I made an amplifier and effects app for iOS which lets users amplify their voice or instruments using any connected input and output the resulting audio over any connected output.

The main motivation for this was a new cable I got. It has USB-C with a DAC on one end and a guitar jack on the other (after using it for a while I wouldn’t recommend this specific model as it generates lots of noise). Initially I used this cable to connect my guitar to my laptop and then use either Logic or MainStage to have a virtual amplifier, but then I had to think of the cute little Marshall MS-2 pocket amplifier I had as a child, and wanted to build an app with this (and more) functionality for iOS (which is possible now that the iPhone supports USB-C, and with that generic USB audio devices).

Features

The app features are listed below:

Freely choose input and output

You can change the input and output device you want to use, for example you could amplify your voice using the built-in microphone out to a bluetooth speaker (keep in mind that bluetooth will add latency) to make an announcement, or use a multi port adapter with an additional audio adapter to route the generated audio back to a mixer if you forgot to bring your amp or pedalboard to band practice.

Dual Gain Stages

There is pre- and post-gain, which lets you adjust the signal level in exactly the way you want/need. Pre gain is applied right after the input, post gain right before the output.

Output Meter

cropped screen recording of the output section showing me badly playing guitar in a way that creates a clipped signal

The application shows a waveform of the current output signal, a level meter, and a clip indicator which flashes red if the output signal is above 100% level.

Since v1.1.0 the update interval of the output meter can be configured in order to match your preference or requirements.

Distortion, Reverb, and Delay

The app has configurable distortion, reverb, and delay plugins with built-in presets to choose from and properties to configure.

Equalizer

There is also a 6-band EQ with additional settings for each equalizer band.

Configurable Plugin Chain

You can enable/disable plugins, and change their order (distortion, reverb, delay, noise gate, eq) within the mixing chain.

(Added in v1.1.0) Noise Gate

The Noise Gate plugin allows for muting the input if the level falls below a configurable threshold.

(Added in v1.1.0) Metronome

Use the metronome to practice your beat keeping, it can be used even when no input is selected.

(Added in v1.1.0) Tuner

The app features a tuner which can be used to tune instruments or measure frequencies.

Planned Updates

If you want to help with testing the new features listed below, you can join the TestFlight Beta.

  • Pitch Shift effect/plugin
  • Configurable EQ Frequency Bands
    • Ability to add/remove bands
    • Ability to change EQ band center frequency

The app is completely free to use, without tracking or ads, and can be downloaded on the AppStore.

I hope this app is useful, if not don’t hesitate to tell me the ways I can improve it.

Download on the App Store