Alfa Romeo Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
192 Posts
Discussion Starter #1
Hi
I am changing over my head unit in my Sportwagon this weekend to the Avic-F30BT.
My SW has the Bose upgrade. Does the Bose sub signal run from the existing head unit seperately, or is it tapped off the rear speaker feed?
Just wondered because there is no sub adjustment on the standard head unit, but on the Avic there is. It would be nice to be able to adjust the sub seperately.

So basically, is there a seperate sub out on the factory head unit

Thanks
Steve
 

·
AO Silver Member, 155 Lounge Winner 09
Joined
·
7,713 Posts
No subout on factory unit. The signal is summed from the other channels.

If using the RCA preouts on the AVIC, you feed the BOSE amp with only the front/rear outputs, and leave the sub output unused. Unfortunately, there'll be no independent sublevel control.

:)
 

·
Registered
Joined
·
192 Posts
Discussion Starter #3
so does the Bose system take its front/rear signal from the original head unit connector behind the existing head unit then? I imagine it does.
Shame about the sub output. I wonder if it possible to 'split' the Bose sub audio signal off of the wiring in the rear of the car and run a seperate RCA lead to it? Doubt its that simple!

So, if I change to the Avic system, using the correct din lead adapters... what tells the Bose sub to switch on? I assume its all done for me in the Pioneer-to-Alfa conversion wiring loom.
 

·
AO Silver Member, 155 Lounge Winner 09
Joined
·
7,713 Posts
Yes, the BOSE system takes its audio signal from the 'speakerwire output' ISO plug. However, the audio signal in 'BOSE mode' is relatively low level, and not a fully amplified signal like normal high level speakerwire outputs. It's somewhere inbetween the typical high level output voltage and typical low level RCA outputs. For example, your AIVC might offer 4V (peak) RCA outputs, at full volume. The BOSE system is around 6V. High level speakerwire outputs might be 10V.

It does mean, if you use the RCA preouts on your AVIC, the signal strength is relatively weak, so 'full volume' won't be as loud as with the factory headunit. If you use the speakerwire outputs, it will be overly loud at low volume settings. Not much you can do about it, because the sensitivy of the BOSE amp is not readily adjustable (unlike the 'gain' adjustment on an aftermarket amp).

The BOSE amp has 4 inputs (FL/FR, RL/RR). But it's a 6-channel amp. The sub is run from 2 channels. These sub channels are fed from 'internal' connections, so it will not be possible split these channels off without opening the amp and knowing what to do (I've never seen inside, or a wiring diagram, so no idea what would be involved.

The BOSE amp - like an aftermarket amp - has a remote trigger wire input. From the factory headunit, you will find this wire in the yellow mini-ISO plug, and usually labelled as 'BOOSTER' on the wiring schematic sticker (not to be mistaken with the 'BOOSTER DET' wire in the main powerwire ISO plug; this wire triggers the headunit into BOSE mode, so has a different purpose); when the factory headunit is turned on, the booster wire goes from 0V to +12V and triggers the BOSE amp on. This wire needs to be connected to the AVIC's blue 'remote output' wire.

:)
 

·
Registered
Joined
·
190 Posts
Chaps,
At the risk of taking this thread slightly 'sideways' would you happen to know how easy it is to identify the 'Booster Det' wire in the main ISO plug (i.e. has anyone got a pin-out ?)

My problem is that along with the Bose system I have a factory fitted nav system in my 159, and, well, let's be honest, it's a little bit pants for a premium audio system isn't it. So, I'd like to disable the 'Booster Det' feed on the Bose system so that it can no longer be 'arrogant' enough to turn off all the equaliser and loudness functions of the head unit that are currently permanently disabled by the Bose. I'm suspecting that this might also disable level matching from the head unit to the Bose amp, but I'll happily deal with that one when I get to it. :rolleyes:
Thanks in advance
Bill
 

·
Registered
Joined
·
190 Posts
jwq, top man :thumbs:

looks like that's exactly what I needed to know, and even my Dutch is up to working that one out !
Thank you.
 

·
AO Silver Member, 155 Lounge Winner 09
Joined
·
7,713 Posts
Yes, it's A2. Though that schematic is for the 147/GT, and some of the other connections are slightly different to the 159, but no big deal in this situation.

If you have one of the factory headunits, there should be a sticker on the top, with the schematic.

This is a typical (non-nav) 159 schematic, attached.

:)
 

Attachments

·
Registered
Joined
·
190 Posts
Shiny,
likewise thanks for the post, looks like it might be all documented once I get in there, but fore-warned is fore-armed and all that, so any info is much appriciated.
 

·
Registered
Joined
·
190 Posts
Best BOSE modification ever - and it takes about 20 minutes.
Get A2 disabled and the audio goes a long way to transforming into what it always should have been :D.
What were they thinking ?
 

·
Registered
Joined
·
190 Posts
Yeap, just clipped the wire and insulated. I was waiting for the audio to be blasting away when I put it back together as it's also meant to trigger the line level for the Bose but there wasn't a great deal of difference.
Nothing distorts and even if the amp is being driven harder the speakers are still being driven exactly as before by the amp so they're seeing no difference. Having the graphic and loudness no longer 'greyed out' on the Bose makes a massive difference. :)
 

·
Registered
Joined
·
192 Posts
Discussion Starter #13
I did exactly this on my Mazda RX8 a few years ago, that also had the apparently 'Premium' Bose system.
I altered the wiring as you have done to re-enable treble, bass and loudness.

However...

About a month later both front tweeters failed and then a while after that, the sub started rattling - which turned out it had split the cone.
They really don't like being over-driven.

Neither could be fixed under warranty.

So beware :(
 

·
Registered
Joined
·
190 Posts
I did exactly this on my Mazda RX8 a few years ago, that also had the apparently 'Premium' Bose system.
I altered the wiring as you have done to re-enable treble, bass and loudness.

However...

About a month later both front tweeters failed and then a while after that, the sub started rattling - which turned out it had split the cone.
They really don't like being over-driven.

Neither could be fixed under warranty.

So beware :(
Very valid point, especially as you now have the ability to drive the tweeters and sub at much higher levels.

I guess in theory that if Bose have matched their 'speaker ratings to the output power of their amp correctly then there shouldn't be a problem, but I have little faith in that and I suspect if it is wound up too much on a regular basis the tweeter's could well become toast quite quickly.

In my mind this isn't a mod. that ups' the power and increases the SPL, more a mod. to improve the sonic quality at sensible levels.
 

·
Registered
Joined
·
769 Posts
Best BOSE modification ever - and it takes about 20 minutes.
Get A2 disabled and the audio goes a long way to transforming into what it always should have been :D.
What were they thinking ?
Is A2 the single wire on the Yellow ISO plug ?
 

·
AO Silver Member, 155 Lounge Winner 09
Joined
·
7,713 Posts
No. The 'A' means it is a wire in the main power-ISO plug. :)

'B' is the speakerwire-ISO plug, usually co-joined with A.

The 'C' plugs are the mini-ISO plugs, blue-green-yellow, interlocked. The single wire in the yellow mini-ISO plug is actually C6. In the schematic posted above, it is labelled 'BOOSTER', and is an output wire, +12V, to trigger an amplifer (incl BOSE amp) on/off.

:)
 

·
Registered
Joined
·
3 Posts
Yes, it's A2. Though that schematic is for the 147/GT, and some of the other connections are slightly different to the 159, but no big deal in this situation.

If you have one of the factory headunits, there should be a sticker on the top, with the schematic.

This is a typical (non-nav) 159 schematic, attached.

:)
Hello everyone,

Just recently i'm mexperiencing this annoying engine (whining, alternator, whatever,....) noise from my gt's bose sound system. Maybe off topic, but the noise is coming from the rear right speaker only, and since it's not permanent, plus it stops if I hit the headunit, i suppose that the problem is coming from the head unit. This is why the head unit is now at a service shop (a blaupunkt service place) for investigation.
Reading this post, i'm also very much interested in disabling the bose mode of the head unit. Actually, when my car was brand new, i don't know why, but the bose mode was disabled and the sound was much better!!!

After my first battery fault, when i replaced it and the system got power again, my headunit was turned to Bose mode and to my surprise, the sound level was decreased.This is when a local blaupunkt dealer explained to me that there is Bose and default mode for the headunits, but he couldn't explain how this happended from the beginning. To complete the story, my headunit changed the mode from Bose to default and back to Bose, another 2 times, i think following a low battery incident. To my disappointment, i have tried to simulate low battery incidents since then hoping to switch again to No Bose mode, but without any luck.

Any way, since i'm now again dealing with the sound system, i would like to apply this modofication, since i'm reading that the members of this post agree that it is really an upgrade! I just don't understand which is the A2 pin, i don;t see such a mark on the picture. Some help please?

P.S. Has anyone ecperienced this engine sound with the factory bose system?

Thanks a lot for your help!
 

·
Registered
Joined
·
3 Posts
Hello everyone,

Just recently i'm mexperiencing this annoying engine (whining, alternator, whatever,....) noise from my gt's bose sound system. Maybe off topic, but the noise is coming from the rear right speaker only, and since it's not permanent, plus it stops if I hit the headunit, i suppose that the problem is coming from the head unit. This is why the head unit is now at a service shop (a blaupunkt service place) for investigation.
Reading this post, i'm also very much interested in disabling the bose mode of the head unit. Actually, when my car was brand new, i don't know why, but the bose mode was disabled and the sound was much better!!!

After my first battery fault, when i replaced it and the system got power again, my headunit was turned to Bose mode and to my surprise, the sound level was decreased.This is when a local blaupunkt dealer explained to me that there is Bose and default mode for the headunits, but he couldn't explain how this happended from the beginning. To complete the story, my headunit changed the mode from Bose to default and back to Bose, another 2 times, i think following a low battery incident. To my disappointment, i have tried to simulate low battery incidents since then hoping to switch again to No Bose mode, but without any luck.

Any way, since i'm now again dealing with the sound system, i would like to apply this modofication, since i'm reading that the members of this post agree that it is really an upgrade! I just don't understand which is the A2 pin, i don;t see such a mark on the picture. Some help please?

P.S. Has anyone ecperienced this engine sound with the factory bose system?

Thanks a lot for your help!
Hello again,
i think the answer to my question was just some post below, sorry for that...
It is the booster det pin..
I just didn't recognise the A,B,C codes

Best regards!
 
1 - 20 of 20 Posts
Top