Stock Headunit 2 channels into four

[idkcaraudio]

Hi,

This is my first time upgrading the sound system on any car, so I'm pretty clueless about car audio in general. I have a 05 mini with the premium hk sound system, but I find the sound disappointing and I want to upgrade it while keeping the stock headunit so the car looks the same after I'm done. The problem is, I realized when I removed the hk amp, there's only two inputs to the amp. So I guess this headunit is weird because the amp is not built in. Is there a way I can somehow double the output so I can add a subwoofer? I know some of you are going to tell me to use a line out converter, but I want to run a high pass filter on the mains at 80 hertz and let the subwoofers take care of the bass, and running a line out converter from the speaker outputs would limit bass below 80 hertz, right? Is there any other way of doing this?

Click to read more...

 

[Lasherž]

Hi,

This is my first time upgrading the sound system on any car, so I'm pretty clueless about car audio in general. I have a 05 mini with the premium hk sound system, but I find the sound disappointing and I want to upgrade it while keeping the stock headunit so the car looks the same after I'm done. The problem is, I realized when I removed the hk amp, there's only two inputs to the amp. So I guess this headunit is weird because the amp is not built in. Is there a way I can somehow double the output so I can add a subwoofer? I know some of you are going to tell me to use a line out converter, but I want to run a high pass filter on the mains at 80 hertz and let the subwoofers take care of the bass, and running a line out converter from the speaker outputs would limit bass below 80 hertz, right? Is there any other way of doing this?

You can tap the subwoofer's speaker-level output the same as a speaker, just make sure the LOC can handle the power. Technically it's true that an LOC will reduce the quality of the bass signal because it will have to re-amplify it, but the way you avoid that is by playing a 50 hz tone and adjusting the fader to find out which speakers don't produce a tone and avoid them for splicing a signal from. If they produce an audible signal at 50hz then there's not that much signal loss and the lc2i will be able to easily fix the downsides without noticable differences if set up right. Alternative if you're that concerned about it you could always get two lc2is or a lc6i and use one sourced from the subwoofer signal and one off the fullest range speakers in the car.

In my '14 accord my door speakers produce full range even up to high volumes, while the back speakers have the effect you're worried about, with pretty much no noise from a 50hz tone. Still I was able to tap the rear speakers for a subwoofer, but I would get a much better result by tapping the door speakers, allowing me to use less bass restoration.

Also for a general rule of thumb, I would keep the factory amp unless you want to potentially lose some sounds like door chimes. Sometimes manufacturers will route alternative noise sources through the amp directly rather than through the head unit to mix it, then the amp. It's best to just get an LOC that can handle slightly amplified speaker wires. The two I mentioned from audiocontrol can handle 400W per channel @ 4 ohms. No factory amp is going to produce that sort of power even for a subwoofer, so you'd be good with those.

 

[idkcaraudio]

You can tap the subwoofer's speaker-level output the same as a speaker, just make sure the LOC can handle the power. Technically it's true that an LOC will reduce the quality of the bass signal because it will have to re-amplify it, but the way you avoid that is by playing a 50 hz tone and adjusting the fader to find out which speakers don't produce a tone and avoid them for splicing a signal from. If they produce an audible signal at 50hz then there's not that much signal loss and the lc2i will be able to easily fix the downsides without noticable differences if set up right. Alternative if you're that concerned about it you could always get two lc2is or a lc6i and use one sourced from the subwoofer signal and one off the fullest range speakers in the car.

In my '14 accord my door speakers produce full range even up to high volumes, while the back speakers have the effect you're worried about, with pretty much no noise from a 50hz tone. Still I was able to tap the rear speakers for a subwoofer, but I would get a much better result by tapping the door speakers, allowing me to use less bass restoration.

Also for a general rule of thumb, I would keep the factory amp unless you want to potentially lose some sounds like door chimes. Sometimes manufacturers will route alternative noise sources through the amp directly rather than through the head unit to mix it, then the amp. It's best to just get an LOC that can handle slightly amplified speaker wires. The two I mentioned from audiocontrol can handle 400W per channel @ 4 ohms. No factory amp is going to produce that sort of power even for a subwoofer, so you'd be good with those.

I'm alright with losing the door chimes, the factory amp is failure prone and underpowered so I definitely don't want to keep it around. The problem with tapping into the rear or the front speakers is, I have no rear speakers, and the fronts are going to be running a high pass filter. My plan is to replace the rear 6.5 fullrange speakers with small subwoofers, and I won't be running the front components full range, so that's why I don't really have anything to tap into right now, I have no fullrange speakers, which is why I was hoping there's a way to somehow double the input.

 

[idkcaraudio]

Are bass blockers a viable option? I know it's a 6 db/octave roll off, but I mean it's not like I'll be using my car for audiophile listening sessions. If I wired the appropriate cap inline with the component speaker set, then I can run my amp full range and use a loc to give a signal to the 2 channel subwoofer amp, right? Any drawbacks to this?