Sub System vs Pinyin Reader

An app for audio engineers and sound designers. It will let the user place virtual speakers around and see the sound pressure levels that they produce, including the interactions between sources. Colorful graphs for SPL. Frequency response based on virtual microphones. Speakers and Mics are moved around using touch functions. Zoom in, out. All graphics are touchable. Best use is to understand how acoustical summation is produced.

Learn Chinese pinyin step by step with clear audio for every sound. Practice initials, finals, whole syllables, and the four tones—perfect for beginners starting Mandarin. Need a simple way to hear standard Mandarin pronunciation? Tap any card to listen, repeat, and track your progress with built-in study stats. No account required. • Initials (shengmu): b, p, m, f and full set • Finals (yunmu): a, o, e, i, u, ü and combinations • Whole syllables (yinjie): zhi, chi, shi, ri… • Tone chart with audio for each tone • Learning statistics to see your practice • Offline-friendly: lessons work without Wi‑Fi Ideal for parents, teachers, and self-learners building a solid pinyin foundation before reading Chinese characters.