Comparison

Surface Builder vs FAC Polyflo

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

Head to head
About

Surface Builder

Create custom MIDI control surfaces for audio applications. Design interfaces with buttons, knobs, and faders to send and receive MIDI data, control audio clips, and customize appearance. Supports AUv3 plugins and standalone use.

Highlights
  • Customizable MIDI control surfaces
  • AUv3 plugin and standalone modes
  • Send/receive MIDI data (notes, controllers, pitch bend)
  • Audio clip playback control
  • Multi-scene interface design
  • Drag and drop interface customization
Features
Read full description

Surface Builder is a tool for creating control surfaces that send MIDI data to one or more audio components in order to simplify remote control tasks. You start by creating a surface of a given size, adding buttons, knobs, faders, etc. to the surface and configuring them to generate the required MIDI output. Surface Builder allows you to send note on/off, controller change and program change values as well as being able to emulate modulation wheel and pitch bend data. Buttons can also be configured to send bulk MIDI data using a single key press. You can build surfaces that span multiple scenes and link between them for large complex interfaces. Incoming MIDI data can also be used to control or trigger elements of the interface, giving a bi-directional stream of MIDI data. Surface Builder can be added as a pure MIDI plugin which allows processing of MIDI only, or as an instrument plugin, allowing you to process audio passing through it. You can even load it as an intrument and configure a surface to start and stop audio clips either manually or remotely. Surface Builder was designed to be used as an AUv3 plugin within your favourite DAW, but it can also be used in standalone to send MIDI directly to MIDI hardware using direct access to their MIDI ports. Many different object types are supported including buttons, switches, lights, rotary knobs, faders, sliders, XY-Pad, keyboards, as well as text, image and box objects. Each object has many different styles and colours, so no two surfaces look the same. Drag and drop an audio file onto a button and that button becomes a clip player. Attach rotary knobs to control the clips volume and pan. Throw on top of that a LP/HP filter knob and you are cooking on gas. Drop PNG transparent image icons on buttons to customise the look and feel. A button can record and playback bulk MIDI commands, on both button press and release. So pressing a button could send the notes of a chord when pressed, and appropriate note offs on release. A surface can consist of up to 6 scenes for really complex designs. Buttons and switches can be used to switch scenes and also to show and hide other objects to make better use of screen space. Once your surface is complete switch to presentation mode to hide all the toolbars. Each surface can be saved with compressed audio and images all in a single surface file. Features ○ AUv3 and standalone modes. ○ Bluetooth MIDI support. ○ Drag and Drop interface. ○ Send and Receive Note On/Off. ○ Supports all Control Change parameters. ○ Supports Program Change commands with bank support. ○ Multiple Audio Clip playback. ○ Record and playback bulk midi data. ○ Multi-Scene. ○ Multi-level undo/redo. ○ MIDI Monitor ○ Presentation Mode. ○ iPhone and iPad compatible.

About

FAC Polyflo

This AUv3 plugin allows you to modulate and sequence MIDI instruments and modular hardware. It outputs both MIDI and analog CV simultaneously, supporting hybrid digital and analog setups. Convert various signals into control voltages for deep and flexible modulation.

Highlights
  • AUv3 plugin for modulation and sequencing
  • Outputs MIDI and analog CV simultaneously
  • Converts signals to control voltages
  • Two LFO generators with syncing
  • Integrated envelope follower
  • Six FLO(W) processors for signal shaping
  • Universal Purchase for iOS, macOS, Vision Pro
Features
Read full description

• AUv3 plugin to modulate and sequence MIDI instruments and modular hardware • Outputs MIDI and analog CV simultaneously for integrated hybrid setups • Fully functional in software-only environments with full MIDI support • Converts LFOs, MIDI notes, pitch, and control changes into control voltages • Includes two LFO generators with random spline, cross-modulation and syncing • Integrated envelope follower to track audio input or sidechain signal • Six FLO(W) processors for combining and shaping signals with math and logic • Each FLO supports 18 inputs with individual polarity, divider and multiplier • Multi-out support, built-in waveform viewer, Audio FX, and MIDI FX • Advanced Responsive Design, portrait and landscape views • Universal Purchase: AUv3 for iOS (iPad/iPhone), macOS and Vision Pro FAC Polyflo is an AUv3 plugin for modulating and sequencing MIDI instruments and modular gear via control voltage. It outputs MIDI and analog CV simultaneously, making it well-suited for hybrid setups that combine digital and analog equipment. The plugin includes two LFO generators offering 10 waveforms, including classic shapes and random spline, with support for cross-modulation and syncing. It also features an envelope follower that tracks audio FX input or an external sidechain. The generated signals, together with the host clock and MIDI input, are fed into six independent FLO(W) processors. These processors combine, shape, and route inputs using math operations, conditional logic, and comparators. Each FLO includes individual polarity, division, and multiplication controls, providing deep and flexible modulation that balances chaotic creativity with precise timing. Each FLO processor output is connected to its own output bus, enabling easy integration with hardware via DC-coupled audio interfaces like the Expert Sleepers ES-9. For simpler setups, FLO outputs can be routed to the stereo output. FAC Polyflo can also convert MIDI notes, pitch, and control changes into control voltages, making it a powerful MIDI-to-CV solution. If you prefer to work exclusively with software, the plugin runs smoothly in software-only environments with full MIDI support, making it equally suited for purely digital workflows. FAC Polyflo works as both an Audio Unit FX and MIDI FX, featuring a clean, touch-optimized interface with precise control and waveform visualization. It’s available as an AUv3 for iOS (iPad/iPhone), macOS, and Vision Pro, and requires a compatible AUv3 host app to run. This is an AUv3 Effect and requires a compatible host to work The documentation is available at fredantoncorvest.com/FAC_Polyflo.html

Screenshots

Surface Builder4 screens
FAC Polyflo3 screens

Verdict

The call

The clearest difference is in-app purchases: Surface Builder at none against FAC Polyflo's 3. Surface Builder also leads on iOS requirement (13 vs 16.4). FAC Polyflo's advantage is price ($9.99 vs $14.99) and review sentiment (100% vs 80%). 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

Surface Builder costs $14.99 and FAC Polyflo $9.99 up front. FAC Polyflo sells 3 one-off in-app purchases. Surface Builder asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

FAC Polyflo holds the better App Store score, 4.9 against 4.7. Both are backed by a comparable volume of ratings — 15 and 11 respectively. Written reviews point the same way: 80% of Surface Builder's written reviews are positive against 100% of FAC Polyflo's.

Scorecard5 real differences · 5 level
Surface Builder versus FAC Polyflo: the parameters behind the verdict, then further details
ParameterSurface BuilderFAC Polyflo
Price$14.99$9.99 — better
Rating4.7 (15 ratings)4.9 (11 ratings) — better
Positive reviews80.0% of reviews100.0% of reviews — better
Number of ratings15 — better11
Update frequencyEvery 3 weeks—
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidPaid
DevicesiPhone, iPad, iPodiPhone, iPad, Mac
Requires iOS13 — better16.4
Further details — not scored
Size32 MB5 MB
Age rating4+4+
Developer4Pockets.comFrederic Corvest

Customer experience

Surface Builder

All ratings15 ratings
Positive93.3%
Neutral6.7%
Negative0.0%
Written reviews15 reviews
Positive80.0%
Neutral13.3%
Negative6.7%

FAC Polyflo

All ratings11 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews5 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Surface Builder

No in-app purchases

3 purchases

FAC Polyflo

One-time3
  • Small Tip$1.99
  • Medium Tip$4.99
  • Large Tip$14.99

Questions

Is Surface Builder free?
Surface Builder costs $14.99, with no in-app purchases.
Is FAC Polyflo free?
FAC Polyflo costs $9.99, and also offers in-app purchases.
Which has better reviews, Surface Builder or FAC Polyflo?
FAC Polyflo is rated higher. Surface Builder averages 4.7 out of 5 from 15 ratings, while FAC Polyflo averages 4.9 from 11 ratings.
Do Surface Builder or FAC Polyflo have ads?
Neither Surface Builder nor FAC Polyflo shows ads.

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