Speaker-Eating dashboard?

My Mazda 626 seems to have an appetite for speakers.
I have replaced the passenger's side front speaker for the third time a
couple weeks ago, and already it's buzzing like a bee is trapped in it.

The speakers installed are capable of MORE than the rated wattage of the
JVC Cd player (~22 Watts per channel, speakers are 50W or more)
All the other speakers work great, including the Driver's side dash
replaced in January as a set with the one that went bad a couple weeks ago.

There aren't any leaks, there doesn't appear to be any 'stray magentism'
anywhere around, no obstructions or protrusions of any type into the
speaker area.

I'm out of 'inexpensive' speakers (the last one that blew was a Clarion,
not the most expensive, but not a cheapo by any means...) Connections are
tight.

Usually audio problems don't throw me, but this one has me stumped.

Any ideas?

 

Find a cheap speaker, hook if up electrically but don't install it
physically. Just extend the wires and leave it somewhere in the car to
figure out whether it is related to the physical installation or a short
from the radio.

 

50W continuous? I have some 2' tall floor speakers rated for 50W
music power but only 1W continous (instructions said not to exceed 8V,
peak-to-peak, for more than 2-3 minutes).

If you don't blast them at high power all day, about the only
electrical thing that usually ruins speakers in a hurry is DC from the
amplifier. Switch a digital voltage meter to read DC volts and see if
there's more than about 0.1Vdc across the amp terminals (an analog
meter won't work for this). Don't measure to chassis ground because I
think that most car stereos now use two floating outputs (an easy way
to get higher power without higher power supply voltage).

Have you tried pressing the speaker cone to see that it moves in and
out without binding? Some of my Ford factory speakers (base audio
system) that scraped the magnet when moved also buzzed, but I had a
Ford radio cause a buzz because of some power supply problem (I think
it was the power supply that drove the LCD).

 

You need more power. A good rule of thumb is that the amp should be
rated at 2 times the speaker rating. This prevents clipping which
speakers apaprt.

 

you sure about that? it's true that distortion tears up speakers, and an
underpowered amp can lead people to crank the volume up beyond clipping,
but i've never heard it suggested that the amp be rated for more power
than the speakers.

 

If the one side is failing, swap the good and bad speakers. does the
bad speaker become good? and the good speaker turn bad? is the stereo
properly grounded?

 

What size are these speakers?

 

Any chance that the speaker mounting area could be distorted, which might be
pulling the speaker frame out of alignment and causing the cone voice coil
to rub on the magnet gap?? Maybe some old accident damage? Just a thought.

Dave

 

Very, very common in the high-end and pro audio worlds.

You get two bonuses. Headroom, which can do wonders for clarity, and
no clipping which prevents your speakers from dealing with DC.

There's not much that speakers hate more than DC, which happens to be
0 Hz. (drive it all the way in or out and hold it there!) except maybe
water. <G>

 

If they're pressed metal frames and you overtorque the mounting screws
they almost always warp.

 

Have you ever listened to a *continuous* 22 watts, let alone 50? You
don't want to....

Driving a low-powered amp into clipping, yes. But clipping kills
tweeters first, then mids and eventually it *could* kill the woofers.

Overpowering a speaker usually kills the woofers first *IF* you can
stand the level and the racket of the woofer cones overextending and
having the coils hit the magnets.

High amounts of DC voltage usually "cooks" the coils.

Someone else's idea of putting in a "cheap as possible" speaker is a
start, but since the dead speaker's mate is a known good speaker, use
it instead. If it stays alive, you'll have to chalk this pair of
failures up to Murphy.

FWIW, I was a tech in a hi-end audio shop and we were known to do
intentional speaker-killing at times.. under "controlled conditions" you
know..

 

You know, the car was in an accident at some point, but all the doors open
and close like they're supposed to, so I didn't think of it...

 

5"

 

Shoot...have you ever listened to a continuous *ONE* watt?!?!
% watts true RMS is enough to drive you...OUT of the car!

This is my THIRD speaker in this position!

Oh Boy! Where do I sign up!?!?!?!

I used to do testing for Underwriter's Laboratory certification at one
place where I worked. We made OEM power supplies; one of our products was
for a 'secret' project for IBM back in 1982...

At any rate, I would drip water into the power supplies, throw shorts into
various circuits, disable the safety circuits and THEN throw shorts into
the circuits, throw the switching section into overload, etc etc. I had
what looked like a motorcycle sheild in front of me to catch sparks and
capacitor spew...

Ah, how I long for the Good Ol' Days...

 

The last one I pulled worked flawlessly!

I'll try the meter thing, but I'm also on my second head unit. I upgraded
the one in the Supra and pulled that one for this car.

 

All good suggestions!

 

Except for one thing: A speaker without an enclosure will produce pretty
much zero bass, which will tempt you to turn it up and fry it. Find a
cardboard box about the size of a small bookshelf speaker. Seal it well with
tape, cut a hole that's right for the speaker, and use speed clips over the
edges of the hole for securing the speaker.

 

I have wooden 'test boxes' I use for testing speakers/radios. No Problem!

 

In my situation it seemd to follow about the 3rd time my teen borrowed the
car...every time. I'm sure you know that distortion will kill a speaker as
quick as power. This one seemed to think the volume had to be on max for it
to work at all.

 

It doesn't?!

(He don't know me too well...)

I have a JVC headunit in my Supra, powering a 100Wx4 channel amp, and 4
100W MB Quarts at each corner. Since the roof comes off the car, I wanted
something I could hear over the road and wind noise.

3rd year and no problem! I rarely have problems with my installations.
That's why this is so perplexing.

But, I am a bass player, so I want to HEAR the bass. It's just odd that
it's always this one speaker! The left front has been in there since I
took the original pair out. I always replace with 4 ohm speakers so the
balance is correct all the way around.