I would make sure the calliper pins are not corroded and properly lubed.

I had a deal on one of my taurus where i had some brake noise.
It turned out the aftermarket pads were slightly too big and
the rotor wore a grove in them and i had some chatter when the
grove got wore in deep enough.

The rears is would make sure the emergency brake is not dragging
and the shoes are properly adjusted.

Bob

Sorry... this is likely caused by the pad/lining material used.  

The crunching noise you hear is an indication that something is not
right.  I would take it back and explain to them that the car did not
make this noise prior to the repair, do a test drive and have them get
it up on the lift to see what's rubbing or grinding.

There is always the possibility that the repair was probably done
correctly and then something else decided to wear out on you
coincidentally after it was done.

Why is it always the shop did something wrong?  Don't get em wrong , shops
have been known for not doing jobs right, I have been wrenching for about 15
years, and I always hear the same thing.  

My car never did this or that before I brought it in.  Could it be the owner
of the car causing the problem?  
Like stopping 10 feet from a stoplight while doing 55 mph?  Customer I had
came in once a year for brakes and always complained that they didn't last
long enough and wanted to know if we used "junk" brake pads.  I have always
used Bendix parts and WILL NOT use anything else.  So I did a little
experiment,  I told the customer to lets go on a drive to see if there might
be something with the car that might be causing the shortened brake pad life.

Well during the first couple of minutes of riding with them, I discovered the
problem.  She was a brake at the last possible moment and then when the light
turned green it was a drag race to see how fast she could go before she had
to jam on the brakes to stop again.  I pointed this out to her and she was
mad at first and then after we got back to the shop she apologized and said
that after doing some thinking about it that it made sense.  

I use the same brake parts and do the exact same job that I do on a customers
car and I have never had any noise, pulsation, etc. from my brakes.  And I
drive aggressive to.  The only difference is that when I see a red light I
don't push the gas pedal to the floor to see how fast I can go I let off and
let the car coast down then use my brakes for the last little stopping power
that I need.  

I don't know the whole story here, but I just get so tired of getting blamed
for doing something wrong.