# SPL Graph — Sound Level and Noise Logging > Real-time sound pressure level analyzer, logger, and frequency analyzer. (iPhone/iPad app by Andrew Smith.) - Source: https://appshunter.io/ios/app/spl-graph/id307451201 (this page in markdown: same URL + `.md`) - Developer: [Andrew Smith](https://appshunter.io/developer/291822462) - Category: Music - Price: $9.99 with in-app purchases - Rating: 3.70/5 from 3 App Store ratings · 14 written reviews indexed - Age rating: 4+ - Requires: iOS 15.0 · 30 MB - Languages: American English, European Spanish, German (Germany), Polish, Chinese (Traditional, Taiwan), Chinese (Simplified, China), French (France), Swedish, Japanese - Released: 2009-03-27 - Data updated: 2026-08-14 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/spl-graph/id307451201/reviews.md ## What is 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, 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. ## Key features - Real-time sound pressure level analysis - Audio recording and playback - Optional video capture - Octave and 1/3 octave band analysis - 3D frequency plot - Ln SPL value calculation - Email notifications for noise limits ## Pricing and in-app purchases Base price: $9.99. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | Remote Noise Monitoring | $19.99 | per month | | Remote Noise Mid Level | $79.99 | per month | | Remote Noise Large | $149.99 | per month | **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Octave Band SPL Logging | $9.99 | one-time | | Video Capture Option | $19.99 | one-time | ## Recent user reviews (10 of 14) All indexed reviews: https://appshunter.io/ios/app/spl-graph/id307451201/reviews.md ### 5/5 — Using for energy use assessmen *2026-02-26* I am so pleased with this app, even though i am using only a tiny part of its functionality. I set it up with my phone to record and save 15 second average intervals of the sound level near my gas water heater. I now have a timed record of its activity to compare to the usage data on my smart meter. This is a sanity check on my gas bill and whether the gas meter i am being charged from is really mine or if it belongs to another unit (multifamily building). Thanks for writing and maintaining this app! ### 1/5 — Incompatible iphone5 5s *2015-04-04* I bought a different iphone5, a 5s instead if a 5 and found this app will not record or playback except as noise. Info indicated that iphone6 has a dissabled high sample rate capability. Before iphone6 it stored recalled and played files. Now the files are garbled even if graphics seem to be working ok. ### 2/5 — A Little Explanation Might Help *2014-12-18* This is a useful app, but has a number of rough edges: Every time the app is opened, a message appears that it is “now compatible with iTestMic.” But, when this box is clicked, one is taken to a 404 page for StudioSixDigital that says “Ever feel like you’re in the wrong place?” As 404 pages go, it’s a pretty nice one, but anything that results in a 404 doesn’t reflect well upon whatever causes it. Please don’t constantly put up a dialog box that the user cannot get rid of and when clicked results in a 404. The first time that this app was opened, it would not graph anything. It would appear to record sound, with a red “Graphing” a the center bottom, but… no graphing. However, when opened up a SECOND TIME, it appeared to work - at least for the first type of plot. (On an iPhone 6.) In the app description, there’s a very nice looking three-dimensional plot. However, I have not been able to figure out how to see any plot that resembles that one. I can only get a single step of plot: like the second one in the app description: a fine red line on a green background. (In this plot, the X and Y axes can be conveniently compressed or expanded by pinching and un-pinching.) Luckily, this single type of plot is what I need, so this is okay, but if the description is going to show three different types of plots, it would seem reasonable that the user could actually see all three types of plots. If the developer could address these rough edges, I would raise my rating, providing that the Apple iOS App Store allows such a thing. ### 1/5 — octave band spl logging *2013-11-13* octave band logging ist auf dem iphone 5s auch nach update nicht möglich "restore my purchase" funktioniert nicht ### 4/5 — Meter did all I asked *2012-09-01* This app was used to record a master piece of music used a a reference point, in order to check on db levels in some adjacent rooms. From the db levels recorded I was able to prove that the necessary db attenuation was being achieved. The photo roll provision included within the app was used in email to show to others that it had done its work etc. Great product! ### 4/5 — Crashes with iOS 4.3.3 *2011-05-29* Great app but it crashes with iOS 4.3.3 when trying to adjust db calibration. An iPad version would be nice to have! ### 5/5 — This is the best sound meter app that I *2010-12-16* I really appreciate the graph and the ability to save the graph image. The app saves a screen capture of the graph image to your iPhone camera roll so you can document your readings. Worth the price! ### 3/5 — Dauerschallpegelmessung... *2010-04-08* ist nicht nur ein langes Wort sondern bedarf einer langen Aufnahmezeit. Ein erster Test über eine halbe Stunde verlief ohne Komplikationen. Das Ergebnis kann per Screenshot gespeichert werden. Hier wäre ein Datenexport per eMail wünschenswert. Dann könnte eine Vergleichsstudie in Excel etc. gelingen. Das Display müsste ausgeschaltet werden können um Strom zu sparen, denn eine Aufnahme mit Stromspeisung ist nicht möglich. Wenn das funktioniert gibt es auch 5 Sterne da meine Anforderungen voll erfüllt würden. ### 4/5 — La migliore *2009-08-27, version 0* .... Tra quelle che ho provato. Interessante poter monitorare con il grafico l'andamento e la media del periodo. Ok bravi, anche se il prezzo non è modesto..... ### 4/5 — Excellent app *2009-08-07* I've found many uses for this application, the most valuable being the ability to measure sound exposure in various environments. I hope the developer will consider adding the ability to graph peak spl exposure concurrent to average spl. This is the only reason why I did not add a fifth star. Otherwise the interface is stable, effective, and easy to use. ## Frequently asked questions about SPL Graph ### What is SPL Graph used for? SPL Graph is an audio sound pressure level (SPL) environmental noise analyzer, real-time frequency analyzer, chart recorder, and data logger. It helps users plot sound levels over time, record audio, and analyze frequency data. ### Does SPL Graph have ads? No, SPL Graph does not contain advertisements. It is a paid application that offers additional features through in-app purchases. ### What are the in-app purchase options for SPL Graph? Optional in-app purchases include capturing video of events and performing octave and 1/3 octave band analysis, including a 3D plot of the results. ### Can SPL Graph be used with professional microphones? Yes, SPL Graph works with the built-in iOS microphone and can be upgraded for professional standards by adding iTestMic, iPrecisionMic, or iAudioInterface2 for ANSI or ISO Type 1 or 2 results. ### How long can SPL Graph record sound level data? SPL Graph can record up to 24 hours of sound level data with single-second resolution. The graph dynamically rescales and adds time as data is collected. ### What is the price of SPL Graph? SPL Graph is priced at $9.99. This is a one-time purchase for the core application. ### What devices is SPL Graph compatible with? SPL Graph is available for iPhone, iPad, and iPod touch devices. ### How often is SPL Graph updated? The latest version is 9.0, released on 2025-12-20, indicating regular updates to improve functionality and compatibility. ## Version history (last 5 releases) ### 9.1 — 2026-08-12 -Fixed GPS coordinates not appearing in saved files -Increased GPS coordinates to 6 decimal places -Bug fixes and stability improvements ### 9.0 — 2025-12-20 -Bug fixes and stability improvements ### 8.9 — 2025-11-24 -Updated for new iOS devices -Bug fixes and stability improvements ### 8.8 — 2025-06-14 -Bug fixes and stability improvements -New iOS version support ### 8.7 — 2024-11-20 -Updated for latest iOS devices and calibrations -Bug fixes and operational improvements ## Apps similar to SPL Graph | App | Rating | Price | Category | | --- | --- | --- | --- | | [Sound Decibel Meter-NIOSH,OSHA](https://appshunter.io/ios/app/sound-decibel-meter-nioshosha/id1571075296) | 4.5 (335) | Free | Music | | [Decibel meter for personal use](https://appshunter.io/ios/app/decibel-meter-for-personal-use/id6448749318) | 4.5 (28) | Free | Music | | [Bass Tester & Booster Pro](https://appshunter.io/ios/app/bass-tester-and-booster-pro/id941024213) | 3.9 (225) | Free | Music | | [AudioTools, dB, Sound & Audio](https://appshunter.io/ios/app/audiotools-db-sound-and-audio/id325307477) | 4.8 (5,055) | $19.99 | Music | | [Spectrum Analyzer: Spectrogram](https://appshunter.io/ios/app/spectrum-analyzer-spectrogram/id981810895) | 4.2 (195) | Free | Music | | [SPL Meter](https://appshunter.io/ios/app/spl-meter/id309206756) | 4.1 (27) | $0.99 | Music | ## More apps by Andrew Smith - [Speaker Polarity](https://appshunter.io/ios/app/speaker-polarity/id293263027) - [SPL](https://appshunter.io/ios/app/spl/id293573990) - [RTA](https://appshunter.io/ios/app/rta/id298839433) - [FFT](https://appshunter.io/ios/app/fft/id298840058) - [RT60](https://appshunter.io/ios/app/rt60/id298840320) - [Generator](https://appshunter.io/ios/app/generator/id298840802) All apps by Andrew Smith: https://appshunter.io/developer/291822462 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-14.*