Your missing the point. RJs are loud in the cockpit, requireing David Clark type headsets, irregardless of being company provided or not. I've never ridden in a mainline cockpit which any of the pilots ever wore David Clarks.
The E170 was delivered to US Airways in 2003 from Embraer equipped with Sennheiser HME25KA-2s.
US Airways operated the E170s with Sennheiser HME25KA-2s.
The E170/190 family is equipped to accept HME25KA-2 or any 4 pin ANR headset....or conventional headset/mic plug.
US Airways operates it's E190 fleet with Sennheisers.
After the RAH acquisition of the US Airways/MDA E170s, some HME25KA-2s grew legs. RAH refused to maintain or replace the Sennheiser HME25KA-2s and swapped them out with DCs.
I use a Telex ANR.
T8