thanks for your efforts!
Regarding the ML system in the TX, does the output (volume and quality) significantly drop when the sound is faded towards the rear?

 

[serbiansizzle]

I also requested to join the group.

 

[JBHorne]

Happy to jump on the train and have submitted a FB request. Thanks for your efforts!
Regarding the ML system in the TX, does the output (volume and quality) significantly drop when the sound is faded towards the rear?

This will be a more in-depth and technical response, as I see this concern comes up frequently, even in TX groups. Before addressing the specifics, it's important to understand the reasoning behind why engineers make these design choices. These are my own opinions, coming from a self-proclaimed hobbyist audiophile.

I can only speak to the potential improvements in the TX, which may eventually be implemented in the GX, but understand the tuning is nowhere near the same (every ML component part number is different for example). Previously, fading the audio to the rear caused a near-total loss of bass response, even in the TX. This issue has been mitigated to an extent. The speaker placement was chosen based on a clear prioritization: first-row, second-row, and then third-row occupants, in that order. As with all system designs, this involves trade-offs and compromises are made based on the prioritized goals.

Optimizing for an exceptional third-row soundstage would require placing midrange drivers further toward the rear. However, this introduces a significant drawback—midrange frequencies are highly localizable, and their placement at the back could create a comb filtering effect, where sound waves from different locations arrive at the listener’s ears at slightly different times, causing phase interference and degradation in audio quality. The greater the physical separation between speakers, the more pronounced this effect becomes.

Low frequencies behave differently due to cabin gain and standing waves, which reinforce their omnidirectional nature. For instance, a 50 Hz wavelength measures approximately 6.86 meters (22.5 feet), longer than the vehicle itself, creating a sound field that is evenly distributed throughout the cabin. I can say that bass performance when faded towards the rear has improved. However, the original prioritization of the first and second rows still applies, so the third-row experience will never match the front-row fidelity.

Not to bash on aftermarket systems, but just upgrading (or adding) rear woofers, for example, without careful tuning introduces phase cancellation and spectral imbalances in many cases. This is why I would caution against prioritizing rear-fill enhancements at the expense of overall system coherence - "be careful what you wish for" logic. Mark Levinson’s decision to prioritize the front row is apparent and makes sense given these technical constraints.

Regarding the GX specifically, the subwoofer placement in the tailgate is not ideal. Many would likely prefer it to have been housed in the rear quarter panel rather than the tire inflator. However, my guess is that this decision was likely made before Mark Levinson's involvement in the system's final tuning, and once again, there were priorities and design compromises made.

Hope this helps!

 

[JBHorne]

So you somehow got a meeting, attended it and drank the cool-aid? It stil sounds bad, but for reasons?

One of the reasons I no longer post on forums is because people like you try to hide behind their keyboard, while people like me are actually getting things done. Like I said, and I included in my update in my Facebook group, I am very pleased with the outcome for my TX. I don't own a GX, and was just trying to provide some perspective here. It's people like you and others that have commented from the GX population that have really turned me off on providing any further assistance for your model. I was able to get Lexus and Mark Levinson to fly in a team of senior directors and chief engineers to meet with me, take this to the highest levels in Japan, and provide a solution that I am very content with, firsthand. I highly doubt you have done anything close to that, but I wish you the best of luck.

 

[vraa]

I was able to get Lexus and Mark Levinson to fly in a team of senior directors and chief engineers to meet with me, take this to the highest levels in Japan, and provide a solution that I am very content with, firsthand.

I look forward to seeing what changes Lexus and ML team suggest!

 

[M2L2024]

This will be a more in-depth and technical response, as I see this concern comes up frequently, even in TX groups. Before addressing the specifics, it's important to understand the reasoning behind why engineers make these design choices. These are my own opinions, coming from a self-proclaimed hobbyist audiophile.

I can only speak to the potential improvements in the TX, which may eventually be implemented in the GX, but understand the tuning is nowhere near the same (every ML component part number is different for example). Previously, fading the audio to the rear caused a near-total loss of bass response, even in the TX. This issue has been mitigated to an extent. The speaker placement was chosen based on a clear prioritization: first-row, second-row, and then third-row occupants, in that order. As with all system designs, this involves trade-offs and compromises are made based on the prioritized goals.

Optimizing for an exceptional third-row soundstage would require placing midrange drivers further toward the rear. However, this introduces a significant drawback—midrange frequencies are highly localizable, and their placement at the back could create a comb filtering effect, where sound waves from different locations arrive at the listener’s ears at slightly different times, causing phase interference and degradation in audio quality. The greater the physical separation between speakers, the more pronounced this effect becomes.

Low frequencies behave differently due to cabin gain and standing waves, which reinforce their omnidirectional nature. For instance, a 50 Hz wavelength measures approximately 6.86 meters (22.5 feet), longer than the vehicle itself, creating a sound field that is evenly distributed throughout the cabin. I can say that bass performance when faded towards the rear has improved. However, the original prioritization of the first and second rows still applies, so the third-row experience will never match the front-row fidelity.

Not to bash on aftermarket systems, but just upgrading (or adding) rear woofers, for example, without careful tuning introduces phase cancellation and spectral imbalances in many cases. This is why I would caution against prioritizing rear-fill enhancements at the expense of overall system coherence - "be careful what you wish for" logic. Mark Levinson’s decision to prioritize the front row is apparent and makes sense given these technical constraints.

Regarding the GX specifically, the subwoofer placement in the tailgate is not ideal. Many would likely prefer it to have been housed in the rear quarter panel rather than the tire inflator. However, my guess is that this decision was likely made before Mark Levinson's involvement in the system's final tuning, and once again, there were priorities and design compromises made.

Hope this helps!

Thanks @JBHorne!! Greatly appreciate the thorough reply and unfortunately, I kind of suspected something similar to your reply - figured the frontal prioritization is by purposeful design. I love the vehicle but like most of us unhappy with the audio quality, we expected much more from Lexus. I'm confident 99% of the people who read and understand the impact of your persistence are very impressed - thank you for "doing" vs just bitching. p.s. I also joined your FB group and have sent a constructive email to Andrew G.