# Adding a subwoofer system to a Lexus IS350 :)



## simplicityinsound (Feb 2, 2007)

Just adding a low end component to a system is something I rarely do, for the most part, I don’t think the end result is very good, as the sub will often overwhelm the poor interior speakers, and also not blend very well. However, I do make occasional exceptions to decent stock systems.

The Mark Levinson equipped system in the Lexus IS is perhaps one of them. Although from experience, the blending of the new subwoofer with the interior speakers is still subpar IMO when compared to a full system upgrade, the ML system does get decently loud without distortion that they will not be overwhelmed by a moderate sub.

So here is me adding just a sub bass portion to a 08 Lexus IS350. 

The goals:

1. To do a sub system that is decently loud but not extremely space consuming in the trunk.

2. Have a slight show factor to it despite just having subs and an amp as the customer is in the process of upgrading the car cosmetic wise. Having a fully symmetrical setup was an absolute requirement.

3. To still have a usable trunk after the install so the setup needs to be durable and strong.

So...let’s get started. There isn’t much to see on the interior.

I installed a soundlinq iPod adapter to his stock headunit and lead out the plug in the armrest as he requested. The adapter was supplied by him as well:










The customer also supplied me with a JL HD750/1 sub amp, and I installed the JL remote bass controller in a blank panel on the driver side of the dash:










So everything else is stock.

Moving on.

the original idea we had was to have the amp in the trunk along with the subs. but, after doing a lot of measuring and visualizing, I keep coming back to the conclusion that in the very narrow trunk of the IS350, having the amp on the same plane (to maintain symmetry) as the subs does two things, it crowds the space and makes everything look too busy, and secondly, it takes away available space to trim around the subs to make things look a little bit flashier.

So after much deliberating, I decided to go with a different approach all together.

Here is what I came up with m.

So here is the stock rear seat:










Flip down the center armrest and viola! The JL amp is trimmed in black CF vinyl, which goes along with the mods he’s already been carrying out in the interior - wrapping things in black CF. Above it, I put an F-sport equipped badge on a raised vinyl platform, as the car so far has F sport intake and F sport exhaust installed, with prolly more F sport to come.










A close up shot of the rack you can see the details of the panel with the CF, the routed edges and the F sport badge.










So he can hide it when it wants to and showcase it by flipping down the arm rest. This frees up the trunk for the subs and also maintains symmetry 

A few quick build pics of this little rack:

First, I traced the stock ski pass through panel and cut it out of 1/4" mdf, with the holes dripped out to match the stock bolts, the raised logo platform was made using 1/8" hardboard, and is cut to be about 1/16" bigger than the actual logo all around:










Then, it was wrapped in black CF vinyl and the emblem plate attached:










And then it was bolted to the car. What I did was, using the 6 stock bolts, I got much longer bolts and ran them from the trunk side, through the amp rack into these holes and then through the cosmetic trim panel. This means the amp rack (a picture will show this later) is extremely secure using bolts and the trim panel is also tied into the same structure. 










So that’s it from the interior, I also removed his stock subwoofer from the rear deck to promote venting, but didn’t take a pic of it hehe


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## simplicityinsound (Feb 2, 2007)

Moving onto the trunk.

First is the fully hidden view, with all the trunk pics, it was hard to get the lighting right to actually show it, but oh well:










So as you can see, very little of the trunk space was taken up. I measured it to be about 7.5" at the floor and less than 4" at the top. You can see the new wall I built along with a cutout. There is a raised Lexus logo in the middle of the grille cutout plate but it’s hard to see with the lighting.

Pop it off and here is what you see.

3 image dynamics ID8 dual 4ohm subs are lined up in a box. I did some raised vinyl cosmetic trim around the subs to accent it a bit. The box is trimmed in silver CF vinyl, to match the exterior of the car and maintain the CF theme. The main wall panel is done in breathable non backed carpet and blends very well in the stock trunk.




























Here is a shot of that grille cover so the raised logo can be seen a little better:










And a close up of the subs and the surrounding silver CF vinyl trim:










And the view of the trunk with the entire car in perspective:


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## simplicityinsound (Feb 2, 2007)

So onto the build pics...

First is the wiring that runs back into the trunk, neatly organized and tied under the seat cushion area:



















Now here is the amp rack. Basically, it’s a series of MDF platforms and spacers built together, bolted to the interior divider using the stock bolt holes as mentioned earlier. So when the amp is then slide into the opening, and the mounting feet secured, it spaces the amp just right and places it right behind the stock pass through hole. 

On the driver side is a Cache Audio CLoc+D electronic lineout converter/line driver. In intentionally mounted off to the side so that after the sub box goes in, I can still reach it to adjust the gains. 

This is a great little piece by the way, as Cache is under the same company as Diamond.










Here is the sub enclosure. As you can see, extremely thin. 1.25 cubfeet of interior airspace, so giving each sub about .4 net. You can see the raised vinyl accent done using 1/8" hardboard:


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## simplicityinsound (Feb 2, 2007)

Then silver CF vinyl was applied:



















Here is the main front panel:










And wrapped in black carpet:










And finally, the grille that goes over the subs. basically a MDF ring with HD metal mesh attached to it. To properly raise the logo in carpet, the Lexus emblem was cutout in 1/4" MDF:










And wrapped in black carpet as well:










So that’s it, I don’t get to do sub only system too often, but this one was enjoyable hehe...hope you like it.

The 3 ID8s get quite loud actually, sounding like a powerful 12. One thing to note is that the stock system has an undefeatable 35 Hz subsonic filter in place, so in a sense, it’s well suited to 8" subs to begin with. As mentioned before, the blending, especially at high volumes, could be better (as they make the interior speakers go down to 35 Hz as well), but it’s not bad at all 

Cheers,

Bing


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## Bluenote (Aug 29, 2008)

Niiiiiice!


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## Kenny_Cox (Sep 9, 2007)

i like the looks of that lil cache thing. where can one purchase one?


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## simplicityinsound (Feb 2, 2007)

find someone that sells diamond audio, they should carry it as well


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## twing (Dec 21, 2007)

Bing, the craftmanship of your work is superb man. Great job


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## KAPendley (Nov 19, 2007)

Good job Bing....time to invest in a welder bro! I would LOVE to see how inventive you could get if you started using steel and such in your installs, and saved the MDF for the enclosures and panels.


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## gymrat2005 (Oct 4, 2009)

As always, extremely impressive Bing. You are truly a craftsman.


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## simplicityinsound (Feb 2, 2007)

KAPendley said:


> Good job Bing....time to invest in a welder bro! I would LOVE to see how inventive you could get if you started using steel and such in your installs, and saved the MDF for the enclosures and panels.


i am not so sure how long i can get away with working out of my garage if sparks start flying and i start welding hehe  that is a step that certain people may not look too kindly upon 

but i am giving it somet though...however, from my experience out here in cali, a well put togehter MDF structure will easily be strong enough to last hte life of hte vehicle.

but i do have some ideas for down the road hehe


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## Powers (Apr 10, 2008)

Come out here and build mine! Haha


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## akanoon (Aug 12, 2008)

Awesome as usual Bing!

Question: Is the "main front panel" secured to the actual box or car? Or does it just fit really tight so it doesn't need to be actually mounted (sorta like the grille). I'm assuming the box is secured to the car. Just wondering how to secure the front panel without screwed and stuff showing but still being able to get it off if I need to.


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## Knobby Digital (Aug 17, 2008)

Very clean looking, but having done a few sub setups in a very similar car, I'd be concerned w/ how much sound can actually pass through into the cabin (even if there are rear speakers that have removed from the deck).

I'm sure it sounds fine or whatever, but there has to be a terrible loss of efficiency with the ski-pass sealed off so well.


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## simplicityinsound (Feb 2, 2007)

Knobby Digital said:


> Very clean looking, but having done a few sub setups in a very similar car, I'd be concerned w/ how much sound can actually pass through into the cabin (even if there are rear speakers that have removed from the deck).
> 
> I'm sure it sounds fine or whatever, but there has to be a terrible loss of efficiency with the ski-pass sealed off so well.


that is interesting, becuase the half dozen or so i didn, once the stock subwoofer (the only speaker on the rear deck), has been removed, the bass gets into the cabin quite well to my experience.  more so even than say G35s. hehe

b

p.s. i think one thing that may be going on is. if you do say a bigger sub, a beefy 10 or 12, waht will happen in a rearward facing subbox is then the front face of the subbox will be past the area in the ceiling of the trunk where the vent hole left by removing the stock 8" sub is...so basically, it will sorta seal off the trunk. but in this case, the subbox is so far towards the front of the trunk that the entire area where hte stock sub was is left fully open 

b


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## JayinMI (Oct 18, 2008)

And we all know how many G35's you do 

Jay


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## ISTundra (Jan 3, 2009)

Nice install! I added subs to my IS350 (a pair of 10W3’s in a prefab box) and I have to agree it doesn’t blend very well at all with the factory system and its DSP. 

I do think that blocking the rear seat pass thru as you did does cut down some on the amount of bass getting into the cabin. I removed the factory sub so I have a port, but I still have to crank up the sub power pretty heavy to get enough bass into the cabin. My car is becoming a rattle trap because of this.

Where did you tap the factory signal? I originally tapped the sub channel but it sounds better off the rear door speaker.


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## Knobby Digital (Aug 17, 2008)

ISTundra said:


> I do think that blocking the rear seat pass thru as you did does cut down some on the amount of bass getting into the cabin. I removed the factory sub so I have a port, but I still have to crank up the sub power pretty heavy to get enough bass into the cabin. My car is becoming a rattle trap because of this.


Yep. I've got an IS300 that I've done a few setups in the trunk in.

Even with the 6x9's out of the rear deck, a single 12" in a rectangular box had as much output as a dual 12" slanted back box butted to the back seat w/ the ski-pass covered, except below 30hz or so.

I also get significantly more output and less trunk rattles w/ my IB setup than w/ the woofers firing away in the trunk.


Not dissing. The trunk looks great.


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## WLDock (Sep 27, 2005)

Great work BING! So I know you use the two side blocks on the box to screw the trim panel wall to. *But...how does the grill stay in place?* Press fit?

Also, The forward VS. back firing thing has me wondring??? 

My plan in a 2007 VW Passat is to fire two 10's forward in a slanted box with the ski hole open to get bass through. I won't be using a ton of power. However, some think that rear firing is still better? I think I might have to plan this install so that I can test both directions before I make a decision....Would be sort of a pain in the ass if I put the amps on the box but I think they are going under the rear deck?

I don't know? I really like the look of subs firing back like in this install...and the stealth panel. But I wonder if that will block bass even more?

Anyway...I know this was a simple one for you BING but....again very clean install that looks SWEET!


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## sydmonster (Oct 5, 2009)

NICE! as usual and as its become expected! 

but... 35Hz subsonic filter...hmmm


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## simplicityinsound (Feb 2, 2007)

its good protection for the ID8s anyway


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## bigwilly43729 (Feb 11, 2009)

I have a buddy who just got an IS-F and he is interested in adding a subwoofer. He doesn't like the bass from the Mark Levinson (sp?) system. Since the car already has a sub, would you just use the output from that for the Cache unit?


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## sydmonster (Oct 5, 2009)

simplicityinsound said:


> its good protection for the ID8s anyway


true, do you think these could play for as long & as loud if they were allowed to go down to roll off?


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## simplicityinsound (Feb 2, 2007)

well, that i cant say for sure, but in general when using 8" subs, i tend to do a subsonic of some type, usually 20-35hz.  i mean you can certainly have it go fully rolling off...but in general, i turn on a subsonic to prevent umm...over cranking the subs hehe

yeah this is just off the sub channel of the ML system.

b


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## bigwilly43729 (Feb 11, 2009)

simplicityinsound said:


> well, that i cant say for sure, but in general when using 8" subs, i tend to do a subsonic of some type, usually 20-35hz.  i mean you can certainly have it go fully rolling off...but in general, i turn on a subsonic to prevent umm...over cranking the subs hehe
> 
> *yeah this is just off the sub channel of the ML system*.
> 
> b


Thx!!!!


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## sydmonster (Oct 5, 2009)

cheers bing, im looking at posibly using these as beefy midbasses and wanted to how low they could go, but indeed a 35Hz subsonic filter would apply to a midbass anyway.


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## WIZARD1325 (Sep 17, 2011)

build one for me please


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## jaikai (Aug 8, 2011)

Installs like these are the reason why I find this forum so addictive...

Very nice.


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