S4PK

Well... I just got my 2002 silver/silver premium, cold, bose. I have 700 or so miles on it and I have been using the "recommended settings" for the hidden EQ. I tend to think of myself as one of those audiophiles, and if I would have not bought some serious stereo stuff for my last few cars, I could have bought an S4 with that money. Anyway, I was disappointed with the sound and told myself I'd spend some time this weekend wit hmy Audiosource 1/3 octave analyzer and find out what the deal is.

Results:

At 55555555, and all tone controls centered, the response is not all that bad for a stock radio. In general, when you tune a car you do not look for a flat curve (it sounds like hell), you look for a SMOOTH curve that is elevated at the lowest frequencies, and slowly slopes down from there. There are problems at 55555555 though. The bass is set up for a stationary car, and there is a mid bass rise at 160hz that could be an anomally of the mic's relationship to the seat etc. but I heard a lot of bid bass crud, so I tend to think it exists. The mid range is slightly elevated, but the treble is actually pretty good.

So through some experimentation, I got a pretty smooth IASCA type curve out of the EQ with the tone controls set a 0. The settings are 82358235. This is just the begining, as I ran out of time and had to stop.

Some final thoughts:
-The midrange control in hinged at 1-2k and narrow, bad design.

-Haven't looked at the effect of different eq settings for front and rear.

-So-far sounds great on a lot of music.

REMEMBER THIS JUST SETS THE FIELD LEVEL TO ADD WHATEVER BASS, MID, TREBLE YOU WANT.

BOTTOM LINE-- I'LL LET YOU KNOW NEXT WEEK...

82358235--try it hold down 5 and turn the radio on. Volume changes the # up or down, P-Scan changes to next number.

Pat-SoCal

but you sound like you know what you're doing.

Gonna try 82358235 next time.

thanks.

Mike@VAST

Thanks for posting a setting based on some testing!

Driver8

Tried it...it really seemed to add "presence" to the stock sound, and it also appeared to fatten up the low end somewhat.

Thanks!

itsfknmikv

the bass the same?

Thanks in advance

RobC

If you'll click <a href="http://photos.yahoo.com/maxhawkgt">here</a> you can find the frequency response graphs of each EQ setting. This was measured coming out of the radio (at the Bose amp connector) with the tone controls flat and the volume at maximum.

What the graphs will show you are the center frequency and the amount of maximum boost or cut at that frequency. Keep in mind that this omits the EQ that's located in the Bose amp.

zerinS4

I need the IASCA disc to tune..argh..you don't have the '97 IASCA disc do you?

S4PK

The only valuable measurement is with a microphone (especially BOSE, they are known for non linear response speakers, covered up with amplifier eq).

P.S. I'm still not satisfied with my current settings... need more tests of each EQ, rear and front separately...

S4PK

But I use a few different discs. One of them has a longer pink noise track... Audi is not hip on REPEAT...

E-mail me if you are looking for my Iasca disc...has 75 tracks.

S4PK

There is no easy solution...If it was an actual science, someone would have made the perfect stereo already. And judging from how many companys make the stuff....