SPL Reference
Sound level meter & analysis
Only for iPhone
Free · In‑App Purchases
iPhone
Turn your iPhone into a serious field toolkit for measuring, analysing and documenting sound—from quick indicative checks to calibrated external-microphone workflows.
SPL Reference combines live sound-level measurement, detailed session evidence and professional reporting in one focused app. See the level now, understand how it changed, inspect its frequency content and preserve the context behind every measurement.
MEASURE WITH CONTEXT
• Live A-, C- and Z-weighted measurements
• Fast, Slow and Impulse time responses
• LAeq, LAFmax, LCpeak and time-history views
• Pause, resume, event markers and integrity evidence
• Clear distinction between indicative readings and reference-calibrated chains
ANALYSE WHAT HAPPENED
• 1/1- and 1/3-octave frequency analysis
• Spectrum and spectrogram history
• Statistical exceedance levels from L1 to L99
• Cursor inspection and stored analysis detail
• Noise-exposure assessment using NIOSH, OSHA and configurable models
BUILD A TRACEABLE WORKFLOW
• Projects and organised measurement sessions
• Notes, photographs and optional location evidence
• Saved microphone and input-path profiles
• Acoustic calibration records and before/after drift checks
• Route, gain, sample-rate and hardware evidence
• Professional PDF reports for review and sharing
OPEN MEASUREMENT LIBRARY
Browse a growing public sound-level archive powered by GitHub. Explore shared measurements and follow publication links from inside the app. Measurements are never uploaded automatically.
START FREE. UPGRADE ONCE.
The free tier includes the built-in microphone, five active measurement minutes per calendar month, two saved measurements and one project. Lifetime Professional Unlock removes the free limits and unlocks the complete professional toolset with one purchase—no subscription.
IMPORTANT
Phone microphones and connected hardware vary. SPL Reference clearly identifies indicative and calibrated workflows and does not claim that an unvalidated device is a certified sound-level meter. Occupational-noise results support assessment and documentation; they do not replace applicable professional judgement or legal requirements.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
New in 1.1
• Continue active measurements in the background, with Lock Screen and Dynamic Island Live Activity support.
• Browse the public measurement archive inside the app, with improved contribution review, retry and privacy controls.
• More reliable microphone and input selection, clearer connected-source status, and safer saved-path matching.
• Expanded calibration workflows with improved CEL-177/CEL-182 handling, gain and headroom guidance, calibration-file compatibility, and microphone response correction.
• Richer sessions and professional reports, improved charts and evidence handling, long-session performance improvements, and project photograph fixes.
• Optional 180° portrait rotation.
• Measurement accuracy, persistence, and stability improvements.
The developer, Direct Sound Records Ltd, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Location
- Contact Info
- User Content
- Other Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- DIRECT SOUND RECORDS LTD
- Size
- 6.8 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later.
- iPhone
- Age Rating
16+
- 16+
- Frequent
Medical Treatment information
Contains
User-Generated Content
- In-App Purchases
Yes
- Lifetime Professional Unlock $4.99
- Copyright
- © 2026 DIRECT SOUND RECORDS LTD