Comparison

SPL Graph vs Midiflow Channels (Audiobus)

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • 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
Features
Read full description

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.

About

Midiflow Channels (Audiobus)

This music app acts as a MIDI effect for Audiobus 3, enabling users to filter and remap MIDI messages across specific channels. It allows for granular control over MIDI data flow within your audio setup.

Highlights
  • Filter MIDI messages by channel
  • Remap MIDI channels
  • Use multiple instances
  • Integrates with Audiobus 3
Features
Read full description

This MIDI effect app for Audiobus 3 allows you to filter out MIDI messages on specific MIDI channels. Furthermore, you can remap the channel to a different value. + Filter out messages on specific MIDI channels + Remap channels + Use multiple instances of this effect in Audiobus NOTE: This app requires Audiobus 3. Insert it into one or more MIDI effect ports to affect the data going through the respective pipelines.

Screenshots

SPL Graph3 screens
Midiflow Channels (Audiobus)2 screens

Verdict

The call

The clearest difference is rating: SPL Graph at 3.7 against Midiflow Channels (Audiobus)'s 3.0. SPL Graph also leads on review sentiment (64% vs 25%) and update cadence (every 6 months vs every 12 months). Midiflow Channels (Audiobus)'s advantage is price ($1.99 vs $9.99) and in-app purchases (none vs 5). On ratings volume, ads, monetization model and device support 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

CostPrice · In-app purchases · Ads · Monetization

SPL Graph costs $9.99 and Midiflow Channels (Audiobus) $1.99 up front. SPL Graph sells 5 in-app purchases, starting at $19.99 per month. Midiflow Channels (Audiobus) asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

SPL Graph holds the better App Store score, 3.7 against 3.0. Both are backed by a comparable volume of ratings — 3 and 2 respectively. Written reviews point the same way: 64% of SPL Graph's written reviews are positive against 25% of Midiflow Channels (Audiobus)'s.

UpkeepUpdate frequency

SPL Graph ships an update every 6 months, Midiflow Channels (Audiobus) every 12 months. The most recent releases landed on October 31, 2026 and November 2, 2026 respectively.

Scorecard6 real differences · 4 level
SPL Graph versus Midiflow Channels (Audiobus): the parameters behind the verdict, then further details
ParameterSPL GraphMidiflow Channels (Audiobus)
Price$9.99$1.99 — better
Rating3.7 (3 ratings) — better3.0 (2 ratings)
Positive reviews64.3% of reviews — better25.0% of reviews
Number of ratings3 — better2
Update frequencyEvery 6 months — betterEvery 12 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationPaidPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.010.2 — better
Further details — not scored
Size30 MB5 MB
Age rating4+4+
DeveloperAndrew SmithJohannes Doerr

Customer experience

SPL Graph

All ratings3 ratings
Positive66.7%
Neutral0.0%
Negative33.3%
Written reviews14 reviews
Positive64.3%
Neutral7.1%
Negative28.6%

Midiflow Channels (Audiobus)

All ratings2 ratings
Positive50.0%
Neutral0.0%
Negative50.0%
Written reviews4 reviews
Positive25.0%
Neutral25.0%
Negative50.0%

In-app purchases

5 purchases

SPL Graph

Subscriptions3
  • 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
One-time2
  • Octave Band SPL Logging$9.99
  • Video Capture Option$19.99
None

Midiflow Channels (Audiobus)

No in-app purchases

Questions

Is SPL Graph free?
SPL Graph costs $9.99, and also offers in-app purchases.
Is Midiflow Channels (Audiobus) free?
Midiflow Channels (Audiobus) costs $1.99, with no in-app purchases.
Which has better reviews, SPL Graph or Midiflow Channels (Audiobus)?
SPL Graph is rated higher. SPL Graph averages 3.7 out of 5 from 3 ratings, while Midiflow Channels (Audiobus) averages 3.0 from 2 ratings.
Do SPL Graph or Midiflow Channels (Audiobus) have ads?
Neither SPL Graph nor Midiflow Channels (Audiobus) shows ads.
Which is updated more often, SPL Graph or Midiflow Channels (Audiobus)?
SPL Graph ships an update every 6 months, and Midiflow Channels (Audiobus) every 12 months. Most recently, SPL Graph was updated on October 31, 2026 and Midiflow Channels (Audiobus) on November 2, 2026.

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