I think alot of the issues people are having with the ML can be fixed by fading it a bit into the back seats. Centered, the sound stage is too far forward (typical of ML and new cars) as well as "narrow". In the drive seat you sound stage is between the center dash speaker and the left. Fade it behind you to the front to middle of the rear seats and turn it up a bit. Bass is always going to be an issue on stock units but the mid bass is very good if you tune bass up a bit. Highs are ok, mids are muddy like most systems. Its not the worst system and its only $1k over the stock. So in reality you aren't getting a big difference than stock, some more speakers and a different tune on the amp/different amp. Alot of the issues are likely via the tune on the amp. I'm talking to a shop about bypassing the amp and adding a new 12 channel that can be tuned, tbd but assuming it will make a much higher impact than if in 5 years Lexus recalls the ML amp (which is likely locked and will never have a TSB).
Mark Levinson 21-speaker audio sounds terrible on the GX 550 Luxury + (2 Viewers)
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So we've heard.
That won't do anything to fix the bass cutout at higher volumes though. A fix is coming soon. Just make sure to get it documented with your dealer so you can get on the list for a replacement amp.
I also set the bass higher than I think it "should" be and pushed the fade to the rear - and surprisingly, it did remove the bass cut-off and overall does sound much better. I can put it to max and never have cut-off. Doesn't make any sense but it's what I hear?! All I can think of is that amp will only send lower frequencies up to a certain dB, and when you push the fade back, the fronts never see the same dB and don't cut-off? All just a guess. Not suggesting it shouldn't be fixed, but this workaround seems to do the trick.
What is your source that they are working on a new amp or just assuming bc they did it for the TX
Service manager at my dealership. He had spoken with Lexus (after documenting the issue) and was told that a fix for the GX amp is expected "this fall", likely an amp replacment similar to the TX.
Someone posted this on the Lexus LH forum, and to my untrained ear, it really helped a lot. Also, bass hasn't cut out since I tried this. Sound improvement is especially noticeable at mid/low volumes. Sound is subjective, but maybe worth a try to see if it helps.
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That's a partial workaround, not a fix. Hang tight. There will be replacement amps coming.
Hope they replace the amps too of course! Yes, it is a workaround for the amp issue, but many (me included) think it just sounds better with these settings, so worth a try. Sound is subjective, so some will like it, and some won't. Seems to help with the lack of bass, especially at low/mid volumes. Anybody just go to a car stereo shop and replace the amp? I don't know much about that, so may not be a reasonable solution. And of course, we shouldn't have to pay to fix a Lexus problem.
All in all, I love my new GX. Looks so good. 2025 Luxury in Nori Green. Just picked it up yesterday. Replaced a 2017 Toyota Highlander, so big upgrade for me.
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Fixes are starting to flow in - transmission TSB available now, new amps under production, hood fix well known. You'll get there. Just work with your dealer so you're on the list for any needed repairs or service tasks. The only item on my list they haven't yet addressed (AFAIK) is the way that the audio source doesn't lower volume adequately when Siri is active with CarPlay. Easily fixable with software also.
Great upgrade and lovely color!
Please allow me to momentarily de-lurk...
Hello fellow Lexus owners . I also have a new OT+ with the ML issue. I've nearly worn out the strangely restricted DSP controls for tone and balance to no avail.
Regarding front-rear balance, for an even balance, I need to set the fade about %75 rear.
This situation is quite the quagmire and so far, we're all a long way from a "premium experience".
While waiting on the amp / software update, I'm learning about a disturbing trend and I'm surprised it's not more of a "thing" among audio types yet.
Apparently, the Lexus Mark Levinson system in the GX 550 Overtrail+ (and other models) uses a closed, proprietary digital loop 'to ensure a consistent and optimized audio experience'.
This design provides specific benefits but also creates significant limitations for owners, particularly when facing issues like poor sound quality.
Aftermarket customization isn't possible with the stock ML system.
Without a costly upgrade starting ~$2,000 (or considerably more), affected owners can't do any of these:
1. Use an external DAC (Digital-to-Analog Converter).
2. Install an analog input of any type.
3. Swap the amplifier.
4. Fine-tune the DSP.
5. Independently replace speakers.
6. Add a standalone subwoofer.
7. Replace the head unit.
8. External EQ or other signal processing.
The upgrade consists of a new DSP and other equipment, installation and system tuning.
The factory amp and DSP form a single, non-separable unit
This upgrade isn't a simple swap but a total system overhaul.
In addition to a new DSP, an upgrade of this type would typically include the following:
1. Line Output Converter (LOC) or DSP with high-level inputs.
2. Vehicle-specific wiring harness.
3. Remote turn-on trigger - Will allow the new DSP and amplifier to power on and off with the vehicle.
4. New 5 or 6 channel amplification and wiring. The factory Mark Levinson amplifier will be fully bypassed.
5. New speakers: The factory speakers were designed to work with the Mark Levinson DSP, they may not perform optimally with the new system.
Most audiophiles or high-end car audio shops would recommend replacing at least the most critical speakers to take full advantage of the new components.
6. Speaker wiring: New speaker wires from the aftermarket amplifiers to each speaker is often necessary.
7. Sound-dampening materials and acoustic treatment.
8. Expert installation: This is not a DIY job for a closed-loop system.
9. System tuning.
It's not just Lexus, this type of proprietary closed-loop audio systems is a trend in the automotive industry.
Setups like this also include additional "fun features":
1. Inaccessible settings: The detailed EQ, time alignment, and crossover settings are locked within the DSP and are not accessible to the end-user or even most audio technicians.
Only Lexus can provide the correct software updates to change these settings.
2. Systemic flaw vulnerability: A systemic, widespread problem can result from a flaw in the initial factory tuning or hardware, possibly leading to an issue that affects
all vehicles with that specific setup. This is what appears to have happened with the weak bass and phasing issues in the Mark Levinson systems of the GX 550 and TX.
3. Dependent on manufacturer fixes: Since the system is locked down, any major issues require a fix directly from Lexus, such as a software flash delivered via a technical service bulletin (TSB).
This combined with the increasing integration of other system components (like HVAC) into "infotainment systems", leaves me wondering about the future of car audio.
Hello fellow Lexus owners . I also have a new OT+ with the ML issue. I've nearly worn out the strangely restricted DSP controls for tone and balance to no avail.
Regarding front-rear balance, for an even balance, I need to set the fade about %75 rear.
This situation is quite the quagmire and so far, we're all a long way from a "premium experience".
While waiting on the amp / software update, I'm learning about a disturbing trend and I'm surprised it's not more of a "thing" among audio types yet.
Apparently, the Lexus Mark Levinson system in the GX 550 Overtrail+ (and other models) uses a closed, proprietary digital loop 'to ensure a consistent and optimized audio experience'.
This design provides specific benefits but also creates significant limitations for owners, particularly when facing issues like poor sound quality.
Aftermarket customization isn't possible with the stock ML system.
Without a costly upgrade starting ~$2,000 (or considerably more), affected owners can't do any of these:
1. Use an external DAC (Digital-to-Analog Converter).
2. Install an analog input of any type.
3. Swap the amplifier.
4. Fine-tune the DSP.
5. Independently replace speakers.
6. Add a standalone subwoofer.
7. Replace the head unit.
8. External EQ or other signal processing.
The upgrade consists of a new DSP and other equipment, installation and system tuning.
The factory amp and DSP form a single, non-separable unit
This upgrade isn't a simple swap but a total system overhaul.
In addition to a new DSP, an upgrade of this type would typically include the following:
1. Line Output Converter (LOC) or DSP with high-level inputs.
2. Vehicle-specific wiring harness.
3. Remote turn-on trigger - Will allow the new DSP and amplifier to power on and off with the vehicle.
4. New 5 or 6 channel amplification and wiring. The factory Mark Levinson amplifier will be fully bypassed.
5. New speakers: The factory speakers were designed to work with the Mark Levinson DSP, they may not perform optimally with the new system.
Most audiophiles or high-end car audio shops would recommend replacing at least the most critical speakers to take full advantage of the new components.
6. Speaker wiring: New speaker wires from the aftermarket amplifiers to each speaker is often necessary.
7. Sound-dampening materials and acoustic treatment.
8. Expert installation: This is not a DIY job for a closed-loop system.
9. System tuning.
It's not just Lexus, this type of proprietary closed-loop audio systems is a trend in the automotive industry.
Setups like this also include additional "fun features":
1. Inaccessible settings: The detailed EQ, time alignment, and crossover settings are locked within the DSP and are not accessible to the end-user or even most audio technicians.
Only Lexus can provide the correct software updates to change these settings.
2. Systemic flaw vulnerability: A systemic, widespread problem can result from a flaw in the initial factory tuning or hardware, possibly leading to an issue that affects
all vehicles with that specific setup. This is what appears to have happened with the weak bass and phasing issues in the Mark Levinson systems of the GX 550 and TX.
3. Dependent on manufacturer fixes: Since the system is locked down, any major issues require a fix directly from Lexus, such as a software flash delivered via a technical service bulletin (TSB).
This combined with the increasing integration of other system components (like HVAC) into "infotainment systems", leaves me wondering about the future of car audio.
Great information but why is the speaker replacement an issue?
Hey sids,
That's a great question, and it gets to the heart of why modern, premium factory audio systems are so difficult to upgrade.
The short answer is that the system's amplifier and speakers are designed as a single, interdependent unit. Swapping in different speakers, even if they are high-quality, will almost certainly throw the entire system out of whack. It's like replacing a part in a highly tuned, custom-built engine with one that doesn't match—the whole thing performs worse.
Here’s a more detailed breakdown:
- Fixed Digital Tuning: Every Mark Levinson system is precision-tuned at the factory for the specific speakers installed in your GX 550. This "snapshot" tuning is stored in a Digital Signal Processor (DSP) within the amplifier. The DSP adjusts for things like:
- Speaker flaws: It corrects for the cheap materials or frequency response imperfections of the factory speakers.
- Cabin acoustics: It accounts for how sound bounces off the vehicle's unique interior materials and shape.
- Sound timing: It adjusts the timing of each speaker to ensure the sound from all channels reaches your ears simultaneously, creating a precise soundstage.
Swapping speakers means the DSP's perfect "snapshot" is now working with speakers it doesn't recognize. The equalization will be all wrong, and the audio will almost certainly sound worse, not better.
- The Impedance Trap: This is a huge technical obstacle. The Mark Levinson amplifier and its speakers have a specific impedance (electrical resistance) that they are designed to work with.
- Amp protection: Most aftermarket speakers have an impedance of 4 ohms, but Mark Levinson systems are known to use speakers with unusually high impedances (often 8 ohms or more).
- Reduced performance: If you connect a low-impedance aftermarket speaker to the high-impedance Mark Levinson amp, it can cause the amp to strain, overheat, or go into a protection mode, reducing power output and hurting sound quality.
- Warranty risk: At best, you get disappointing sound. At worst, you could damage the expensive factory amplifier and void your warranty.
- Modern Systems are "Closed-Loop": The system is a closed loop, where the speakers, amp, and DSP are inseparable. The only way to properly upgrade is to bypass the entire factory audio system, including the amplifier, and start from scratch with a new aftermarket system that can be correctly tuned. This is a massive project.
In my past life I was an installer. Tin Ear is pretty much spot on. If you need more bump in the ML system, just about the only thing you can do is tap the front door woofers for a high level input amplifier, for simplicity sake, one that has built in DSP.
I plan on attempting this when I eventually get my GX. Of course ill report back with detailed instructions for my valued forum members. I’ll be using one of the two mono amps:
I think I’ll wind up using the Kicker since it’s a much simpler design and they’re built in tuning is pretty darn good and also simple. I also have experience with this class amp with my BIL’s Wrangler install I did and couldn’t believe how much power these little things cranked out.
For a sub I’ll use the Dayton Audio RSS315HO-44 12" or if I can get my hands on another Peerless XLS 12” (but that’s almost an impossible find) which was one of the most musical subs I’ve ever heard. The model was XLS-P830500 I believe and last I checked you can’t just get one… you had to buy like 300 of them in bulk before the Tymphany factory would even talk to you. Group buy anyone? Haha.
Edit: For clarification, using the door woofers rather than the anemic subwoofer is your best bet as it’s likely to carry a broader frequency range than the sub in the tailgate. But for the benefit of all I’ll try both locations.
I plan on attempting this when I eventually get my GX. Of course ill report back with detailed instructions for my valued forum members. I’ll be using one of the two mono amps:
Kicker 47KEY500.1
Or the expensive:JL Audio VX600/1i
I think I’ll wind up using the Kicker since it’s a much simpler design and they’re built in tuning is pretty darn good and also simple. I also have experience with this class amp with my BIL’s Wrangler install I did and couldn’t believe how much power these little things cranked out.
For a sub I’ll use the Dayton Audio RSS315HO-44 12" or if I can get my hands on another Peerless XLS 12” (but that’s almost an impossible find) which was one of the most musical subs I’ve ever heard. The model was XLS-P830500 I believe and last I checked you can’t just get one… you had to buy like 300 of them in bulk before the Tymphany factory would even talk to you. Group buy anyone? Haha.
Edit: For clarification, using the door woofers rather than the anemic subwoofer is your best bet as it’s likely to carry a broader frequency range than the sub in the tailgate. But for the benefit of all I’ll try both locations.
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Adding on, I used to advise people to buy a vehicle with the cheapest audio it can come with. In fact, if you had an option to get a new car with a hole in the dash to get that and add your aftermarket system then. Now these days I tell people the opposite because systems are so damn integrated. But today’s ML Lexus systems seem to be an outlier along with a growing list of other manufacturers.
Thanks remmy. Let us know how it goes.
Thanks Remmy. I don't know a lot about car audio, but would love to find a way to get more bass without a huge investment or worry about an installer tearing the car apart. Are you saying that this one amplifier could be used to improve the woofers in the front doors, while keeping the rest of the factory system intact? Can one amp be used for both speakers? Where do you think this amp could be mounted to be as discrete as possible? And you think this can all be done even with all the issues Tin Ear brought up? Thanks so much for this info.
No. I’m implying an external aftermarket amplifier with aftermarket subwoofer is a solution. Everyone complains the system has no bottom end.
The signal wiring would likely tap off the front door drivers. I suppose a specialized LoC could also sum the subwoofer channel but I don’t know how effective that would be since users report little actual sound from the factory tailgate sub.
The Kicker brand amplifier is tiny compared to typical subwoofer “mono block” amplifiers. Like really tiny and can go down to 1ohm stable which people here who know, know that’s crazy… in a good way.
I haven’t had a good sit down with a GX yet but I’d wager this amp could be squeezed into almost anywhere.
I’ve attached a pic of the install I did in my BiL’s Jeep last year. Mounted next to it is the 4 channel version as well. Being in a Wrangler you can see how small they are. Very impressive for their size.
The signal wiring would likely tap off the front door drivers. I suppose a specialized LoC could also sum the subwoofer channel but I don’t know how effective that would be since users report little actual sound from the factory tailgate sub.
The Kicker brand amplifier is tiny compared to typical subwoofer “mono block” amplifiers. Like really tiny and can go down to 1ohm stable which people here who know, know that’s crazy… in a good way.
I haven’t had a good sit down with a GX yet but I’d wager this amp could be squeezed into almost anywhere.
I’ve attached a pic of the install I did in my BiL’s Jeep last year. Mounted next to it is the 4 channel version as well. Being in a Wrangler you can see how small they are. Very impressive for their size.
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Over the last few days, not sure if my speakers "broke in", but the system sounds so much better. On the Facebook Mark Levinson group, the recalled TX amps were all version 1200 or 1201, and the improved amps were all 1400 and 1401. All the posts on GX amps I have seen have part number 86280-60890 and version 1200, but looks like I have part number 86280-60891 and version 1400, so I'm wondering if I have a new amp? I have only had my GX for a few weeks. If this is correct, I thought maybe this could be good news that perhaps they are acknowledging a problem with the GX too, and perhaps they have a corrected amp that they are now installing in new builds. Seems like this could lead to a TSB being issued for GX and everyone can get the upgraded amp? Does any other GX owner have this part number and version? You can check by going to Settings>Software Update>Model Info, then scrolling down to AP SW section for Parts No. and Version.
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