Master FX App is made by iMusicAlbum
Available in iTunes App Store

iMusicAlbum has recently been offering quality audio processing options for iOS music production that are highly convenient for many uses.
Their latest is this live audio multi-effects app for external sources such as vocals, instruments etc. Additionally it can be used in the Audiobus effect and output slots, making this a very versatile app.
Primarily Master FX is intended for use with guitars, vocals, or any other instruments that can be adapted to your device where the app will process desired effects. Recording can be done within the app itself as well as your favorite iDAW.
Sadly, at least at the moment I am writing this, Master FX does not support inter-app audio. This means if you use Audiobus to facilitate recordings of external instrumentation that you are only able to record 16 bit audio. Otherwise apart from that this can record at 24 bits. For electronic music 16 bits is just fine, but for live vocals or guitars it is less desirable.

Master FX comes with 7 effects modules and limiter at the main output. 6 effects can be run simultaneously.
The built in effects are: Chorus, Reverb, Delay, Compressor, Flanger, Pitch, and a 3 band Parametric EQ.
The order of each module can be customized to fit whatever preferences you may have for the signal order. Furthermore, two assignable pad banks (6 each, A&B) can accommodate your presets for quick FX switching via the “Live” tab.
Add to that independent “left/right” channel recording to capture a guitar and vocals at the same time.

The effects are not simply just wet/dry sliders, but actual independent modules. This means by selecting the module tab the corresponding effect unit opens up full screen to present you with all of its adjustable parameters.
They are still not exactly “specialized” effects such as what you would find in a stand alone effects app (like Audio Reverb, EchoPad etc) but they are each quite good in their own right. For live situations they are especially handy being all in one app, on one screen.

Several carefully crafted presets are included for certain and specific scenarios or instruments in mind. You can also create and save your own preset banks.

Recording can be done directly to Master FX, and files are easily managed. If you’ve used any of iMusicAlbum’s other apps like the excellent “AudioMastering” app, you will feel right at home with the same style of file manager. Not to mention the whole design of Master FX is also designed with the same uniform interface as this developer’s other audio apps.

For a full list of specs, video tutorials, and app details please visit iMusicAlbum

Managing files in the app is one thing but moving files around needs to be easy too. Anybody familiar with iOS Music production knows that moving files around between our various other apps or cloud services is a must. No problem. Master FX has the bases covered with Dropbox, AudioCopy/Paste, iTunes Playlist & File Share, “Open In” and WiFi tools for importing and exporting with ease.

I’ve been testing Master FX mostly as it’s intended, by recording and processing audio captured with my iRigMic. I found no issues or problems at all. Even though iRigMic is mono, Master FX, with the right selection of modules and signal path set, did a great job of giving my recordings body and fullness that resembled a stereo recording with no discernible difference.
I am impressed.
I also tried it as an “Effect” slot in Audiobus and had just as good of an experience.

For an all in one multi FX app, Master FX does a fine job in each of its possible situational applications.
Stable, easy to use and understand it should make for a top choice.
My only gripe is that it doesn’t currently support inter-app audio, and the Reverb and Chorus could be a little bit better. Nothing bad, they are decent, I just feel they are not this app’s strong point.
This is more of a “student of many” rather than a master of anything in particular. If you’re looking for a particular, highly specialized effect type this probably shouldn’t be the first choice. However if you want a collection of good effects to use simultaneously and packaged neatly in one app for live uses with real world instruments or vocals, then this is a list topper. Check out the tutorial on iMusicAlbum’s website (linked midway and top) for the two channel recording. Many of you should find it particularly interesting.