Spektral

Spektral is a professional real-time audio frequency analyser built for sound engineers. Identify feedback frequencies, measure system response, characterise room acoustics, and monitor environmental noise compliance.

Top 10 in Music on the Mac App Store.

SIX ANALYSIS MODES
• RTA: live spectrum display with logarithmic frequency scale, 20Hz to 20kHz
• Spectrograph: scrolling time-frequency heatmap with adjustable range and scrollable history
• Transfer Function: dual-channel H1 estimator with magnitude, phase, coherence, impulse response, and Auto-EQ
• SPL Monitor: environmental noise compliance with Leq tracking and professional PDF export
• RT60: reverberation time across octave bands (125Hz to 4kHz): T20, T30, EDT and R² goodness-of-fit, via interrupted pink noise or an impulse
• STIPA: Speech Transmission Index to IEC 60268-16 with per-band MTF and SNR, a built-in test signal, and a clear Bad to Excellent rating

PRECISION TOOLS
• Selectable FFT size from 2,048 to 16,384 points for fine low-frequency detail when you need it
• Input level metering: a floating mic/reference meter plus per-channel input meters to confirm signal at a glance
• Cursor with parabolic interpolation for sub-bin frequency accuracy
• Peak hold with smooth decay
• Adjustable smoothing: 1/1 to 1/24 octave
• Frame averaging up to 32 frames, plus infinite
• Musical note display on peaks and cursor readout
• Zoomable frequency and dB axes

SPL MONITORING & COMPLIANCE
• A-, C-, and Z-weighting based on IEC 61672 methodology
• Time weighting: Slow, Fast, and Impulse (IEC 61672)
• Microphone calibration via reference meter or acoustic calibrator
• Live VU meter with configurable caution/warning thresholds
• Leq measurements: 15-minute, 1-hour, and 8-hour rolling windows
• Session statistics (min/max/average) with time-history graph
• Professional PDF reports with metadata, equipment, and calibration details
• Quick presets for Environmental, Occupational Safety, Live Event, and Studio use

REMOTE MONITORING (add-on)
• Deploy iPhones as wireless SPL monitoring stations at multiple measurement points
• Live dashboard on your Mac showing current SPL, Leq, and peak levels for every site
• Satellite map with colour-coded annotations and heat propagation overlay
• Per-site detail views with full SPL time-history graphs
• PDF compliance reports with a dedicated page per remote location
• iCloud sync, no servers, no accounts, no configuration
• One-time in-app purchase, works across all your devices

TRANSFER FUNCTION & MULTI-POSITION CAPTURE
• Dual-channel H1 estimator with coherence and phase
• Impulse response (linear and ETC) with automatic reflection detection (arrival time, distance, and level)
• Comb-filter prediction overlaid on the magnitude trace
• Delay alignment: FFT-based detection, a guided wizard, and manual sub-sample fine-tuning
• Selectable measurement and reference channels on multi-input interfaces
• Multi-position capture with quality scoring and weighted averages
• Intelligent Auto-EQ: up to 6 parametric suggestions with smart gain limiting
• Session PDF export with per-capture detail pages
• Requires a two-channel audio interface

BUILT-IN TOOLS
• Pink noise generator with adjustable output level
• Soundcheck mode with automatic peak identification
• Snapshot compare: freeze and overlay a trace for A/B
• Separate visual gain and SPL calibration

DESIGNED FOR PROFESSIONALS
• Dark interface optimised for low-light environments
• Keyboard shortcuts for every function, keeping your hands on the desk
• 60fps rendering via Metal-backed Canvas
• Works with any Core Audio input device
• Native SwiftUI, no Electron, launches instantly

COMPLIANCE & REPORTING
Monitor off-site noise propagation at live events, track occupational exposure in studios, characterise room acoustics, and verify speech intelligibility. The measurement workflow professional acousticians use, in a native Mac app. Spektral is not a certified Class 1 or Class 2 instrument.