Does anyone know where the factory amp is located at? Or Does anyone have a picture of it? The reason why i'm asking is that i'm thinking about replacing the factory amp with an aftermarket one. Anyone know if it is possible?

 

The ML factory amp is located under the front passenger seat. I'm not sure if it's possible to switch it to an aftermarket amp however.

 

Here ya go: http://marklevinsonlexus.com/overview.asp?model=gx

Why do you want to change out the amp?? You will likely lose DSP and surround sound if you go with aftermarket amp because all the processing is done by the ML amp in addition to amplifying signal. In addition, you're not gonna find many aftermarket 8-channel amps out there. Stick with the ML amp.

If you want better sound, then consider getting a self-amplified subwoofer (ex: Infinity BassLink) to boost the low end.

 

The factory system sounds good, don't get me wrong. I have 2 12" jbl subs in the back and the factory system is not blending well with it. I don't watch movies in my car and besides, if someone is, they use the headphones so i don't really need the surround sound. Since its a hassel to mess with the factory amp, i guess i won't mess with it. Maybe, switching out the factory speakers then perhaps?

 

Correct me if I'm wrong, but on my '04 GX, the ML amp is under the driver's seat.

Might want to check the ratings of the speakers before you start dumping $$ in to new ones. I don't know what the specs are of the ML system in Lexus, but w/ Bose systems in other cars, I know they do some funky things b/w the amp and speakers regarding impedance, etc.. Depending on how you have your JBL subs hooked up, it might explain why they aren't matching up well.

Good luck and keep us posted on how it all turns out

 

Hate to say it, but your blending problem probably has more to do with your subs than the rest of the system. From my many years ago as a car audio maniac, JBL subs are not known to be high end nor mid end. I am not sure if that has changed recently. I would make sure that your subs are being driven by a high quality amp with a good crossover. I would cross your subs at 60 hz...because this is where ML subwoofer crossover at. Secondly, you may want to disable the small ML subwoofer in the back (if not done already). Make sure that your JBL subs are in the correct position and PHASED CORRECTLY...this requires you to experiment.

Lastly, you may want to take it to Circuit City or whereever and ask them to hook up Infinity BassLink to your Lexus. Then, see if the Infinity blends better.

Good luck.

 

I bought the jbl for sq and it does have sq. Its not spl so it does not get crazy loud, it hits the notes when it is played. Maybe i didn't describe it correctly. I guess what i'm trying to say is that the ml system is not playing loud enough. On the factory eq, i have the bass turned all the way down, mid turned a little over half way, and the high set close to the highest. I'm underpowering these subs by the way. I used a dmm to see where its clipping it at and then i turned it down even more. Thats why i wanted to know if i should change the factory amp, giving the oem factory speakers a little more juice so that it can balance out the system. I hope this makes sense.

Thai, What systems do you have experience with?

 

Lex, the problem may be that there's no seperate volume control for the sub output on the ML system (as far as I know). On my old '98 LX, I had replaced the factory headunit with an Alpine unit that had separate volume for subwoofer output and added a seperate amp just for the sub and left the factory amp alone to power everything else. That seemed to work great because I could always get the sub to be at just the right volume to match the rest of the system. But with the stock ML headunit in my GX I think it would be difficult because there's no way to finely tune the volume of the seperate sub channel.

 

I think that is where your mistake is...the "BASS" setting is not only for the small subwoofer in the back. The small subwoofer in the back is not a true subwoofer in the traditional sense. Your 6x9 woofers in the front doors get some of the bass frequencies too. This is how Lexus/ML gets around having a big subwoofer. Basically, for the front stage, you have the tweeters, center channel, and midrange speakers. They all get the usual mid to high frequencies. The 6x9s in the front lower doors get the lower frequencies, including some bass frequencies. This is why Lexus/ML puts 6x9s in the front doors, instead of 6.5 round speakers (as they have done in other vehicles). They do this to help with getting bass to the front seats. The rear 6.5 "subwoofer" is to produce bass for the rear passengers...it is too small to make bass loud enough for the front passengers. In essence, with the GX system, you have 3 bass producing speakers...2 in the front (via 6x9) and 1 in the rear (via 6.5 sub in small enclosure). (BTW, the new JBL systems in Toyota cars do a similar thing and are called, "Distributed Subwoofer System.")

My brother's LX470 ML system is similar to the GX except that it has 6.5 woofers in the lower front doors. His system is clear and excellent sonically, except that there is not much bass up front. I believe (MY THEORY) that Lexus/ML realized this and incorporated 6x9s in the front doors instead of round 6.5 to get more bass up front...more bass for everyone in the vehicle.

This is why ALL of their SUVs have 6x9s in the front doors because the interior volume is huge. Their cars (ES, GS, IS) have 6.5" round speakers in the front doors but they do have a big subwoofer (8-10") in the rear deck. The environment in these cars are smaller and, thus, are easier to produce bass from one source. Hell, even their new Reference system (LS460, LX570) uses 6x9s in the front doors to augment low notes.

In addition, i am not sure if BASS setting is mainly for subwoofer frequencies. You need to check with Lexus/ML about which frequencies apply to which BASS/MID/HIGH settings. That is, the BASS setting may affect some midrange frequencies as well as bass frequencies. So, when you drop the BASS all the way down, you may be affecting more than just bass frequencies...some of your lower midrange may drop as well, which may explain your lack of integrated sound. In other words, my guess is that you have good upper frequencies and good lower end, but weak somewhere in the middle frequencies. Am i right??

My advice: turn the BASS up slowly until the sound becomes full and then blend your JBL subwoofers with that sound to add "ooomph" to your low end. Again, i would crossover at 60 hz or below. In other words, adjust the system till it sounds right...THEN you add in your JBL subs (via gain or whatever control you have on the sub amp) slowly to get the low end that you want.

 

Thai you are such a great addition to this forum. I did that just a while ago and came back inside the house to see your reply and read it. I did just that and it sounds better now. The highs were there and the lows were there, it was just the mids. So i turned up the mid one notch, and the bass 2 notch. Now everything sounds better at every volume. Thanks!

 

Cool...i am glad that you are happy with your ML...trust me, you guys are lucky to have ML system in your cars!