[Orion] Heil HC-4 vs HC-5?

[Eric Rosenberg]

I recently swapped the Heil HC-4 ("DX") element in my Proset with the HC-5 "normal". Netiehr is new. I suspect hey're both ~10-13 years old. 

The specs Heil posts on their website say the mikes are fundamentally the same (same frequency range, with the HC-5 having a mid-range 'bump' presumably to increase fidelity), I did note that the impedance is different. There's a physical difference, too. The HC-5 has a larger hole, which I assume has an impact on the frequency response. 

I've noticed that the HC-5 needs a significantly higher mike level -- almost at the top of the range -- to drive the Orion.  If I run it through the computer's built-in sound card and use the high-boost setting, the radio is seriously (negatively) overdriven.

Is this to be expected? If not, is there a remedy? 

Thanks, 

Eric W3DQ
Washington, DC