Sample Rate and Bit Depth: What Do They Mean for Your Sound Quality?


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If you’re recording music with a  digital recorder, you’ve probably come across the terms sample rate and bit depth. These are the two main factors that determine the level of detail in the sound. The sample rate determines the frequency range of your recording and the bit depth determines the dynamic range. Read on to find out which settings are the best to use for your productions.

bit depth example in colors

Bit depth example in colors

Sample rate in bit-depth

Sample rate: audio pixels

Bit Depth

You can compare the sampling frequency of a digital signal with the number of pixels in a digital photo. As with digital photos, digital sound is divided into very small parts. With photos, those pieces are called pixels and with sound samples. The sampling frequency is expressed in kilohertz (KHz). The standard sampling frequency for CD is, for example, 44.1 kHz. That means that every second of your recording consists of 44,100 samples. Unlike photos, you will not hear any “blocks” at very low sample rates. The sound becomes mainly muffled.

Why 44.1 kHz?

In the late 1970s, Sony and Philips decided to choose 44.1 KHz as the default sample rate for their digital audio devices. That number may seem random, but there is definitely an idea behind it. The sample rate must be at least twice the highest rate you want to capture. If the sample rate is lower, the converters may misinterpret the super high frequencies. This phenomenon is called “aliasing.” Since, in theory, the human ear can detect frequencies from 20 Hz to 20 kHz, the sampling frequency should be at least 40 kHz. The additional 4.1 kHz is intended as a kind of buffer for the low-pass filter that is used to prevent aliasing above 20 kHz.

Why higher than 44.1 kHz?

Audio interfaces and DAWs often offer the ability to record at much higher sample rates, sometimes up to 192 kHz. This has several advantages. For example, the low pass filter mentioned above can be set much more gradually. Also, with the extension of time and the change of pitch, the noise will disturb you less. Keep in mind that the higher the sample rate, the larger your audio files will be. Plug-ins also require a lot more computing power from your computer at higher sample rates.

Hit my parts

So the sample rate tells us how many pieces the recording is made of. But how many different pieces can we choose from? In other words: in how many steps do we go from the softest sample to the hardest sample? We determine this with the bit depth. With most DAW and audio interfaces, you can choose between 16-bit or 24-bit. If you make very smooth recordings at a low bit depth, you have the possibility that the softer passages will disappear in the noise and you may even get distortion.

99 problems but a little is not one

The standard bit depth for CDs is 16 bits, which gives us a dynamic range of 96 dB. That’s a considerable improvement compared to say tape (+/- 80 dB), but in the studio world, 24-bit is generally chosen. With the 144 dB that we have then in dynamic range, we hardly really have to worry about the noise that the digital medium adds to the signal. In fact, it’s better to record and mix a little too low than too high.


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What is sample rate and bit depth

BIT DEPTH

-translated from eurpean language-

Bit Depth

As a digital music producer, you will soon come into contact with the terms Sample Rate and Bit Depth. These terms are often experienced as complicated and are also used interchangeably. Starting today, you will no longer have to make those mistakes, because you have LesinProducing and we will do our best to explain it to you as well as possible. So here we go!

Bit Depth

As a digital music producer, you work 99% of your time on your computer or laptop. In order to record and edit sounds with a computer, the sound must be translated into the digital language that a computer understands, that is, “binary codes” (with all those zeros and ones).

SAMPLE RATE

Sample Rate Image A movie is actually a complete series of images that are put together, which our brain then interprets as a moving image. This is how it works with digital audio. Digital audio is basically a series of snapshots, which our brain experiences as one continuous sound. The frequency with which snapshots of the audio are taken, we express it in “Sampling frequency”. The greater the number of snapshots taken, the more detailed the result. In the world of digital audio recording, 44.1 kHz and 48 kHz are / were the most common sample rates. “But what exactly does 44.1 kHz mean?” I heard you think!

44.1 kHz means 44,100 “snapshots” that are taken per second. At 48 kHz this is 48,000 “snapshots” per second. Today you come across sound cards that support recordings of up to 96 kHz or even 192 kHz. That’s respectively 96,000 and 192,000 “snapshots” per second.

Okay, so far, because I know you have a few questions on your mind right now. Let’s see if we can answer your questions right away:

Question 1: If my sound card supports 96kHz recording, for example, where can I configure this?
Answer: In Cubase you can set the sample rate in Project -> Project Settings. In Logic X, do this in File -> Project Settings -> Audio.

Question 2: Is the difference between 44.1 kHz and 96 kHz audible?
Answer: The difference between 44.1 kHz and 96 kHz is almost inaudible.

Question 3: If we don’t experience / hear 92 kHz as “better”, what good is it?
Answer: To answer this question, we are introducing a new term, the “Nyquist Frequency”. Simple explanation: generally people can hear frequencies from 20Hz to 20,000Hz (= 20kHz). If you want to record a 20 kHz sound source, it must have a sampling frequency of at least 40 kHz. The “Nyquist frequency” of the 40 kHz sample rate, in this case 20 kHz. In this setting, 20 kHz is the highest frequency that can be recorded with a 40 kHz sample rate. Some musical instruments are said to have a higher range than our hearing (20 kHz). According to some, it is important to record these instruments as well as possible, although these instruments contain frequencies that we do not hear directly at first, but that we can feel / experience. If you want to achieve this,

Question 4: Why not record everything at the highest possible sample rate?
Answer: One reason is that the higher the sample rate, the larger the storage space. For example, if you need 5 MB of storage space for a few seconds of audio at a sampling rate of 48 kHz, you will need no less than 4 times more storage space for the same seconds at 192 kHz, that is, 20 MB.

BIT DEPTH

When Sample Rate takes vertical “snapshots”, the bit depth is based on the resolution (sharpness of the translation). Easy said; the higher the bit depth of the “digital translation”, the sharper the “translated” result. The result is a nice smooth waveform at higher bit depth. So you can take 44,100 “snapshots” with the sample rate, but if the resolution (depth of supply) is not sharp enough, the result will not be a smooth waveform. Bit depth is also about dynamic range. With each +1 bit, a dynamic range of + 6dB is added. For example, a 16-bit bit depth has a 96 dB dynamic range, and a 24-bit has a 144 dB dynamic range. For CDs, use 16-bit and for DVDs, 24-bit.

Bit depth, an important factor almost unknown

Bit depth, an important factor almost unknown

Very often we see people talking about topics that are important, like bitrate for example. Most of the time without understanding exactly what that means. Sometimes they even do trial and error and for various reasons it may be that the result they obtain is misleading, since they are not considering that modifying the bitrate without looking at the sample rate and the bit depth, is to act blindly and therefore the Results will always be misleading and we should not draw definitive conclusions from them.

We have detected that many people instead of giving a reading that allows them to understand what bitrate, sample rate or bit depth are, prefer to manipulate them without understanding them and, based on the result of one or two songs, they often reach conclusions. wrong about what is the right combination.

Bitrate

It is bitrate It is the amount of information that passes per second, that is, the amount of detail that an audio file can contain in a video. The bigger the bitrate means what will be passing more information per second; therefore the file will be bigger but it will contain more details, which will give it a higher quality. We will put an example to understand it very easily. Images that we have a great draftsman or painter and that we ask him to make a portrait of a person but we tell him that I can only use 5 colors and he cannot mix them.

As a result we will obtain practically a caricature and not a portrait itself. In other words, it will have less quality if we understand quality to be a faithful copy of the original.+

On the other hand, if that same painter asks you to make a portrait, but we stop using the entire color palette, you will be able to make a very realistic portrait, of very high quality, very faithful to the original.

Why did this happen? Because it contains much more information. There are many more shades. That explains exactly how bitrate affects the quality of a video or audio file.

Sample rate

When we record a video, for example, it is as if we were taking a series of photographs and then quickly saw them one after the other and that would give us the illusion of movement. In exactly the same way that cartoons worked in ancient times. Obviously if we only use three drawings per second the quality of the cartoon will be very low because you will see a series of jumps and not an action continues. If instead we use 24 drawings per second we will see a very high quality cartoon where we will seem to see an action continue without any Jump.

The sample rate is the number of samples per second that are taken to form a video or an audio file. Audio on a professional CD uses 44100 samples per second. If we lower that quantity we will notice a loss of quality and if we increase it to more than 44100 samples we will be able to obtain a very high quality HD.

Bit depth

The bit depth determines how many “steps” the curve or wave will contain that will contain our audio or video file. Obviously, the more steps the wave pattern has, it will be more faithful and, on the contrary, if it contains few steps, the wave pattern will be very rough.

So here we are understanding the importance of bit depth that for example in music affects even the dynamics of music. That is, how much can the volume of an instrument rise and fall in different passages. At different bit depth rates we will obtain different levels of decibels

Dynamic Range and Bit Depth, those great strangers

Many times we listen to songs and they seem like absolute songs and other times they seem like a waste of time. To some extent it is because of the music that is heard. But today we are going a little further. I dare say that part of the fact that we end up liking it is due to the fact that there are two concepts that have not been taken into account in production lately.

I mean the Dynamic Range.

What is it? Well, it’s just the difference between the highest possible peaks and the noise threshold. Yes, there is always a noise basis, even in the best soundproof studio. And how does that affect what you hear is a great song? Very easy, since this variation in amplitude influences the sound intensity, how the song flows, the difference between strong and weak. The specific nominal amplitude of each equipment must also be taken into account, which is called the dynamic ceiling or Headroom. Normally it stays at 120Db, since it is the limit that integrated circuits allow. What we hear from all this is the SNR, signal noise ratio, that is, the relationship between residual noise and the average signal of the subject.

If we transfer this to our tasks as musicians, it means that no frequency that we are using within our theme should be fixed, which is called average, and that too much compression is bad too, since it can crush the sound, since applying a compressor decrease dynamic differences. This also includes mixing and normalization (which we will talk about later) where some resources can help us to make our theme cover the widest dynamic range in all its frequencies. For example: If the amplitude of the mid frequencies is reduced, approximately the frequencies of 250Hz, it is possible to boost frequencies of 5KHz.

Another resource that sometimes we fail when we are playing a synthesizer, whether analog or digital, or when we are mixing is Bit Depth or Bit Resolution / Quantization.

Bit Depth is the amplitude of variations of a sound wave. Translated into Christian, the number of bits recorded per sample. This affects the previously explained concept, dynamic range, since the greater the bit depth, the greater the possibility of working with wide dynamic ranges, which is called the rule-of-thumb. Since for example, if we work with 8-bit synthesizers, which are so fashionable, we are saying that this synthesizer, the wave that sends the output, only allows to register 256 variations in the amplitude of the wave. Let’s remember that 8 bits = 2 to 8. With this I don’t mean that an 8-bit synthesizer is bad, each one does its job, but there are many cases where pears are asked from the elm, when we all know that you have to go to the pear tree. I would like to emphasize this concept especially for we use analog synthesizers, drum machines, samplers. Since the bit depth within a PCM, the digital representation of an analog sound, recreates the maximum dynamic range, which means that the sound will be more real.

So let us return to the question asked above. How does this affect my theme to sound good? Well the bit depth limits the amount of dynamic range and signal noise ratio. This means that if we cover a higher bit resolution we will be able to interact with more precision within the theme that we are composing and therefore improve the output signal of the set.

Even so, I am sorry to be this party pooper, the bit depth problem comes from the fact that nowadays we use a format that has very low and bad compression, such as MP3 or WMA. Although you export at 24 bits, it does not mean that the MP3 / WMA has a bit depth of 24 bits, since you have mastered them at 24 bits but then it has been compressed and that is where it fails. This also happens even if we copy directly to a CD, since CDs are burned at 16 bits.