notroman

iTrader: (1)

I want to ask here before I jump to the Facebook groups. I've owned my LS430 for 4 years now and the entire time the bass in the car has been very weak. I just assumed the ML system was not designed with bass in mind and continued on with my life. However, after being in several cars now with factory radios putting out significantly more bass and reading multiple people online say the stock system has noticeably strong bass it has started to bother me so I decided to see if I can dig in further. My experience with car audio is limited to just head unit installations so I'm hoping someone with more experience can help me out.

I tried turning up the bass level in audio settings and while it obviously increases the bass somewhat, it's hardly anything worth writing home about. I verified the rear sub is in fact an original Mark Levinson sub and the cone/foam seem to be in good shape. When music is playing, it does emit some bass although it's weak. I took the sub out and put a multimeter on the coil and it reads a consistent 12.4 ohms. I suspect this is low for a 16 ohm sub, but I could be wrong. The limited reading I've done on the subject says I should be seeing 13-15 ohms. Is accurate and if so, what does this mean? Is there anything else I could check while I have everything apart? I can put the multimeter on the plug coming from the harness to see how much power is coming through it but this is where my lack of knowledge becomes very apparent. Is it even something worth checking and what would I be measuring? The current? Maybe there are additional troubleshooting steps I can take that I am not aware of.

BigBoomer

That resistance is spot on. Nothing wrong with that Sub.
I suspect that you have an underperforming Sub channel in the Amplifier, so the Amp may be damaged.
I assume that the sub cone does move a little when you are playing something bassy?
If it doesn't move at all (rest your fingers lightly on the cone) then the Sub channel in the Amp is kaput!

notroman

iTrader: (1)

Correct, the cone does move a little. Overall the front speakers produce significantly more bass than the subwoofer in the rear which is a problem. I'll start looking at amps. It's always dicey buying them used since they are known to fail so much. Thank you.

alextv

That speaker looks awfully good for a car that old especially the LS430. My 2001 LS430UL is garaged in NC not a hot climate and all the foam etc had deteriorated about 90%. There are foam kits available specifically to repair these speakers and if not done properly can make the assembly too stiff. If that was done to yours that could be the problem. Yours looks too good and was either replaced or repaired. Being too stiff would cause the symptom you describe.

demark1

FWIW, my car has that exact issue. I adore the ML system, it was best/clearest ever. But bass has gotten weaker. I find that I push up bass in the tone controls and also set car to emphasize rear speakers more on the fader.

I listen to classical primarily, and Strauss waltzes (like the Emperor, with punchy bass parts) as a test/indicator.

Honestly, I thought my hearing was going, and it may be a bit, but I expected that to be a high-frequency drop rather than bass. I took off the back speaker cover and it looks GREAT and still plays. So it's my hearing, or imagination, or the system has changed over the years. I am honestly not 100% sure which.

Yamae

That must be the problem caused by the power supply circuit. There is a voltage boost circuit inside of it and aged ML amplifiers tend to have this problem.

Most of failures are caused by the leaking electrolytic capacitors there and a skilled guy would fix it simply replacing those but sometimes semiconductors are failed though.

ML's engineers preferred to use capacitors that contained QAS (Quaternary Ammonium Salt) like ECUs for LS400 had used those. QAS capacitors provide good performances even at cold circumstances but the lifespan is much shorter than conventional electrolytic capacitors due to the corrosion of lead wires and the QAS leaks out. It is the often case that copper traces around are eaten badly since the leaking liquid is strong alkali. So you have to be careful for those. It would be better to replace those capacitors before the leak starts.

alextv

The speaker is already out so a simple test would be just to hook up another subwoofer ( doesn't have to be exact impedance but don't go below 12.4). A 16 ohm should work to test or hook this speaker to home amp with 16 ohm output (most home amps are 4 or 8 ohm so don't if that is the case). At this point you are trying to determine if speaker or amp is the problem.

BigBoomer

You can test with an 8ohm sub and there are many on here who are running 8ohm subs, but don't crank the volume up too high if you do that.

Another possible failure mode is the solder in the Amp. In the early 2000s all electronics manufacturers were required to switch to lead-free solder, and the early attempts at that were not great.
It's one of the reasons early 2000s cars have so many electrical faults. The Lexus cars from that era are better than ALL the other manufacturers, but are not immune to the problem as we see with occasional failed ML Amps, NAV Units, and certain ECUs.

If you think your hearing might be going, get your ears tested.
A friend who kept accusing me of mumbling has since found out he can only hear 3kHz-10kHz in one ear and 200Hz-15kHz in the other.
He now knows to keep me on one side of him if he doesn't have his hearing aid in as I have a low voice. <LOL>
Most "fade" in your ears is loss of high-frequency but not always.

I listen to a lot of ProgRock and I find that Peter Gabriel is pretty good to test with as his music has a VERY wide dynamic range and plenty of bass.
Griegs "In the Hall of the Mountain King" is also a good workout for any audio system as it starts whisper quiet and builds to a crescendo.

notroman

iTrader: (1)

Thanks for all the responses and suggestions, guys. I unfortunately do not have other speakers to test with (nothing 8 or 16 ohm, anyway). I will start looking for a used amp and/or repair options (in case I need to get the used one or my original one serviced). Seeing how these amps are known to fail, I am okay having a backup if it turns out to be something else. I will at the very least take the amp out and inspect the capacitors for any obvious visual leaks in the mean time.

The hearing loss comments made me laugh. I don't think I'm quite there yet. I do know older people lose hearing in the higher frequencies as I've already had a few interactions with people where I heard a noise that they did not. We used an app on the phone to figure out the frequency of the noise. I can confirm my ability to hear bass with my other cars, all of which except the Miata put out more bass than the LS.

alextv

My 2001 LS430UL amp has shown no signs of failing. If your speaker did not look so good I would not suspect the speaker as per my previous post. You can take a brand new speaker and barely touch the center and produce exactly your symptom. That's why I was saying if it has been repaired it could be too stiff.

notroman

iTrader: (1)

I took note of your comment and will keep it in mind. At the moment I'm not suspecting this to be the case, but anything is possible. The previous owner had everything done at the dealership (I even have receipts of him having the dealer install the Bluetooth adapter and various requests for detailing). It would be strange for someone to go to the dealer for every little thing and then do the subwoofer separately. There's not any notes in dealer receipts about the customer complaining about poor sound, although he did complain a few times that the factory air was riding too stiff. I suspect this car spent its life in the garage. It also had ceramic tint installed very early on in its life which likely helped with protection against heat and UV.