Optimizing Sound Quality From the Raspberry Pi 3

Posted on Posted in Beginner, Guides

Contrary to what people might say online from time to time, the Raspberry Pi 3 has adequate sound output as long as you are sure to optimize a few settings that might be causing problems. It probably goes without saying that the Pi will never be the equivalent of more expensive hardware that you would find in a dedicated sound system (unless you want to go the route of purchasing a DAC for your Pi), but it is completely serviceable for those of us who want the control offered by using the Pi to drive a sound system instead of proprietary hardware.

In my current sound system, I have installed a Raspberry Pi running the latest version of Raspbian and Mopidy to replace a much more expensive radio tuner and media player, but I have kept the system's original amp. This lets me not drive the Raspberry any harder than I need to (higher volume might introduce some clipping and other sound issues), and I can offload any equalizer or balance functions to the amp which is better equipped for the task.

Even with that in mind, there was some slight tweaking involved in optimizing the Pi's audio settings. 

The following resources are used or referenced in this guide:

Upgrade the Audio Firmware if Necessary

When the Raspberry Pi 3 was released, audio quality was not great. In fact, it was pretty terrible. Most of the reports online talking of terrible sound quality were likely dealing with that issue. Thankfully, however, many of the issues (such as excessive noise and clicking sounds) were able to resolved with firmware updates since the initial release. As a result, one of the first things that you should do when trying to improve the Raspberry's audio quality is to make sure that you have the latest audio firmware. Running uname -a will give you the Linux kernel version and running the /opt/vc/bin/vcgencmd command will let you know what version of the firmware you are currently running. If your version appears out of date, you should update everything using the standard update method:

1. sudo apt-get update

2. sudo apt-get upgrade

3. sudo reboot

 

Check The Sound Settings in Raspbian

Once you're sure that you're running up-to-date software and firmware on your Pi, you should check the audio settings that are available. You can do this using the command alsamixer, which will bring up a GUI of sorts for setting your audio controls.

The primary thing that you will want to do in this interface is to check the Pi's volume levels. Raspbian sets the default volume to 20% of the maximum, and this volume setting is distinct from any volume setting that you will find in Mopidy or your media player of choice. If you're finding yourself turning your speakers, amp, or the media player volume to 100%, you should instead turn up the Raspberry's volume here a sufficient amount to allow the volume levels of the other components in your system to be lowered. Any component that you have pegged at 100% volume is going to introduce clipping and other sound distortions that will make the situation worse.

As you'll note in the image to the left, I have increased my Pi's volume settings pretty substantially - to 88% of maximum volume. This setting allows me to turn my amp and Mopidy to about half volume for comfortable listening. Anything higher from the Pi appears (for me, at least) to introduce distortion in the sound output.

When the Pi was initially set to only 20% volume, I would need to max out my amp in order to get the appropriate volume for music, and the settings had introduced a substantial amount of noise. This setting has removed all such noise, and the audio output is really indistinguishable from the original sound hardware that the much cheaper Pi is replacing.

Consider an Equalizer For Fine-Tuning

While the Raspberry Pi's sound output is never going to be perfect, some very minor fine-tuning might be valuable for your setup. While Raspbian does not have an equalizer installed by defualt, our guide for installing an equalizer in Raspbian will walk you through the process of installing an equalizer and making some minor changes to better balance your sound output. Be warned that since the Raspberry is not a sound powerhouse, any huge changes in the equalizer are likely to introduce their own problems. 

Conclusion

The above settings should help you get solid sound quality from your Raspberry Pi. If, however, you still don't find the resulting sound quality to be sufficient, there are still a number of options that are far cheaper than going out and buying some expensive proprietary sound system. While staying in the Raspberry environment, you can consider adding an external audio chip and DAC (digital-analog converter) to your device to improve the sound quality. We have written a brief guide of some of the options currently on the market. These devices add an additional board to the Raspberry Pi for sound processing and will improve the sound quality and add additional output ports that may better match your current system. Alternatively, we list some of the most popular Raspberry Pi alternatives that may be better suited to your needs.