ListenAid - precise, clean & fast audio spectrum analysis. Turn your iPhone, iPad, or Mac into a high-precision audio measurement laboratory. ListenAid is a professional-grade Real-Time Spectrum Analyzer (RTA) and Spectrogram designed for audio engineers, acoustic consultants, musicians, and students. Built entirely on Apple’s Accelerate framework and Metal graphics, it delivers incredibly fluid, high-resolution analysis with zero lag. Whether you are tuning a PA system, analyzing room acoustics, or visualizing the harmonic content of an instrument, ListenAid provides the tools you need with the precision you expect. HIGH-PERFORMANCE VISUALIZATION - Metal-Accelerated Graphics: Experience a silky-smooth 60/120 fps display that visualizes audio data in real-time without draining your battery. - Hybrid View: View the instantaneous FFT spectrum and the scrolling Spectrogram history simultaneously. - Gestures: Pinch to zoom frequency and amplitude axes independently. Double-tap to reset. ADVANCED DSP ALGORITHMS - Standard FFT: Fast Fourier Transform with adjustable buffer sizes (up to 65,536 points). - Reassignment Method: A cutting-edge algorithm that sharpens spectral peaks, allowing for frequency precision that exceeds standard FFT limits (Sub-sample accuracy). - CQT & CWT: Variable-Q and Continuous Wavelet Transforms for musically relevant analysis. - Transfer Function: Compare a live signal against a reference signal (Dual-Channel Analysis). PROFESSIONAL AUDIO ROUTING - Multi-Channel Support: Fully supports external USB audio interfaces. Select specific input channels for measurement and reference. - High Sample Rates: Supports hardware sample rates up to 96kHz (and higher, hardware dependent) for high-resolution analysis. - Smart Bluetooth: Intelligently manages Bluetooth profiles to ensure high-quality monitoring without degrading input quality. SYSTEM TEST & TOOLS - Signal Generator: Built-in low-distortion Sine Wave generator. - Loop Player: Playback your own test loops or music directly from the app to test system response. - Cursor Mode: Inspect specific frequencies with a cursor showing Hz, dB, Musical Note, and Cents deviation. - Peak Tracking: Automatically detect and track the strongest frequencies with high-precision interpolation. MIDI REMOTE CONTROL - Control the MacOS app remotely via the iOS app. - Trigger loops, sweep a sine, toggle L/R-Solo, or invert polarity remotely while walking the room. TECHNICAL SPECIFICATIONS - True dual channel simultaneous independent real-time FFT - Window Functions: Hanning, Hamming, Blackman, Flat-Top. - Averaging Modes: RMS, Exponential, Peak Hold, Off. - Resolutions: FFT sizes from 256 to 65k. - Scales: Logarithmic (Hz) and Linear (Musical Note/Piano Roll). - Color Maps: Greyscale, high-contrast scientific color palette WHO IS THIS FOR? - Live Sound Engineers: Ring out feedback and tune systems using the built-in generator and transfer function. - Studio Engineers: Visualize the frequency spectrum of your mix in high detail. - Musicians: Use the precise Note/Cents cursor for instrument intonation. - Educators: Visualize sound waves and harmonics in the classroom. Privacy Policy: ListenAid processes all audio data locally on your device. No audio is ever recorded or transmitted to the cloud.