Engine Sounds Compared to iPhone Version

I am new to XPlane and before getting the full XP9 I decided to try it out on the iphone. I was really impressed with the engine sounds that seem o make you feel you are really moving. Even in the Cessna 172. I decided to get the full desktop version but was disappointed in the Cessna engine. It is very similar to most of the unrealistic engine sounds that have been common in MSFS including FSX, and even seems to play in a predictable loop. It's not my sound system either. My sound card is fine. Are there ways to improve it? Thanks Tom