Hi Guys,
Right, so I've just installed an aftermarket sub into my LS. It's got the factory Nav unit so used a line output converter on the factory sub output. Here's my problem. It doesn't hit much above 60-70Hz...

Does the factory sub only get fed from about 20-70hz?

​​​​​​It's a dual channel converter, I guess I could run off the 2 rear door speakers in parallel, but do they get fed down to 20hz?

If not, could I, run 1 channel off a door speaker, 2nd channel off of the factory sub output? It has gain knoba so I could use my Oscope to match the levels.

Let me know opinions.
Thanks

 

is your aftermarket sub being fed with an aftermarket amp as well?

 

There is a way to change the original settings.

 

Yes, it is being fed with a seperate amp as well.

 

Now if I could adjust the frequencies sent to the sub, that would solve all my issues. Any chance you got a link to that full document so I can have a look through to see if it lets me do that?

Thanks

 

yeah try and tap off one of the door speakers for the line out, instead the sub line which is already after the factory amplifier.

btw, the factory amp is under the pass seat so you can make your tap there!

 

Thanks for that!
I've been told on an FB post I made asking for some more info, that out of the radio, theres a single left and right coming out at line level.
That goes to the amp, and distributed/filtered to the appropriate speakers.
If this is true, is there anything stopping me from finding said left and right before the amp, and just running that parallel to the amp for the sub?
I've got my mini oscilloscope dug out, ready to start probing wires 🤣

 

You can find and download the manual visiting here.
The adjusting method is shown at the final part of the manual.

 

Thank you! I'll give it a go tonight when I get back from work!
If this works, lifesaver. Saves me from having to probe wires before the amp with the oscope!

 

Right. So.
Playing with the settings in the service mode, I couldn't hear any difference.


28ish Hz at original subwoofer wires

122ish Hz at the same volume level, at the same wires

​​​​So the Sub output from factory, is deffo filtered.

So found the inputs to the amp from the head unit, and well. I did get a full signal. Great right? Nope. 0.97volts worth across the board regardless of volume..........

So tried probing the front and rear speakers.


Below 44-45Hzish, it flatlines.

The front speakers don't get fed anything below around that sort of region... Rears were similar, forgot to take a picture, also didnt pay much attention as it flatlined at the low bass anyway.

Now at this point, not too sure what to do to send like a 20-180ish Hz tone to the sub.

Any suggestions?
​​​​​

Also, pinout of the Amp I found from a service manual. The GM-9176