Logo Computer scientist,
engineer, and educator
• Software

Simple EQ screenshot

Simple Equalizer for Android

The Android market — or whatever it's called these days — is full of audio equalizer apps, some of them very fancy. I recently came into possession of a Samsung Galaxy tablet with rather shaky audio quality, and I thought that a touch of EQ might help. The Galaxy is not supplied with an equalizer (so far as I can tell), so I went in search of one. I rather expected there to be plenty of free, ideally open-source, implementations around, but what I found surprised me. The free ones are either ad-supported — which I detest — or require elaborate permissions. Why would an equalizer need full Internet access? Not very reassuring.

So I wrote my own. "Simple Equalizer" is only a couple of hundred lines of code — nothing to get too exited about. It's about as trivially simple as an equalizer can be — the whole package is only 20 kB, and half of that is the launcher icons. Source code is available.


Simple Equalizer is available from the Google Play Store (thanks to Alex Novak for hosting this — complaints to me, please, rather than him). Alternatively you can download the app from the link at the end of this page, copy it to your Android device, and then install it using a file manager (Astro, for example). You might need to use the Settings app to allow installations from outside the official Google market. Simple Equalizer requires no permissions beyond control of the audio hardware and, if you're worried about security, you can build it from the source code (also below).


Simple Equalizer is nothing more than an interface to the equalizer controls in the hardware. Since version 2.3, all Android devices have been required to provide such an interface, but they are not required to provide any actual implementation. What's more, the quality of the implementation, even when there is one, varies from vendor to vendor. Simple Equalizer works quite effectively on my Motorola Xoom, adequately on my Samsung Galaxy, and not at all on my HTC One. The HTC has some proprietary audio enhancement thingummy built in, which may explain why it doesn't support the standard Android approach. In all cases, the app appears to work — the sliders move, and I can assure you that the right low-level things are being done. However, some devices simply ignore it, or just don't respond terribly usefully.

'Bass boost' is also a required feature of the Android platform. In principle it can be set to a variable level, but some devices have just 'on' and 'off'. In that case, setting the slider to anything other than zero (far left) is 'off', and anything else is 'on'.

The 'enabled' checkbox applies to the equalizer but not bass boost, which is controlled separately. Bass boost is enabled' whenever the slider is not at zero.

Clicking the 'flat' button turns off the bass boost and sets all the EQ sliders to neutral.

The frequency bands — the number of bands and their centres — is set by the device, and can't be changed. In principle, Simple Equalizer supports up to ten bands, but I've not come across and Android device that provides more than six.

That's it — can't think of anything else to say about such a simple app.

Legal, etc.

Simple Equalizer is distributed according to the terms of the GNU Public Licence, v2.0. That means you may do whatever you wish with it, at your own risk, provided the original author is acknowledged, and source code continues to be made available.


Android APK file
Source code
Copyright © 1994-2015 Kevin Boone. Updated Mar 27 2015