Bose/MOST non-PCM Head Unit upgrade

Right, my car is a 52 plate but apparently is MY03 (reg 03/10/02) and is most likely MOST although I haven't checked for the orange wire yet. It has a single din OE head unit and a dealer fitted Alpine DVD/Nav unit which frankly isn't very good and would prefer to get rid of it for an all in one unit. I have a Becker Cascade head unit sitting in my garage which came out of my last car and I would prefer to have this fitted as it does everything I need with minimum fuss. I assume from reading through old posts that it's not as simple as plug and play. However, it seems that it can be done by changing the amp and having the dealer disable the hu/amp from the MOST ring. A sticking point seems to be the sub which I'm told is a 1 ohm sub. However, is it 2 x 2ohms in parallel to give 1 ohm (i.e. change it to series and get 4 ohm) or is it 2 x 0.5 ohm in series (meaning is there a way to change them to 2 ohm or 4 ohm). Anybody upgraded and can recommend amps for the job. I don't want to change speakers but if it can be done by running a few cables from the HU to a new amp then I'm prepared to take a look at it and maybe give it a go. Any info appreciated...

can't say many 911's have serious audio systems, best to speak to an audio specialist such as www.cartronics.co.uk Becker is a straight forward fit

Becker may be a straightforward fit on a non-amp or non-MOST 996 but from reading here and on some of the other forums it seems that it isn't quite a straightforward swap if you have Bose and MOST as the speaker output is carried to the amp on the fibre-optic link. I'm not looking for a serious install, I'm looking for a way to plug in my Becker and get rid of the OE head unit and aftermarket Nav unit.

Hi mate For the benefit of future readers, here is my email response to you: I fitted a Pioneer double din unit. If you are running MOST, then the easiest thing to do is to bypass the Bose amp altogether, and wire into the standard speaker circuit. The door and dash speakers are 2 ohms each, so I basically ran them in series using the internal amp. The rear side speakers are 4 ohms, so easy enough. The sub has 2 speakers which are powered in parallel. Running them in series gives you 2.6ohms. These are wired into a small amp running off the sub out of the stereo, I could have run these in parallel with the rears, which I would imagine the stereo to be quite stable at, but I'd like the control that the sub out gives me. All of the wiring was done under the plastic panels in the engine bay. To reverse it, all I need to do is cut the bridging wires, reconnect the amp and then the CDR23(plus remove the antenna and mic)

Tino I saw your email, cheers. I was just thinking about the sub as that seems to be the most difficult part of getting the original parts to work. I was doing a bit of digging and it appears that the sub output comes from the Bose amp to the additional small sub amp. Does it do anything in the bose amp other than convert the sub audio from fibre optic to copper wire? I wouldn't have thought so. If thats the case then you could take your head unit sub output directly to the OE sub amp and leave the subs in parallel. Just thinking out loud here.... If not then a 5 channel amp should be able to power the sub at 2.6 ohms with no issues. My probable route would be to use a 5 channel amp with the door/dash in series as you suggested. Then either take the sub out directly to the Bose sub amp and use them in parallel as original or put them in series to the 5th channel on the aftermarket amp. That seems the simplest way to change the head unit on a MOST car unless anyone else has done something different. I'll lose the CD changer but gain an ipod. No huge loss as I've rarely used the changer on any car I've had.

I went to a number of experienced ICE dealers and the best solution I was given (and fitted) is as follows:- 1. change head unit (I put in an good spec Alpine iDA-100 with bluetooth and iPod compatibility) 2. new amp to drive the front speakers. the head unit drives the rear speakers. (I seem to recall that head units can't effectively drive the full 8 speakers used in a BOSE upgrade ) 3. Scrap the Bose amp as to drive it would need a very specialist and expensive amp...install a sub on the rear parcel shelf with integrated amp instead. (Pioneer do some very good and compact ones) I know have a fantastic sound system with iPod and bluetooth. Costs circa £1000 though :sad: the main issues are the fibre optic cables and the low impedance sub. there isnt a cheap solution for replacing MOST systems

I couldn't find a seperate amp to the rear subs, so as I thought they will run directly off an amp if placed in series. The absolute cheapest way to do it is the way I have done. Stereo runs fronts and rears(it can easily run the fronts, as they are in series at 4ohms)When you but component speakers, its a similiar thing. Then a small cheap amp for the subs placed in series. Sounds OK with my Pioneer Avic 900BT, at least as good as the OE setup.