A VFR pilot maneuvering in a designated practice area reported a NMAC with an aircraft flying through the area.

Narrative

I was flying in the ZZZ practice area to practice maneuvers. When the incident occurred; I was at a location near the VFR waypoint ZZZZZ; and was approximately 9 nautical miles from ZZZ. I announced my callsign; location; altitude; direction of flight; and intentions on the appropriate practice area frequency for the altitude I was at. I visually cleared the area and took note of the location of other aircraft that I either saw visually or heard their location over the radio. I did not perceive any conflicting traffic within the area and deemed it safe to commence the maneuver I intended to practice. I began one steep turn. Upon rollout from the turn; I spotted another aircraft that did not appear during my visual scan while clearing the area before the maneuver; flying close to my location; approximately 200 feet above and within close proximity horizontally; roughly 300 feet or less away. Aircraft Y was heading approximately directly towards my aircraft and direction of flight; to the point where I perceived a hazard. I immediately executed a sharp turn to the right to avoid the other aircraft. From what I recall; the other aircraft did not alter its flight direction to avoid the hazard. I did not hear this aircraft make radio calls to other air traffic.Regarding the cause of this event; I feel that it was a lack of awareness on the part of Aircraft Y. I do not believe the other aircraft saw my plane; given that it did not alter its flight path. The absence of radio calls from Aircraft Y did not help the situation. Although radio calls are not a replacement for visual scans; they offer another tool for pilots to use in locating aircraft that may be difficult to see. If an announcement was made; it may have helped both of us avoid each other. However; it is possible that this aircraft may have been making radio calls. The ZZZ practice area has two frequencies to use. One frequency for operations at or below 2;000 feet and another for operations below 4;500 feet. It is possible that this aircraft may have been using the wrong frequency. I cannot say for certain since I was not monitoring the other practice area frequency at the time. This issue comes down to a need for more training regarding situational awareness and use of the radio as a safety tool; which I feel is very important when operating in areas with heavy traffic.