In the world of digitized sound, two terms are often mentioned when it comes to the recording and play back of audio. Those terms are bitrate and bit depth. Although these two terms are conceptually related and have very similar sounding names, they do not refer to the same action. For example, bitrate means, essentially, the specific speed with which data packets of sound are played back. Thus, if an mp3 is 200 Kbps, it will be processed at 200,000 "bits" during every second of playback. On the other hand, the bit depth refers to the amount of bits used for every sample of sound included in a waveform, which translates into a certain measure of precision in the representation of digital sound. Thus, if a bit depth is very high, the audio is going to be very accurate from its original state.
Bitrate
Quite often tossing around the term "bitrate" may lose meaning in most people’s minds, except for perhaps those in the audiophile tech community. However, in practical terms, bitrate can have an everyday effect on you. For instance, let’s look at music. If a bitrate is really high, this means more space is required on your PC in order to store it. Thus, compact discs are notorious for using up tons of space, they have a high bitrate, which is why these days it is very popular to change audio CD music into another format in order to save space, such as putting all your music onto your iPod, or uploading it to Dropbox. However, when this is done, usually a loss of audio quality is experienced. However, in the past few years, adding more storage space on your PC is a cheap and easy thing to get, translating into more people going back to listening to music at very high bitrates in order to keep the high sound quality. But is there really a big enough difference in a high versus a low bitrate to make you decide to compress or not compress? The answer depends on how you listen to your music. If you use a good pair of stereo headphones, you are certainly going to notice poor quality from low bitrates. If you’re using cheap earbuds, you’re likely not going to notice much difference.
Bit Depth
The same confusion can be said for the concept of bit depth, but again, this term can turn out to have practical aspects to your everyday audio experience. Let’s look at music as we did with bitrate. Firstly, bit depth is measured in bits, or binary digits, basically ones and zeros. So, when a piece of audio happens to increase by one bit, the sound precision doubles. This is an important factor because the number of bits that the audio increases or decreases by is going to directly determine the quality of the music recording and playback. A low bit depth equals an inaccurate recording with a big loss in the more subtle sounds. As an example, suppose you have a big collection of old records or cassette tapes, and you want to take your collection and transfer it all as digital audio to store on your computer. Here, the bit depth is going to be crucial. Not only will a high or low bit depth affect how much sound you get out of the original records and tapes during the transferring process, but also will directly affect how much or little interference from background signals you’ll get.
Getting Great Sound Quality
If you take into consideration the concepts of bitrate and bit depth, you can manage to achieve an ideal sound quality, whether you are recording audio or playing it back. For instance, when considering bitrate, a question that is often asked is, if a higher bitrate means better sound quality, then how high of a rate should be used? The answer lies largely with the human ear itself. As a standard, any bitrate higher than 320 Kbps will rarely be picked up by the human ear, unless you are using very powerful studio headphones, together with a fine-tuned ear, and you are listening to a genre of music such as classical, where subtle differences are inherent. Overall, setting a bitrate of 320 Kbps is perfectly adequate for most people’s listening. For bit depth, getting it at just the right level is largely determined by what type of audio you’re dealing with. For example, if it’s music, bit depth will be important if, say you’re dealing with music that is comprised of quiet, subtle sounds. Also, you’ll want to be sure to achieve the right bit depth if you’re concerned with too much background sound in your recording. Every audio recording you ever make has an inherent amount of what is called noise floor or interference from outside signals. This noise floor level can be minimized by setting a high bit depth. Overall, either recording or on playback, setting a default bit depth of 16 bits is the industry standard, especially when listening to mp3 files. However, you can set the bit depth to a higher level such as 24 bits, or even lower to 8 bits. But remember that whenever you increase your bit depth, although your sound accuracy increases, the amount space needed to store that extra data increases too.