Mobile Metronome and Tuner App Needed for Musicians

I'm looking for a developer to build a mobile metronome and tuner app for musicians — from beginners to touring professionals. The core piece is a precise tuner that detects pitch through the device microphone in real time, with minimal latency and reliable performance in noisy environments like rehearsal rooms or stages. It needs to support multiple instruments and tunings, plus a clear needle or circular indicator of how far the note is from being in tune.

The second part is a metronome with flexible rhythm settings: custom time signatures, accents on chosen beats, smooth or stepped tempo changes, and saved presets tied to specific pieces. A separate requirement is stable background operation — the metronome sound must not stop when a call comes in, the screen locks, or the user switches to another app. This matters during rehearsals and recording sessions.

I expect a clean interface, fast response time, and reasonable battery use during long background sessions. Both iOS and Android versions are needed, sharing the same core logic. Open to discussing stack and architecture, but pitch accuracy and background reliability are the priority.

Key points to cover:
— accurate, low-latency tuner;
— flexible rhythm and accent settings;
— uninterrupted background playback during calls;
— consistent functionality across iOS and Android.