Comparison

Undersong vs NotePulse

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

Head to head
About

Undersong

This audio effect acts like an instrument, generating synthesized notes in key based on incoming audio. Explore a vast array of sound combinations with various materials, modes, and patterns for unique ambient performances.

Highlights
  • Generates in-key synthesized notes from audio input
  • 12 material types and 10 performance modes
  • 10 pattern options for sound shaping
  • Self-generating ambient pad mode
  • Gravity feature for melodic anchoring
  • Customizable scales and root notes
  • Integrated reverb effect
Read full description

Undersong is an AUv3 audio effect that plays along with whatever audio you send it. It's technically an audio effect, but it acts more like an instrument. It's based on an idea I had for a live performance that ended up taking on a life of its own. The short version is that everything Undersong plays comes from the audio coming in. It listens to your track for "action", like a pluck, a drum hit or a swell, and each of those can spawn a particle. A particle is one small synthesized note, often a pluck but not always, and it's always in key. Soft playing gets soft and lower responses, and digging in gets you brighter ones. I feel like Undersong is something that wishes to be the main focus of a composition, but how you use it is totally up to you. I really enjoy using it as the centerpiece of ambient jams with a bit of percussion or a slow moving bassline alongside. If you're not sure where to start, send in a drum loop (even just a series of blips or clicks will work...), turn up the Mix to 100% and just experiment for a while. Twist some knobs and see what you find. You can't break it. The particles can be one of 12 materials, mostly inspired by modular synthesis techniques. Each material can then be performed and shaped by one of 10 modes and 10 patterns. That makes for 1200 combinations before you turn a single dial. One of the modes, Aurora, stops making particles altogether and turns into a self-generating ambient pad that your playing strikes. It's one of my favorite things in the device. I tried to build this like a playground for ambient performances. It's maybe a bit like sitting down at someone else's modular rig... it takes some exploration. I've set up an environment that I think is inspiring and I hope you can find your way around and enjoy it as well. There's various ideas and features hidden throughout (in plain sight) that work nicely together or on their own. Gravity, an idea I brought over from my Augur device, pulls the notes toward your root so the melodies sound like they're actually in your key. With Ear on, Undersong listens for the pitch you're playing and answers in unison, grain plays tiny pieces of your own audio back as notes, and Input lets little glimpses of your audio through, so you hear the thwack of your pick or your snare, but ringing at the particle's note. Step puts everything on a steady rhythm, one note per step, with Density deciding how busy it is. Step plus the Loop pattern is a fun little corner to jam in. Freeze holds whatever's currently ringing out so you can play over it. There's a Drone dial that builds a bed under everything, and 35 scales plus your own custom ones. Plus a quick one-knob reverb, because I really like reverb and I think almost every one of my devices has received at least a little reverb, just in case you need it quickly. To sum up, I'm proud of this and I have been consistently getting lost in it while building and testing. I feel it's the kind of device that you have to get to know a bit. It's pretty dense. It's maybe not for everyone, but for the people who it resonates with, I'm glad you're here and I hope it brings you some inspiration. If you run into any issues or have some feature requests for a later update, don't hesitate to reach out at ian@ijoaudio.com. I appreciate you very much. Cheers! ian - ijo audio

About

NotePulse

Features
Read full description

NotePulse transforms MIDI files into an interactive visual learning experience, helping you connect the music you hear with piano keys and traditional musical notation. Watch notes approach a full 88-key piano keyboard in the synchronized Notes view, or switch to the Live Grand Staff to follow the performance as written music. Keyboard and Score modes help you understand where each note belongs on both the staff and the instrument. Features include: • Synchronized MIDI playback, animated notes, piano keyboard, and grand staff • Live Grand Staff with Keyboard and Score viewing modes • Multi-track playback using SoundFont instruments • General MIDI instrument playback and per-track instrument selection • Adjustable playback speed for focused practice • A–B looping for repeating difficult sections • Track controls for mute, solo, volume, pan, transpose, color, and instrument selection • Left- and right-hand guidance • Score quantization and adjustable staff presentation • Support for user-selected MIDI and compatible SoundFont files • Online MIDI catalog with downloadable songs for offline use • Downloadable NotePulse Sound Library • Session import and export • Adaptive layouts for iPhone and iPad • Built-in starter music for getting started immediately NotePulse is designed for musicians, students, educators, and anyone interested in exploring how MIDI performances translate into piano movement and traditional musical notation. Import your own MIDI files through the Files app, explore downloadable music from the NotePulse catalog, or use the included starter collection. NotePulse remembers your practice settings, track configuration, visualization preferences, instrument selections, loops, and playback position for individual MIDI files. Your imported MIDI, SoundFont, and session files are processed locally on your device. Online catalog content and the NotePulse Sound Library are downloaded only when needed. No account is required. See the Music. Feel the Pulse.

Screenshots

Undersong4 screens
NotePulse4 screens

Verdict

The call

The clearest difference is price: NotePulse at $0.99 against Undersong's $9.99. Undersong's advantage is update cadence (daily vs every 10 days). On ads, in-app purchases, 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

Undersong costs $9.99 and NotePulse $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Undersong ships an update daily, NotePulse every 10 days. The most recent releases landed on October 25, 2026 and October 7, 2026 respectively.

Scorecard2 real differences · 7 level
Undersong versus NotePulse: the parameters behind the verdict, then further details
ParameterUndersongNotePulse
Price$9.99$0.99 — better
Rating5.0 (11 ratings) — better—
Number of ratings11 — better—
Update frequencyDaily — betterEvery 10 days
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.017.0
Further details — not scored
Size19 MB5 MB
Age rating4+4+
Developerian johnstonNoorcon Inc.

In-app purchases

None

Undersong

No in-app purchases

None

NotePulse

No in-app purchases

Questions

Is Undersong free?
Undersong costs $9.99, with no in-app purchases.
Is NotePulse free?
NotePulse costs $0.99, with no in-app purchases.
Do Undersong or NotePulse have ads?
Neither Undersong nor NotePulse shows ads.
Which is updated more often, Undersong or NotePulse?
Undersong ships an update daily, and NotePulse every 10 days. Most recently, Undersong was updated on October 25, 2026 and NotePulse on October 7, 2026.

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