I am in agreement with K4IA, the ClearSpeach Speaker is a "MUST" have for the DX-70 in the mobile application. Yes, the DX-70's "NB" (noise blanker) is weak at best, but with the CS speaker it (the DX-70) is wonderful.
I was not very sure at first, however, now I have been using it for over two years and it REALLY DOES WORK!
Cheers and 73,
Cliff Owen, N3FI