ARC vs SUS4 Loop Builder
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ARC
Create music with a versatile groovebox featuring eight tracks for synths, samplers, and drums. Its intuitive interface allows for real-time performance and easy arrangement into songs, all while staying in key and scale.
- Eight dynamic tracks (synth, sampler, drums)
- Key and scale locked note/chord pads
- 16-pad sampler with import/record
- Deep synth editing and 25 arpeggiator patterns
- Full mixer with EQ and individual track effects
- Song mode for arrangement and live performance
- MIDI input and iCloud sync
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Eight tracks. Synths, samplers, drums. Play it like an instrument. ARC-24 is a groovebox for iPhone and iPad. Pads, loops, and a mixer in one place. Everything stays in key. Pick a key and a scale and the pads follow, so you can play fast without landing on a wrong note. Record a loop, keep overdubbing while it runs, and fix whatever you fumbled on the grid afterwards. Once you've got a few loops going, chain them into a song. Or leave the transport running and fire them off by hand from the mixer. • Eight tracks that sort themselves out. Synth, sampler, or drums, decided by what you play first. Overdub while the loop cycles. • Note and chord pads locked to your key and scale. Hold latches notes so they sustain. Pulse retriggers them on the beat. • A sixteen pad sampler. Import WAV, AIFF, MP3, M4A, AAC, or FLAC, pull audio from a video, or record through the mic. Chop it into slices across the grid, or map one sample over every pad and play it pitched, in scale or chromatic, at the original length or at tape speed. • Ten drum kits, from 909 and trap to lo-fi, boom bap, and hand percussion. Tune, pan, and level every pad. • Synth editing that goes deep enough to matter. 21 presets to start from, two oscillators, filter, envelope, and LFO when you want to build your own. Save the keepers. • 25 arpeggiator patterns, all of them in your key, from slow drifting phrases to sixteenth note runs. • A piano roll editor. Move, stretch, and delete notes while the loop keeps playing. • A real mixer. Faders, pan, mute, solo, and three band EQ on every channel. • Every track gets its own effects rack, not a shared send. Resonant low and high pass with cutoff and resonance. Compressor and gate. Distortion, bit crusher, ring mod, flanger. Tempo synced delay in digital, analog, or tape. Reverb with chorus and tape wow. Character for texture, air, width, and warmth. • Motion, so synth parts never sit still. Slow LFOs drift the filter as the loop runs, and Bloom opens the cutoff every time you play a note. • Song mode. Arrange loops into sections, or switch between them live from the mixer without ever stopping. • MIDI in from a USB or Bluetooth controller. • Export to WAV or AAC. • iCloud. Start something on the iPad, pick it up on the phone. Seven days free, the whole app. After that one purchase unlocks it for good. No subscription, no renewal, nothing to cancel.
SUS4 Loop Builder
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Build a song one loop at a time. A looper and multitrack overdub tool for guitar, vocals and anything with a mic. Layer parts, keep them in time, and export stems when the idea is worth finishing. SUS4 Loop Builder is a multi-track looper for building song ideas from scratch. Record a bass line into the first layer, layer a chord progression over it, add a melody on top, and keep going until the idea has a shape. Each layer has its own level and effect controls so the mix develops as you build. When you have something, export the full mix or individual stems to your DAW for proper production. The loop library saves your builds so you can come back to them, reference them, or share a stem with a collaborator. • Multi-track looping — record and layer on top of previous loops • Per-layer level and effects controls • Loop library for saving and revisiting ideas • Stem export — export individual layers or the full mix • Multi-track export to your DAW • Subscribe monthly, or unlock the full SUS4 suite forever: unlimited loops, multi-track export, per-layer effects, and the full loop library All recording stays on your device. No audio is uploaded. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is update cadence: ARC at weekly against SUS4 Loop Builder's monthly. SUS4 Loop Builder's advantage is iOS requirement (16.0 vs 18.1). On price, ads, in-app purchases 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
Both are free to download. ARC sells 2 one-off in-app purchases and SUS4 Loop Builder sells 2 in-app purchases, starting at $0.99 per month. Whichever you choose, the download price is not the number that matters.
ARC ships an update weekly, SUS4 Loop Builder monthly. The most recent releases landed on October 5, 2026 and October 12, 2026 respectively.
| Parameter | ARC | SUS4 Loop Builder |
|---|---|---|
| Price | Free | Free |
| Rating | 4.3 (3 ratings) — better | — |
| Positive reviews | 33.3% of reviews | — |
| Number of ratings | 3 — better | — |
| Update frequency | Weekly — better | Monthly |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad | iPhone, iPad, Mac — better |
| Requires iOS | 18.1 | 16.0 — better |
| Further details — not scored | ||
| Size | 52 MB | 20 MB |
| Age rating | 4+ | 4+ |
| Developer | Daelan Wood | ThePaulSmith |
In-app purchases
ARC
- 7-Day TrialFree
- ARC-24 Full Version$9.99
SUS4 Loop Builder
- SUS4 Loop Builder Pro Monthly$0.991 Month
- SUS4 All-Access7 Days trial$4.991 Month









