Audio formats and frequencies: The science behind perfect sound
In the world of hi-fi audio, sound quality is paramount. However, for many, understanding the different audio formats and frequencies can be confusing. In this article, we'll explore in depth the most common audio formats and how frequencies affect our listening experience, helping you make more informed decisions about your equipment and audio files.
What do audio file formats mean?
Audio file formats are simply ways of storing sound information.
When raw audio data is output from the audio interface through the analog-to-digital converter, pulse code modulation (PCM) is used to encode it.
To reproduce this modulation by coded impulses through a physical system, it is necessary to organize the information in a file that can be reproduced.
Types of audio file formats are distinguished by the containers that hold them and the data compression methods they use to keep PCM streams in order.
Although these formats represent the same information, they differ in quality and storage space.
Some audio formats include unique features, such as metadata storage, which provides information about the content or file.
A closer exploration of PCM
As we mentioned previously, PCM, or Pulse Code Modulation, is the method by which we transform analog signals into signals that can be used in the digital domain. This conversion process involves encoding waveforms with a certain bit depth and sampling rate. Bit depth refers to the number of bits per sample, while sample rate indicates the number of samples taken per second.
Most digital formats typically have a 24-bit/44.1 kHz sampling rate.
The three main sets of audio formats can be understood simply by dividing them into three main categories:
- Uncompressed audio format
- Lossy compressed audio format
- Lossless compressed audio format
Comparison between lossy audio files and lossless audio files
Within the vast world of audio files, there are lossy and lossless formats, which are distinguished by the degree of data compression.
Data compression is a practical tool that allows you to store more files on a hard drive. It's like condensing several individual files on your computer to create one smaller file. It is important to note that this type of compression differs significantly from the audio compression process used in music mixing or production.
Contrary to popular belief, there are data compression methods that manage to reduce the size of files while preserving all the integrity of the information present in the audio stream. These audio formats are known as lossless compressed formats.
On the other hand, there are lossy compressed formats, which remove data from the audio stream with minimal impact on sound quality. However, it is important to keep in mind that this type of compression involves the loss of information.
Comparison between compressed audio formats and uncompressed audio formats
Audio formats that have not undergone any type of compression are known as uncompressed audio formats.
These formats act as containers that hold audio data in its raw state, without any reduction in its quality or size. Although these files may take up more space compared to compressed files, they offer the highest level of detail and auditory fidelity.
They are widely used in various stages of musical production, such as recording or mixing.
However, it is important to note that not all uncompressed audio files are identical. The quality of these files varies depending on the process of converting the analog signal to digital. The various types of analog-to-digital converters employ different levels of precision and accuracy.
By using a higher bit depth and a higher sample rate during the conversion process, more information can be captured.
Bit depth refers to the number of bits of information present in an audio sample, which is directly related to the resolution of each sample. For example, a CD uses 16 bits per sample, while DVD audio uses 24 bits per sample.
The precision with which an analog-to-digital converter can measure the amplitude or volume of the signal is what determines the bit depth.
Understanding bitrate
Bitrate refers to the amount of data a file produces per second.
When listening to digital audio, it is common to find files that have the "kbps" mark at the end to indicate the associated bit rate.
Each second of an audio recording contains a specific number of bits. This amount is calculated as "data per second."
The bit rate, which represents the amount of data encoded each second, is used to evaluate the quality of a file format.
Although files with lower bit rates result in more efficient compression and smaller files, audio quality may be compromised. In the early days of hard drives and computers, when storage space and bandwidth were limited, it was necessary to use lower bit rates.
In today's digital environment, where storage and bandwidth are less of a concern, it is recommended to use the highest possible bitrate when working with compressed formats.
For example, for an MP3 file, the high quality standard is usually 320 kbps. With this high quality setting, it can be difficult to differentiate between compressed audio and uncompressed audio when listening casually.
High resolution audio
So, you may be wondering, what about high quality audio?
High quality audio is characterized by not having a uniform standard.
However, when talking about high-quality audio, producers and engineers often refer to audio files with sample rates or bit depths higher than the CD standard, which is 16-bit/44.1 kHz.
For us, high-quality files are in formats such as 24-bit/48 kHz, 24-bit/96 kHz, and 24-bit/192 kHz.
The advantage of high-quality audio files is that they contain much more information than low-quality files or compressed audio, which results in better sound quality. Although these files take up more storage space, it can be worth it if you are looking for quality.
Some of the most popular high-quality audio file formats are WAV and AIFF, although formats such as FLAC and ALAC also exist.
Popular audio file formats
Although there are a variety of audio file formats available, some are much more common than others.
On your journey through the world of music production, you'll likely come across only a few types of audio formats. Here are some of the main ones you should know:
MP3
The most commonly used audio format for casual listening is MP3.
In the early 2000s, MP3s gained popularity thanks to the file-sharing revolution started by Napster. In October 2001, Steve Jobs surprised the public by pulling out of his pocket a small device with 1,000 of these files.
The attractive thing about MP3s was the ability to store a large amount of information in such small containers without losing sound quality.
Of course, one of the reasons MP3s became the epicenter of illegal music downloads was their ease of encoding from CDs.
Today, MP3s remain one of the most widely used audio file formats. Even major digital music download stores, such as Bandcamp, continue to use MP3 as their primary format.
They are extremely convenient for storing music on tablets or portable playback devices, and work on almost all playback devices.
The bit rate at which MP3s are recorded can have a big impact on sound quality. For example, an MP3 encoded at 128 kbps will have lower sound quality than an MP3 encoded at 320 kbps.
AAC
AAC files are lossy compressed audio files developed by several digital technology companies, such as Bell, Microsoft, and Dolby. The premise behind the creation of the AAC format is its supposed greater efficiency compared to MP3.
If you've owned an iPod at some point, chances are you've listened to audio files in AAC format, since the iTunes store uses this format.
AAC is considered to be slightly more efficient than MP3, and many argue that it offers better sound quality. It is used by the Apple Music streaming platform, as well as YouTube.
WAV/AIFF
WAV (Waveform Audio File Format) files are one of the most popular lossless and uncompressed audio formats. AIFF files are often preferred over WAV files as they both contain the same amount of information and function in a similar way.
Both are based on PCM (Pulse Code Modulation), which is one of the simplest methods for audio storage in the digital realm.
The difference is that WAV files were developed for PC users by IBM and Microsoft, and that is why they are more common on Windows platforms. WAV is also the standard encoding format for CDs.
On the other hand, AIFF (Audio Interchange File Format) files were developed as an alternative to WAV for Apple users. Although their use is not as widespread as that of WAVs, they are more compatible with metadata. Unlike WAV files, AIFFs allow the inclusion of data such as song titles and artwork.
Both formats use PCM, which means there is no compression or loss of information. If you work with Logic, you'll likely come across AIFF files as one of the few options available.
The main drawback of these formats is their large size. A 16-bit/44.1 kHz CD-quality file takes up approximately 10 MB per minute of audio.
Despite this, they are preferred formats by audio engineers who seek to preserve maximum sound quality.
FLAC/ALAC/WMA
FLAC files are open source lossless compressed audio files. This audio file format was one of the first to become popular among lossless formats. FLAC is an abbreviation of Free Lossless Audio Codec. These files are about half the size of a standard WAV or AIFF file at the same sample rate.
Despite their small size, FLAC files maintain lossless audio quality. They even surpass the quality of a standard CD, as they can offer up to 32-bit/96 kHz resolution.
The advantage of FLAC files is that they allow users with storage limitations on their devices to enjoy lossless audio. Although it may be difficult for the average listener to distinguish between FLAC and MP3, many audiophiles debate the differences.
ALAC is very similar to FLAC, but was developed by Apple. These acronyms correspond to Apple Lossless Audio Codec.
ALAC is a great alternative to FLAC for Apple Music or iOS users. However, it is important to note that ALAC files tend to be slightly larger than FLAC files.
The option available for Windows users is the WMA format, which refers to Windows Media Audio. This format was created by Microsoft specifically for the Windows operating system. WMA has the ability to handle sample rates up to 24-bit/96 kHz, reproducing audio without data loss.
It is important to note that Microsoft has also developed a variant of WMA with loss of quality. This option can be beneficial for Windows users who want to reduce the size of their audio files without sacrificing too much quality, compared to the MP3 format.
OGG Vorbis
OGG Vorbis files, also known simply as the Vorbis format, are lossy compression files created as an alternative to AAC and MP3. The particularity of this format is that it is not subject to any patent. The Spotify streaming service uses the OGG Vorbis format at 320 kbps.
"OGG" doesn't actually mean anything, and is not a compression format itself. Rather, it is a multimedia container designed to host a variety of compression formats. The term "OGG Vorbis" commonly refers to files containing the Vorbis format.
Vorbis emerged in 2000 and became popular due to its association with open source software. Compared to most lossy compression formats, it offers superior audio quality.
Other less common types of audio formats
DSD
DSD is a high-resolution audio format used in Super Audio CDs. It comes in various variants such as 2.8, 5.6 and 11.2 MHz. This format offers high-fidelity uncompressed audio files, ideal for a quality listening experience, although it is not very practical for streaming.
The distinctive feature of DSD files is that they use only one bit, unlike uncompressed files, which use bit depth and sample rate. For DSD files, this single bit is sampled 2.8 million times per second to recreate the file.
DSD files are comparable to high-resolution 24-bit/96 kHz files in terms of sound quality. However, despite their exceptional quality, they are not widely compatible with many operating systems. In fact, a third-party D/A converter is required to use a DSD file on Mac or Windows systems.
For those willing to invest in an external D/A converter and appreciate the quality of single-bit sampling 2.8 million times per second, the DSD format could be interesting.
MQA
MQA is another lossless high-resolution audio compression format, designed for more efficient streaming. Tidal uses MQA for high-resolution streaming, and it is also used on many CDs.
How to select an audio file format
So, after digesting all this information about audio file formats, what do you do with it?
Choosing the appropriate audio format for each need can make a big difference.
The choice of audio format will depend on whether you value sound quality or storage space more, as well as the devices you use for playback.
If you are a casual listener, you may be satisfied with compressed file formats with high bit rates, such as AAC or MP3 at 320 kbps.
On the other hand, if you are a music producer or recording engineer, you will probably prefer to use uncompressed audio files with high sample rates. 24-bit/48 kHz WAV and AIFF formats are popular options in this case.
However, for serious and critical listening, many audiophiles suggest the FLAC format.
In conclusion, the information provided is invaluable for those looking to improve the audio quality on their devices. Understanding the different high-quality audio formats and the importance of having a suitable DAC for their playback is a fundamental step in this process.
When making the decision to explore these formats, it is essential to equip yourself with a DAC that allows optimal encoding and playback of these files.
For more information about products that meet these needs, we invite you to consult the following link https://ifi-audio.com.mx/.
Ultimately, investing in a high-quality audio system can significantly transform your listening experience and music enjoyment.
