Comparison

SPL Graph vs Hi

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

Hi

Calculate and design custom ball-pack dampers for your audio equipment. This app helps you select the right reservoirs, number of balls, and dimensions to effectively reduce vibrations for improved audio playback. Build your own cost-effective damping solutions tailored to your needs.

Highlights
  • Select damping solution based on audio equipment weight
  • Choose reservoir shape and ball diameter
  • Calculate number of balls per reservoir
  • Determine net volume and dimensions
  • Reduce microvibrations and oscillations
  • Cost-effective DIY assembly
Features
Read full description

With this app, you can select a suitable ball damping solution for your audio equipment. Based on the app’s recommendations, you can acquire the right type of ball reservoirs that suit your preferences and the correct number of balls, and then assemble the dampers yourself cost-effectively. Provide the app with the weight of the device to be damped, how many ball reservoirs (usually 3–4) and which shape (cube, box, cylinder, pouch) you want to divide the balls into, as well as the ball diameter. As a result, you’ll receive detailed information such as the number of balls per reservoir, their weight, and the net volume and dimensions according to the chosen shape. Ball-reservoir dampers effectively prevent all kinds of microvibrations, oscillations, and vibrations generated either within the device itself or transmitted to the device through structures such as the floor, power cables, signal cables, or equipment stands. They also help with unwanted airborne vibrations. Eliminating the effects of harmful vibrations and shaking on sensitive audio devices and speakers—especially subwoofers—is extremely important to ensure flawless audio playback. Likely audible improvements include increased bass precision, improved volume dynamics, newly revealed details in the music, and more natural-sounding vocals and instruments. The balls follow the vibrations, which are dissipated as heat. Damping is 360 degrees—horizontal and vertical, in every direction. It’s easy and inexpensive to build by yourself. By varying and scaling this same solution, you can dampen vibrations in many devices, either underneath or on top. You can tailor the design according to your budget, aesthetic, and other quality preferences. When placing dampers above or below, make sure not to block any cooling vents. Recommended materials: - Reservoirs: Cotton and/or thin leather, as they do not cause static electricity. Wooden or leather containers in the shape of a cylinder, cube, box, or hexagon. - Balls: Precision balls, such as 4.5 mm or 5.0 mm airgun pellets, which are affordably available.

Screenshots

SPL Graph3 screens
Hi1 screens

Verdict

The call

The clearest difference is price: SPL Graph at $9.99 against Hi's $34.99. SPL Graph also leads on ratings volume (3 vs 1). Hi's advantage is rating (5.0 vs 3.7) and review sentiment (100% vs 64%). On ads, monetization model, device support and iOS requirement 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 Hi $34.99 up front. SPL Graph sells 5 in-app purchases, starting at $19.99 per month. Hi asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Hi holds the better App Store score, 5.0 against 3.7. Both are backed by a comparable volume of ratings — 3 and 1 respectively. Written reviews point the same way: 64% of SPL Graph's written reviews are positive against 100% of Hi's.

UpkeepUpdate frequency

SPL Graph ships an update every 6 months, Hi fortnightly. The most recent releases landed on October 23, 2026 and August 18, 2026 respectively.

Scorecard6 real differences · 4 level
SPL Graph versus Hi: the parameters behind the verdict, then further details
ParameterSPL GraphHi
Price$9.99 — better$34.99
Rating3.7 (3 ratings)5.0 (1 ratings) — better
Positive reviews64.3% of reviews100.0% of reviews — better
Number of ratings3 — better1
Update frequencyEvery 6 monthsFortnightly — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationPaidPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.0 — better15.6
Further details — not scored
Size30 MB15 MB
Age rating4+4+
DeveloperAndrew SmithArtificial Intelligence Technologies J.K. Oy

Customer experience

SPL Graph

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

Hi

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

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

Hi

No in-app purchases

Questions

Is SPL Graph free?
SPL Graph costs $9.99, and also offers in-app purchases.
Is Hi free?
Hi costs $34.99, with no in-app purchases.
Which has better reviews, SPL Graph or Hi?
Hi is rated higher. SPL Graph averages 3.7 out of 5 from 3 ratings, while Hi averages 5.0 from 1 ratings.
Do SPL Graph or Hi have ads?
Neither SPL Graph nor Hi shows ads.
Which is updated more often, SPL Graph or Hi?
SPL Graph ships an update every 6 months, and Hi fortnightly. Most recently, SPL Graph was updated on October 23, 2026 and Hi on August 18, 2026.

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