so i had a sealed box with a jl12w6 in it powered by a 500/1 jl amp running off the amp sub signal and it sounded okay but not awesome, it sounded pretty decent. well i was convinced that if i went to a custom ported box (i have had both types of boxes in the past so i know the differences) that it would sound a lot better and get some much better air flow going. i pulled the trigger and it was $257,, not too bad. when i went to pickup the car the bass sounded bad and not in a good way, it just sounded really off. the installer claimed that he could tell the signal was being restricted or retarded by the ML signal so he would have to get a good clean pre-amp signal to make it sound better.

well he got the pre-amp signal and it sounds almost worse... i am very close to just cutting my loses and asking for my money back but what is the best way to get a good signal from the car (05 ls430UL w/ ML)??

the installer says he is going to call JL first thing in the morning and ask them and also to try and call Lex and get the vehicles audio schematics. i'm not exactly what these schematics entail but do any of you all have good clean high end-ish sub setups running off the factory ML head units and if so how did you get the bass signal and does it sound proper?? thanks,

 

How is the installer getting the signal from the stock ML system? Are you using something like the JL Cleansweep or JBL MS8?

 

Sounds like he’s using the cheap signal converter. You should look in to the jl clean sweep, which should take care of the bad signal. But then again, your sub didn’t sound bad at first. Now the installer make’s the sub sound worse every time he touches it. I would ask to put everything back and go somewhere else.

 

The tech may not be getting the right pre-amp signal line out.

The clean signal would be to get the pre-amp signal that is going from the head unit into the ML amp. If the tech is taking any line level signal being output from the amp then no matter how that signal is sliced, diced, or filtered it is still gonna be a very dirty signal. That's because line level output signal from the amp is the original pre-amp signal plus the ML amp's inherent distortion which is then amplified again by the subwoofer amp (which magnifies the first amp's distortion by another million times or so and adds its own layer of distortion)...definitely low fidelity.

The key is getting an accurate schematic so that he can tap the correct pre-amp output and also to filter out mid and high freqs before input to SB amp. Likely needs a good crossover to filter out anything above 100-150hz before feeding it to the subwoofer amp, unless the SW amp has an inbuilt crossover.

 

thanks jabberwock for the help, i will pass this along.

 

audio schematic is located on this page just in case anyone else needs it.

https://www.clublexus.com/forums/ls4...-ml-amp-2.html

 

Apparently the pre-amp out on the ML system is a fixed volume signal and the volume is controlled by the ML amp. Without purchasing a couple hundred $$ clean sweep type device we are just trying to get the proper signal to the from the car to the JL amp for the sub.

 

Its kind of odd that your original sealed system w/ the JL12W6 sounded 'okay' and the subsequent ported systems sounded so bad. I've run some speaker level (line out converters) to integrate aftermarket amps/subs resulting in much enhanced sound relative to typical stock setups. Not just more thump, but often improved clarity throughout the range.

It may be that you have a tuning problem w/ the ported system. Doing a quick search it looks like Box volume is recommended from 2.5 to 3.2 cuft. w/ a port tuning frequency of about 34hz for the jl12w6.

I believe you have a UL and I hear that the trunk is pretty sealed from the cabin so if you can at least remove the stock sub it may help w/ getting the upper end of the subwoofer harmonics into the cabin for better system integration.

Many people are looking at the subwoofer alone to give bass impact. While a sub is important for the deep foundation of sound the midbass area is what gives music its hard hitting power. If we had midbasses (the 6.5"ers in the doors) that can handle this duty than it would be good to cross the sub over lower at about 50 or 60hz or so. However from what I hear coming out of my ML system, the midbass/drivers are pretty marginal. So when I add my aftermarket sub the lowpass crossover will be set to about 100 to 125hz and of course I will choose a sub that can play up well this high to give my system more midbass impact. Low coil inductance will help choose the right sub. I have heard that the JL12w6 is a good performer, but have no personal experiance its ability into the midbass area.

While simple add on amp/subs such as these will not give the control and ultimate sound quality of a fully integrated system w/ discrete amps per driver, EQ and time alignment; it will enhance the sound, keep the hassle low and keep the Nav. My plan is to add a sealed 12 or 15" w/ about 500 watts, try lowpass set at 125hz and call it a day. At least until I get bored.

 

well this is what happened to me, after close to 3 years i was finally bored to death and wanted more, hence the supposed upgrade to the ported box. the box has about a 10" external port that goes right up to the stock sub location, and yes three is a hole cut in the trunk fabric to accommodate this plus the removal of the stock sub.

i am now told that i have to bring it back by on monday and get a clean sweep-ish (signal blending) type device installed,, around $126 or something. if this doesn't make it sound any better than the previous sealed box than i am going to respectfully request that they put it all back the way it was and refund my monies.

i've had systems that will beat anything you will hear at your normal parking lot pimping neighborhood meets in the past and i just wanted something that put out a little more bass for a lot less coin, is that too much to ask for¿

 

It will be intersting if the JL Cleansweep remedies this. The auto EQ of the Cleansweep should flatten the signal bumps coming from the ML system at speaker level. Didn't think that the stock signal sounded so pumped up, but then maybe that is how the sound is somewhat decent coming from the tiny little 8" running infinite baffle.

Sojah, I'm follwoing your story w/ interest 'cause if the ML system does add a big bass bump I too will have to find a way to add some signal processing to tame it... But if I went to the trouble of adding some DSP, might as well use one of those uber-integraters like the JBL MS-8. And that is a slippery slope to more amps, component speakers, install time/effort and lots more money spent. A heartfelt 'goodluck' to you and you're right, it shouldn't be too much to ask for.