SPL Graph vs Audio Unit Player
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
SPL Graph
This app analyzes sound pressure levels and environmental noise in real-time. It logs audio, captures video, and performs frequency analysis, with options for advanced octave band analysis and professional microphone integration. Receive email notifications for exceeding noise limits and auto-save data for continuous monitoring.
- 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
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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.
Audio Unit Player
This music player offers real-time audio processing, including time stretching, pitch shifting, and a 31-band equalizer. It supports AUv3 effects and allows for A-B loop playback, making it ideal for practice, transcription, and performance adjustments.
- Real-time time stretch (50-200%)
- Real-time pitch shift (-12 to +12 semitones)
- 31-band equalizer with presets
- AUv3 effects support
- A-B loop playback
- Background playback
- Audio file export
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This app is a music player that can process the following effects in real time. - Time stretch (0.5-2.0 double speed) - Pitch shift (-1 ~ +1 octave) - 31 band equalizer - Reverb - AUv3 (Audio Unit v3) host [Use cases] - Karaoke's training. (Can be changed speed units of 10%, pitch shift in semitones easily) - Can playback at reduced tempo to copy phrase for guitar or bass, the keyboard instrument. - Can playback by changing the pitch to play by changing the key in the band performance (Developer himself has experience). [Function] - Perform time stretch (50 - 200%) / pitch shift (-12 - +12) in real time. - 31 bands EQ (Hz: 20, 25, 31.5, 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1k, 1.25k, 1.6k, 2k, 2.5k, 3.15k, 4k, 5k, 6.3k, 8k, 10k, 12.5k, 16k, 20k). - EQ preset (Abundant Built-in Presets / Custom Presets). - Reverb: Adjustable decay time (Low freq, High freq) / 13 presets - Reverb preset (Built-in Presets / Custom Presets) - Can be used as an AUv3 host. - A-B loop playback. - Center Cancel / Center Emphasis. - Lch, Rch each mute. - Quick fast forward, rewind (specify the number of seconds). - Check and set current position graphically in wave view. - Supports Auto-Lock ON/OFF. - Supports background playback. - Supports export (file writing) function (Each effect (speed/pitch/EQ) value set for each song is also reflected. The range specified in the loop section is output.) In addition to loading "music" data included in the standard music app, it also supports the function to import audio files from other apps ("Voice Memos" etc.). [How to import from "Voice Memos"] 1. Start the app "Voice Memos" and tap the mark "..." of the file to be imported from the list. 2. Tap "Share" on the sheet displayed from the bottom. 3. Tap "More" found by scrolling the displayed list of sharing destination apps to the right. 4. Select "AU Player" if available. The file is copied to this app. ================================================ [Note 1] This application will not be able to read songs of the following formats. - Songs from Apple Music, iCloud, iTunes Match - Songs that are protected by digital copyright (DRM) [Note 2] Depending on the state of your device, your custom AUv3 effects may not appear in the list. As a solution, you can solve the problem by starting "GarageBand" once and restarting this app. ================================================
Screenshots
Verdict
The clearest difference is price: Audio Unit Player at Free against SPL Graph's $9.99. Audio Unit Player also leads on update cadence (every 2 weeks vs every 6 months) and ratings volume (30 vs 3). SPL Graph's advantage is ads (none vs shown) and iOS requirement (15.0 vs 17.0). On rating, review sentiment, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Audio Unit Player is free to download; SPL Graph costs $9.99 up front. SPL Graph sells 5 in-app purchases, starting at $19.99 per month and Audio Unit Player sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
Audio Unit Player holds the better App Store score, 3.9 against 3.7. That said, the two scores are not equally well evidenced: Audio Unit Player has 30 ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 64% of SPL Graph's written reviews are positive against 67% of Audio Unit Player's.
SPL Graph ships an update every 6 months, Audio Unit Player every 2 weeks. The most recent releases landed on September 16, 2026 and October 1, 2026 respectively.
| Parameter | SPL Graph | Audio Unit Player |
|---|---|---|
| Price | $9.99 | Free — better |
| Rating | 3.7 (3 ratings) | 3.9 (30 ratings) — better |
| Positive reviews | 64.3% of reviews | 66.7% of reviews — better |
| Number of ratings | 3 | 30 — better |
| Update frequency | Every 6 months | Every 2 weeks — better |
| Ads | No — better | Yes |
| In-app purchases | Yes | Yes |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 30 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | Andrew Smith | Loop-Sessions.LLC. |
Customer experience
SPL Graph
Audio Unit Player
In-app purchases
SPL Graph
- Remote Noise Monitoring7 Days trial$19.991 Month
- Remote Noise Mid Level7 Days trial$79.991 Month
- Remote Noise Large7 Days trial$149.991 Month
- Octave Band SPL Logging$9.99
- Video Capture Option$19.99
Audio Unit Player
- Always remove banner ads.$3.99
Questions
Is SPL Graph free?
Is Audio Unit Player free?
Which has better reviews, SPL Graph or Audio Unit Player?
Do SPL Graph or Audio Unit Player have ads?
Which is updated more often, SPL Graph or Audio Unit Player?
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