[net.audio] Auto cassette deck vibration - !@#%$

bill@hpfcms.UUCP (bill) (04/26/85)

I recently saw a note in net.audio concerning vibration noise in car
cassette decks.  Well, I'm on my fourth deck in my car (a Ford Tempo '84)
and I've just about given up on listening to my tapes.  The vibration is
horrible.  It seems to occur in the frequency range (4k-8k hz?) where
alto saxes, high male or females voices, piano, oboe, etc. live.  The
first three decks were Alpine, and the current deck is a high-end Yamaha.

I guess I just want to know:  Do we as consumers have any right to expect
close-to-flawless sound reproduction in car cassette decks, especially in
the day and age when cars do less and less vibrating?  Also, are there
any installation accessories which are designed to further isolate the
deck from the car vibration?  If so, what are they and where can I get
them?

I'm really fed up because the deck sounds great when the car isn't moving,
or when the car isn't running.  It doesn't seem to be tied to potholes or
any other such obvious vibration.  It most often occurs when I think the
ride feels vibration-free!!!!!

Bill (stop the car - I want to listen to a tape) Gates
hpfcla!bill-g

rfg@hound.UUCP (R.GRANTGES) (04/30/85)

[]
There are literally millions of Americans who don't have the troubles you
do. Ergo, there must be something unusual (note: un - usual = not - usual)
about your case.
1) Is it shared by all ford tempo owners?,m if yes, it's the car. If not,
2) If its only your car, is it the way you drive? Is it the routes
you drive? (What roads? I thought those thingswere for motorcycles, I use
these things with the two steel rails that help keep the wheels pointed in the
right direction,)
3) Is it your installation? Did the same person install all 3 sets wrong?
Did two or more do so? Perhaps they forgot the vibration isolating bushings
between the mounting bolts and the dash (if there were any). Perhaps...
lots of possibilities.
4) Do your own work? Try loosening the mounting bolts and letting the unit
just sit in the dash, if it will. SDoes it work better now?

You are not alone and there is no magic. Also there is no free lunch.  If
it don'rt work you can fix it if you try.

-- 

"It's the thought, if any, that counts!"  Dick Grantges  hound!rfg

bmw@aesat.UUCP (Bruce Walker) (05/01/85)

In article <14700017@hpfcms.UUCP> bill@hpfcms.UUCP (bill) writes:
>I recently saw a note in net.audio concerning vibration noise in car
>cassette decks.  Well, I'm on my fourth deck in my car (a Ford Tempo '84)
>and I've just about given up on listening to my tapes.  The vibration is
>horrible.  It seems to occur in the frequency range (4k-8k hz?) where
>alto saxes, high male or females voices, piano, oboe, etc. live.  The
>first three decks were Alpine, and the current deck is a high-end Yamaha.
>
>Bill (stop the car - I want to listen to a tape) Gates
>hpfcla!bill-g

You may be changing the wrong component; try a new car. :-)/2

I wrestled with that problem in a car I owned a couple of years ago.  I had
a Panasonic (not particularly hi-end) system which was too big to be placed
in-dash so I mounted it beneath the glovebox on a little shelf that the car's
maker (Mitsubishi) had stuck there for some unknown reason.  Everything was
fine until you hit about 55mph (90kmh) at which point wow & flutter values
were about 100%.  So I removed the shelf and used it as a template for a 7/16"
plywood replacement reinforced down the front with a piece of 1.5" on-a-side
by 1/8" thick steel angle-"iron".  This whole affair was securely mounted to
the car's chassis with the aid of 3/8" threaded rod and whatever else was
necessary to mechanically couple the deck to the car.  The theory is: either
completely decouple the unit with viscous damped shock absorbers (I couldn't
find anything readily available) or else *tightly* couple the unit to 
something whose vibration rate is low, in this case the car's chassis.  You
want to avoid having any mounting arrangement which allows some free movement
in any axis which would allow mechanical resonances to occur.  Also avoid
mounting to anything which is coupled in some way to the engine (firewall,
perhaps, or transmission hump).

Anyway, my mounting method worked reasonably well, and probably increased the
burgler-proofness as well.  On my current car, I searched high and low to come
up with a unit that would fit in the dash.  This way, the unit is inherently
well mounted up front and only needs reinforcement behind.  I have had no
problems with this arrangement.

Bruce Walker     {allegra,ihnp4,linus,decvax}!utzoo!aesat!bmw

Accuracy Disclaimer:  I am not a mechie, so take these comments with a grain of
		      silicon.