Understanding Sample Rate, Bit Depth & Depth Rate

In the world of music and audiophiles, there are some terms that you might come across that may confuse you. And it goes a step further when it comes to the latter, as there are many ways to enjoy listening to music that is a separate world altogether. It’s like a Pandora’s Box has been opened once you venture deeper in being a true audiophile or if you want to be fairly familiar with how that specific world works for hardcore music lovers.

Terms such as Sample Rate, Bit Depth, and Depth Rate are the technical terms that are commonly thrown around that the ordinary music listener will not immediately understand without basic knowledge.

But, how does one understand those technical terms? Read the article for further details.

Sample Rate, Bit Depth, and Depth Rate: Where to Begin?

When it comes to handling those terms (and possibly other ones too), where does one begin, especially if he/she doesn’t have prior knowledge beforehand? No need to worry about that, as listed below are the basic explanation for each technical term mentioned in the title, along with others that you must know or are part of other terms:

Sample Rate

The first of the three terms mentioned above – this term is a form of measurement (i.e. number of samples per unit) related to music. It also contains the amplitude value of a signal waveform, and it is sometimes called by its other name of sample frequency.

Do take note that a signal waveform is the soundwaves that we hear as sound and music in layman’s terms. Meanwhile, amplitude means the movement length of a specific item, process, or task; in this case, the movement length of a signal waveform.

To have the best audio output and quality from a sound or music file, the sample rate/frequency must be higher in number. And the higher it is, the accompanying file size will also be larger as a result. Don’t be surprised to see the file size of a sound or music file having extremely large file sizes when those are rendered in the highest sample rate possible.

The other technical term named bit depth (also sometimes called depth rate) is heavily related to sample rate, as it means the number of bit samples that can be found on the properties of a sound or music file. This is basically how good or bad the output quality of a sound or music file will be when played. Many common bit depth values are being used by many, which are 16-bit, 24-bit, and 32-bit respectively. The commonly used bit depth used by the sound and music industry is 16-bit, which is commonly found in music CDs.

When measuring sample rates, the used unit of measurement is hertz (Hz). The average hertz measurement of a sound or music file that an average human hearing bandwidth can tolerate is above 40 kHz (wherein the amount of 44.1 kHz is the industry standard).

understanding sample rate, bit depth and depth rate
From MasteringTheMix

Bit Rate

Not to be confused with either sample rate or bit depth; this term basically means the quality of the audio itself. The measurement unit used for bit rate is Kilobits Per Sec (kbps or k); the higher the kbps value, the better audio quality will be achieved.

Do take note that when a sound or music file has higher bandwidth and greater audio quality, it is not surprising for that to have a high amount of kbps value within its properties. Additionally, it will also affect the file size, as the higher the kbps is, the bigger the file size will be.

For the best sound or audio quality, the recommended industry standard for bit rate values is around the range of 64 to 128 kbps; wherein many uses the value of 96+ kbps as the best option for higher bandwidth with good audio quality while having a manageable file size as a result.

From MasteringTheMix

Audio Quality

This basic term refers to both the accuracy and enjoyability of either a sound or music file (mostly the latter in this case) when played from an audio source or player (i.e., mp3 player or mp3 files being played in your smartphone, etc.). The other terms, such as the previously discussed sample rates, bit depth, bit rates, file size, and encoding used, will fall under this main technical term.

Bandwidth

This technical term refers to the speed at which data can be both received and transferred by a device that can read various types of file formats. In this case, the bandwidth here is referring to the sound and music data of an audio file and the speed of the data (the sound and music data) it travels to the file player (i.e., music player, smartphone, etc.). Do note that the transfer speeds for both sending and receiving are highly dependent on the bit rate value.

In order to experience the best listening experience when dealing with both sound and music files, the bandwidth and bit rate of the audio source must be high values. Having high values will result in a good sampling rate. This is the case, especially when it comes to analog playback with 16-bit sample rates. 

There are many recommended rates for bandwidths that both sound and music engineers and makers can follow in order for their respective audio files to achieve the best results when played. For example, such as for MP3 audio files, the recommended bit rate/sample rate ratio would be 96-320 kbps/44.1-48 kHz, while the preferred rate ratios would be 128 kbps/44.1 kHz or 96 kbps/44.1 kHz, respectively.

It All Comes Down to Digital Audio, but What Exactly Is It?

All of those mentioned technical terms that are part of the music world all boil down to one thing, and that is that most of them come from the production and distribution of digital audio. But you may be wondering what precisely digital audio is? How does it work, and how is it produced?

The term digital audio refers to a system wherein it is possible to store, recreate, and most importantly, manipulate music files such as sound and music files. Usually, those mentioned tasks are done via information input/encoding in a computer system.

Additionally, many analog-specific properties such as amplitude and frequency are converted digitally and to be handled in the same computer system where the digital audio can be accessed. Basically, everything has been converted into software-ready files and data that the computer system can read, manage, edit, and store.

This is where the other technical term called audio sample falls into, which we will be checking next.

Digital audio concepts - Web media technologies | MDN
From MDN Mozilla

What Is Audio Sample?

Now, as for this specific term, do not confuse this with the earlier technical term sample rate, as this only refers to the term “sample” itself. That basically means that it is a series of converted data via snapshot measurements.

Samples are gathered at a specific time of an audio wave, where a certain volume of amplitude is recorded. The recorded data is converted by the system handling digital audio into data that is binary in nature, where the system can “digest” it on its end. The said digestion process will help the computer system handling digital audio in handling and processing the data recorded in those samples.

The consumed data is handled by the system by making thousands of measurements in mere seconds, which can be a mind-blowing fact once known. That is done in order to successfully recreate an analog wave, which is basically the sound or music that we hear with our ears.

Audio Sample Rate Clocked at 44.1kHz: Why Is That?

When it comes to the sample rate that many sound and music files have in their properties, the common value amount is always 44.1 kHz. Is there a specific reason for the seemingly clocked (and locked) sample rate? 

Sure, it may be the common industry standard when it comes to consumer audio electronics and goods, but there is a specific reason as to why that specific sample rate is used. Do remember that a human’s hearing can hear frequencies from the range of 20 Hz to 20 kHz. However, anything more than 20 kHz will cause many to not naturally hear higher frequencies of both sound and audio files.

To solve that issue, the implementation of the 44.1 kHz sample rate was introduced and standardized in order for many consumer goods related to audio to be properly used and enjoyed by the buying public. Additionally, when it comes to only 40 kHz, a specialized low-pass filter is needed for the prevention of audible aliasing.

Aliasing happens when the signal waves above a Nyquist frequency (a frequency containing half of the normal sample rate) are not properly recorded by analog-to-digital converters (ADCs) during a system process of making digital audio.

Thanks to the implementation of the 44.1kHz sample rate, frequencies that are hard or nearly impossible to be recorded in the 22.05 kHz range are now possible. 

Why Are There Other Audio Sample Rates?

Now that we have discussed the 44.1 kHz sample rate that is the industry standard, we should check the other audio sample rates that are present in the music market today. Do remember that the higher the sample rate is, the harder for normal human hearing to hear it without the need for specialized tools for hearing it.

First up would be the next alternative standard, the 48 kHz sample rate. This higher rate is used for sound and music files that need to closely replicate the audio that they have inside. It also means a higher audio output and quality, which is perfect for audio files that are part of other multimedia files such as the audio track of a movie file, etc.

Furthermore, sound engineers and music production studios usually prefer this audio sample rate, as it provides more audio clarity, quality, and output than the commercialized 44.1 kHz sample rate. You can hear the difference when you are watching movies in a theater house as most of them use 48 kHz for their audio sample rates, than that of watching the same movie on your television or computer with only a 44.1 kHz audio sample rate.

The other higher audio sample rates such as 88.2 kHz, 96 kHz, 176.4 kHz, and even 192 kHz are used by most sound engineers in their profession, which results in higher Nyquist frequencies which are supersonic in nature as a result.

Is it Possible to Distinguish the Differences of Sample Rates?

The simple answer to this question is basically a yes, but only if you are a trained/seasoned sound engineer who can easily distinguish the differences on their own accord. However, normal everyday citizens without proper experience with it will hardly notice the differences; some will not even notice at all.

Furthermore, the advances in both technology and analog/digital conversion have made distinguishing those differences even harder nowadays. So don’t be surprised that one day it might become impossible to do that in the near future.

Is Having a Higher Sample Rate in an Audio File Better?

You might be wondering now if higher is better in the case of the sample rate of an audio file. In theory, the simple answer for that question will be no doubtfully a big yes. However, in the real world, it is a different answer altogether, with some complications on the side.

As mentioned earlier, the larger the sample rate and the better audio quality used for processing an audio file, the bigger the file size it would be as a result. Imagine how huge the file size would be of an audio file using a 176.4 kHz or even a 192 kHz sample rate. Sure, it will sound amazing, but it will eat up a lot of storage space as a downside.

Additionally, many computer systems handling digital audio, by default, automatically convert audio files to either 44.1 kHz or even 48 kHz to balance everything out. And when it comes to handling multimedia projects such as making a video, it is much easier and more valuable to have an audio track in 44.1 kHz than anything else that is higher, as it will be harder and longer to render (the process of which the computer completes the production of a video) overall.

This is also the case when choosing the correct bit depth of an audio file that you are working on. Having either 16-bit or 32-bit can be crucial to the audio output and quality of the project you are working on.

However, the commonly used bit depth for everyday usage and consumption is 16-bit, as many sounds and music that we hear every day fall into that range. Higher bit depths such as 32-bit are usually used for expensive and higher audio projects such as movie audio tracks and sound effects.

Still, it is up to you and what kind of audio-related project or process you are handling when it comes to choosing the right audio sample rate.

Conclusion

Having more knowledge about those audio technical terms can help you enjoy more when it comes to listening to music and hearing sounds. This is especially helpful to people who have a career connected to music or just simply their love for music as a whole.

Additionally, it can help you learn more about how the world of audiophiles works, especially for those who have already dived deep into that specific world of enthusiasts and collectors alike. Also, if you are the kind of person who wants the best when it comes to consuming multimedia, especially when it comes to music, having some knowledge about sample rate and bit rates can help you distinguish if the music you are listening to is of high quality or not.

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