[s-cars] Replacing Original Bose Head Unit

[Kirby Smith]

Adam D.

As much as I dislike Amar (a legend in his own mind) G. Bose and the
stuff he sells, I can't resist pointing out a few areas where I disagree
with your comments.
a) amplifiers are only stressed if they are undersigned.
b) Low frequencies are not more difficult to generate cleanly in an
amplifier than mid-range frequencies.
c) Big is relative.

On the other hand, I agree that his stuff distorts very badly at levels
just above the design point - the Bose radio being an egregious example.

kirby

"Adam D." wrote:
>
> The problem with replacing anything within the signal path of a Bose system
> is that Bose applies heavy equalization to compensate for gross frequency
> response errors in their speakers.  Rather than actually making a decent
> speaker driver, Bose chooses to cover up their crappy designs by altering
> the signal.  The biggest drawback of this method is increased strain on the
> amplifier.  In order to get decent output at the frequency extremes from a
> full range driver they boost the bass and treble considerably, effectivey
> making those sounds (which happen to be the most difficult for an aplifier
> to reproduce cleanly) "louder" and demanding more power from the amps.  So
> in order for this method to work the amps have to be big.  The Bose amps are
> not.  This is why the sound totally changes character as you turn up the
> volume.  Distortion sets in and the sound becomes brittle and glarish in the
> highs, and flabby and flatulent in the lows.  No Highs?  No Lows?  Must be a
> Bose.
>
> To make matters worse Bose speakers have a wierd impedence...something like
> 2.7 ohms, and the line level signal from the head unit is an odd voltage as
> well.  These quirks (especially the heavy equilization) will almost
> invariably alter the performance of any aftermarket equipment  (usually for
> the worse) you try to install.  So unless you remove all vestiges of Bose
> from your car, better keep it stock and find a factory changer or the
> compatible Sony (S4) or Panasonic (S6) unit.
>
> TTFN,
> Adam Dieckerhoff
> Head Tech, Achtuning LLC
>
> '93 S4 (black/ecru)
> '00 A6 2.7t (black/melange)
> '00 TT 180qc (silver/gray)
> '86 5kcstq (its baaaack!)
> fourquattros at hotmail.com
> Bellevue, WA.   USA
>
> ----- Original Message -----
> From: "Timothy Lynch" <tlynch at aquaengr.com>
> To: <s-car-list at audifans.com>
> Sent: Wednesday, June 12, 2002 9:41 AM
> Subject: [s-cars] Replacing Original Bose Head Unit
>
> > This is a multi-part message in MIME format.
> > --
> > [ Picked text/plain from multipart/alternative ]
> > As with everyone that owns a UrS4 or UrS6 w/o the CD changer option, I
> > have been running through hoops in an attempt to find a solution.  I
> > have been told that if I replace the head unit that I would have to also
> > re-run the speaker wires in order to bypass the speaker amps (which
> > supposedly wouldn't sound as good as the factory system), or replace the
> > entire system head unit, wires, and speakers (very pricey solution).
> > Other options are to install an RF modulator type CD changer (my last
> > choice) or to locate the original CD changer that was offered as well as
> > the correct harness (nearly impossible to find and requires more
> > patience than I think I have).  I was thinking (dangerous sometimes as
> > we DIY's all know), what if I were to purchase an aftermarket head unit
> > that has no built-in amp (i.e. Alpine 7995)?  Would there be any
> > problems with doing this?  Are there any other alternatives that anyone
> > has done and been happy with the results?  Thanks!
> >
> > Tim Lynch
> > 1992 Audi S4
> >
> >
> > --
> >
> >
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> >
>
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