Boosting Sound Levels of External Mics on Android
Many Android users have experienced issues with getting inadequate sound levels when using external microphones with their devices. The main problem is that external mics often record at volume levels that are too low, resulting in audio that is quiet, muffled, or unintelligible.[1]
This can be frustrating for anyone trying to record high-quality audio with an external mic on their Android phone or tablet. The quiet recordings fail to capture the nuances of the audio source and lack the clarity needed for applications like music recording, podcasting, video voiceovers, interviews, and more.
There are several factors that contribute to Android’s low microphone input levels. Understanding the reasons behind the problem is the first step to boosting the sound and resolving the issue.
Reasons for Low Sound
There are a few common reasons why you may experience low volume from external microphones on Android devices:
Interference: Wireless microphones like Bluetooth headsets can sometimes encounter interference from other devices using the 2.4 GHz band, which can introduce noise and reduce the signal. Sources of interference include WiFi routers, Bluetooth speakers, microwaves, and more. Using the 5 GHz WiFi band and keeping sources of interference farther away can help.
Impedance mismatch: Microphones have an electrical impedance rating that needs to match the input impedance of the device it connects to. If there is an impedance mismatch, the signal strength will be reduced. Professional external mics often have very low impedance, while consumer devices have higher impedance inputs. An impedance matching adapter like the iRig Pre or a preamp can correct the mismatch.
Gain settings: The microphone gain, or volume, may simply be set too low in the OS or recording app settings. Boosting the gain provides more amplification of the mic signal. However, setting the gain too high can introduce background noise, so finding the right balance is key.
Hardware Solutions
One way to boost the sound levels of external mics on Android devices is to use hardware solutions. Two common hardware solutions are using an external preamp or getting a more sensitive microphone.
An external preamp can boost the output signal from the microphone before it reaches your Android device. Adding a preamp between the mic and your phone provides amplification and can increase the overall sound level being recorded. Some popular preamp options to consider are the Shure X2u XLR-to-USB Signal Adapter or the Rode VXLR+ Microphone Preamp Adaptor (1).
Getting a more sensitive external microphone is another hardware option. More sensitive mics require less gain and amplification to achieve higher sound levels. Look for mics with higher sensitivity ratings expressed in decibels. Some good sensitive external mics for Android include the Shure MV88+ Video Kit and the Rode VideoMic Me-L (2).
While software solutions can help, using the right external hardware like a preamp or sensitive mic is key for boosting sound levels when recording audio with an external mic on Android.
Adjust Recording App Settings
The recording app you use on your Android device can directly impact the gain applied to your external microphone’s input. Many recording apps like the built-in Recorder app on Samsung devices have settings to control gain levels.
To boost an external mic’s levels, first open your recording app’s settings. Look for options to increase gain or reduce noise reduction. For example, the Samsung Recorder app has a “Speech enhancement” option that can be disabled to increase gain on external mics (source). Disabling any noise reduction or automatic gain control can also help external mics capture louder volumes.
Try testing different gain levels in your recording app while monitoring your mic’s input levels. Applying too much gain can distort the audio, so find the right balance for your situation. Using a dedicated recording app like Open Camera might offer more advanced options compared to built-in recording apps.
Use Dedicated Recording Apps
One of the best ways to boost the sound levels of external mics on Android is to use apps that are designed specifically for high-quality audio recording with external microphones. Some recommended apps include:
Field Recorder (https://www.soundonsound.com/forum/viewtopic.php?t=86181) – This app is optimized for recording audio with external mics and allows you to adjust gain levels. It provides high-quality recordings in various formats.
USB Audio Recorder PRO – As the name suggests, this app works seamlessly with external USB microphones. It provides professional-grade tools for audio editing and recording.
Lexis Audio Editor – A premium recording app that lets you precisely adjust input gain for optimal quality when using external mics. Useful tools for trimming, normalizing, and mastering audio.
Using an app designed for external mics, rather than just the default voice recorder app, will ensure higher quality recordings and more control over the input levels from your external microphone.
Enable Microphone Boost
Many Android devices have a microphone boost or audio gain setting built into the system settings that can help increase the volume of external mics. To enable this:
- Go to Settings > Sound & vibration > Advanced
- Look for an option called “Microphone boost” or “Extra volume in mic” and toggle it on
- You may also see a slider to adjust the Microphone gain level – move it to the right to increase the boost amount
Enabling this setting specifically boosts the gain from the external mic port, which can significantly increase the volume capture from mics plugged into the headset jack or USB-C port. Just be careful not to set the boost too high, which can cause distortion.
According to this Reddit discussion, the mic boost option appears on many Samsung Galaxy and Google Pixel phones, but may not be present on all Android devices.
Modify Audio Framework
One way to boost the gain on external mics is by modifying the settings in Android’s audio framework. This can be done by connecting to the device via ADB (Android Debug Bridge) and running commands to adjust the input gain parameters. According to Stackoverflow user inder123, the following ADB shell commands can be used to modify the audio framework settings and increase mic gain on a per-device basis:
First, connect to the device via ADB and open a shell:
adb shell
Then set the input gain parameters. For example:
setparam audio_hal.period_size 960
setparam audio_hal.in_period_size 480
setparam audio.gs.in_period_size 960
The specific parameter values that need to be set will vary across devices. Some experimentation may be required to find the optimal gain boost for a given external microphone. Just be careful not to increase the gain too much, which can introduce distortion.
Modifying the audio framework parameters directly via ADB requires root access on the Android device. So this method may not work on all phones. But for devices where root access is available, it provides a way to customize the mic input gain from within Android itself.
(Source: Stackoverflow).
Use DSP Boost App
One option to boost microphone levels on Android is using a digital signal processing (DSP) app. DSP apps apply audio filters and effects to process and modify the audio signal. Some popular options include:
PlayerPro DSP Pack – This free app from PlayerPro works as an add-on and provides various DSP effects. It has options to adjust the microphone gain up to +30dB to significantly boost levels.1
Smart Voice Recorder – This voice recorder app has a dedicated microphone gain control to increase levels on recordings. The maximum boost is +20dB.2
Microphone by WonderGrace – This microphone app allows adjusting the gain with options up to +30dB boost. It works for microphone input and recorded audio.3
The advantage of DSP apps is they can provide significant boosts through software processing alone. The drawback is they may introduce artifacts or distortion at higher boost levels. Overall they provide an accessible option to increase microphone levels without hardware changes.
Consider Hardware Mods
Some users with technical expertise report success from carefully modifying their hardware for a microphone gain boost. This involves identifying the mic input points on the device’s circuit board and increasing the input voltage to the microphone.
According to one source, “For some reason, the microphone volume of my SM-G903F was too low. It had some troubles and repairs, which may have caused it – I don’t know…” (xdaforums.com).
However, hardware modifications like this require advanced technical skills and could potentially damage your device if done improperly. Use extreme caution and only attempt hardware mods if you fully understand the risks involved.
Conclusion
In summary, there are a range of solutions available to boost the sound levels of external microphones on Android devices, from simple to more advanced:
- Adjust the recording app settings – Many recording apps have settings to increase microphone gain/volume which can provide a quick boost.
- Use dedicated recording apps – Specialized apps like Open Camera often have better audio controls compared to built-in camera apps.
- Enable microphone boost – Some devices have a toggle to enable microphone boost/loudness in the sound settings.
- Modify the audio framework – You can modify the audio framework files to increase microphone gain system-wide, but this requires root access.
- Use DSP boost apps – Apps like Volume Booster provide system-wide volume boost by modifying the digital signal processor.
- Hardware mods – For the most control, you can mod the analog hardware circuit to add microphone pre-amps for gain.
With some testing and tweaking, you should be able to find a solution to significantly boost the sound levels of external mics on your Android device.
