Wait a moment, the part version No. on my GX, which built in Jan 2025 was 1300. the part No is 86280-60890. I guess 1200 was the version No. for TX?
Mark Levinson 21-speaker audio sounds terrible on the GX 550 Luxury + (2 Viewers)
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I have the same part number and version as you do and I’m not experiencing any audio difficulties or performance issues. My vehicle was built in July 2025 and delivered in late August 2025 .
A few weeks ago, I was using ChatGPT to aggregate some data related to this issue as well as the TSB that fixed the issue in the Lexus TX. The following is the final output that resulted from a series of prompts asking if the Mark Levinson issue had been addressed in my specific 2025 GX550 Overtrail+:
On your AP SW screen you now have:
- Parts no.: 86280-60891
- Version: 1400
Here’s how that lines up:
Known TX “fix” reference
- The TX TSB (L-SB-0029-25) ties the correction to amplifiers in the 86280-0E3xx family, with software versions in the 13xx–14xx range after replacement. Owners report the fixed units show “Version 1400” (or higher) on their AP SW screen.
GX situation
- The GX550’s amplifier family is different: 86280-6089x, not 0E3xx. Catalogs list 86280-60890 as the “base” ML amp. Yours (…60891) is a later revision not yet tied to a public bulletin.
- The fact your software version is 1400 suggests you’re running the same generation of firmware that TX owners describe as the “fixed” set. That’s a positive indicator that your amp revision incorporates similar updates.
- But: Lexus hasn’t published a GX bulletin or campaign, so there’s no official confirmation that 60891/1400 is the GX equivalent of the TX fix. It looks promising, but not “documented.”
Bottom line
Your GX’s 86280-60891, Version 1400 strongly suggests you have a newer Mark Levinson amplifier revision with updated firmware, analogous to the TX’s fixed amps.
However, since the TSB is TX-only, Lexus hasn’t formally declared this a GX “fix.” So functionally you likely benefit from the update, but it isn’t recognized as a campaign item for your VIN.
I hope that this is useful to some of the members of the forum following this thread!
My July 2025 production Luxury+ also has the 86280-60891 amp, version 1400.
The bass does not appear to fade in and out, but the default frequency response and fader tuning is still pretty garbage, IMO. The 120-200hz-ish region of male voices is super over emphasized and "woof-y", like a poorly integrated, overpowered sub. I still get very little volume when fading the audio to the rear speakers.
My "okay enough, but not in love" tuning is to fade the audio to the rear two clicks, and turn down the treble by one click. I keep speed-sensitive volume and surround sound both on, because the speed sensitive volume seems to be very specifically tuned to the surround sound frequency response; bass and treble seem to get really oddly emphasized if I disable surround sound. It's a bummer, because I think surround sound worsens & disperses the pinpoint spatial imaging of vocalists.
The bass does not appear to fade in and out, but the default frequency response and fader tuning is still pretty garbage, IMO. The 120-200hz-ish region of male voices is super over emphasized and "woof-y", like a poorly integrated, overpowered sub. I still get very little volume when fading the audio to the rear speakers.
My "okay enough, but not in love" tuning is to fade the audio to the rear two clicks, and turn down the treble by one click. I keep speed-sensitive volume and surround sound both on, because the speed sensitive volume seems to be very specifically tuned to the surround sound frequency response; bass and treble seem to get really oddly emphasized if I disable surround sound. It's a bummer, because I think surround sound worsens & disperses the pinpoint spatial imaging of vocalists.
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Wife and I had a dance party on the way home from the dealership.
I have a home studio and some audiophile quality equipment.
I turned the bass down to just over 55%, the mid down to about…35-40% and set the treble to about 60%, and I moved “center” to about 55-60% toward the front speakers and that seemed to remove the low end mud and cleaned up the mids.
The branded product is just a marketing gimmick. I fell for it with my 2012 Highlander Limited’s JBL system, which honestly may sound better.
But, it’s important to remember that listening to music in a car is not like listening to a live symphony in Viennese music hall.
So, yeah, probably not worth it, or, pay for it because it’s probably better than the factory default….maybe.
Similar thoughts on my September-build Luxury+ that was delivered last week. I'm withholding too much judgement as I did experience a very similar acclimatization to my '17 GS350 ML system, with notable differences.
For reference, I'm a hi-fi enthusiast with multiple high-end stereo setups at home, my latest built around two floor-standing transmission-line speakers that are flat down to 25 Hz powered by a 300 watt Class-A hybrid amp.
While driving, I almost exclusively listen to high-bitrate MP3 or FLAC files from my Android phone via Bluetooth, using the wonderful Poweramp app. At first my '17 GS's ML system sounded insultingly thin. I had only been able to test drive a base-stereo equipped-GS prior. After finding similar threads online at the time, I discovered that disabling surround sound & speed sensitive volume, coupled with tuning the 3-band EQ (coupled with tweaking parameters in Poweramp) transformed it into one of the best car sound systems I've heard (and best I've owned). My favorite test track is the Peter Gabriel-Genesis song "The Chamber of 32 Doors" - the bass, among other details in this track, is incredible and in my GS it's quite the experience.
Back to the '25 GX - I've found like others that it is heavily front-biased and the liftgate-mounted sub is of little consequence as opposed to the sub in the GS. This is also due to the GX's lack of rear door woofers. Where my GS can withstand almost mazixing out the EQ bass, in the GX I'm experiencing distortion in the front-door woofers above 65% or so with 'indie' rock (from bands like the Charlatans that aren't terribly bass-heavy) - this is with the fader set to middle.
I'm keeping mids near 50% as the front mid drivers get a canned sound above that. This is the only way I can achieve a bit of a 'punchy' bass-emphasized sound that I prefer but it easily leads to overdriving the front door woofers which have to carry too much of the mid-bass load.
With time I'm growing accustomed to the sound profile of the GX ML but do find it a missed opportunity to provide a richer sound experience in such a premium vehicle. Like others have suggested, even just having a separate subwoofer level adjustment could provide a marked improvement. The biggest disappointment for me is that where my GS ML system can be significantly augmented by the output device EQ (my phone), the GX ML system is far less robust. I'm not sure why you'd tout the speaker count or system wattage when it is overall a fairly thin-sounding system lacking the fullness of many 'base' audio setups. Enthusiasts seeking those specs will hear the system's lack thereof.
I'll keep tweaking settings and hoping for the best.
Let us know if you're able to tweak the settings to your liking!
Here is a suggestion from another forum that could be beneficial. I have yet to take delivery of my 550 so I cannot test & report.
forum.ih8mud.com
Mark Levinson - Spotify Equalization setting for me
Hi all, If you have seen my other posts you will know I am not a fan of the Mark Levinson audio in the GX550. I’d still tell people to not buy it/seek it out as a paid option. Having said that after much playing with the Spotify playback equalization curves (available on the paid-for...
forum.ih8mud.com
That's my workaround right now, although it's in the music app I use to listen to my own FLAC/MP3 files (Poweramp). Same idea, and it does offer some improvement, although it's a bit tricky in that the GX ML system seems to be very sensitive to low frequencies due to the way it's designed and laid out.
With the built-in 3-band equalizer flat in my '17 GS350, the ML system seemed a bit flat and thin, but tweaking that along with the Poweramp EQ worked wonders, revealing a very strong system. In the GX, it's tough because the front door woofers easily get overloaded and distort with very tame source material and EQ levels. Certain more modern tracks really give it fits, but then you have to crank up the low end on older classic rock, for instance. Hard to find levels that work for everything in an eclectic collection.
I'm not sure if it's break-in or just my acclimation to the system, but I'm marginally more pleased with how it sounds lately - but if you move the fader to center, there's very little quality sound for the second row.
I want to correct my post here. I just experienced some sort of bass limiting in my car.
I was switching from quieter vocal jazz to heavy hitting phonk bass music just after starting my car this weekend and the car definitely cut out the majority of the bass 1-2 minutes into the song. Afterwards, the bass was anemic and mega disappointing. I hope my car qualifies for a potential future amp replacement like the TXs.
What's fascinating is the car had what I thought was way too much bass when the song started, and then way too little bass afterwards. I wonder if it's part of some dynamic frequency response algorithm based on the music or whether it's just straight up safety protection. Either way, it doesn't live up to the Mark Levinson systems in older Lexuses. Disappointing.
GX550 Forum Photos
GX550 Forum Photos
