Tech Tips: Bit Depth and Sample Rates

Today’s audio interfaces and music creation software can work with a good selection of bit depths and sampling rates so for those who are not familiar with how they work, it can be downright confusing selecting which to use in a recording.

The key device used in digital recording is called an Analog to Digital Converter – or ADC. The ADC is responsible for taking the electrical voltage of an audio line and converting it to a digital number than can be understood by a computer. By capturing a snapshot of the voltage thousands of times per second, you can get a very good recreation of the original audio signal.

The Essentials

Bit depth is essentially the number of digits in the “digital picture” of each sample. The higher the bit depth, the more dynamic range you’ll get. This means louder peaks, softer quiet sounds and less noise (lower noise floor). The amplitude decay of the wave form is also more natural with higher bit depth.

Sample rate on the other hand represents the number of snapshots or samples taken per second which are measured in Hertz (Hz). The higher you’re sampling rate, the higher the frequencies you’ll be able to capture. This means that you should always strive for a sample rate that can capture at least twice the highest frequency you want to record. A higher sample rate will also make EQ, metering and dynamics processing far more accurate and analog-like.

While it may sound like a great idea to simply use the highest bit depth and sample rates available, there are a few drawbacks. First off, recordings stored 24-bits will use 50% more disk space than those stored at 16-bits. Recording, playing and processing 24-bit samples will also use more CPU resources than 16-bit ones. This means that you won’t be able to work with as many simultaneous tracks in a 24-bit project as you can with a 16-bit one. The quality may also suffer during the conversion process if the digital data needs to be compressed down to its final format.

The Right Choice?

The best way to decide whether the benefits outweigh the drawbacks is by tackling every project to it’s on an individual basis as not all audio recordings benefit equally from using higher bit depths and sampling rates. A higher bit depth is most beneficial when working with music that features vocals recorded with very high quality microphones or that focuses on natural acoustic instruments. If you’re working with music that uses highly compressed or very synthetic sounds, such as pop or rock, the benefits of higher sample rates/bit-depths are much less noticeable. You should always consider whether working at a higher bit depth and sampling rate is justified based on the size and type of project (and if your computer can even handle it).

Putting it to Use

It is very possible to make great sounding recordings using a 16-bit depth and 44.1 KHz sample rate. This has been the format used for CDs for over 15 years and there are many great sounding discs out there that prove the point.

Taken individually, if you want higher quality, the biggest benefits with the least amount of tax to your computer can be attained by using a higher bit depth as opposed to sample rate. With a bit depth of 24 or higher, you’ll have a lot more headroom, the noise floor will be much lower and the stress to your system will be much less than opting for a higher sample rate.

If you decide to record with a higher sampling rate as well, it is a good idea to us a multiple of your final destination format. This means if your final format will be CD (16-bit/44.1 KHz), then sample at 24-bit/88.2 KHz. This will avoid many of the errors that may happen when down-sampling from a higher rate. Keep this rate for all of your post-production. Once you’re done, you can convert the sample rate to 44.1 and finally down-sample the bit depth to 16-bits for the CD.

It wasn’t too long ago that creating a great quality recording required hundreds of thousands of dollars’ worth of studio equipment. Now, pretty much anyone with enough knowledge, dedication and patience can churn out pro-grade tracks in the comfort of their own home. But before you can start, you'll need the right gear as well! Take a look at our selection of Recording Equipment and we'll make sure to get you the best deal around!

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