SPL Graph 9.0 - App Store

---

About SPL Graph

SPL Graph is an audio Sound Pressure Level (SPL) environmental noise analyzer, real-time frequency analyzer, chart recorder and data logger. It includes: * Plot sound level over time * Record audio while plot is running,...

SPL Graph is an audio Sound Pressure Level (SPL) environmental noise analyzer, real-time frequency analyzer, chart recorder and data logger. It includes: * Plot sound level over time * Record audio while plot is running, playback to identify sounds that may have caused problems * Capture video of events (optional in-app purchase) * Do octave and 1/3 octave band analysis (optional in-app purchase) * Show a 3D Plot of octave or 1/3 octave results * Calculate Ln SPL values, L01, L10, L50, L90, L95, LMax and LMin * Email notifications when sound exceeds pre-set limits * Auto-save results after set intervals, and email the results to you * Start another plot after auto-saving for continuous operation SPL Graph works by averaging the SPL for a period of time that can vary from 0.1 second to 60 minutes, applying an optional weighting filter, and plotting the sound level, recording the raw audio signal, if recording is turned on. For sound intervals of 1.0 second to 60 minutes, the optional octave and 1/3 octave logging modules allows storing the spectrum of the sound, for each interval. The app works very well with the built-in iOS device microphone. To upgrade the app to true professional standards, add our iTestMic, iPrecisionMic, or iAudioInterface2 with an appropriate microphone, and get ANSI or ISO Type 1 or 2 results. With iPrecisionMic, you can send the system in to our calibration lab and get a calibration certificate for ISO 61672 and ANSI S1.4. SPL Graph can record up to 24 hours of sound level data, with single second resolution. The graph starts with a one-minute plot window, and as a minute is recorded, the graph re-scales automatically and adds another minute to show the data collected so far. The overall SPL level, or LEQ, is displayed for whatever portion of the test is showing on the graph. Tap the play button to play back the recorded audio, and you can use the cursor to scrub the audio location on the graph. Use this feature to listen to events that you can see on the graph. With the optional octave logging module, you can also record the octave or 1/3 octave band levels. And, you can view the data on the 3D plot for a graphical view of frequency over time. You can scroll and scale the graph vertically, in dB, by using standard swipe and pinch gestures. You can also scroll and expand and contract the time axis using gestures. Zoom out to a full 24 hours, or zoom in to a single minute, showing second resolution. Double-tap the screen to zoom out to show the entire graph on the screen. The time scale grid changes dynamically, highlighting minutes, ten-minute, and hour lines as as it runs. As the graph runs, the overall LEQ (average SPL) for the entire time period is computed and displayed on the screen. Swiping across the graph brings up a cursor that displays the exact dB level and time for any point on the graph. You can turn on audio recording, so that you have a record of the sounds that were happening while the graph was being stored. You can use this to figure out exactly what the sound was that caused a peak on the graph, for example. Recordings can be compressed or uncompressed. If you exit the app, or are interrupted with a phone call, the graph data will not be lost. SPL Graph will automatically save the graph, and reload it when you next open the program. You can also save a graph in one of ten files on the iPhone, so that you can recall the graph later. SPL Graph supports saving graphs directly on your iOS device. You can recall these graphs and bring them up on the screen, and listen to the sounds that were made while the graph was recorded. You can also store an image of the screen to your photo roll. Use Dropbox or iTunes Files Sharing to export the results to your computer. You can also export data in tab-delimited files for XLS import using iCloud. The filters are all ANSI type 1 or better, and include A-weighting, C-weighting, and all octaves band filters from 32 to 16kHz.

Version History -Bug fixes and stability improvements 9.0 12/20/2025 -Updated for new iOS devices -Bug fixes and stability improvements 8.9 11/24/2025 -Bug fixes and stability improvements -New iOS version support 8.8 06/14/2025 -Updated for latest iOS devices and calibrations -Bug fixes and operational improvements 8.7 11/20/2024 -Updated for latest iOS devices and calibrations -Bug fixes and operational improvements 8.6 10/19/2024 -Updated for latest iOS devices and calibrations -Bug fixes and operational improvements 8.5 07/11/2024 -Updated for latest iOS devices and new iOS versions -Bug fixes and stability improvements 8.4 10/19/2023 -Bug fixes and improvements -Support for more iOS devices and iOS versions 8.3 07/17/2022 -Bug fixes and stability improvements -Updated for latest iOS and devices 8.2 09/25/2021 -Bug fixes and stability improvements 8.1 02/08/2021 -Bug fixes and stability improvements -Support for direct data file access in Files app -Support for latest devices and iOS versions 8.0 08/26/2020 -Updated for iOS 13 7.3 10/09/2019 -Updated for iOS 13 -Fixed issue with setup menu -Bug fixes and stability improvements 7.2 08/12/2019 -Updated for latest iOS devices -Bug fixes and stability improvements -Temporarily removed 3D plots while we upgrade them 7.1 04/09/2019 -Updated for latest iOS and devices -Improved SPL calibration -Added Remote Monitor option 7.0 07/11/2018 - Added support for iPhone X and latest iOS 11 - General bug fixes and stability improvements - Fixed issue with recording M4A format audio files on iOS 11 - Fixed dropping last second or missing first second in data files - Fixed Notifications not working in some cases - Fixed possibly losing saved gmail address & password - Fixed keyboard blocking text fields in Notifications setup page - Fixed logic errors with saving files if incomplete email information is set - Failed emails now cause alert message with cause - Fixed emails failing to send - Fixed possible crash when sending emails with a slow network connection -Added activity indicator to show sending test emails 6.9 05/25/2018 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 SPL Graph - Fixed crash with warning if there was a problem with the email server, now notifiies 6.8 10/02/2017 -Fixed possible crash if email settings were not valid -Added live update calibration system for iOS devices 6.7 09/11/2017 -Bug fixes and stability improvements 6.6 08/28/2017 Bug Fixes -Fixed .txt and .text files not saving in iCloud mode, if auto-save was turned on and email files was turned off -Fixed crash at save time if auto-save was turned on with no run time set 6.5 08/13/2017 Major Upgrade - Please review the help screen in the app for full details. You may need to re-enter some setting information. * Fixed possible crash when setting cursor in an audio file, when another was within 10s of it. * Auto-saved files no longer drift in time. * Auto-saving moved to background thread for shorter gaps between files. * Enabled 0.1s resolution for octave mode for faster iOS devices. * Added computation of graph Leq for selected time limits and weighting. * Notifications Upgrade - Major Change - - Multiple Notifications are now available, tap "Add" on the Notifications Setup page. - All notifications are checked once/second to see if any have been triggered. - Name notifications as needed. - No limits to how many you can make. - Notifications now support Day of Week masking. Allows for different notifications on different days of the week. - Time window for each notification. Specify a time window in 24-hour hh:mm format. - Ln triggers added. Set triggers based on Ln or Leq. Time means "look back n seconds for Ln level". - Record Audio added. If this is enabled, a clip of the audio that triggered the notification will be recorded and saved locally and to iCloud or Dropbox, if enabled. The clip time will be the same as the Leq / Ln time, up to a maximum time of 30 seconds. File name format is "NyyyMMdd-HHmmss" - Email Audio file option added. - Fixed: removed 20s minimum notification lockout 6.4 08/05/2017 * 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 6.3 03/18/2017 - Updated for iOS 10 and new devices 6.2 11/21/2016 - Updated to support iPhone 7 and iPhone 7 Plus. 6.1 09/24/2016 SPL Graph, best noise monitoring and audio sound level logging app -- Fixed issues with Running Leq mode on the minimal display -- If auto-save is turned on, when a test is stopped it will also be automatically auto-saved. 6.0 08/11/2016

---

Previous Versions

Here you can find the changelog of SPL Graph since it was posted on our website on 2025-06-25 21:30:25. The latest version is 9.0 and it was updated on 2026-06-10 19:55:47. See below the changes in each version.

---

Related Apps

Here you can find apps that are similar with SPL Graph.

---

Disclaimer