Just got them today.  Nice looking set. 

They sound terrible.  Loud and annoying. 

They have ran for 11 hours. 

They are new spectrum units.  How do I quiet them down?

You can try some oil or light grease on the gears. You will need plastic compatable lube that won't eat the plastic.
Remove the bottom covers on the trucks and see if the gears are dry. Sometimes you can find lots of grease inside but from laying around on there side is not where it is needed.
If this does not help then you can remove the shell and lube the inside.

Bob

    Lube.  Did that already.  The worm gears and inside the trucks.
Plastic compatible grease.  No help.

   The only thing that I haven't lubed is the motor. 

   Any other suggestions??

You can try swapping the trucks around sometimes this will quiet them.
Check the drive shafts to see if they are bent.
If you have a motor with out of balance flywheel that will cause drive shaft flopping and noise.
I have had luck with this sometimes and have also had Service send me parts under warranty if you are nice to them.
You can send them back for repair or replacement under warranty or return them locally if you can.
Sometimes changing the wheel around in the trucks also works.
Some of these are whisper quiet and others very noise, Can't say for sure what works but i have gotten some to quiet down.

Bob

    Shafts are straight.

    Swapping trucks, we'll see.

    Motors seem to be balanced decently. 

    27 hours on them, I'd say their broken in now.

    Moved trucks around, wheelsets around, no better. 

Just the motors in the frames (no trucks) are noisy.   

Overall, not happy.  So much for DCC w/ sound on my other locos...
               
...can't hear them if these F7s are running. 

On the other hand, they should last forever...they'll hardly ever be ran.

Welcome to the club!  I have owned my Spectrum SP F-7 AB set for almost two years.  They run well, but are noisy.  On the plus side, the B unit has side numbers, unlike the Kato B SP unit.  It is my thought that most Bachmann (and Spectrum) N is built for rugged use on beginner layouts.  However, I find myself running Kato locomotives most of the time.  Kato is in a class by itself.  I even got rid of all my Bachmann track and switched entirely to Kato UniTrack.  However, I do prefer to run Bachmann locomotives, over Atlas, when I am not running Kato.  Both Bachmann and Kato are less likely to stall.  With Atlas diesels, I have to clean the track very frequently to keep Atlas diesels from stalling.  We will not even discuss Walthers or others, though my one Intermountain F-7 runs well.  Basically, I change to Bachmann when I informally want to run trains and remember years past in N.  When I run quiet trains prototypically, I use the Katos.