Figured out why my speakers were sounding so empty and no bass
 

the reason was audio over Bluetooth

now, no matter what car, connecting audio over bluetooth will sound slightly worse than direct connection via usb,

but what surprised me is the difference between bluetooth and hardline connection (av cable, usb).
I really thought the speakers on my 2015 ES were busted as i was getting absolutelly no bass over bluetooth.

my 2 previous cars, a benz and an infiniti both sounded fantastic over bluetooth while hardline sounded even better.

But on my ES, the difference is STAGGERING. Audio over bluetooth is like listening to am or non-hd FM. i'm thinking the culprit is having an older version of bluetooth compared to my other rides.

anyhow, connecting directly via usb = speakers sound very decent, bass is decent, basically i have zero complains with the stock audio (non mark levinson).
i stopped using audio over bluetooth, the sound quality is just abysmally bad.
anyhow, thought to let you guys know.

interesting, i have strictly used bluetooth due to the convenience of auto-connect. I will have to try usb connection

Do you have the sound settings configured the same for both sources? Maybe you have something like surround on over Bluetooth and not for USB.

both on default EQ settings (3 settings, treble mid and bass i think). all in deadcenter default settings.

for the first 2 weeks of driving, i really thought the OEM sound system was really bad. Voices sound kind of hollow, there's absolutely no bass. but once i connected my iphone via usb, the speakers sound perfectly fine to me. i'm sure the mark levinson system is much better, but the stock ones aren't bad at all.

one thing to note, i'm not listening to songs stored on my phone, i'm streaming spotify. Phone is an iphone XR.

Perhaps the bluetooth is interfering with LTE signal? not sure.

i do not store music anywhere, i only listen to spotify. Which means even via usb the sound quality (for you audiophiles) is still abysmal. but this is the nature of streaming music as it's heavily compressed. but even if it is heavily compressed, on my previous vehicle bluetooth audio was perfectly fine for my taste.

Interesting I may try this next time

dang it, i should have tested this with my note 9 before i sold it and went back iphone.

can anyone test with a newer android?

No difference here.
 

Played the exact same mp3 music file from USB drive and from the phone via Bluetooth - while switching back and forth between the two sources. I could not detect any difference - definitely not in the amount of bass.

My phone is LG G5 running Android 7.0 (Nougat).

My Android is running Oreo and Bluetooth streaming is fine, when I use it.

You were also specifically asked about DSP settings - did you check that those are configured the same?

yes, surround checked on both to ON

You should try it with them off. It sounds 100x better on the ML, so I would assume it would also on the standard system.

i have tried both on and off, i prefer on with the standard audio

I tried to duplicate this morning and had the same quality on both. Using iPhone X.

Is Bluetooth volume set to max on the phone? It should. Otherwise you will be increasing volume on the head unit to compensate and it is quite possible that Lexus will cut low frequency response in order not to overdrive the speakers.