BOSE low level ?
 

Hi All,

Like many I am a little underwhelmed by the bass in the S8.

Hence my decision to add a sub and amp.

Install looks fairly simple (the battery location really helps) but I have a question regrading line converters.

Having read various threads online there seems to be a discussion about whether I need to use a line converter or not?

I suppose the question is whether the signal to the Bose sub is low level already, I am tempted just to adapt some RCA's and splice them into the sub speaker cables rather than using a converter. I am concerned that if they are already low level inputs the converter would just add more unnecessary lowering of the input.

Also if I go down this route, could someone please clarify the wiring from the speaker cable into the RCA. Every guide I see online uses both speaker cables to a single RCA (Sheild negative, centre positive etc.), where as I need both RCA into the amp. Do i just ground the shields from each RCS to avoid noise interference?

Thanks in advance.

Tom

The Bose signals are low level already. You can just tap in to the existing inputs to the Bose amp and feed another amp straight from them, no converter needed.

The Bose wiring has four channels and a single shield connection which is *not* body ground - its a floating ground for the audio channels. Connect your RCA centre pins to the wires for the rear speakers, and the shield to the audio ground in the Bose harness (I think its white, not 100% though).

If your amp ties its RCA grounds to body ground you may get some interference, in which case you'll need to use an isolation transformer. You can get those online.

Many thanks, thats just the information i needed.+++

That's the basic difference between the Bose and non-Bose setups in a D2 and the relevant settings inside the RNS (and wiring connectors) are changed to reflect this.
Bose - 4-channel low-level line out to the Bose amp which then drives all speakers.
Non-Bose - front (door) speakers directly driven from RNS, rears are low-level line out to amplifier(s?) built into the rear shelf speakers which then drive the rear doors as well.

At least that's what I understand, but I may be corrected.... ;)
I think the connector label on the RNS even shows that only the front speaker connectors are available for use; line-out (all 4 ) is a separate block anyway.

Does anyone have a wiring diagram for the Bose harness?

One of these (attached) should cover it, depending on the year of your S8. If you search the PDFs for 'bose', there's numerous relevant pages. Check the page heading though to make sure you're looking at the A8 and not the A6.

Honestly, I must finally get around to understanding the wiring diagrams. I must say that I am struggling to understand them.

I did find this on posted by Audinutt on Quattroworld that suggests this is the Pin layout for the connector. (attached) The diagram is labelled as from a 2000 S4, but I assume original poster knows he stuff!

If I was taking this as my reference I would use the rear line levels left and right to connect to my left and right on the RCA centre cable, and connect the shielded cables from both RCA to the Line Level common ground. I would also use the switched power as a feed for my remote turn on.

Does this sound about right, makes sense in my mind anyways.

That's it +++ The line level wires are much smaller than the speaker wires so it'll be obvious if that diagram matches what's in your car.

I think I still have my original Bose plug in a box somewhere - my Bose amp is long gone, replaced by a Phoenix Gold Route 66 :D I kept the bits though so I'll have a look later and see if it matches the diagram.

Having attempted to attack this side of the install tonight I can confirm that for my 2002 S8 this is the correct pin layout.

RCA's and remote now installed.

As a tip to anyone trying this, I struggled for ages to remove the Bose plug from the amp. In the end I looked online and found a picture of the connector. It is held in place at the bottom edge by the design of the plug and cannot be removed in situ. You need to remove the side trim, or at least bend it out of the way and release the amp to undo the clip.

So quick update on this.

I had been umming and arring about what kit to go for and looking on eBay and gumtree etc. Ending up with the more expensive option ad buying some JL audio gear off a lad in Oxford.

JL Audio CP212-W0v3
JL Audio JX1000/1D

JL audio is great gear and this bundle had the larger 1000d amp included.

In Hindsight this set-up is complete overkill, after setting up the amp to its optimum settings the bass was ridiculous. So now have it running at about quarter power, 80hz and no bass boost and its sounds great - I just think I should of bought the single sub and the smaller amp! Although surely this now presents and opportunity to upgrade the headhunt and internal speakers?+++

I must say though that even with the bass at its initial settings the S8 is extremely well put together any rice car would have virtually self imploded, but the old girl barely shook.

Pictures attached