Global Audio Settings

You can start using Audio Evolution Mobile straight away using the default settings but you may want to use the options in the Settings to tailor the app to you own preferences. The global app settings are accessed via the Settings button on the top row of the Arranger Screen if your device screen is big enough to include it. If your device has a smaller screen and doesn't display the button, you can access the Settings via the More button. 

There are many, many options available within the Settings and each option has a description to let you know what is being changed. As such, little can really be added by covering them all one-by-one in this manual, but since we are talking about setting up your project in this section, it is perhaps important to point out a few of the Audio settings available. These options are all found in the Audio section of the Settings.

Audio Input

First to note is Audio Input. This allows you to select the input for the app to use for recording audio (if you're not using an external USB audio interface). Selecting Audio Input in the Settings opens the following dialog.

The first time you install and launch Audio Evolution Mobile this will be set to Default Input as shown above. This will be the microphone your device uses to record audio using its standard settings. This will quite likely mean that the device applies processing such as automatic gain control as the recording is made, meaning it will adjust the sensitivity of the mic between quiet and loud passages to create a recording which is as loud as possible at all times. Such processing might result in the recording sounding more 'pleasant', but once it's hard-baked into the recording it can't be changed and that might be a problem. If you make a recording where the loud and quiet passages need to be kept at their true relative volume levels, it might be better to select 'Mic, no processing, lowest latency'. This option bypasses any processing, such as auto gain, your device might automatically apply to audio recordings and allows you to have the mic's raw signal recorded. On some Android devices, it also is required to get the lowest latency, although it usually does not matter much. Although the 'Mic, no processing, lowest latency' option might sound ideal, on many Android devices, this leads to a very low input gain resulting in a very soft signal. Unfortunately, Android has no way to set the analogue input gain, so you will need to experiment on which option is best in your case. 

Alternatively, when using a USB audio interface with the eXtream USB audio driver, input gain can usually be controlled on the USB audio interface itself with a physical knob or an internal gain control that can be accessed by the app. No automatic gain control is applied in that case.

NOTE. Because no automatic gain control is being applied to the recording when using 'Mic, no processing, lowest latency', recordings made using this setting can be very quiet as they initially appear on the track clip. You can increase the level of the recording by Normalizing the audio clip. Normalizing boosts the level of the entire clip so that the loudest part of the recording is at the maximum volume level set for the normalization process by the user. All other parts of the recording are also boosted by the same amount, meaning they still all retain their correct relative volume levels compared to each other. Unfortunately, any noise present will be boosted as well, although that could be solved by using a noise gate effect. Once you have normalized your recording you'll realize that you now have a much more honest sounding recording than is available with the other options. Normalization is very quick and easy to do; for more information on how to do it, please see here.

Audio System

The next option to draw attention to is the Audio System. This allows you to select the Android audio system used by Audio Evolution Mobile (when not using a USB audio interface with the eXtream driver). You can choose between AudioTrack and Oboe/AAudio. Oboe/AAudio offers the lowest latency and cleanest sound, but it is worth pointing out the presence of AudioTrack for the benefit of older devices which might prefer it. By default Audio Evolution Mobile is set to use Oboe/AAudio, your device's native sample rate and a buffer size factor of 2.

NOTE. You might experiment with these options and find yourself thinking that AudioTrack (and, potentially, non-native buffer size settings for Oboe/AAudio) makes the sound richer and more lush sounding? Although seductive, this is actually a reason to try to avoid using AudioTrack (or those settings) when making music if possible. Just as your device might, by default, apply some post-processing to its mic recordings, so, it seems, AudioTrack applies some processing to sounds before they are outputted through the speakers. Oboe/AAudio does not apply any processing when using the native sample rate, so if you want to hear your music as it actually sounds - and, when making music, you do - those are by far the better options to choose (if your device can handle them) and will allow you to make your own processing decisions more accurately. 

Oboe/AAudio: Buffer size

Using the native sample rate will also offer the lowest latency possible but it also has the highest CPU load. This is why Audio Evolution Mobile is set by default to use Oboe/AAudio with a buffer size factor of 2, meaning that it uses the lowest latency ('fast') audio path, but with a slightly higher latency than possible. For the lowest latency, you can set the buffer size to 'Native buffer size' (which equals to a buffer size factor of 1, but an even higher CPU load). If latency is not of a concern, but you are facing audio glitches due to high CPU load, you can increase the buffer size to 4x or 8x.

Force OpenSLES

When you are experiencing audio glitches or other artifacts when recording audio (without a USB audio interface), it is always a good idea to try with this option turned on. Instead of the latest Android audio system, AAudio, the older OpenSLES audio system will be used. Some Android device manufacturers have a bad implementation of AAudio, so forcing OpenSLES might be a solution in this case. Note however that with this option enabled, the track-to-track latency (variation) cannot be determined as accurately as with AAudio.

Recording File Type

The Recording file type option allows you to select the format your audio recordings are made using. The choices are WAV, AIFF or FLAC. All three formats are lossless, meaning they keep all of the audio quality of the audio source. WAV and AIFF are both uncompressed formats meaning they are exact copies of the source, and so take up more storage space on your device. They are essentially the same quality, but store the data differently with WAV being the de facto standard and AIFF being Apple's own format. FLAC is lossless, but it is a compressed format, meaning it still contains all of the audio data but in a much smaller file size. It is generally considered to be wise to use WAV if you are going to be editing your audio a lot. If you are making a recording which you do not anticipate having to edit and want to save storage space, then FLAC is probably the perfect choice.

Automatic Track Creation

The last  Audio setting option to draw attention to here is Automatic Track Creation. This is a very useful feature which, when active, automatically creates, and records to, a new audio track in the timeline when Record is pressed and no other track has been armed. This means you can open Audio Evolution Mobile and with one button press, you're already recording audio. Automatic Track Creation is ON by default.