Unless you've tried it for yourself and found out the hard way then nobody's in a position to comment
Erm, actually, I`m probably one of the best people to comment - our repair centre has been inundated over the years with peole unsuccessfully trying to connect to BOSE equipment.
Seems like a YES then (for someone).
Sorry gents, didn't mean to sound short. It was more a response to zirk, when after 2 other lads had said they'd done it, actually stated, in fewer words, it couldn't be done.
It infuriates me the amount of hearsay that goes on within the electronics industry, I work in sales/installation of AV, as such our shop also has a workshop and the amount of bull$hit people/engineers/customers come up with is just ridiculous! Mostly because they are uneducated, just like sheep following what the other bloke does/says, just like the people buying bose. We have learned, that to test and investigate equipment, you have to try it for yourself. That way, you really WILL know if it works or not. This is only a internet user board, we can only offer advice.
Secondly Dave, some in-car amps will drive 2 ohm speakers and have a switch for this very purpose so not necessarily required to rip out standard speakers should you choose to go down the route of an aftermarket amp
Thats true, but many people are simply connecting an aftermarket head unit instead, and none of those will run four channels at 2 Ohms.
But the speaker cables are fed to the boot space so an aftermarket amp would be required, unless new speaker cable is laid, when, you might as well change the speakers. As such, it is in the owners interest to ask questions and purchase the correct equipment.
I actually said ‘Seems like a NO then’, even TB said it was a ‘non starter’, noticed he’s not getting comments?
Ok, going to put my neck on the block now and say, Yes it could be done, assuming you have the right knowledge, tools and test equipment.
Firstly a few things to consider, there’s a big difference between Audio levels to Speaker (Low Impedance) and Audio Line levels (High Impedance) as weave already established. Its not all about getting the right levels matched (Volts) but also the correct impedance, a miss match in impedance can cause strange effects ranging from an increase to quiescent noise (standby / background noise) to changes to the signal frequency response, i.e. the sound has too much Bass or Treble instead of sounding Flat.
It’s also worth considering Audio levels and the Human Ear, the human ear does not responded to linear level changes. In other words you need 10 times as much level change for the Ear to recognise that level to be twice as loud, i.e., going from 10 Watts to 100 Watts is recognised as being twice as loud to the Ear.
All Audio level changes (Volume and Pre Set Controls) are logarithmic, so again as Dave pointed out a miss match could give you an all or nothing effect on the volume control with the added bonus of too much distortion at an early stage of volume, which is not how the system was designed to work, added with the possibility of frying the Front End of the Amplifier.
Some people ears associate distortion as being Loud, then by turning down the volume a couple of db’s gives the effect of being greatly reduced in volume, but in fact its just the ear determine the difference between a clean and distorted sound, with the system reaching its limitations (i.e. Squaring the waveform).
You may think I’m waffling on a bit here, but the real point I’m try to make is that unlike most things today variable, Audio modules are not designed for Plug and Play without consequence results.
If you really want to do the Head Unit to Bose thing properly, you going to need the following.
Dual Beam Oscilloscope, a decent 4 Ohm load, a quality Volt and Impedance meter, and of course a Bose set up and the Target Head Unit. That way you can measure the Peak or Peak to Peak levels going into 4 Ohms, and with some simple maths, calculate the RMS volt levels (0.7071 DC levels at that impedance) and determine the correct audio and impedance levels when then inputting the HU to the Bose Amp, then again measure the New HU into 4 Ohms, then make the necessary wire wound resistor array to suit the Donner Head Unit.
Most things are possible, but people can only advise on what’s practical under the circumstance.