dino11216

all you need in high low adaptor

dino11216

what did you set your gain and bassboast to?

chillum

Awesome details. Im going to do this too. But Ill leave the BO sub in place running and just tap off the sub lines.

http://www.crutchfield.com/g_721/Lin...s.html?tp=2001

use this to tap off the sub speaker wires and then it convert to RCAs

chillum

Does anyone know the wattage of the amp to the B&O sub is?

The line output converters have peak wattage ratings

elf_cruiser

Tks for the replies - I would guesstimate the stock wattage to the sub at around 75-100 watts. I hooked up the 12" sub in the box using the factory leads, and it was better than the stock sub, but not enough for a 1200w speaker, so I added the amp. Most if not all amps have speaker-level inputs, which is how I hooked this up. Line level signals are generally cleaner, but I have no idea how to get a line-level signal out of the B&O, abnd if there was one, it wouldn't be filtered like the stock sub lead. Running the new amp off the stock subwoofer leads makes for a very filtered frequency range. You have the crossover form the B&O system, coupled with the crossover in the amp (set to 150 hz in my case) and they multiply to give a very sharp cutoff above 160-180 hz. It's nice hearing some Chili Peppers bass riffs where Flea works his way up the neck, and the sound transitions from the sub to the mids in the doors very evenly. I like a system where 20hz, 40hz, 80hz, 160hz all play at the same SPL, so you can really hear detail in the bass guitar and drums...

Dino112 - i took the 40hz "bass boost" out completely, as it was muddying up the sound, and the gain is set to about 2/3 - full on would be too much for the rest of the system... The only thing I would do differently is spend a few more bucks on a better woofer with a bigger magnet and a rubber surround. The bass isn't quite "tight" enough for my liking, but everything could always be better, and swapping out the driver is pretty damned easy. Just like the 350 hp isn't fast enough either

Here's another thing to think about for you guys that want to replace the factory sub. Mounting it to the rear deck is a pretty bad design to begin with. You are limited to free-air subwoofers that are not going to kick the back of your seat like a sealed enclosure. Also - even the stock little sub would rattle the crap out of my doors, brake light, etc. which can be kind of annoying. Having a proper enclosure that's bolted down to the floorpan means that the vibration is sent into the chassis, not the rear walls and doors of the car. Less rattling, more bass.

One small detail - remember to renew your AAA membership - cause the way I mounted it, I can't get to the spare tire - whoops!!!

r3zon8

id really like to see a sub install using the factory spacing along the left or right side of the trunk. even if it doesnt hit as hard as a standalone box you dont lose any trunk space just a thought...time to google around

elf_cruiser

Absolultely possible if you don't mind cutting the car up. Custom fiberglass enclosures can be made so you will still get a tight sound. This is somethign I would leave to a very high end audio shop, though - it takes special tools and talent to build that kind of stuff...

Rbeal

I dont know much about subs, but as opposed to using a new box, or enclosure, what if you just dropped like a JL W7 or something into the factory location with a new amp...wouldnt that pump the car full of bass without requring too much extra..or does a nice loud sub require an enclosure...isnt the trunk technically a huge enclosure


btw im a newb, so dont rip me apart too much

tomagster

The system looks great. I wanted to know if anyone has actually just replaced the B/O sub with a freeair sub, and if so how much work it was.

elf_cruiser

The trunk airspace is way too much for a sub. Maybe like a 48" dia speaker? Besides that it isn't sealed - yuck. If you want to feel that solid thump, like a midget kicking your seatback - you need a sealed enclosure to match teh size of the sub. Each sub has a recommended enclosure size, most 12's are around 1-1.5 cu ft. 10's can be less. Higher end speakers don't need as much air space to create the same SPL. More airspace generally = more SPL but less "definition" or "tightness". Ported boxes are even louder, but also lack a tight feel.

As for replacing the stock sub - you can certainly do that without too much headache. There are several write-ups on that topic here, just search. All in all, it's probably the same amount of work as what I did, just less $$.

Audi just should have used an enclosure from the factory - I'd like to talk to Mr Bang or Mr Olufson about that...