just to clarify, you just have 1 rca cable running from the LOC to the amp?

 

Yeap. One rca.. Thanks for this threadd i'm finally getting that low bass i've been missing!

 

I wish there was a DIY for this since I know nothing about car audio.

 

mIStaboi- glad to share. Yeah, I'm glad that you also noticed an improvement. My wife was pustule to a little Van Hallen (yes she's pretty cool) with the top down and the song "jump" came on while I was walking across the parking lot and I was like wow!! That sounds pretty good, ha it was our car. Cool !!!!

 

Ha, that should have said " listening" --dang autocorrect!! Anyways,
Jace_91- yes I also used just one RCA. Most sub amps are set up for this one input. But you could also use a y spliter and make it into 2 RCA. Try it! Would will be pleased.

 

can someone please please do a write up?

 

^^ theres a thread in the audio section.. its really not hard at all. when i had my is250 i did it without knowing anything. do a search "sc430 aftermarket amp install" you should find it easily. i'd link you but its a pain on my phone to do so

 

yep, theres an amazing write up by zgone, I will take some pictures when im in the trunk tomorrow and show the new way thats outlined in this thread, I think im going to try and run both the left and right wires of the LOC to the sub wires, becuase my amp has a L/R input for the RCA.

 

Thanks for all the input guys. Great info here. Whats a good LOC to use? I know scosche has 2 and 4 line output. Really looking forward to doing this DIY mod.

 

UPDATE:

I hooked up my sub last night and had my line-out converter installed as per Zgone's instructions, to the door speaker outputs. I wasn't impressed with the sound, so this morning I tried switching to the sub output wires, and just as the OP said, there is a HUGE difference. I've attached a diagram of how I set-up my line-out converter for anyone that is interested.

 

Love the thread guys, I actually had the exact same experience when switching my sub amp input from the front door woofers to the OEM sub wires. I disconnected the sub, ran the wires to the high level input on my Alpine MRP M500 mono sub amp, removed the factory sub altogether (not sure if that was actually necessary or not), and it sounds 10X better now. It's pushing a 12" Kicker Comp sub, just an old sub in a sealed box that I had from former cars. The bass is plentiful.

Anyway, I do notice that the factory non-ML system seems to be cutting the bass level as the volume goes higher and higher. If I adjust the amp so that the bass sounds nice and full at low volume, it starts decreasing as I crank it up. Likewise, if I amp it up so that the bass is solid at high volume, it is then overpowering at low volume. This is a 2007 IS350 non-ML by the way.

Anyone have ideas on how to make it stop behaving like this? I assume Lexus did this because they knew their little 7" sub with 30 watts driving it couldn't keep up when the system volume was turned up, which is understandable. But now that I have removed that bottleneck, how do I disable this "feature" they've left me with?

 

Supernin- I hqve the same problem withthe bass cutting down as the volume goes up. I use a bass **** to adjust it back up when this happens and adjust it back down for low volume listening. I'm not sure if the amp is doing the processing or it's the headunit. If it is the amp, maybe if we could tap into the low level before the amp, could avoid the cut in bass. The only problem is that out of the head unit is a balanced output and all of the amps I know of are unballanced. Anyone know how to convert from balanced to unbalanced RCAs ?

 

Is it possible to add a bass **** to an amp if it didn't originally come with one? I mean it has a gain adjust **** directly on the amp of course, but that's in the trunk. I think your solution is probably the way to go because I'd bet it's the head unit cutting the bass prior to it ever being amplified.

 

I found that the bass cut out at higher volumes when my LOC was connected to the door speaker wires, but not when I switched it to the sub wires?

Regardless, I have a bass **** as well that I purchased seperately off ebay, not evey amplifier can accommodate one.

You may want to check that your head units "ASL" mode is set to off as well. It's the setting that adjusts the volume as the car goes faster/slower. I find the stereo sounds consistantly better with it off.

 

Thanks for the diagram !