How to Choose the Sample Rate and Bit Depth in a DAW
When you’re ready to create a new song or audio project in a DAW (Digital Audio Workstation), you may be prompted to customize the settings for that project before you can actually begin working on it. These settings often include a choice of templates, naming the project, selecting the location to store it, and a varying collection of additional settings depending on which DAW you’re using and the type of project you’ll be working on. While some of these settings are fairly straightforward, there are two that may be less familiar to you but combine to have a significant impact on the audio quality you’re able to achieve and the performance of your computer as you work: Sample Rate and Bit Depth. Sure, you can just stick with their default settings and hope for the best (Been there, done that!), but the defaults may not be the optimal settings for your specific project or computer. Gaining an understanding of Sample Rate and Bit Depth will allow you to make an informed decision and open the door to both better sound quality and a smoother production process.
If you’re new to recording you might be wondering what these terms even mean, so let’s quickly go over a few audio basics to get you up to speed. As you may know, sound travels in waves, which are represented by the waveforms displayed in DAWs. In the real world, these waves are continuous, uninterrupted signals. Computers, however, don’t process information that way. The original “analog” signal must first be converted to digital before we can work with it in a DAW. Audio interfaces perform this conversion by taking digital snapshots (Samples) of the analog audio signal. Sample Rate determines how many of these snapshots are taken per second, and is measured in kilohertz (kHz). Sample rate settings typically range from 44.1 kHz (44,100 samples per second) to 192 kHz (192,000 samples per second). The standard sample rate for CD releases is 44.1kHz, and audio for video projects has a standard of 48kHz. Sample rates above 44.1kHz (combined with a Bit-Depth of at least 24) are often classified as “High-Resolution”, although it’s becoming more common to reserve that distinction for 96kHz and above.
· “Hertz” is defined as “cycles per second”, or in this case snapshots per second.
· As a reminder for those of us who don’t typically use the metric system, the prefix “kilo” multiplies the amount by 1000 (e.g., 1kHz=1000 Hertz).
Bit Depth determines the amount of information captured in each sample, establishing the available dynamic range (which is the difference between the loudest and quietest signal levels) and the number of volume level values that can be recorded. The term “Bit Depth” is sometimes used interchangeably with “Resolution” --in fact, Presonus Studio One 6 replaces “Bit Depth” with “Resolution” in its settings menu. Most DAWs and audio interfaces offer choices of 16-bit and 24-bit depths, and some also provide 32-bit and higher options. The higher the Bit Depth, the greater the dynamic range. The greater the dynamic range, the more headroom and the lower the noise floor. In practice, this reduces the risk of digital clipping distortion and unwanted noise. A bit depth of 32 offers an enormous dynamic range which can prevent the damaging effects of digital clipping that occur when a signal is recorded too loudly, and negate the rising noise floor when boosting a signal that was recorded too quietly. This makes it a valuable option for location recordings where audio levels are unpredictable and fluctuate too quickly to adjust the input gain. For most studio recordings, though, 24-bit is the standard for both music and video audio. It provides ample dynamic range and produces smaller file sizes than 32-bit. If the gain is set properly for recording, clipping is not an issue. There is not believed to be an audible difference in sound quality between 24-bit and 32-bit audio. While 16-bit is the standard for CD releases, some now consider it inadequate for the recording, mixing, and mastering phases of production. This is mostly due to potential distortion and audio artifacts that may occur during the digital engineering process. These technicalities go a bit beyond the intended scope of this writing, but if you wish to learn more I’d recommend researching “audio aliasing” and the “Nyquist Theorem”.
Higher Sample Rate and Bit Depth settings achieve greater audio fidelity by reproducing the original analog sound waves more accurately. It may be helpful to picture each Sample as a plot point on a graph. Higher Sample Rate and Bit-Depth settings add more (and more precisely placed) plot points to the graph. The more plot points there are, the more faithfully the original sound wave is recreated when they are connected. (Remember those connect-the-dot puzzles you did as a child…or adult? Hey, I’m not judging). The downside of higher settings is that they are more taxing on CPU and create larger file sizes, so choosing the best settings is often a compromise between the settings you’d like to use and the limitations of your equipment.
How do you choose the best settings for your projects? There are several factors at play, and I’d recommend the following steps to help sort them out. First, check your audio interface and DAW to see which settings are available. Next, evaluate the limitations of your computer’s CPU and available storage by doing some test recordings at various settings to see how your CPU responds. Then compare the resulting file sizes and audio quality differences. Keep in mind that you’ll probably do some additional processing that will further tax your CPU, so if it’s already laboring it’s probably a good idea to choose lower settings. Once you’re familiar with the limitations of your equipment, you can factor the project type into the equation. A classical music recording may benefit from the highest settings and audio quality your computer can muster, but a gritty rock song probably doesn’t need to be that pristine. Likewise, a professional voiceover will likely have higher standards than a startup podcast. A bit of online research should reveal which settings are typical for projects like yours, and you can use those as a starting point.
Sample Rate and Bit Depth work together to determine the sound quality limits of your music or audio project, and impact your computer’s performance. A little time spent testing various settings could improve your sound or workflow considerably. I’ve found that 48kHz, 24-bit usually works well for me while recording and mixing music. I can then choose to master at the same settings or lower to suit my preference or to match any requirements for public distribution. Although 44.1kHz, 16-bit may not be the optimal setup for recording and engineering today, if these are all your computer can handle then go ahead and use them. You can still produce quality recordings with these settings. If your computer can do more, I recommend first increasing the Bit Depth to 24, then the Sample Rate to your preference. Above all, it’s the quality of the music that’s most important.
Additional notes:
· If you plan to use pre-recorded loops in your project, check to see if your DAW is able to convert their sample rates. If not, choose a Sample Rate that matches the loops’ so that they play back at the correct speed.
· Remember that you can convert a higher-quality audio file to a lower-quality file, but converting upwards won’t improve the sound quality. Therefore, it’s generally recommended to record and mix at higher settings when possible.
Which Sample Rate and Bit Depth settings work best for you? Let us know in the comments below.