Replacing Factory Subwoofer

itrice · 07-28-2004, 01:42 PM

I have searched and found answers to some of my questions, but still haven't quite found what I need. I have the RF package (got because it was on the lot and got a good deal) and am not satisfied with the subwoofer. I would like to keep the space open under the back seats so I am looking to put an amp under the passenger seat. The questions I have is
1) Is the factory sub and amp crap or if replace the amp with a quality one will the sub sound ok?
2) If the factory sub is ok, how hard is it to just bypass the sub channel and have the factory amp drive the speakers and have another amp drive the sub (trying to get by with using what I already have)
3) If the sub is crap, what size is it (I have seen posted anywhere from 6"-10")?
4) If you replace the factory sub can you use same enclosure? Has anyone tried this?

Thanks

eakes · 07-28-2004, 02:58 PM

What you ask is certainly subjective. Others may have different opinions but here are mine on the issues you raise: The factory amp, HU and speakers are one step removed from junk. The HU has design problems which put it in the barely useable with modifications class. The radio front end design is severely lacking - much too noisy. Off air reception on both AM and FM is marginal at best. The AUX input requires a 2 vp-p signal for reasonable listening level with a 'normal' volume control setting. Since most devices that would connect to the AUX input provide 0.3 to 1 vp-p, one must crank the volume control excessively to have a reasonable listening level.
The amp is by far the weakest link being way underpowered. There is nothing that can be done here except bypass it and use a better amp.
The speakers in the RF package are moderately good, except they cannot handle very much power. The dash tweeters are OK.
In my LE KC I replace the HU with an aftermarket one (Blaupunkt). The factory amp is still physically in place but is unplugged. I have installed RS crossover networks for the front door speakers and the side dash tweeters. The center speaker is not being used. I replaced the rear door speakers with Sony 6x9 3-ways. The subwoofer under the driver's seat is not being used. The new HU delivers 22 watts RMS per channel. With the 6x9s in the rear, I am reasonably happy with the overall sound quality. I have a 10-disc changer and an XM Commander satellite receiver connected to the HU.

I would not consider the factory sub to be adequate in any way. It is, I believe, a 6 inch speaker, I do not think it would perform well with a different amp (it certainly doesn't work well with the factory amp). I do not know if a different speaker would fit in the underseat enclosure.

The factory HU provides front and rear, left and right channels to the factory amp. The factory amp routes the audio to each of the speakers. It has outputs for the front door, rear door, center dash and side dash speakers plus the subwoofer.
Since the HU has no direct output for the subwoofer, one has to jump through a number of hoops to keep the factory amp and use a separate amp for a sub.

I think it is best to replace almost the entire system - HU, amp and some speakers. If you like a lot of powerful bass, you would definitely need a new subwoofer with amp.

itrice · 07-28-2004, 04:03 PM

Thanks for the info. I know the factory HU isn't great but I would like to keep the factory look (hoping Nissan will get problem fixed and I will have a new HU put in). Looks like I need to find a 5 channel amp. If anyone has tried to put a different sub in the factory box let me know.

Sammy Sandbag · 07-28-2004, 04:34 PM

It won't work from what I can tell. I took apart the factory sub enclosure and it uses an off size speaker. Not only that but it is a very shallow depth and uses a bolt through the bottom of the enclosure to hold the speaker in.

1stime · 07-28-2004, 07:33 PM

eakes are you sure the rear door speakers are 6x9's??

eakes · 07-28-2004, 08:19 PM

Quote:

Originally Posted by 1stime

eakes are you sure the rear door speakers are 6x9's??

The factory rear door speakers are 6.5 inch. I replaced them with 6x9s, sorry that wasn't too clear in the original post.

04LX · 07-28-2004, 09:47 PM

I have a shop in my town that I am working with to produce custom fiberglass sub enclosures that will fit below the rear cab seats, painted to match the factory exterior with an amp tray so everything looks in place, should have the first one finished next week. I will post some pics as well as some pricing if anyone is interested.

bestatchess · 07-29-2004, 07:56 AM

Quote:

Originally Posted by 04LX

I have a shop in my town that I am working with to produce custom fiberglass sub enclosures that will fit below the rear cab seats, painted to match the factory exterior with an amp tray so everything looks in place, should have the first one finished next week. I will post some pics as well as some pricing if anyone is interested.

I am interested. Will this mount 2 amps?

itrice · 07-29-2004, 09:07 AM

I looked at factory box today and agree, doesn't look like you could do anything with it. Does anyone sell custom box for under drivers seat? I want to keep the space under the rear seats. I have seen the post on instructions to build a box for under the front seat, but at this time I do not have the time or space to build one. I would like to put a single 10" if possible, not sure there would be enough air space. A custom fiberglass box that matched interior would be great.

smoketitan · 07-29-2004, 01:09 PM

just get the wood pieces cut from home depot( they will cut it to spec) and some liguid nails and a few wood screws and it will only take you a few hours to put it together and cover it--for way cheaper than what you will have to pay to get one made. and under the front seat the woofer cant have a mouting depth more thand 4.5" max--- 4" would the best though for breathing room

04LX · 07-29-2004, 10:03 PM

The sub enlosre could fit two amps depends on the size, plus we have some room to make adjustments based on your amp needs, right now we are trying different 10" subs to see what fits and sounds best. I will post some pics next week, how do I start a new post? I dont see a tab for it.

bestatchess · 07-30-2004, 06:29 AM

Go to Visual/Audio/Interior and there is a tiny little tab at the top left in a little blue box that says "NEW THREAD"

jr357 · 08-05-2004, 06:56 PM

go to soudoffaudio.com they make a box that custom fits under back seat for two 10inch or two 8inch woofers,i have them building me one right now,plan on removeing factory sub under seat and putting amp for sub under seat,hope this helps

duffer18 · 08-06-2004, 07:50 PM

I was talking to a local Atlanta installer today trying to find an overall system that I liked and was willing to pay for. He had an interesting solution to the sub problem. Blaupunkt Overdrive 10" or 12" sub, it has a mounting depth that is just over 2" deep. He said they could build a box to fit behind either seat for the 10" or behind the passenger seat for the 12".

They didnt have one out to listen to so I am not sure if they are the greatest sounding and the 10" seems to retail around $275. So I would figure they will charge about $100 for the enclosure.

But it was an interesting solution...