Making the ML sub sound better
03-26-07, 10:27 PM
#1
Intermediate
Thread Starter
Making the ML sub sound better
Today I finished my project to improve the bass quality of the '06 GS ML audio system—and I didn’t replace the subwoofer. I'm very pleased with the result. Tighter, deeper bass. Much better bass detail. I can now hear the bottom octave notes rather than them getting lost in the muddle. All I did was add a new bass amplifier. This allows me to run the ML bass control clicked down 3 steps (suppressing midbass plumpness), then use the new amp's gain and EQ boost to achieve the low end boost needed to reveal the deepest notes.
I chose the Kicker ZX450.2, a stereo amp that can run in bridged mono mode. It had two features I wanted in particular. 1) It can accept speaker level signals, and 2) it includes a wired remote gain control for easy bass tweaking without messing with the ML’s touchscreen.
The bridged mode is useful because the ML sub has a higher voicecoil impedance than usual, 14 ohms, so I wanted plenty of voltage swing to be on tap.
Turns out that this amp was also very easy to match to the system due to the way the input stage is designed, as it has both speaker and line-level inputs. These are tied together with resistors, and it allowed me to use the line input jack terminated with a short to scale the input signal from the speaker input, which feeds into it with a series resistor. It might not have been necessary, but I’m now sure that the input cannot be overloaded.
Here are the steps I followed:
1) Unsolder the leads from the sub, and splice them to a length of thin speaker wire to run to the amplifier’s high level inputs. Feed both channel’s inputs in parallel. The trunk lining has to be removed of course, but it’s easy once you find all the clips.
2) Solder new speaker wires to the sub and run them to the amp’s outputs. In bridge mode, use the L+ and R- outputs.
3) On the ML amplifier, the 24 pin connector nearest the rear of the car has a gray wire at pin 12. This is switched Accessory voltage that turns on the amp. Splice a thin wire to this wire, and run it to the remote turn-on terminal of the new amplifier.
4) Run an 8 gauge power lead direct from the battery, thru a fuse block and then thru the firewall below the battery (alongside an existing harness), then under the door trim panels and into the trunk. The amp is grounded in the trunk. Need to also pull the trim panels in the passenger foot well to route the wire through.
5) Mount the remote gain control module near the driver. I put it inside the ashtray. It fits perfectly after ejecting the ashtray insert (I don’t smoke)—and the door still closes. The console panel is easy to pull up to facilitate mounting the control and running the wire out the bottom, but that’s already been detailed in other threads. Run the supplied phone cable from there across the passenger foot well, under the carpet, then follow the same path as the power lead into the trunk.
6) Purchase a pair of RCA phono plugs. Solder a wire across the signal/ground terminals of each plug, creating a shorting plug. Insert them into the low-level inputs of the amplifier. This attenuates the high-level input by 22 dB, but the amp has 36 dB of gain, so it lets me set the amp’s gain control to the second mark of 7 (about 10 o’clock position). Plenty of gain.
7) Set the Crossover switch to Low-Pass.
8) Set the Bass Boost control on the amp to the same 10 o’clock position—this gives 5 dB boost at 36 Hz—clarifying the deep notes. This control has a maximum boost of 20 dB , so watch out!
9) Set the amp’s crossover control to max (200 Hz). It is not really needed. Setting it to a lower corner will cause certain midbass notes to disappear.
10) Set the bass control of the ML system to 3 clicks below mid point.
11) Mount the amp as you like. As I seldom use the trunk for anything, I tied each end of the amp to the chrome hold-down loops in the floor of the trunk, using large cable ties.
All of the above adjustments of course can be tweaked to obtain the sound as preferred, but these are good starting points.
I chose the Kicker ZX450.2, a stereo amp that can run in bridged mono mode. It had two features I wanted in particular. 1) It can accept speaker level signals, and 2) it includes a wired remote gain control for easy bass tweaking without messing with the ML’s touchscreen.
The bridged mode is useful because the ML sub has a higher voicecoil impedance than usual, 14 ohms, so I wanted plenty of voltage swing to be on tap.
Turns out that this amp was also very easy to match to the system due to the way the input stage is designed, as it has both speaker and line-level inputs. These are tied together with resistors, and it allowed me to use the line input jack terminated with a short to scale the input signal from the speaker input, which feeds into it with a series resistor. It might not have been necessary, but I’m now sure that the input cannot be overloaded.
Here are the steps I followed:
1) Unsolder the leads from the sub, and splice them to a length of thin speaker wire to run to the amplifier’s high level inputs. Feed both channel’s inputs in parallel. The trunk lining has to be removed of course, but it’s easy once you find all the clips.
2) Solder new speaker wires to the sub and run them to the amp’s outputs. In bridge mode, use the L+ and R- outputs.
3) On the ML amplifier, the 24 pin connector nearest the rear of the car has a gray wire at pin 12. This is switched Accessory voltage that turns on the amp. Splice a thin wire to this wire, and run it to the remote turn-on terminal of the new amplifier.
4) Run an 8 gauge power lead direct from the battery, thru a fuse block and then thru the firewall below the battery (alongside an existing harness), then under the door trim panels and into the trunk. The amp is grounded in the trunk. Need to also pull the trim panels in the passenger foot well to route the wire through.
5) Mount the remote gain control module near the driver. I put it inside the ashtray. It fits perfectly after ejecting the ashtray insert (I don’t smoke)—and the door still closes. The console panel is easy to pull up to facilitate mounting the control and running the wire out the bottom, but that’s already been detailed in other threads. Run the supplied phone cable from there across the passenger foot well, under the carpet, then follow the same path as the power lead into the trunk.
6) Purchase a pair of RCA phono plugs. Solder a wire across the signal/ground terminals of each plug, creating a shorting plug. Insert them into the low-level inputs of the amplifier. This attenuates the high-level input by 22 dB, but the amp has 36 dB of gain, so it lets me set the amp’s gain control to the second mark of 7 (about 10 o’clock position). Plenty of gain.
7) Set the Crossover switch to Low-Pass.
8) Set the Bass Boost control on the amp to the same 10 o’clock position—this gives 5 dB boost at 36 Hz—clarifying the deep notes. This control has a maximum boost of 20 dB , so watch out!
9) Set the amp’s crossover control to max (200 Hz). It is not really needed. Setting it to a lower corner will cause certain midbass notes to disappear.
10) Set the bass control of the ML system to 3 clicks below mid point.
11) Mount the amp as you like. As I seldom use the trunk for anything, I tied each end of the amp to the chrome hold-down loops in the floor of the trunk, using large cable ties.
All of the above adjustments of course can be tweaked to obtain the sound as preferred, but these are good starting points.
Last edited by DrexLex; 03-26-07 at 10:32 PM.
03-27-07, 02:09 PM
#3
Intermediate
Thread Starter
Some photos after the install
Shows the mounting of the bass gain control in the ashtray. Puts it right below the volume control--no need to look away when driving.
03-27-07, 02:13 PM
#5
Intermediate
Thread Starter
Shows the connections to the amplifer. The Power and ground cables are on the other end of the amp.
Last edited by DrexLex; 03-27-07 at 02:34 PM. Reason: fixed photo
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03-27-07, 02:18 PM
#8
Intermediate
Thread Starter
Shows running the power and gain control leads under the door kickpanel trim to the rear of the car. Accesses the trunk by feeding the wires between the backseat and the door jamb. Comes thru into the trunk alongside other cables, under the trunk trim panels.
03-27-07, 02:24 PM
#9
Intermediate
Thread Starter
Does not need to be done at all. It's a matter of taste. I had installed a few systems from scratch in my previous cars, and knew what good bass could be, and decided not to go that route in the GS since I wanted the NAV and integrated controls. So I went for the best option offered, Mark Levinson, but was somewhat disappointed by the plump bass quality (not quantity) and no user EQ to fix it. This new amp w/ EQ/gain adjustments fixes it for me, and only cost $230. That's less than I paid for the iPod adapter.
03-27-07, 02:28 PM
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Does not need to be done at all. It's a matter of taste. I had installed a few systems from scratch in my previous cars, and knew what good bass could be, and decided not to go that route in the GS since I wanted the NAV and integrated controls. So I went for the best option offered, Mark Levinson, but was somewhat disappointed by the plump bass quality (not quantity) and no user EQ to fix it. This new amp w/ EQ/gain adjustments fixes it for me, and only cost $230. That's less than I paid for the iPod adapter.
I need more punch (Techno/rave music)
Where can I get one of those Ipod adapters? My Camry came with a jack, is there something special the GS needs?
03-27-07, 02:40 PM
#11
Intermediate
Thread Starter
The iPod adapter is made by Vaistech. Look at www.vaistech.com, great info there. Not sure you need it for the Camry, as you at least have a jack. Since the 06 GS didn't even have an aux input jack, the adapter was needed. It works great, and allows full steering wheel controls and onscreen song titles. I never touch the iPod except to sync it with the PC.
Last edited by DrexLex; 03-27-07 at 02:49 PM.
03-28-07, 07:10 AM
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Whew nice job and wonderful write up!. hey DrexLex I live all the way in SC mind if I drive over there so you can hook my up to? 
how much the set up cost? and how long it take for you to install?
how much the set up cost? and how long it take for you to install?
03-28-07, 01:34 PM
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Great write-up. Thanks for the step by step. Been some time since I did a car stereo, but with your step by step, it's something I could do! 
I have noticed the plump bass, but it's still too cold (Northeast) to freeze my knuckles doing anything about it.
I have noticed the plump bass, but it's still too cold (Northeast) to freeze my knuckles doing anything about it.