How to remove background noise from audio file in Android?

Background noise refers to any unwanted sounds that are picked up during audio recording. This could include ambient sounds like traffic, appliances humming, computer fans, or echoes from room acoustics. Removing background noise can greatly improve the quality and clarity of audio recordings.

There are a few main methods for removing or reducing background noise from audio files on Android devices:

Use built-in noise suppression settings in Android’s audio settings menu

Download third-party noise suppression apps
Apply noise reduction filters in audio editing software
Use noise gate and noise profile tools during recording

Edit audio files in professional editing software

By applying one or more of these techniques, you can effectively clean up the background noise in audio recordings on your Android device. This will lead to clearer, more professional sounding audio.

Check Audio Settings

The audio settings on your Android device like microphone gain can affect the amount of background noise picked up while recording. Higher microphone gain amplifies all sounds, including unwanted background noise. Reducing the microphone gain can help eliminate unwanted background hums, echo or white noise.

To adjust the microphone gain on an Android device:

Open the Settings app and go to Sound & vibration > Advanced
Tap on Microphone and switch from High sensitivity to Normal sensitivity

Lower the microphone volume levels if needed to reduce background noise pickup

Additionally, enabling noise suppression in your Android audio settings can help reduce ambient noise. Go to Sound & vibration > Advanced and toggle on Noise suppression. This analyzes incoming audio and filters out background noise.

You can also try using wired headphones with an inbuilt microphone for recording. The microphone is closer to the mouth so picks up less ambient noise. Make sure to enable noise suppression for best results.

Adjusting these settings appropriately blocks out unwanted background interference so your voice audio sounds crystal clear. Monitor the sound levels and re-adjust as needed for optimal quality.

Use Noise Suppression Apps

There are several excellent noise suppression apps available for Android that can help remove background noise from audio recordings and calls. Two of the most popular and effective options are Krisp and RNNoise.

Krisp uses AI-powered algorithms to detect and suppress unwanted noise in real-time during calls. To use Krisp:

Download and install the Krisp app on your Android device.
Allow the app the required permissions to access your microphone.
Open the Krisp app and connect your headphones if you want to use Krisp during calls.

Make or receive a phone call as normal. Krisp will automatically detect and suppress background noise.
Adjust the noise cancellation intensity in the Krisp app settings if needed.

RNNoise is an open source noise suppression library developed by Mozilla. It can remove background noise in recordings. To use it:

Download and install an audio editing app that supports RNNoise filters like WavePad.
Import your audio file into the app.
Apply the RNNoise filter to remove background noise.

Adjust filter intensity if needed to optimize noise reduction.
Export the cleaned audio file.

Following these steps will allow you to leverage powerful noise suppression apps to remove unwanted background noise on Android devices.

Noise Reduction Filters

Noise filters like low-pass filters are a common technique for reducing background noise in audio recordings. They work by attenuating the higher frequencies while allowing lower frequencies to pass through. Since background noise tends to occupy higher frequencies, applying a low-pass filter can help reduce that hissing, humming or static noise in your audio (Noise Reduction using Filters).

You can apply noise reduction filters in audio editing software like Audacity. Simply open your audio file in Audacity and go to Effect > Noise Reduction. Click Get Noise Profile to sample a section that only contains background noise. Then select the entire track and go to Effect > Noise Reduction again. Adjust the sliders for Noise Reduction, Sensitivity and Frequency Smoothing to filter out the background noise (Noise and noise reduction using filtering). Start with moderate settings and preview the audio to ensure you are not distorting or muffling the speech/music while removing the noise.

Noise Gate

A noise gate is an audio effect that silences audio signals below a set threshold. The gate ‘opens’ to allow sounds louder than the threshold to pass through unchanged, while sounds quieter than the threshold are reduced in volume or eliminated completely (Wikipedia).

Noise gates work by analyzing the amplitude or loudness of an audio signal. When the signal level drops below a configured threshold, the gate will close and silence the audio. Once the signal rises above the threshold again, the gate opens back up to let the sound through.

Noise gates are very effective at removing constant background noise like hiss or hum. They can also tighten up the sound of percussive instruments like drums by silencing the natural decay or ‘ringing’ of the drum hit.

To use a noise gate:

Set the threshold level so it is just above the level of the background noise you want to remove.
Adjust the attack time, which controls how fast the gate reacts when a sound exceeds the threshold.
Set the release time, which determines how fast the gate closes after the sound drops below the threshold.

Use shorter attack and release times for percussive sounds, longer times for vocals and sustained instruments.
Enable the gate for the track you want to clean up, usually on individual instruments rather than the full mix.
Listen carefully and tweak the settings until just the unwanted noise is reduced while preserving the desired sounds.

With the right settings, noise gates can significantly improve the clarity of recordings by reducing background noise. Just take care not to cut off the attack or decay of musical sounds with overly aggressive gating.

Noise Profile

One of the most effective ways to remove background noise from an audio file in Android is by creating a noise profile. A noise profile allows you to sample the background noise to identify its characteristics. Audacity and other audio editing software use the noise profile to accurately target just the background noise in the recording without affecting the rest of the audio.

Here are the steps for capturing a background noise profile in Audacity on Android:

Open the audio file in Audacity and isolate a portion that only contains background noise you want to remove. Make sure there is no speech or other sounds in this selection.
Go to Effects > Noise Reduction. Click “Get Noise Profile”. This samples the selected audio and builds a profile of the background noise.
Select the entire clip you want to clean up. Go back to Noise Reduction and click “OK”. This will remove noise based on the profile.

You can adjust the noise reduction intensity for more or less aggressive filtering. Preview the changes before applying.

The noise profile is key for targeted background noise removal. By properly sampling just the noise itself, you teach the noise reduction effect exactly what sound to filter out. This can help clean up recordings without affecting the rest of the audio quality.

Audio Editing

One way to reduce background noise in an audio file is to edit out any silent sections. Background noise can often “fill in” the gaps when there is no speech or primary audio occurring. By removing long pauses or silence between words and sentences, there is less opportunity for that background noise to be noticeable.

When editing audio to remove background noise, first identify sections where there is silence or minimal foreground sound. Cutting out these quiet sections can dramatically reduce the amount of background noise that is heard.

Some tips for editing audio to minimize background noise:

Use audio editing software like Audacity or Adobe Audition to visualize the waveform and see silent sections.

Slice out any gaps longer than 0.5 seconds between words or sounds.
Carefully listen and ensure you are not removing natural pauses that should remain.
Add very brief (0.1-0.3s) crossfades between edited sections to smooth out transitions.

After removing silence, consider running additional noise reduction filters on the remaining audio.

With precision editing to eliminate excessive silence in an audio track, the background noise can be significantly reduced for a cleaner sound.

Recording Techniques

One of the most effective ways to reduce background noise while recording audio on your Android device is to use proper recording techniques. Here are some tips:

Use a unidirectional microphone that picks up sound from only one direction. This prevents the mic from capturing ambient noise coming from the sides and rear. Point the mic directly at the sound source to maximize signal pickup.

Get close to the microphone when recording your voice or other audio source. The proximity effect boosts bass response as you get closer to the mic. This allows you to capture a strong signal before any background noise enters the mix.

Position the microphone as far away from the noise source as possible. The further the distance, the lower the noise volume. If needed, treat the recording space by hanging blankets or portable acoustic panels to absorb sound reflections.

Enable any background noise reduction features your Android device may have. Many Android phones have built-in noise suppression that can be activated in the audio settings.

These techniques allow you to capture clean recordings with minimal background noise. Experiment with mic placement and room setup to optimize the signal-to-noise ratio.

Room Conditions

The physical characteristics of a room can cause various audio issues that lead to unwanted background noise in recordings. Hard, flat surfaces like walls and floors can create problematic echoes and reverberation that get picked up by microphones (Yang, 2019). These effects are caused by sound waves bouncing off the surfaces and interfering with direct sound from the audio source.

There are a few tips to optimize room acoustics and reduce excess reverberation:

Add sound absorption materials like acoustic panels, curtains, and carpets
Avoid bare, hard surfaces which reflect sound

Use furniture and textiles to break up open spaces
Place absorptive material strategically around microphone setups
Record in rooms with irregular shapes to reduce standing waves

Proper acoustic treatment can significantly cut down on unwanted reflections and background noise. Paying attention to room conditions is crucial for achieving clean, professional-sounding recordings free of excess noise.

Conclusion

There are a few key methods for reducing background noise in audio files on Android devices. First, adjusting the audio settings and enabling noise suppression can help filter out ambient sounds. Installing a dedicated noise reduction app provides more advanced noise cancellation options. Audio editing apps allow you to apply noise gate and noise profile filters to precisely target background noise.

It’s important to reduce unwanted background noise in order to deliver clear audio quality. The techniques covered in this guide, from built-in settings to downloadable apps, provide Android users with various ways to clean up the audio recordings from their device’s microphone. With some experimentation, you can find the right approach to effectively minimize background noise for your situation.