I just finished installing an Alpine CDA-9811 unit to a 98 GLE. After reading some threads on whether i need or don't need an adapter, i tried two techniques to avoid having get the adapter. First i tried to strip some RCA cables and connect them from the RCA outs on the deck to the car speaker wires. When i did this, there was a popping sound everytime i turned the volume down to 0 or up from 0 and also when i changed from the Tuner to the CD function. So this definitely wasn't going to work. Then i just wired it regularly by connecting the speaker outputs from the deck to the car speaker lines. Doing it like this didn't give me the popping sound, but i noticed that even when i turn the volume up to 1, it sounds louder than a normal deck would. And then when i turn it up one or two more levels, it just gets loud too sensitively. I doubt i can even turn it up past 5, cause i'm afraid to blow the speakers.

Is that how it should be since i didn't get an adapter? For anyone who has wired it directly, does your volume increase too quickly?

Also i went to Best Buy and Circuit City, and neither place had the Bose adapter. Both places said that I didn't need the adapter and that when they install HU's to BOSE, they just wire it straight up. There was even an installer at Circuit City who said he had a 99 Max w/Bose and wired it straight up. But he also said he blew his speakers eventually. So why would you tell someone to wire it that way if you blew your speakers?? Another reason not to take your car to them..

the bose adapter had dials so you can set fine tune the volume levels so it sounds normal... other than that, i think that's all it does.

i'm not too worried about blowing the speakers but will wiring it straight up do anything to my headunit?

This is the way I was planning on connecting my new HU. I hate to hear that, I would really like to hear what Don (pearlmax96) has to say about releiveing this problem. I know that he says that he has hooked up many decks this way.

I noticed there is also slight hissing when wired directly from the speaker outs to the speaker ins.

I really wouldn't recommend hooking the speakers directly up to the HU. From what I've gathered from all the other threads and members is that the Bose speakers are 1 ohm and if you hook up a aftermarket deck directly to them, it will overhead the HU and fry it. But I guess we'll let someone else verify this.

sorry i didn't mean directly into the speakers but into the speaker ins behind the dash which in turn, goes to the amps first.

You need the adapter. By the PAC piece, it has the input adjustments.

Shane