All electronic components are subject to damage from vibration. How easy it
is to damage them is determined by the quality of construction. Some Korean
made amps have almost no support on the PC board, the only thing holding the
board down is the connectors at the ends and the transistors down the sides,
thus any large vibration is sure to eventually break either the leads on the
transistors or the solder joints to the PCB where they connect. Low quality
solder contributes to this type failure as it is too brittle to withstand
much movement. Relating the vibration from a pothole to that caused by bass
is comparing apples to oranges, Bass is a sustained rhythmic vibration where
the bump from a pothole is a large movement, but is not sustained. Here is
something you can experiment with. Take a metal coat hanger. Make large
bends back and forth over a long period of time, say bend it, wait 10
minutes, then bend it again. See how long it takes to break. Then take
another coat hanger and bend it rapidly through a shorter bend and see how
long it takes to break. This is in essence the same forces applied to the
transistor leads in the amp. You will note the one that is subjected to
steady bending fails first. Take note that if an amp has defective solder
connections the vibration can cause it to fail much quicker.

huh....I guess building a simple, small enclosure out of 3/4" mdf, braced
with a large
centre brace and several corner braces per side, using copious amounts of
glue
and nailing the whole thing together must mean I have no clue how to build a
box....

For the application these subs are in and the budget that the customer is
on, this
box is substantially "good enough".  He originally had a sealed pre-fab
enclosure
that was FOR THE L5/L7 square subs (mfg by Kicker)...it was 5/8" particle
board, no bracing or divider.  Seems Kicker thought THAT was good enough....

I appreciate the vibration thing...but the back panel of the enclosure had
some serious
pounding going on.  To me, its kinda like being punched in the gut by a pro
boxer repeatedly.
Eventually, somethings gonna give....

I've done it many many times in the past, and with no issues.  Its just that
for some reason these L5's seem
to be delivering a walloping on the box....

anyways, good to know it wasn't that....

bmoney

Ya, no kidding everything in the trunk vibrates, but put your hand on
your sub box, then put it on the back of the back seat (or anywhere
else).  You don't feel a difference?  What is your box made of, lead
and concrete?

Like the box itself more than the floor, back of the back seat, sides
of the trunk, gotcha.

You're right, I DON'T know how to make a box, I'm not a carpenter or
an installer, so I just bought one like 90% of everyone else.  It's
made of MDF, not lead and concrete, just like 90% of everyone else's.
And probably, the people who DO build their own aren't pros either.
I'd guess a lot of custom or home-built boxes aren't any better than a
pre-fab box from a store.

Probably, Ive done it in the past without problems, but I understand
the arguement against it, and it does make sense..  If you're trying
to minimize the vibration to your amps, you can't say 'on the box' is
as good as anywhere else.