I have a 98 A4 2.8. It has the bose stereo system (i know this b/c it says bose on all the speaker pannels, as well as bose when i turn it on). However, when attempting to access the hidden eq by holding "5" while turning on the radio. The radio just turns on as if i wasn't holding the number 5. I tried turning on the radio in different forms. By turning on the key, by just pushing out the button w/o the key, etc. I still could not access the eq. The only button i found results with was holding 3, which set the radio to saying "ver 01".

Any ideas? Does my radio not have the hidden eq feature?

I've never heard of the hidden eq?

Check out the tech articles at www.audiworld.com under the electronics section, check out the one about "hidden eq". Aparently it was discovered on S4's, and is applicable to the a4's, bose as well as not bose.

It is basically a 4 band graphic eq for both the front and rear sound stages, thus 8 levels to play with. From what I've read, it adds a lot of help for both systems.

I think i figured it out. I'm an idiot. I assumed that symphony implied bose, and concert implied non-bose. This is aparently not correct. for the hidden eq, you need the symphony deck, not the concert deck.

BUMMER!!
My 04 Bose Symphony does NOT have the hidden EQ. But I do have all the other hidden features.