FAQ

Sound recording

The new version has a capability of recording, that will be based on:

• recording the user input into an event file

• then batch rendering of sound into a WAV file. 

This 2 step recording will not change a great deal the user experience, but it will definitely allow small machines to cope with io.

Where are the WAV files I recorded?

Regarding the Android version of your device, there are 2 options:

Android 11 onwards: the WAVs are recognized by the media system, so any WAV reader should locate them in the MUSIC libraries under com.synprez.fm

before Android 11: the WAVs are located as simple files in a directory Android/data/com.synprez.fm/files. By default, this directory is located in what Android calls "external storage": this may be a real SD card if you have a physical slot on your device, or an emulated storage otherwise (in either cases this storage is visible if you connect your device to a computer).

The setup page of the app, accessible from the menu, will tell you the exact location of WAVs file, but unfortunately the "root directory" is a very technical name (like "/storage/emulated/0"), that file browsers report as "internal", "main storage", "SD card" etc.

The most likely place to find the files from a file browser is "main storage" (the default on most machines), but if there is an SD card they can also be located there. Normally, there should be no more than 2 places to look!

Is it possible to have a simple interface?

The DX7 interface was basically a series of buttons identifying a parameter, and a slider connected to an LCD display to setup this parameter. I tried to make interface easier to use, but the truth is that on small screen, this is tedious to shift from one function on another (there are more than hundred parameters to define a sound). Actually, the area to scroll horizontally the widget strip is limited to the upper part, where you can find the titles (Volume, Memory etc.). This is to avoid changing by accident some parameters while scrolling. I plan to add a more intuitive design on the next release. No release date for the moment

Why support small devices and not dedicate the application to tablets?

A lot of synthesis applications work on tablets, the challenge was to make a high quality synthesis on small devices. Leaving aside sound parameters setup (tedious on a small device), the synthesis is supposed to be possible on either devices. This is why I prefer putting no restriction on screen size too, because FM synthesis can be fun also on small machines! ;-)

Is there a VST version?

No, but there is an equivalent project that is called Dexed, and that use the same sound banks, so you should not be lost :)

Dexed: home page on github

What about MIDI interface?

This version supports MIDI for Android devices 3.1 and above:

• for USB cable controllers, you need an USB OTG cable to connect your Android device, as described here

• for BTLE (Bluetooth Low Energy) MIDI controllers, you have to pair your keyboard with your Android device, more data here 

Features you won't find so far

• recording/playing MIDI file

• saving sound file in compressed formats (MP3, Flac etc.)

• recording samples/playing samples: a soundfont reader is in the pipe, not available for the moment

• other synth emulation: for the moment, just FM, but an extension of PWM for any waveform (sometimes called "phase distortion") is in the pipe too.

I cannot pair my BTLE controller with my device

Using a BTLE controller requires to pair you controller with you Android device, the way you pair your BT headset or earbuds:

• make sure you have the Bluetooth activated on you Android device, or else you won't be proposed BT pairing

• the time to pair is short, because it drains energy from the battery (on both controller AND device side), so make sure you have activated the pairing on your controller (button) and the app (menu "scan Bluetooth keyboard") at the same moment

• check you have allowed the "Location" and "Nearby devices" when you were prompt to (usually the first time you try the pairing)

REM: on Android 13, a bug appeared regarding pairing of some BTLE devices, and was fixed in Android 14. So if you experience suddenly pairing problem while upgrading your Android device from 12 to 13, try to move to 14 directly.

Which BTLE controllers can I use?

I personally own 2 BTLE keyboards:

• an AKAI LPL25 wireless (2 octaves)

• a KORG microKEY Air (3 octaves)

Others probably work as well, but I never tested them.

Pedals

There are several types of pedals in the MIDI specifications:

• hold pedal

• sustenuto

• soft pedal

• legato pedal

• hold2 pedal

Describing each of them is besides this document's point, knowing that the pedal is only used to activate/deactivate the hold in the Arpeggio section. This hold is very special, because it does not release the sound when the key is depressed, only when it is pressed again.