Speed of Sound

    Speed of Sound icon

    Speed of Sound

    by: 103 8.2

    8.2 Users



    Warning: This is heavy on the battery! Please use a car charger.

    Speed of Sound automatically adjusts your music player's volume while you're driving about with your GPS, lowering the volume while driving slowly or at a stoplight, and cranking it up on the highway. This is a feature available in some more expensive cars and sound systems. We're giving it to you for free to use on your phone. Just start up your music player, plug your phone into your car stereo, and open Speed of Sound.

    When you're done with your drive, you can take a look at a map of what songs you listened to and where. Don't worry about tagging that one song-you-can't-remember-the-name-of, just check the map afterwards.


    • Customizable volume levels and speeds
    • Map of songs you listened to on your drive, compatible with Google Music, HTC/Samsung music players, WinAmp, and any player that supports scrobbling
    • Smooth volume adjustment
    • Smart speed filter that avoids random GPS jumps
    • Options to auto-activate when plugged into headphones, charger, selected Bluetooth devices, and when the app starts
    • Tasker integration as an action


    While this app is great to use while driving, it's designed to keep your eyes on the road and not your phone/radio. So don't mess with this app or your phone at all while driving.


    We'd love to hear your feedback. Submit an issue on GitHub, or send us an email with your thoughts.

    Help Translate

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    • Can I use this with my car radio?
    That's what it's for -- as long as you have an aux input and a decent cable to plug into your phone and radio, you're all set. If you don't have that, this won't be of much use unless you want to listen to music on your phone's awful speaker.

    • What are some recommended settings?
    The defaults that come with the application have been tested in the wild and have shown to work well. That said, everyone's tastes are different. We recommend choosing a slow and fast speed that aren't too far apart, because the effect is greater than you might think. Also, many phones get really quiet below a volume of 60, so pick volumes that are not too far apart.

    • This drains my battery!
    Yes, yes it does. Plug your phone into a charger while you drive.

    • Why does my phone seem to "jump" between volume levels?
    Unfortunately, this behavior shows up on many phones. We do our best to make volume changes smooth, but a lot of phones will only change the volume in increments of 5% or so. Not a whole lot we can do here, sorry.

    • Where's the source?
    The code is available under the GPLv2 on GitHub:
    Feel free to fork, file bugs, or stare in awe.


    • Position & GPS - We sorta need this to know how fast you're going.
    • Bluetooth - Used to auto-activate when you connect to a Bluetooth music player.
    • Internet, Accounts, Network, External storage - All for Google Maps alone.

    Feature banner photo CC-BY davebloggs007:

    Tags: speed of sound car audio

    Users review

    from 103 reviews



    Users comments for Speed of Sound

    joe Lenhardt

    by joe Lenhardt

    Sep 24, 2017  |  "Awesome"

    Works exactly as i had hoped.



    Jul 03, 2017  |  "Awesome"

    Thank you for the great app. Simply functional! Highly recommended.

    Josh Phillips

    by Josh Phillips

    Feb 16, 2017  |  "Awesome"

    Brilliant app, works perfectly for me on Bluetooth. It takes some tweaking of the upper and lower speeds and volumes, but I'm glad the options are there for fine-tuning.

    Kent Wilson

    by Kent Wilson

    Jan 21, 2017  |  "Great"

    How about support for JBL Charge 3? It is not shown in list of available devices, so it can't be selected. Because I would rather this app not affect another BT device connecting to both at the same time. But like it otherwise.

    Ahmed Abdou

    by Ahmed Abdou

    Dec 03, 2016  |  "Poor"

    Developer not answering

    Paul s

    by Paul s

    Oct 11, 2016  |  "Awesome"

    Great idea