Bose audio question... compatibility

[imported_circa1656]

i own a 1990 - 200 turbo. it has the factory 6 speaker bose system that came in most models form this time... when i bought it the bose stereo cd player had been long gone and the previous owner said he could never get the sound right. i currently only get playback though certain speakers at erratic moments (which may just be a non grounded wire) and when the volume is turned up to a fairly loud level the playback becomes very very muddy and cracky... i have been told that bose speakers may possibly run on a different ohm setting, is this true? if so is there an adapter that will allow crytal clear playback through audi/bose speakers when being sent from a non bose deck unit? if anyone can direct me towards any leads it would be much much appreciated,

thanks!

 

[audi5e]

There are wiring connectors behind the radio that may have come loose over the years, I would check those. I gather that you are changing the head unit, if so check that the new head unit can handle both 4ohm and 2 ohm speakers. then you should not have a problem. if you climb in the boot of your car you should be able to see the bottom of the speakers on the back ledge. most speaker manufacturers either print on the speaker or place a sticker there. you should be able to get the ohm ratting from there. most people will not be able to tell the difference in the clarity between 8ohm 4ohm and 2ohm, not to mention that fact that road/wind/car noise detracts from the listening quality anyway. hence why car systems tend to have a lot more bass than a home audio system.

check that your model does not have a K/L diagnostic line going to the radio. models that were fitted with the factory radio normally had these lines, it should not cause a problem for the new radio, but it will cause a problem for your dealers diagnostic equipment when he plugs it in to your car.... (some models had this others not.)

The intermittent playback and the "muddy" sound at high volume are probably related problems.

Remember, depending on what kind of weather the car has been exposed to over the years, the bose speakers themselves could be damaged, brittle cones, etc.

 

[AndyMac]

No HU I know of can handle a 2 ohm load. The impedance (ohms) of a speaker has nothing to do with clarity or sound quality. Impedance is simply the amount of resistance the speaker presents to the amplifier and thus how much current will flow when the speaker is connected. A 2 ohm speaker (like Bose) will pull more current from the amp than a standard 4 ohm speaker, however the amp used needs to be able to handle this heavier current draw. This is referred to as being 2 ohm stable. If the amp (or HU in this case)isn't 2 ohm stable, then it will overheat and shut down or burn out when connected to Bose speakers.
It is far more likely in your case that the interference referred to is because the Bose amp (located in the trunk) doesn't like being connected to an aftermarket HU. This is usually due to either the adapter being used to connect to the Bose amp (introducing noise) or the fact that the Bose amp is a bit wierd in the way it is setup and you can get popping when changing from CD to radio, or when you first turn the unit on.
The muddy sound is traditional Bose muddiness. I've found no crystal clear clarity on Bose setups, and the bass is very woolly. The bass & treble controls seem to have little effect on the sound even when used with the Bose encoded head unit.
I would buy some half decent aftermarket speakers and replace all the Bose stuff and run them directly off the HU. This could be done for as little as £130 and will be a big improvement.

 

[audi5e]

There is quite an amusing series of posts on the subject here, http://www.pioneerprodjforums.com/ubbthreads/showflat.php?Cat=&Board=UBB6&Number=46637&page=11&view=collapsed&sb=5&o=&fpart=1

read near the bottom, they give the formula's relevant to this conversation...

Andy, a question, if an amp could 'handle' running different impedance speakers (say 4ohm is the 'rating' but the amp is 2ohm stable)and the voltage remained the same (eg 12V), is it likely that distortion could be introduced into certain frequencies at 2ohms since the amp is no longer running on the 'rated' impedance? ie the design of the circuits were optimally around 4ohms, i then switch to 2ohms, surely this would or could introduce noise? (of course there are so many other factors that affect sound)
OR would this simply be a case of higher output in watts due to the lower resistance?

 

[imported_jimmy154]

Go to caraudioforums.com or diyaudio.com (not think they deal with cars though, but way more knowledgeable then caraudioforums.com).

Did you solve your problem yet?

It has "six speakers" coaxial in front (I would assume) and tweeter and woofer in back. The back speakers are ampliefied. So I have to run my HU faded to the front at 4 out of 6, otherwise I would hardly hear the front. What is your HU?

I suspect ohms are not your problem. You can measure DC ohms easily with a multimeter, then deduce nominal impedence.

Wait! I had that same problem I think. Speakers played erractically. But it was with the original tape deck. I had a JVC cd-player, so I put it in and the speakers played fine ever since. Never figure out what the problem was, I wanted a cd player anyway.