Upgrading rear speakers?

[chb]

Its always struck me that the lightweight blaupunkt amp in the drivers footwell would be a ripe candidate for an upgrade. Has anyone ever done this or has any info on how feasable this would be? Aim would be to take the feed from standard sound system and then feed into a replacement amp with a beefier output (modded speakers may follow).

I may be in my 5th decade, but i still crave bass.

 

[Techno]

I am interested in this too as (although looking for an A2) I have spliced in an aftermarket amp and other kit into my A4 of a similar vintage. Electrically it's possible, but it is the physical size of the locations I'm particularly interested in eg; what space is available in the drivers footwell etc. for amplifiers and processors?

 

[chb]

Its the space in the foot well that gives me hope...there's lots!
Main thing I am not sure about is input V and A and what each pin does!
Superficially it looks like a simple power amp...if so then it should be a doddle to upgrade to something worthwhile.

 

[ajsellors]

Hi,

yes, the driver's footwell compartment is quite big and is normally empty apart from the rear speaker amp. Cars with the boot mounted sub-woofer (BOSE) however have the toolkit relocated under there but still have enough room for the larger amp.

With the standard arrangement the head unit's own internal amp runs the front speakers and the secondary one in the footwell running the rear. The rear line out signals go from the head unit to the amp and the speaker feed from the amp to the rear speakers.

Cars with the BOSE sound system have a larger amp located in the same place which runs all speakers. The head units amp is not used and all 4 line outs are run to the secondary amp. All Audi head units can be programmed to select whether line outs and/or the internal amp is to be used.

To upgrade the system you could replace the existing rear amp, but the front speakers would still be run from the head unit. To run all 4 speakers sets from an external amp you would need to disconnect the front speaker wires from the head unit and run them together with the front line outs from the central console down to the foot well. All Audi head units have a sticker on them which shows the pin outs which helps work out what's what. I've attached a picture of the pin-out sticker and head unit wires from a car with the rear amp for reference.

If you are increasing power output you may also want to beef up the feed to the amp. For example, the cars with the more powerful BOSE amp have a thicker wired main power feed plus and additional secondary feed from an extra fuse over the standard smaller amp.

The rear only amp is simple in operation. There's the power feed, run from fuse 2 (the same one which runs the head unit), line ins for the two channels (4 wires) and outputs for the 2 speaker sets (4 wires). The last one is a +ve power on signal from the head unit with turns the amp on when the head unit is turned on.

Pins:

2 red/white +ve feed from fuse 2
3 brown -ve feed

9 white rear left line in signal (from pin 1 on head unit)
4 brown/white line in ground (from pin 3 on head unit)
10 yellow rear right line in signal (from pin 2 on head unit)

5 red/blue power on signal (from pin 6 on head unit)

7 red/green left speaker +ve
1 brown/black left speaker -ve
6 blue/black right speaker +ve
12 brown/white right speaker -ve

regards

Andrew

 

[Sootywg]

Also interested in improving on the Blaupunkt Amp.
I only discovered last week that I even had rear speakers. The aftermarket radio that had been fitted was not connected up to the 20pin DIN that sends power and rear 'line out' to the amp.
I purchased the appropriate loom to connect the rear line out to the 20 pin DIN and lo an behold I had sound from rear speakers..... but I could only tell if I put the fader all the way to the back and ramped up the volume. I do not think the rear speakers are audible at normal settings.

Is this a fault with the current installation or just a poor amp? Don't know.

I will be interested in suggestions for replacements.

Geoff

 

[ajsellors]

Hi,

it could be that the amp is broken or the line levels from the head unit aren't compatible with the amp.

I would check that the adaptor loom is supplying the power on feed to the amp when the radio is on as that may explain the symptoms you are seeing. Powered down you may get break through from the inputs to the outputs and so still hear some sound from the rear speakers at high head unit volume settings.

Try connecting the red/blue wire to a 12v +ve feed and see if that brings the rear speakers to life. If that works then you will need to find an output from the head unit that turns on when its on to activate the external amplifier.

regards

Andrew

 

[bretti_kivi]

I would personally not bother with rear loudspeakers.... and the tweeters are only "crossed" using a cap; you'll probably need a bit more than that if you're feeding it real power.

Have fun finding speaker adaptors, too, since they don't exist.

- Bret

 

[dan_b]

Whereas I think rear speakers are actually pretty important for the front occupants - in my normal seating position in the car, my ears are far closer to the origin of the rear tweeters than the front ones and I'm sure I perceive a greater proportion of the overall sound from them as a result?

 

[Techno]

Would someone be so kind as to post a picture of the drivers footwell compartment perhaps with a ruler laid alongside to give a scale? Depth would be of interest too.

From my point of view the rear treble needs to be lower than that from the front and the overall rear volume lower to help fool us into believing the sounds are coming from ahead of us. If you have some fancy kit with time alignment, then that helps a bundle and really creates an immersive soundstage, then the rear volume can be raised whilst still keeping a realism of the sound being ahead of you.

 

[ajsellors]

Hi,

the compartment has an opening which is like a triangle in shape but with two of the corners cut off. Below, the compartment is larger than the opening but irregularly shaped. The bottom is contored so that the depth is not constant (decreases to the sides, particularly the front. There are also two attached brackets holding captive nuts which are used to secure the OEM amp. The standard fitment amp is fixed between the floor mounting and a side mounting at an angle. Due to the difference in size, the two channel amp only uses one floor mounting point where as the 5 channel (BOSE) amp which is longer uses both.

The minimum depth from the top plate to the floor mounting brakets is 14cm. With the contored lower floor, it is more than this in places but never less for the area under the opening. The longest side of the opening along the length of the car is 36cm and the largest width of the opening is 29cm between the protruding lugs.

I wasn't able the take a direct overhead photo of the whole opening as the steering column prevented the camera being far enough away:


Taken from an angle you can see the whole opening:


For context, this is a view from the back of the car which shows how the foot well compartment relates to the rest of the car. The front foot well compartment actually extends back to where the rear passenger's feet go. There only two under floor bracing plates with cut out holes between the front and back. From the photo you can see the speaker wiring coming down from the central section, going under the beam which holds the front of the front seats and into the OEM amplifier though the hole. (marked with the arrow).


Hope this helps.

regards

Andrew

 

[bretti_kivi]

Whereas I think rear speakers are actually pretty important for the front occupants - in my normal seating position in the car, my ears are far closer to the origin of the rear tweeters than the front ones and I'm sure I perceive a greater proportion of the overall sound from them as a result?

Which is why you can't get decent imaging, as you're getting badly time-aligned signals from eight different points.

Top of the dash, both corners, that's as good as you're going to get for equivalent path lengths.

If you want "surround", go for it. You don't need it with a decent setup for stunning 3d-imaging, soundstage depth and / or width. The 2" drivers I had on the table on Sunday last week are perfectly capable of letting your ears tell you where precisely the bassist is in relation to the drums and where the backing singers are.

If you get the chance, go listen to some EMMA cars.

Re: big, fat amps in the compartments:
- it gets warm in there. I put a damp / wet tent in my passenger side one and then drove 700km last summer to Copenhagen. The tent was seriously warm when I took it out. I would not do it again.
- you need to get 5m worth of cable in somehow, and it needs protecting / grommeting on the way through the aluminium
- there's no easy way to secure the amps from moving without using the original mounting points and / or some interesting fabrication.

I've given it up, as I couldn't fit my amps in easily and still be able to connect them up without tearing my hands to ribbons, so I've turned this into a sub enclosure for a 10"....

- Bret

 

[dan_b]

Which is why you can't get decent imaging, as you're getting badly time-aligned signals from eight different points.

Top of the dash, both corners, that's as good as you're going to get for equivalent path lengths.

If you want "surround", go for it. You don't need it with a decent setup for stunning 3d-imaging, soundstage depth and / or width. The 2" drivers I had on the table on Sunday last week are perfectly capable of letting your ears tell you where precisely the bassist is in relation to the drums and where the backing singers are.

If you get the chance, go listen to some EMMA cars.

- Bret

Good point, the stereo image is very lopsided!
My home hi-fi is very much stereo only. 1x pair of PMC FB1s driven by a pair of Musical Fidelity X-200s in bi-amp configuration.

What's an EMMA car?

 

[bretti_kivi]

EMMA = European Mobile Media Association. UK events listed here: http://www.emma-uk.com/ 2013's Final will be in Salzburg in a few weeks. Should be some stunning audio on display.

- Bret

 

[Bluesplit]

Well my speakers & amp arrived today, unfortunately the tweeters have been damaged in transit but may be getting a cheap pair tomorrow. Looks like I need to try and source an amp connection lead, any tips on the wiring the speakers?

 

[bono05]

Assembled kit,
one pair - 3 ohms, the second - 4 ohm
What is the difference ?

 

[bono05]

I finally did it)). may be useful https://www.drive2.ru/l/506149733559960464/