http://mobile.jlaudio.com/products_amps.php?amp_id=439
I've read that it's better to tap in before the bose amp or in alot of cases better to completely take that amp offline and not use the rear speakers. If this is the case, would there be any noticeable increase to SQ if those rear speakers are taken out physically? Main question here was the high lvl inputs vs using a inline converter. Thanks

 

Physically removing the rear 6x9s and covering the holes will help, as they won't be resonating from the SPL of the amp in the trunk, so yes, better SQ with them gone and the holes plugged.

As for high-level inputs vs. low level - in general there's going to be less noise since there's not another amplifier in the way of the signal. Specific to the Bose - the Bose amp does some strange things with the EQ based on volume to compensate for the fact that the amp sucks really bad. Since it's nowhere near powerful enough to put out a clean, loud signal, it puts out a muddy, louder signal instead as the volume goes up.

 

are you considering the HU as 'another amp'? either route I go with stock HU I'll have to tap into the high lvl wires. I figured the converter was for amps that only have low inputs but since this one has both... I see it as another component to muffle sound quality. Any thoughts?

 

I've been professionally installing for about 7 years now and personally own a 03 coupe. I use my high level out from my Kenwood double din. My factory speakers are just as mint from the day I got my car. The only thing I implore you to do which ever route you take is to make sure your interior speakers are set to 100hz or higher thus turning your 8 speaker system to mid/hi-hi sounding system without ANY bass inside. For bass i have a 2000watt eclipse amp to my 2 8" W7.
I have 0 road or any other noise interference coming through my speakers. Again use high level out, adjust your crossovers at the headunit and your music will be loud as fvck and crystal clear.
Good Luck!!

 

Internal or external, an amp's an amp.

Whenever you have the choice, go with the low level inputs, but if the amp has speaker-level inputs, I don't think you'll gain anything audibly by using an external line-out converter.

However, the Bose amp screws with the EQ quite a bit, so bypassing it will give you audibly better sound by far.

 

I appreciate the time you guys are taking to answer my questions.
Keep in mind I have the bose HU. I don't have control over the low hz. I could use inline 100hz resisters or get a crossover (not what I want to do). How are you controlling your freq on the door speakers without limiting what the amp gets for the sub?

 

Understood. get the clean signal before it gets to bose amp. I hear leaving those rear deck speakers plugged in to the amp while running an aftermarket sub will degrade the overall sound. Im going for clarity not shake your house base. With that said, rear speakers will be removed but undecided if I should cap off the holes or leave open for more base sound. The box is sealed so I don't have to worry about hearing the ports. Anyone had their sub in and listened to a before/after of the rear speakers removed?

 

The sub I'll be using
http://mobile.jlaudio.com/products_s...hp?fit_id=1515
Don't make fun :P I need all my truck space.

 

My mistake, I misread your post. I thought you meant replacing your factory with aftermarket. But as far as adding your subs to the factory, I would just use a quality inline converter. Sometimes people hear a loud buzz when they turn their radio low or off, this can easily be avoided by turning down the levels on the inline converter. Using high level input for your aftermarket amp is NOT suggested. Good luck friend