FAC Phazer vs RiffAlly Slowdown
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
FAC Phazer
This music effect plugin offers a rich sonic palette inspired by classic guitar pedals and hardware synthesizers. It provides extensive control over phasing effects with adjustable LFOs, unique characters, and versatile modulation options for all instruments and genres.
- Inspired by classic phaser units
- Adjustable LFO with tempo sync
- Four unique sonic characters
- External modulation and Step mode
- Stereo phase modulation
- Universal AUv3 purchase
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• Inspired by famous phaser units from guitarist and keyboardist world • Unique sonic character combined with a large amount of control • Adjustable LFO; diverse waveforms and synchronizable to host tempo • Versatile: External modulation (parameters), Step mode, and more • Unique Butterfly Meter: Shows LFO modulation and output level • Suitable for all musical genres and instruments • Stereo, adjustable phase modulation distance between both channels • Includes various presets for inspiration • Advanced Responsive Design, portrait and landscape views • Universal Purchase: AUv3 for iOS (iPad/iPhone), macOS and Vision Pro FAC Phazer will satisfy most fans of phasing effects, seducing them with its rich sonic palette and elegant interface. To achieve the classic phase effect, the original signal is blended with a slightly out-of-phase copy of itself. Altering the timing difference between the two signals produces the swooshing sound characteristic of phasing. Most phaser units available on the market are built around this circuit topology, each with its own specificities and limitations. Guitar pedals provide a great sonic signature out of the box and are a great source of inspiration, but we often overlook the impressive built-in effects sections of some hardware synthesizers. FAC Phazer combines the best of both worlds into a single plugin, offering access to all parameters involved in crafting the phasing effect. The design and development were inspired by both pedals and built-in phaser effects found in hardware synthesizers. This led to the creation of four unique characters: Classic, Midori, Step, and Tirus. All parameters can be applied to each of these characters, allowing you to create new, exciting, and outstanding sounds. The presets Slow, Moderate, and Jumpy Phase Pedal or also Fleur d’Oranger bring the classic pedals sound signature within your reach. If you're seeking more modern characteristics, the Step Sound I preset offers a splendid stepping mode, while the Midori Phase Shift II preset emphasizes the feedback in a unique way. On the other hand, the Tirus Anthem preset is an excellent starting point for exploring phasing effects produced with built-in synthesizer effects. An important aspect that strongly contributes to the variety of the sonic palette provided by the plugin is the modulation options. The LFO can run in free mode, be synchronized to the host tempo, or be defined by external automation parameters. The documentation is available at fredantoncorvest.com/FAC_Phazer.html
RiffAlly Slowdown
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Hear the notes. Repeat the phrase. Play it at full speed. RiffAlly Slowdown helps you work through the part that keeps tripping you up. Slow your practice audio down without changing its pitch, loop the exact section you need, and increase the speed as you get comfortable. START WITH SOMETHING TO PLAY Choose a compatible, unprotected audio or video file from Files, iCloud Drive, or another Files provider. Record a rehearsal, lesson, or musical idea. Or tap Try a practice track and start with Neon Pocket, an original RiffAlly track included in the app. SLOW DOWN. STAY IN KEY. Adjust local audio playback from 25% to 150% speed while preserving pitch. Change pitch separately by up to 12 semitones in either direction to practice in another key. Tap Original to restore normal speed and pitch. REPEAT THE PART THAT MATTERS Set A and B loop points to repeat a difficult phrase. Zoom into the waveform and drag the boundaries to refine your section. Add named markers so the riff, transition, or turnaround is easy to find again. BUILD BACK TO FULL SPEED Use the tempo ladder to choose a starting speed, finishing speed, increment, and number of repetitions. Slowdown steps up the speed as you complete your loop repetitions. BRING A YOUTUBE LINK Find a video in YouTube, tap Share, copy its link, and paste it into Slowdown. YouTube already offers playback-speed choices; Slowdown adds A/B section repetition so you can practice without scrubbing back after each pass. Available speeds depend on the video and YouTube player. This optional mode requires internet and uses the official visible YouTube player. YouTube media is never downloaded or exported, and playback stops when the app is inactive. Independent pitch adjustment, waveform editing, and the tempo ladder are for local media. PICK UP WHERE YOU LEFT OFF Recent sessions restore your local media, speed, pitch, loop points, named markers, and tempo ladder settings. Your imported media and recordings stay on your iPhone. RiffAlly does not receive your practice files or session history. The optional YouTube player connects to Google/YouTube under their privacy policies. The complete local practice workflow works offline, with no account or subscription required. Files stored only in iCloud or another provider must first be available on your device. Supports compatible, unprotected MP3, M4A, WAV, AIFF, MOV, and MP4 files where iOS permits. For imported video, Slowdown practices the audio track; synchronized local video playback is not included.
Screenshots
Verdict
The clearest difference is price: RiffAlly Slowdown at Free against FAC Phazer's $9.99. RiffAlly Slowdown also leads on update cadence (daily vs every 4 months). FAC Phazer's advantage is ads (none vs shown) and device support (3 vs 1). On in-app purchases 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
RiffAlly Slowdown is free to download; FAC Phazer costs $9.99 up front. FAC Phazer sells 3 one-off in-app purchases and RiffAlly Slowdown sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.
FAC Phazer ships an update every 4 months, RiffAlly Slowdown daily. The most recent releases landed on November 3, 2026 and October 31, 2026 respectively.
| Parameter | FAC Phazer | RiffAlly Slowdown |
|---|---|---|
| Price | $9.99 | Free — better |
| Rating | 5.0 (30 ratings) — better | — |
| Positive reviews | 83.3% of reviews | — |
| Number of ratings | 30 — better | — |
| Update frequency | Every 4 months | Daily — better |
| Ads | No — better | Yes |
| In-app purchases | Yes | Yes |
| Monetization | Paid | — |
| Devices | iPhone, iPad, Mac — better | iPhone |
| Requires iOS | 16.4 — better | 17.0 |
| Further details — not scored | ||
| Size | 3 MB | 3 MB |
| Age rating | 4+ | 12+ |
| Developer | Frederic Corvest | Fernando Lanner Cardoso |
In-app purchases
FAC Phazer
- Small Tip$1.99
- Medium Tip$4.99
- Large Tip$14.99
RiffAlly Slowdown
- Small Tip$1.99
- Supporter Tip$4.99
- Generous Tip$9.99









