It shouldn’t. A sound machine is not meant to be so loud that you cannot hear other sounds over it. While you want the volume up enough that it can be heard and be beneficial, it shouldn’t be so loud that you couldn’t hear your child crying during the night. Test your volume control on your machine and set it to something you are comfortable with. If you use a baby monitor, it should still pick up on a child crying even if there is also a sound machine running.