GETTING STARTED

Everything you need to install AudioFlex, activate your license, and process your first track. This guide covers Android. The Windows app follows the same steps except where noted.

Installation

AudioFlex is distributed as a direct download. It is not available through an app store.

1

Enable installs from unknown sources
On Android, go to Settings → Security → Install unknown apps and allow installations from your browser or file manager.
2

Download the app
Download the latest version from the link in your purchase confirmation email or your account page.
3

Install
Open the downloaded file in your file manager and tap Install. Android will prompt you to confirm.
4

If prompted about an unrecognized source
Tap Install Anyway. AudioFlex is signed with a developer certificate but is not distributed through an app store.

// TIP

Android may scan the file on first install. This is normal and takes a few seconds. AudioFlex does not include ads, tracking software, or unnecessary network requests.

License Activation

Your license is a file delivered to you after purchase. AudioFlex ties the license to your device's hardware ID.

Open AudioFlex. You will see the License Activation screen on first launch.
Tap Load License File and navigate to your downloaded license file.
If the file is valid for your device, the app opens to the main screen.
If you see an error, check that the Device ID shown in the app matches the one you submitted at purchase. Contact support if you need help.

// DEVICE TRANSFERS

Switching phones? Contact support with your old Device ID and new Device ID. Transfers are free and processed within 24 hours.

First Run

After activation, AudioFlex opens to the main screen. The first thing to do is point it at your music and set your target frequency.

Go to the Settings tab.
Under Paths, set your Live input folder -- this is the folder the live player reads from.
Optionally set your Convert input and Output folders if you plan to use batch conversion.
Under Pitch Settings, set Target Frequency to match your enclosure tune (see Finding Your Frequency below).
Tap Save Settings.

Live Player Setup

The live player reads from your set input folder, processes tracks ahead of playback, and plays them with no gaps. You do not need to convert files before playing -- the live player handles everything in real time.

Set your Live input folder in Settings (see First Run above).
Go to the Player tab.
Tap Load Folder to list all supported files in your input folder.
Tap any track to start processing and playback.

Queue and +Next

The live player uses a look-ahead queue -- it processes upcoming tracks in the background so playback is always gapless.

+Next (Immediate): Inserts the selected track directly after the currently playing one. It is processed immediately and plays next.
+Next (After Queue): Appends the selected track after all currently queued tracks.
Each track in the playlist shows its status: Processing, Done, Playing, or Queued.

Search

The search screen reads ID3 metadata tags from your files and lets you search by title, artist, album, or genre. Results appear instantly as you type. Tap any result to add it to the queue.

Pitch Settings

These settings control how AudioFlex shifts the pitch of the bass content in your audio.

Setting	What it does	Default
Shift Hi	Enable pitch shifting on the high band (above the crossover point)	On
Shift Lo	Enable pitch shifting on the low band (below the crossover point)	On
Shift Mode	Loudest: auto-detects the best shift per track. Fixed: use a set amount. Semitone: set an exact number of semitones.	Loudest
Target Frequency	The Hz your enclosure is tuned to. AudioFlex shifts bass content toward this frequency.	36 Hz
Frequency Range	Minimum and maximum Hz the auto-detected shift is allowed to land in.	25-60 Hz
Max Hi Semitones	Cap on how many semitones the high band can be shifted.	12
Hi Down Only	Only allow the high band to shift downward in pitch, never up.	Off
Trim Silence	Remove leading and trailing silence from each track before processing.	Off

Crossover

The crossover splits your audio into a high band and a low band. Each band is then processed independently with its own pitch shift, compression, and normalization settings.

Setting	What it does	Default
Cutoff Hz	Frequency at which the signal is split. Audio below this point goes to the low band.	100 Hz
Auto Crossover	Automatically detects the best crossover point for each track based on its content.	Off

// TUNING TIP

For most builds, a crossover between 80 and 120 Hz works well. If your midrange sounds affected by pitch shifting, raise the crossover. If bass content is slipping into the high band, lower it.

Output Processing

Setting	What it does	Default
Stereo Width	Adjust the stereo image width per band. 1.0 = unchanged. Higher values widen the stereo field.	Off
Normalize	Bring each band to a consistent peak output level before it reaches your amplifier.	Off
Subsonic Filter	Remove inaudible low-frequency content below the cutoff. Protects subwoofers from wasted travel.	Off
Filter Cutoff	Frequency below which the subsonic filter removes content.	20 Hz
Filter Steepness	How sharply the filter cuts off. Higher = steeper rolloff below the cutoff.	4

Compression

The compressor reduces the difference between loud and quiet moments in the audio, giving a more consistent output level. AudioFlex applies compression independently to the high and low bands.

Setting	What it does	Suggested Start
Threshold	Level above which compression kicks in. Lower threshold = more of the signal gets compressed.	-12
Ratio	How much the signal above the threshold is reduced. Higher ratio = heavier compression.	4.0
Knee	Smoothness of the transition into compression. Higher = gentler onset.	6.0
Attack	How quickly the compressor responds to a loud signal. Slower attack lets more punch through.	5 ms
Release	How quickly the compressor lets go after a loud signal passes. Too fast causes an audible pumping effect.	50 ms
Makeup Gain	Fixed gain added after compression to restore overall loudness.	0

// NOTE

Threshold values are relative to the maximum digital level. A value of -12 means compression begins when the signal reaches 25% of maximum. Do not enter positive values here.

Settings Profiles

Profiles let you save and recall a full set of settings. This is useful when you switch between builds, change enclosures for a competition, or tune for a specific venue.

Configure all settings for your current build.
In the Profiles section at the bottom of the Settings screen, type a name.
Tap Save As.
To load a saved profile, select it from the list and tap Load.

Batch Converter

The batch converter processes an entire folder of music and writes pre-processed files to your output folder. Use this when you want to load processed files onto a USB drive, or simply have them ready without using the live player.

Set your Convert input and Output folders in Settings → Paths.
Go to the Convert tab.
Tap Convert All or select specific files and tap Convert Selected.
Progress is shown per file. Processed files appear in your output folder as MP3s.

USB Export

After batch converting, copy the files from your output folder to a USB drive. They are standard MP3 files and will play on any head unit or device that supports USB audio without needing AudioFlex installed.

Finding Your Target Frequency

Your target frequency should match your enclosure's tuned resonance -- the point at which your subwoofer and box are most efficient.

Ported box: Use the port tuning frequency from your enclosure design, or measure with a tone sweep and an SPL meter.
Sealed box: Sealed enclosures do not have a single tuning frequency. Start between 30 and 40 Hz and adjust by ear.
Bandpass: Use the upper end of your passband, typically between 35 and 50 Hz depending on your design.

// QUICK METHOD

Use the built-in tone generator (Settings → Tone Generator) to play a sweep from 20 to 60 Hz. The frequency that feels loudest and most pressurized in your cabin is close to your tuning frequency.

Compression Tuning Guide

A good starting point for most builds:

Low band (bass control): Threshold -18, Ratio 4.0, Knee 4, Attack 20 ms, Release 150 ms, Makeup +3
High band (transparent leveling): Threshold -12, Ratio 2.5, Knee 8, Attack 5 ms, Release 80 ms, Makeup +2

Common problems and fixes:

Pumping or breathing sound: Increase the Release time on the affected band.
Bass sounds flat or squashed: Raise the Threshold or lower the Ratio to apply less compression.
Inconsistent volume between tracks: Enable Normalize after compression in Output Processing settings.

Have a question not covered here? Check the FAQ or contact support.