Fred Anton Corvest has been building iOS audio tools since before most developers took the platform seriously, and FAC Punchlab is one of his most practical releases. The concept is straightforward: a modular multi-effects rack built specifically around the kind of processing that makes drums hit harder, mixes breathe more, and masters translate better. Nine precision modules — Attack, Boum, EQ, Fizz, Heat, Phat, Tone, Clip, and Mix — sit in a single scrollable rack and can be reordered via drag and drop. The order matters. Running the saturation before the EQ produces a different result than running it after, and Corvest designed the interface specifically so you can act on that instinct quickly, without navigating submenus or rebuilding a chain from scratch. For iPad producers who spend time on mix bus and master chain processing, this is the kind of tool that earns a permanent slot in the template.
The saturation section alone makes the app worth evaluating seriously. The Phat module gives you five distinct saturation models — each with a different harmonic character, from soft even-order warmth to more aggressive odd-order bite. The Heat module works differently: it is a harmonic exciter rather than a straight saturator, adding upper-harmonic content to push elements forward in a mix without the low-end thickening that heavy saturation can cause. Used together on a drum bus, Phat on the low-mid weight and Heat on the top-end air, the combination adds the kind of analog density that most iOS productions are missing. The Clip and Mix modules handle the loudness end: a clipping stage to control peaks without pumping, followed by a brickwall limiter on the output. The Attack transient module gives precise control over how much punch hits the front of each sound, which on a drum bus is more useful than a full compressor in many situations. And the Boum module — a low-frequency enhancer — adds sub weight without the muddiness of simple bass boost EQ. These are not generic effects with generic names. Each module has a clear job and does it with more precision than most mobile multi-FX apps manage.
The workflow holds up well inside a real session. Loaded as an AUv3 in Loopy Pro, FAC Punchlab sits naturally on any track or group bus, and parameter automation works correctly through the host. The pre- and post-signal waveform monitoring running in real time alongside the rack is a genuinely useful addition here — you can see what the processing is doing to the dynamics and transients without switching to a separate metering tool. In AUM, where routing flexibility matters most, the ability to put FAC Punchlab on individual channels, subgroups, and the master simultaneously — each instance with its own module order — is where the modular approach really pays off. The interface scales well from iPhone to iPad Pro without any layout degradation, and the touch targets are large enough to adjust under live performance conditions without accidentally hitting the wrong control. CPU overhead across multiple instances is low, which is exactly what you want from a dynamics and saturation plugin that might run on every channel simultaneously.
The honest question to ask about FAC Punchlab is whether the modular format adds real value over a fixed-chain dynamics processor. The answer is yes, but primarily for producers who already understand what each module does and why the order matters. If you are still learning the relationship between transient shaping, saturation, and limiting, the drag-and-drop flexibility might feel abstract. For anyone who has hit the ceiling of what a standard compressor + EQ chain can do on a mobile mix bus, Punchlab is a practical next step. It is fully unlocked at purchase with no in-app purchases and no subscription — Corvest supports optional tips for developers who want to contribute, but nothing is held back. The app is currently on sale at $9.69 from $14.99 until June 6th, which is a good window to pick it up.
Key features:
- 9 Precision Audio Modules: Attack, Boum, EQ, Fizz, Heat, Phat, Tone, Clip, and Mix — reorderable via drag and drop to build the exact signal chain the track needs
- Phat Saturation Module: Five distinct saturation models covering soft even-order warmth through aggressive odd-order character
- Heat Harmonic Exciter: Upper-harmonic enhancement that adds presence without thickening the low end
- Attack Transient Shaper: Precise control over transient punch independently of compression
- Boum Low-Frequency Enhancer: Adds sub weight cleanly without muddy bass boost artifacts
- Clip and Brickwall Limiter: Peak control and final loudness maximization without dynamic pumping
- Real-Time Waveform Monitoring: Pre- and post-signal visualization running alongside the rack for immediate visual feedback on dynamics and transients
- Fully Unlocked at Purchase: All nine modules included — no in-app purchases, no subscription. Optional developer tips supported.
- Universal AUv3 and standalone on iPhone, iPad, and macOS
App price: $14.99. Currently on sale for $9.69 until June 6th.
No in-app purchases. No subscription.
Original release: January 19, 2024 | Latest update: September 1, 2025 (v1.2)
