A radio access network (RAN) device may receive a call setup request from a wireless communication device (WCD) seeking to set up a call. In response to receiving the call setup request, it may be determined that (i) the WCD is capable of conducting the call using either a first codec or a second codec, (ii) the first codec is capable of using a sampling rate of over 8,000 Hz, and (iii) the second codec uses sampling rates of 8,000 Hz or less. Based at least on this determination, the WCD may be instructed to set up the call using the second codec.