Dual SPL Traffic Light3.9 - App Store

Dual SPL Traffic Light

Monitor sound levels for events, public spaces, and concerts. Two independent sound monitors allow you to configure this app to any local requirements.

For example, set one traffic light to average SPL over 10 minutes, and set the other to monitor peak levels.

Set one to A weighting, and the other to C weighting, or flat.

This app works fine with the internal iOS device mic. You can also upgrade to our iPrecisionMic or iTestMic to get Class 1 or Class 2 results.

Each traffic light can be linked to a color light bulb using HomeKit, to provide visible notification of sound levels. Place a color light bulb near the sound mixer, stage, or even the manager's office, so that everyone can see if the sound levels exceed your preset trigger levels.

Set the SPL decay (speed and type of averaging) to Fast, Slow, or any Leq value from 1 second to 8 hours. The Leq can be done one time period at a time, or it can be a running Leq of the last time period.

Set the SPL weighting to flat (Z), A, C, or one of the low frequency octave bands, 32Hz, 63Hz, 125Hz, or 32Hz+63Hz.

Includes email notifications for sending emails when either or both meters is triggered into the red level.

Version History -Bug fixes and stability improvements
-Support for latest iOS versions 3.9 Sep 11 -Accessory Connect message disappears on its own
-Lots of bug fixes and stability improvements 3.8 Jun 2 -Bug fixes and stability improvements 3.7 12/22/2025 -Updated for new iOS devices
-Bug fixes and stability improvements 3.6 11/24/2025 -Updated for latest iOS devices and calibrations
-Bug fixes and operational improvements 3.5 11/20/2024 -Updated for latest iOS devices and calibrations
-Bug fixes and operational improvements 3.4 07/10/2024 -Updated for latest iOS devices and new iOS versions
-Bug fixes and stability improvements 3.3 10/19/2023 -Bug fixes and improvements
-Support for more iOS devices and iOS versions 3.2 07/15/2022 -Bug fixes and stability improvements 3.1 09/24/2021 -Bug fixes and stability improvements
-Support for direct data file access in Files app
-Support for latest devices and iOS versions 3.0 08/22/2020 -Updated Dual SPL Traffic Light for compatibility with iOS 13 2.3 10/09/2019 -Updated for any iOS 9 or later
-Fixed issue with setup menu
-Bug fixes and stability improvements 2.2 08/14/2019 -Bug fixes and stability improvements
-Updated for latest iOS devices 2.1 04/09/2019 New! HomeKit support!
HomeKit is used so that this app can control the color of linked color light bulbs to indicate sound levels.
Added support for iOS 12 and new iOS devices 2.0 09/22/2018 General
- Added Calibration Error Report link to support page
- Fixed crash on iOS 11 when saving screenshots
- Fixed crashes on iOS 8 and iOS 9
- Fixed issue with multiple Studio Six Digital apps trying to access our accessories
- Updated App Store in-app purchase accessing and authorization for iOS 11


Live Calibration Updates
- Added cloud-based database for all iOS devices that can be updated in real time
- All devices included
- Includes local default files, in case a device has no internet connectivity
- Different databases for each major iOS version, starting with iOS 10
- New iPhones added to live calibration database 1.9 09/28/2017 -Bug fixes and stability improvements 1.8 08/28/2017 * Updated for latest iOS devices.
* Removed support for older iOS versions, now requires iOS 8 minimum.
* Added simultaneous background launch protection to prevent problems in iOS 10 when plugging in iTestMic or iPrecisionMic when more than one Studio Six Digital app is installed. 1.7 03/17/2017 - Updated for iOS 10 and new devices 1.6 11/21/2016 - Updated to support iPhone 7 and iPhone 7 Plus. 1.5 09/24/2016 Dual SPL Traffic Light, the sound monitor with two SPL meters

-Added a clock to the main display
-Fixed an issue with plugging in an external mic while the calibration screen is open. 1.4 05/20/2016 Dual SPL Traffic Light sound level monitor

** Updated app name and description 1.3 05/15/2016 ** SPL Traffic Light, the dual sound level meter SPL monitor

- Added options for sending emails when SPL conditions trigger red display.
- Added support for iPad Slide Over and Split Screen multi-tasking. 1.2 05/12/2016 Measure 2 simultaneous sound levels using different criteria.

** Updated for iOS 9.3. New calibrations loaded for all iPads.

** Save/Recall Updates
* New! Auto-save file name options are now available from the Save/Recall screen mini-menu. Tap the icon with 3 lines.
* New! Added auto-save Name List to store frequently-used file names.
* Fixed auto-save sequence numbers resetting after app relaunches.
* Fixed case where files may not be saved when using auto-save immediately after Delete All Files.
* Fixed possible crash if action buttons were tapped with no file name selected.
* Improved auto-save naming.

**Improved referral screen layout.

**Now always uses 24-bit audio mode if iPrecisionMic is present.

**Fixed an issue where internal mic gain could change coming out of the background

** Support Menu
* Fixed Forum page access.
* Fixed "Rate This App" access.
* Fixed access to other Studio Six Digital webpages 1.1 04/12/2016 1.0 03/09/2016