Undersong vs Vascular
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- 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
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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
Vascular
Create electroacoustic music by visually connecting sound generators and processors on a canvas. Manipulate stereo position, control synthesis and processing, and build complex signal paths. Explore a vast array of synthesis types, effects, and controllers to craft unique sonic textures.
- Canvas-based sound design
- Modular signal path building
- Extensive synthesis families
- 71 built-in processors
- Advanced controller modules
- Sample playback and manipulation
- Microphone input processing
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Vascular is a canvas-based electroacoustic instrument. Create sound generators and processors by touching the canvas, then connect them to build the signal path. Moving a node changes its stereo position, while each node provides its own synthesis, processing, modulation and rhythmic controls. FEATURES - 55 synthesis families, including subtractive, FM, additive, granular, spectral, physical modelling, wavetable, wave-terrain, pulsar and stochastic synthesis. - 3 macrosynths, complete synthesizers in a single node: resurgent (2 scenes, 3 oscillators, 2 filters, effects), bayarea, a West Coast voice, and poundhard, an FM drum voice from kicks to industrial percussion. - A complete DX7 implementation. - Holos, a special node that combines elements and parameters from other nodes to create a new semi-modular synthesizer instantly. - A sample player for loading your own loops, with time-stretching, forward and reverse playback, stuttering, splicing and tape-style manipulation derived from classic electroacoustic techniques. - Sampled acoustic instruments that generate melodic loops in the session's tonal key. - Drum synthesis, a 303, a 16-oscillator supersaw and live granular processing. - Microphone input for processing external sound. - 71 processors, including filters, distortion, delays, combs, phasing, diffusion, reverb, spectral freezing, convolution, pitch tracking, harmony, vocoding, spectral delays, tape loops and broken-media effects. - Host your own AUv3 instruments, effects and MIDI plugins as nodes on the canvas, their settings kept with your sessions (in-app purchase). - 7 controllers that play or move other nodes: a melodic sequencer with a piano-roll editor; an arpeggiator that turns a single arpeggio into a fugue across up to 6 voices; a drum machine with fills and breaks; a shift register; bouncing cars whose collisions are notes; a Game of Life swept by a playhead; and an LFO controller with 3 LFOs on each of up to 6 nodes. - Kick side chains with adjustable depth, and a master bus compressor. - An effects sequencer with 4 lanes of any processor, each with its own length. - A randomizer that creates whole patches, transforms what is on the canvas, expands it or dismantles it, and deals or removes LFOs, gates and motifs. - A padlock on every parameter, keeping it out of reach of the randomizer and every LFO. - Mute and solo: tap a node to mute it, hold it to hear it alone with its chain. - Angiogenesis, which moves nodes, rewires connections, adds processors and changes their parameters automatically. It never removes your voices, cuts a controller's connections or modifies microphone nodes. - Adjustable mutation rate and automatic adaptation to the processing capacity of the device. - A shared session clock with tap tempo and an independent clock division for each rhythmic source. - 27 scales from 4 musical traditions, plus microtonal tunings imported from Scala files. - Guided paths for restricting generators and processors to a selected musical territory. - A searchable palette, in alphabetical order, with favourites. - Rebalance, which spreads the outputs evenly across the whole stereo field. - A multilayer gesture looper. - 32 pattern slots with adjustable morphing between complete instrument states. - Sessions that store the network, settings and tonal key together. - 48 levels of undo and redo. - Recording, playback, renaming and sharing of takes. - A transport that stops active sound sources while allowing effect tails to decay naturally. AUV3 Vascular also runs as an AUv3 instrument in AUM, Loopy Pro, Logic and other compatible hosts, and follows the host's tempo and transport. The interface runs full-screen in landscape orientation and is operated directly with your fingers. The main buttons remain along the top of the display, away from the hand interacting with the canvas.
Screenshots
Verdict
The clearest difference is in-app purchases: Undersong at none against Vascular's 1. Vascular's advantage is price ($3.99 vs $9.99). On rating, ratings volume, update cadence and ads 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
Undersong costs $9.99 and Vascular $3.99 up front. Vascular sells 1 one-off in-app purchase. Undersong asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 5.0 for Undersong against 4.9 for Vascular. Both are backed by a comparable volume of ratings — 11 and 7 respectively.
Both ship on a similar rhythm, roughly daily. The most recent releases landed on October 25, 2026 and October 26, 2026 respectively.
| Parameter | Undersong | Vascular |
|---|---|---|
| Price | $9.99 | $3.99 — better |
| Rating | 5.0 (11 ratings) — better | 4.9 (7 ratings) |
| Positive reviews | — | 66.7% of reviews |
| Number of ratings | 11 — better | 7 |
| Update frequency | Daily | Daily |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.0 | 16.0 — better |
| Further details — not scored | ||
| Size | 19 MB | 101 MB |
| Age rating | 4+ | 4+ |
| Developer | ian johnston | Absolute Management SIA |
In-app purchases
Undersong
No in-app purchases
Vascular
- AUv3 Support$2.99







