[Elecraft] Transmit audio frequency shift on USB?

[Torrey Mitchell]

I'm having a ball with my newly assembled K3!  I was on the air (USB,
14.170) this weekend trying to fine tune my audio equalization.  Two
gentlemen told me I sounded great.  However my audio was smoothest 30-50 Hz
above my operating frequency.  They are both audiophiles.  My RIT was OFF.
One based his opinion on critical listening.  He said the audio was very
good at our mutual frequency but had a slight rasp to it.  This went away
about 30 Hz higher.  The second gentleman was using a FLEX 5000.  He
indicated that my signal "measured" 50 Hz higher than our stated operating
frequency.  He recorded my signal at both frequencies.  It was clear that I
sounded best 50 Hz high.

 

I am using the TX ESSB option set at 3.0.

 

Do these observations make sense?  If so, do I need to make an adjustment?
It was just the 2nd hour on the air with the new rig, so I'm not 100% sure
that my fine tuning was turned on to 3 digits past the decimal.  But could
there be some other explanation?

 

Thanks and 73,

Torrey N9PY