[Hackrf-dev] NBFM problems

[k6eep at hamsoftware.org]

I am having trouble getting clear sounding audio out of my HackRF One receiver in NBFM mode.
The audio sounds raspy.  
I am using an external 10Mhz GPS disciplined TCXO clock.
I ran all the gains down and up but the raspy sounding audio persists.
RF=0, IF=16, BB=16 as default gains.
Here is a link to my grc setup.
http://hamsoftware.org/SDR/NBFM_quad.grc.png

I am got WBFM working pretty well.  Even have RDS on it.  
I am running this on Ubuntu 16.04.  I used the Ubuntu binaries for GnuRadio.
I am sure I am making some sort of mistake.
Oh, I also tried this on both a USB-2 and USB-3 port. No difference.

I am new to SDR.  Trying to find a good source for grc examples also.
Heck of a learning curve. 
Mike