Temporal Masking in MP3

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Temporal Masking in MP3

Let’s talk about Temporal Masking in MP3

Temporal masking in MP3 is a game-changer for audio compression. Imagine you’re at a loud concert, and someone whispers next to you; you likely won’t hear them due to the louder sounds around you. MP3 encoding uses this principle to create smaller, more efficient files without compromising audio quality. I’ve seen firsthand how understanding temporal masking can enhance audio processing, especially for people trying to maximize storage or bandwidth without losing sound clarity. Let’s dive deep into how temporal masking works, why it’s so effective, and how it contributes to the MP3 format’s popularity.

Understanding the Concept of Temporal Masking

Temporal masking relies on a natural limitation in human hearing. When a loud sound occurs, it “masks” any softer sounds that happen shortly before or after it. This concept allows MP3 encoders to eliminate certain sounds that we wouldn’t notice anyway. When I first worked with audio files, I found that removing imperceptible sounds significantly reduced file size, and temporal masking does this efficiently by focusing on sounds that we truly register.

Why Temporal Masking is Essential for MP3 Compression

Compression is crucial for reducing file sizes in today’s digital world. Temporal masking plays a central role in MP3 compression by cutting out unnecessary data. For example, in a complex piece of music, many faint details would go unnoticed because they are hidden by louder parts. Removing these masked sounds through temporal masking lets MP3s keep essential audio data, which saves space while retaining quality. This technique is foundational to making MP3 one of the most popular audio formats.

How Temporal Masking Differs from Frequency Masking

While temporal masking is about timing, frequency masking is about pitch. Frequency masking occurs when a loud sound within a particular frequency range makes it hard to hear quieter sounds within that same range. I’ve noticed in audio engineering that using both masking techniques together results in smaller files that still sound true to the original recording. Temporal and frequency masking are like two sides of a coin, working together to maximize compression without sacrificing audio integrity.

Temporal Masking’s Impact on Different Music Genres

Not all music is affected by temporal masking in the same way. For example, classical music, with its vast dynamic range, may not be ideal for aggressive masking techniques. In contrast, pop or electronic music, which often has a steady volume level, may compress more efficiently. From my experience, temporal masking tends to work well with most genres, but the subtleties of softer genres require a careful approach to prevent audible degradation.

Potential Drawbacks of Temporal Masking in Low-Bitrate MP3 Files

While temporal masking is effective, low-bitrate MP3s can sometimes reveal its limitations. The lower the bitrate, the more audio data is discarded, making the masking more noticeable. This can result in a “washed-out” or less detailed sound. Higher bitrates, on the other hand, preserve more of the original sound while still using masking techniques to keep file sizes manageable. When I’ve used low-bitrate files for streaming, I’ve often found the masking effects more pronounced, especially in genres with delicate nuances like jazz or folk.

Temporal Masking in Other Audio Formats

Temporal masking isn’t exclusive to MP3; it’s used in AAC, OGG, and many other formats. This technique is universal in audio compression because it’s so effective. Each format, however, has its own approach to applying masking, depending on its design goals and target users. When working with these various formats, I’ve noticed that temporal masking works particularly well in AAC, which is known for maintaining quality at lower bitrates. This adaptability makes temporal masking an invaluable tool in digital audio compression.

Advanced Insights: Beyond Basic Temporal Masking

Beyond simple masking, advanced algorithms can dynamically adjust the intensity of temporal masking based on the audio’s complexity. In my experience, these adaptive methods allow for higher quality at lower bitrates. Some audio codecs even fine-tune masking based on the listener’s hearing profile, a fascinating application that takes masking to a personalized level. By diving deeper into these nuanced adjustments, we can see how temporal masking continues to evolve, making modern audio compression even more efficient.

Latest Words on Temporal Masking in MP3

Temporal masking remains a key factor in MP3’s widespread use, enabling smaller files while maintaining good sound quality. With today’s advancements, it’s more sophisticated than ever, allowing us to enjoy high-quality audio even in compressed formats. If you’re looking to get the most out of your MP3 files, Mp4Gain offers a solution to enhance audio clarity by ensuring optimal encoding.

Frequently Asked Questions about Temporal Masking in MP3

What is temporal masking in MP3?

Temporal masking in MP3 is an audio compression technique where sounds occurring within a short time frame of a louder sound are masked, or made inaudible to the human ear. This allows MP3 encoders to remove parts of the audio without affecting perceived quality, making file sizes smaller.

How does temporal masking improve MP3 quality?

Temporal masking helps improve MP3 quality by removing sounds that are not easily detected by human hearing, focusing only on the most important audio data. This enhances audio clarity while reducing file size, providing a high-quality listening experience even in compressed formats.

What is the difference between temporal masking and frequency masking?

While temporal masking hides sounds based on timing, frequency masking works by concealing sounds that fall within the same frequency range as louder sounds. Both techniques are used in MP3 compression to optimize audio quality and reduce file size.

Why is temporal masking used in audio compression?

Temporal masking is used in audio compression to eliminate sounds that listeners likely won’t hear, allowing for smaller file sizes without compromising sound quality. This efficiency is crucial for formats like MP3, where maintaining quality with reduced data is essential.

Does temporal masking affect all types of music equally?

Temporal masking can have different effects on various music genres. For instance, fast-paced genres like electronic or rock may experience more audible compression effects compared to slower genres, where subtle nuances are less likely to be masked.

Can temporal masking reduce sound quality in MP3s?

While temporal masking is designed to maintain sound quality, excessive compression can sometimes lead to noticeable losses in detail. However, with standard MP3 compression settings, temporal masking typically preserves sound quality effectively.

Is temporal masking used in other audio formats besides MP3?

Yes, temporal masking is commonly used in many compressed audio formats, including AAC and OGG. This technique is essential across various formats to reduce file sizes while keeping the audio quality as high as possible.

How does temporal masking affect low-bitrate MP3 files?

In low-bitrate MP3 files, temporal masking effects can become more apparent as more data is removed, potentially leading to a less natural sound. Higher bitrates typically allow for better masking and preservation of audio quality.

Comments:

I didn’t realize how much temporal masking impacts the audio quality of MP3 files. This article explains so much! Thanks for sharing.

Been looking for this info. Always wondered why some sounds just blend in, and now I get it’s the temporal masking effect!

Great article. I learned a lot about MP3 audio compression and how temporal masking is used. Never saw it explained so clearly before.

Good read, but I’d love to see more on how temporal masking affects specific genres like metal or jazz. Very curious about that.

This is very informative. The way temporal masking works in MP3 files really changed how I look at compressed audio formats.

Can anyone explain how this works with low bit rate MP3s? Are the temporal masking effects more noticeable?

Glad to finally understand what makes MP3s different from other audio formats. Temporal masking is such a cool feature!

So helpful! I’m studying audio engineering and this really helped me understand compression on a deeper level.

Well-explained! It would be great if you could add some diagrams to show how temporal masking works over time.

I never thought MP3s had such detailed processing behind them. Amazing article, thank you!

Wow, this article goes deep. Definitely learned something new about temporal masking and why it’s so effective in MP3s.

Couldn’t have explained it better! Temporal masking is such an important concept, and you did it justice.

As a DJ, understanding MP3 compression is huge. This article gave me a lot more respect for the tech behind MP3s.

Really useful breakdown of a complex topic. Temporal masking makes so much more sense now!

Just what I needed! Been curious about temporal masking, and this article answered all my questions.

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MP3: quality standard?

For many, dematerialized music rhymes with illegally downloaded MP3.

If this comment is often true, since illegal music sharing platforms have made mp3 the primary format for music playback, you obviously need not limit yourself to the single mp3 format.

Mp3

MP3: birth of a format

The MP3 was democratized on the music exchange platforms of the time like Napster, Kazaa, Emule … in the late 90’s and for good reason they allowed you to download an entire album in a few minutes by compressing the music and thus shrinking the files.

Therefore, it is the need to exchange files and shorten the download time (remember we were paying the internet at that time according to your connection time …) making the development of mp3 essential and for many synonymous with dematerialized music.

The MP3 principle is therefore simple and attractive on paper: enable file sharing by drastically reducing the weight of files (more than 90%), and only by keeping what the human ear can do. listen, that is, the frequencies between 20 Hz and 20 kHz.

MP3: bad reputation

Unfortunately, the main consequence of this thin race is that the quality deteriorates: every mp3 has a compression level. The higher it is, the more the musical signal is cut off: this is called destructive compression: we eliminate all information that is considered useless and impossible to return.

Mp3

Therefore, during this period there was the spread of the famous 128 kbps MP3: this figure indicates the amount of information in the file and therefore its quality, the higher and better the sound will be. Therefore, some sort of standard has gradually been established around this bit rate of 128 kbps (kilobits per second), since it is inseparable as the quality of the CD at 1411 kbps.

mp3 – Napster

The Napster interface, one of the first illegal music sharing programs. Note the music ratio at 128 kbps (see less …)

It is clear that we do not reduce the amount of musical information by 90% with impunity and the results are often poor, the quality of the mp3 with 128 kbps is much lower and perfectly noticeable from the original CD. Then the new bit rates of 160 kbps, 192 kbps, 256 kbps and 320 kbps came to maximum, then “VBR” formats for “Variable Bit Rate” and against CBR (constant bit rate)) used earlier: we decreased the bit rate at rest and increased if necessary.

Therefore, we can see that it is difficult to pronounce the MP3 format in general: the results will be very different between a 128 kbps CBR mp3 and a 320 kbps VBR and, to a large extent, for the latter, for the price of one double weight.

Alternatives to MP3

MP3 is not the only dematerialized music format, it is first necessary to divide the compression formats into two categories:

Destructive Compression Formats: We remove content to reduce its size

MP3: the readable standard for 100% of music devices released in 20 years

AAC: Used by Apple in the iTunes music store (Apple Audio Codec), almost as universal as MP3

Ogg Vorbis: a free, efficient yet non-standard format

WMA: Microsoft format, not very standard either, except on Windows PC (can Microsoft have anything to do with it?)

Non-destructive compression formats: we compress the data for storage and decompress it when reading, therefore the sound reproduction is lossless, but it generates files 3 times larger:

FLAC: Free Lossless Audio Codec, it is somewhat the equivalent of Ogg in that it is royalty free and has established itself as the current standard for non-destructive formats (lossless in English)

ALAC: The Apple version of FLAC, which has also been in free form for some time, has the advantage of being compatible with the brand’s products and computers and offers the same benefits as FLAC.

Mp3: Advantages of MP3

MP3 refers to an encoding format that is formally referred to as MPEG-1 Audio Layer III for digital audio. Designated MP3 or MP3 data that stores basic MPEG-2 audio data or MPEG-1 audio data that is encoded. They do not contain any completely different complexity than the format. Find out more about the MP3 file format and its benefits.

As worrying as audio compression is, MP3 is a lossy compression module for encoding data with the expectation of partial rejection and inaccurate approximations of the data. And this ends with a noticeable reduction in file size, now no longer like with uncompressed audio.

The small size and excellent audio quality led to the provision of song data on Highway Records in the 1990s. MP3 served as expanded storage capacity and bandwidth in these hardly expensive times.

In about a year, the MP3 format has addressed controversy surrounding song piracy and copyright infringement. Instead, this file format became a custom format with the advent of avid portable gamers, including smartphones.

How does this compression work? This compression reduces the precision of the explicit parts of the sound that people can no longer hear. This method is ceaselessly referred to as perceptual coding or psychoacoustic modeling.

Then the free time of audio knowledge is recorded with the extraction of the allocated memory. FFT and MDCT algorithms are used here. Unlike CD audio, this audio compression design can reduce file size by up to 95%. Every time you document a conversion at a fixed bit rate of 128 kb / s, the file size is 9% more realistic than the audio on the actual CD.

Advantages of MP3

Here’s a hint about one of the benefits the MP3 audio file format offers. For these benefits, you can also lift whenever you can safely move around in this format, or opt for a lossless option.

One of the main advantages of this file format is that you can document songs, speeches or conversations for hours without affecting the allocated storage space. Basically, up to 95% of the allocated storage space is allocated. And the most important thing is that fine audio is identical with completely different codecs that take a lot of assignment.

The small size of such audio data allows you to map hundreds of data onto a small memory card or memory card. In other words, you can also save more than 170 songs on a CD with a storage capacity of 700 MB. On the other hand, the CDDA option does not mean that more than 15 tracks can be saved.

Instead, due to the logic that the file size is extremely small, you don’t have to spend a lot of bandwidth every time you get a lot of songs. Therefore, MP3 is a great wish for all types of users.

The best thing about MP3 is that you can change the audio level you want based on the available memory allocation. It can also rise between 32 kbps and 320 kbps. On the other hand, indicate that the higher the bit price, the larger the file size.

Audio quality: Bitrate in MP3 files

In many cases the term Bitrate is used, which is the bit rate per second that a multimedia file (Audio or Video) has. Currently the MP3 music format is one of the most widespread (Although there are currently other more current formats such as OGG Vorbis, AAC, Flac, Monkey Audio, …) however the audio quality is variable, this is due to the characteristics with which the MP3 in question has been compressed, including:

Mode: It can be of two types mainly:
Mono: With a single channel (The right and left channel go together, not separated which gives worse audio quality).
Stereo: Two channels (Right and Left, improve audio quality).

Sampling frequency: Audio CDs use 44,100 Hz (22,050 Hz per channel), although there are higher frequencies such as 48,000 Hz used in DVDs and lower, the higher the frequency, the higher the quality.

Bits: Audio CDs have 16 Bits (Although MP3 can be compressed at a lower quality such as 8 Bits).

Bitrate (Bit Rate per second): Audio CDs have about 1,400 Kbps (44100 Hz * 16 Bits * 2 channels), meaning that an Audio CD would have a bitrate of 1,400 Kbps (In MP3 format the maximum Bitrate is 320 Kbps, however, it is assumed that an MP3 with a 128 Kbps Bitrate has a quality similar to CD, although in many cases to achieve a quality similar to CD it is necessary to use a Bitrate of 192 Kbps, and to obtain CD quality it is necessary use 256 Kbps or 320 Kbps).

Some of the most common Bitrates are:
8 Kbps Mono: Telephone Sound.
16 Kbps Mono: Better quality than shortwave.
32 Kbps Mono: Better quality than AM.
64 Kbps Stereo: Better quality than FM.
112 – 128 Kbps: Quality close to CD.
160 Kbps: Quality closer to CD.
192 Kbps: Virtually CD quality.
256 Kbps: Quality CD practically undisputed from an original CD.
320 Kbps: CD quality.

Coding method: It can be of two types:
VBR (Variable Bit Rate, Bit Rate Variable): Encodes the file in MP3 with a variable Bitrate.
CBR (Constant Bit Rate, Constant Bit Rate): Encodes the MP3 file with a fixed Bitrate.
In addition, another factor that influences the encoding of the MP3 file is the CODEC (Encoder-Decoder) used, one of the most common and the best result is LAME (Lame Ain’t an MP3 Encoder) which is also free.
One point to keep in mind is that if we recompress an MP3 file that originally has a 128 Kbps bitrate and convert them to 192 Kbps for example, audio quality is not really gained because the MP3 format has some quality loss (MP3 is a loss algorithm, also called lossy). which has occurred when converting the original file (Ex: CD Audio or a 320 Kbps MP3 to a 128 Kbps MP3) so this recompression does not make much sense since we will not gain in audio quality (As they say where there is no one can not get) and the only thing we will achieve in any case is to increase the initial size of the file.
The opposite case (Recompress a 320 Kbps MP3 file for example at 192 Kbps) if it makes some sense because in this case although we lose some audio quality we reduce the weight (Kilobytes or Megabytes) of each MP3 file somewhat.
In conclusion, it can be said that if we need to encode / compress an MP3 file with good quality, the “ideal” would be to do so:
To be able to start from an Audio CD, although an MP3 at 320 or 256 Kbps could also be valid for a recompression of the file.
In stereo mode (With two channels, right and left).
With at least 44100 Khz sampling rate and 16 Bits.
With a minimum bitrate of 192 Kbps or at most 256 Kbps (Using 320 Kbps would give higher quality but also increase the file size considerably).

What is the Bit Rate or Bitrate in the audio?

Do you want to change the bit rate in your MP3 files? This can be useful if you need to reduce the size of your MP3 files, for example. A 320 kbps MP3 file, the highest bit rate allowed for MP3 files, could be reduced to 192 kbps to significantly reduce the size of the MP3 file.

There would be a loss of quality, but the difference would be insignificant for most listeners who use standard speakers or headphones. If you are an audiophile, in addition to having expensive audio equipment, you probably never use the MP3 format anyway.

Most likely, you will use a compressed or uncompressed lossless format such as PCM Audio, WAV, AIFF, FLAC, ALAC or APE. An uncompressed PCM audio file is approximately 10 times larger than a CD-quality MP3 file.

The MP3 format is a lossy format, which means that the audio quality is sacrificed to maintain the relatively small size of the files. Almost all sites will tell you that you should never convert an audio file from lossless format to MP3 format unless you are well with the loss of audio quality.

What is the normal bit rate in an MP3?

A normal bit rate for an MP3 is between 128 kilobits per second, or kbps, and 320 kbps. Different bit rates in this range have different advantages; To extract music from a CD to MP3, choose the bit rate that best suits your purposes. In general, the higher the bit rate of an MP3, the better the audio quality, but the larger the file size. The most common bit rates in MP3s are 128 kbps, 192 kbps and 320 kbps.

Bit rate

The bit rate of an MP3 indicates the density of the audio information contained in the file. Therefore, every second in a 192 kbps MP3 contains 192 kilobits (24 bytes) of data. The higher the bit rate, the more information the MP3 contains; The more information it contains, the quality is closer to the original audio recording. The bit rate also determines the size of the MP3 file: a four-minute song encoded at 128 kbps occupies a little more than 3.5 MB, while the same song encoded at 320 kbps requires more than 9 MB of space.

Choice of a bit rate

When you convert a sound file or extract your CD collection to MP3, you must specify the bit rate you want the encoder to use. Choose a bit rate based on the type of audio you are encoding and on your desired purpose. If you are converting a conference or other piece of vocal audio, a bit rate of 128 kbps is more than enough. If you are encoding MP3 files for use with a portable media player, a bit rate of 192 kbps usually provides a good balance between audio quality and file size. If you are converting your CD collection to MP3 for archiving, encode the files with a bit rate of 320 kbps.

Variable bit rate VBR

Coding with a variable bit rate changes the bit rate of the MP3 depending on the type of data present at a certain point in the audio. For example, a variable bit rate encoder could encode a portion of dense information from an MP3 at 320 kbps; however, when the audio contains a silent section the encoder lowers the bit rate to 32 kbps. If the bit rate of an MP3 has an unusual number (for example, 204 kbps), this indicates that the creator of the MP3 encoded it with a variable bit rate.

Bit Rate Conversion

Although most MP3 conversion and encoding programs can modify an MP3 at a different bit rate, this is not a good idea, generally speaking. Converting an MP3 to a higher bit rate does not add audio information to the file, so the sound quality does not increase. Converting an MP3 to a lower bit rate reduces the size of the file, but it could also introduce audio defects, since the encoder is compressing a file that is already compressed. If you need an MP3 file to have a different bit rate, re-encode an MP3 from the original audio CD or WAV file.

Everything you wanted to ask about the mp3

WHAT IS A CODEC AND WHAT IS IT FOR?

CODEC is an abbreviation of CODifier-DECodifier, which already indicates its functions. In the case of MP3, it deals with processing the sound, applying various compression methods to reduce the size necessary for its storage, and conversely, to reconstruct the sound from the encoded information. The codecs can be found in the form of an executable file, a DLL, or less frequently, incorporated into the code of another program. The DLL format allows the same codec to be easily used by different programs, while the executable format is usually more flexible in terms of configuration, although it is more complex to use.

WHAT DOES “PSYCHOCAUSTIC COMPRESSION” MEAN?

This very complicated word refers to the main compression technique that MP3 uses (although it is not the only one), which simply consists of eliminating the information (sound, in this case) that, in theory, is not able to perceive the ear human. I say “in theory” because, depending on the compression ratio that is applied, that loss may be more or less noticeable, hence some files do not sound as good as would be desired. The different codec also do not use psychoacoustic principles in the same way, so the quality they achieve will not be the same.

DOES THE SOURCE ORIGIN INFLUENCE THE MP3 QUALITY?

Evidently. The ideal is to start from an original CD. Analog sources, such as vinyl records or tapes, have lower quality in themselves, no matter how much we “digitize” or “improve” them with some programs. Recorded CDs may contain errors (which will end up being noises when played), and we usually do not know from which source they have been recorded (perhaps from previously encoded MP3 files). Re-encoding an already compressed music file, in the same or another format, is also a mistake, since quality is always lost.

DO THE PROGRAMS WE USE TO EXTRACT AND CODIFY THE QUALITY OF MP3?

It also seems obvious, so much so that this point should not be here. But many people do not take it into account, without knowing the reasons very well.

DOES THE QUALITY OF PLAYERS INCLUDE IN THE QUALITY OF MP3?

To hear it, you already know the answer, don’t you? J. To have it stored on the hard drive or on a CD, nope. Jokes aside, and in theory, all decoders should get the same sound from an MP3 file. But unfortunately this is not the case, usually because they do not strictly conform to the MP3 standard. You can find the best explanations on this topic here.

DOES THE QUALITY OF THE SOUND CARD AND SPEAKERS INCLUDE IN THE QUALITY OF THE MP3?

Well, I think you already know where the shots are going, we will not continue along this line. But nobody says “is that MP3 does not sound good” when it has a Sound Blaster 16 (what times those!) And some 800 W TurboPowerSound speakers that cost € 18 uros.

WHAT IS BITRATE?

It is the number of bits that are used to encode a second of sound, if we talk about MP3. It is measured in Kbps (kilobits per second).

As there is often confusion, we will give an example. If we have a 4-minute MP3 encoded at 128 Kbps:

-One second occupies: 128 Kbits x (1 Byte / 8 bits) = 16 KBytes.

-The complete song: 16 KBytes / second x (4 minutes x 60 seconds / 1 minute) = 3840 KBytes = 3.75 MBytes.

The formulas could be more correct, but this is not a mathematical thesis and I think they are enough to understand us.

WHAT DOES CBR, VBR and ABR MEANS, AND WHAT IS THE DIFFERENCE?

They are different coding methods. CBR means “Constant BitRate”, VBR “Variable BitRate” and ABR “Average BitRate”. It is easy to deduce that if CBR is used, the bitrate remains fixed, and if VBR is used, the bitrate changes. ABR can be considered a variant of VBR in which the objective is to achieve a certain final size, since we can set the average bitrate to be used (although it will never be as accurate as CBR).

The great advantage of VBR is that it uses more bits when the fragment to be encoded is more complex, and less when there are silences or it is simpler, so that we will achieve the highest quality using the minimum possible space. If the final size is not the deciding factor, it is the most recommended option.

WHAT IS THE BEST MP3 CODEC TO COMPRESS MUSIC? WHAT IS YOUR BEST CONFIGURATION?

The first question is easy to answer: LAME. In many different tests, done independently and with means that probably none of us will ever have, LAME is considered again and again as the best codec. And since there is no commercial motivation, since it is free distribution software, we can give full validity to these tests. The Fraunhofer codec and some of its “versions” could be valid in certain circumstances, but … do we need to use a commercial or pirate codec with a free and legal substitute? I think not (and from here, what each one does, is his own thing). For me, codec MP3 = LAME.

The second question is much harder to answer. There is no configuration that is perfect for everything (because if not, the modifiable options would be left over and everything would be much easier) J. But there are some recommended options in general, which we can establish with the assurance that the result will be of good quality. I have to admit that I barely change them, but as in this case (and in many others) there are no absolute truths, everyone has to try until they establish the one that best suits their preferences (or their ears).

The first thing that we must be clear about is that, in an MP3 file, size and quality are conflicting terms. We have to look for a practical middle ground. I put that term between 128 and 192 Kbps (some will say it is too low … I will try to justify my opinion). In principle, the purists established the CD quality at 256 kbps CBR. That is, using that bitrate, the sound of the CD and that of the MP3 file were absolutely indistinguishable. But, right now, LAME is already very developed. It uses the most advanced techniques, and manages to do perfectly things that other codecs are not able to solve properly (VBR, Joint-Stereo), which allows you to improve the quality and reduce the size.

In r3mix.net, after the corresponding tests, they have established an “ideal” configuration based on quality criteria. This configuration is so accepted, that in the latest versions of CDex, and other programs, it is already included as one of the preset configurations. But be careful: this does not mean that this is the only option, nor that it will always achieve the highest possible quality. Another thing is that using this option our ear can differentiate the results of the original audio CD, and this is where the “trick” of MP3 compression is.

After having used this configuration, I have observed that, although there are important variations, the average of the files is about 170-175 kbps, and that they rarely go beyond those 192 Kbps that I mentioned before, so I consider that overcoming that bitrate does not it will hardly improve the quality, but it will significantly increase the size. Although I repeat, there will always be someone to whom this bitrate seems insufficient, and will use even 320 Kbps, which is the maximum supported by LAME.

The second part is to take into account the equipment we have. If the MP3s are not going to sound through a card, an amplifier and very good quality speakers, the bitrate can be adjusted a little more without practically noticing variation in quality. The average 160 Kbps seems like a very reasonable amount to me, and that’s how I usually code my CDs. And I can say that they don’t sound bad at all. If someone is able to do a “blind” test and differentiate between several files encoded (correctly) at 160 and 192 Kbps, you really have to congratulate him on his ear.

Finally, if we consider size as a decisive factor, we could go down to 128 Kbps, but considering that the quality may already be too compromised. Summarizing:

Configuration that seems more appropriate for practical purposes, and looking for a high quality (about 192 Kbps):

-Joint-Stereo -> Get reduce the final size without losing quality. Sometimes, where there is a lot of variation between channels and with high bitrates, it could be configured as Stereo.

-VBR MTRH Quality 1 or R3Mix Preset -> Change the bitrrate according to the needs of each moment, improving the quality without increasing the size with respect to CBR (normally).

-Bitrate minimum 64 Kbps -> To compress to the maximum silences and very simple fragments.

-Bitrate maximum 256 Kbps -> So you have room to improve the quality in complicated fragments.

Does the birate of an mp3 affect the quality or is it just an impression?

Since the mp3 appeared, I always understood that it is a lower format than the CD quality, no matter how much bit rate it contains. When it comes to mixing and producing my personal recordings, I have used wave support and when converting it to mp3 it is impossible not to distinguish the differences: at least, the reduction of bass and treble is very noticeable. The dishes of the drums or the bass are very opaque and hidden, sometimes they even disappear. But in these assessments I think that perhaps my subconscious has betrayed me in some cases.

First of all I will explain some basic things about mp3 and its bitrate (or bit rate). Compressing sound means loss of quality, so you have to pay attention to how much information is transmitted per unit of time: the most used encodings for mp3 are 64, 128, 192 and 320 kbps (kilobits per second). Thus, a song of 64 will occupy less space than one of 128 and so on. Nor should we forget the CBR, constant bitrate, and the VBR, variable bitrate. The latter is more advisable when compressing different parts of a recording with various bitrates.

Well, there has always been controversy and confrontation between those who prefer to save space and opt for the musical amount, claiming that the quality differences of the mp3 are almost imperceptible to our ears, and those who bet on the qualitative details of the music, preferring heavier files and with higher bitrates, emphasizing the multiple peculiarities that our auditory system loses to lower quality media. I have been a supporter of the second group, although current opinions about it make me doubt my choice.

I recently informed myself about a study conducted by programmer Jeff Atwood through his blog, in which he tried to discover if normal people, fond of music (but without becoming music experts) notice the differences between mp3 formats . More than 3,500 people participated in the study, who had to listen to 5 different audio files (with bitrates between 128 and 320 Kbps and one without compression) and vote from 1 to 5 depending on the quality they had received. Naturally, users were unaware of the characteristics of the media so as not to influence their objectivity. The results were as follows: the 128 Kbps CBR mp3 was undoubtedly considered the worst; the one of 160 Kbps VBR would be the one of better quality, surpassing even the one of 320 CBR (the variable bit rate would be higher than the fixed one). This is very curious since it is assumed that an original CD would house a quality between 192 and 256 Kbps. According to the study cited, the mp3 of 160 would have more quality than the compact, which seems absurd, so I tend to think that the Most people, after 160, do not distinguish some sounds from others, also taking into account that the subconscious can deceive us and make us imagine what it is not.

In short, the best way to compress, saving on storage and with optimal sound, would be thanks to the 192 Kbps VBR bitrate. From there, onwards, it is very difficult to appreciate nuances and alterations.

We must also consider something logical: if we recompress a file of 128 and convert it to 192 Kbps, improvements will not be achieved and we will lose space. If we do the opposite, go from 192 to 128 Kbps, we will reduce the quality somewhat but reduce the weight of the file.

I think this experiment obviates interesting data such as knowing the player or equipment from which the music was broadcast (computer, speakers, headphones, hi-fi equipment, etc.), listening time (our senses do not lend the same attention for 5 minutes than during 20) or musical style (electronic, rock, classical, etc.), since all these factors can greatly influence the final result.

Even, and this is proven: the volume (if the file is normalized) and the dynamics (a normalization like the one that only Mp4Gain does) manage to make one perceive the music as with higher quality.