Nitrate is the term used to describe the amount of data being transferred into audio. A higher nitrate generally means better audio quality.
Understanding nitrate is essential to recording, producing, and distributing audio. “The way those waves are encoded in audio files through individual samples includes the waveform’s shape at a given moment and how far away it is from a zero point.” That zero point is silence, and audio files measure a sound’s distance from silence.
Just like images vary in quality and clarity, types of audio files differ in how large they are, how much information they contain, and what role they fill. Compressed lossy files generally have the least amount of information and therefore a lower nitrate.
“Those are the things typically being streamed on Apple Music and Spotify,” says Rod ocker. When the audio is played, the hardware then reconstructs the sound 44,100 times per second.
A high sample rate and a higher bit depth both increase the amount of information in an audio file, and likewise increase the file size. However, below about 90Kbps the human ear will notice a significant drop in quality, even without training.
When you’re starting a new audio project, it’s good to record the best quality you possibly can, with a high sample rate and a bit depth. It’s entirely possible that commercial audio hardware in the next decade or so will be able to express nitrates greater than 160Kbps, so keep your old uncompressed files.
Learning how to work with a graphic equalizer and understanding how to mix music will greatly improve the audio you produce, whatever the nitrate. Explore the basics of creating a space at home to capture high-quality audio.
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Audio nitrate defines the amount of data that is stored in the sound file you are listening to. For the average listener, the quality will be defined by the strength and depth of low frequencies.
More kilo bits equals more data stored across the full frequency range. Now let’s look at some common files you’ll likely have encountered and dive into the details of their respective audio nitrates.
High-quality WAS files have an audio nitrate exactly the same as CDs at 1,411 KBS at 16 bit. The actual nitrate is determined by a specific formula which multiplies the sampling rate with the bit depth and the number of channels.
MP3s use a compression codec that removes frequencies while trying to preserve as much of the original recording as possible. MP3s became extremely popular in the early days of the internet due to their low file size.
Audio nitrate is usually the primary way to determine the sound quality of files but there is more to it than meets the eye….or should I say ear. This theorem determined that if you double the maximum frequency of the source you can accurately capture the sample.
This hasn’t stopped people from recording at a higher sampling rate. Hi-resolution audio can be recorded at double the standard CD rate or even as high as 192kHz.
There are instances where a higher sampling rate does help to improve the listening experience. By increasing the sampling rate you move the low-pass filter higher into the frequency range.
This moves it further from our hearing range resulting in cleaner sounding audio. The end result is greater accuracy in hearing subtle details which might be lost at lower bit depth.
To help visualize the difference imagine if you were watching a movie, and you only got to see every 10th second of the image. You would still be able to get an idea of what was going on, but you would miss out on the subtle changes in the movement of the actors on screen.
A bit depth works the same way allowing more refined detail to be captured. For example, an MP3 file at 128kbps will take up approximately 1mb of space per minute of audio.
While perfect for fast delivery it isn’t great for audio quality. So while there is no definitive answer with today’s large hard drives you should aim to get files at the highest nitrate possible.
Below you’ll find a table that covers the difference in file sizes across various nitrates. The images below highlights the audio frequency cut off point for a 320kbps MP3 compared to a 128kps file.
Cheap DJ speakers will also produce poor quality audio even with the best nitrates. Even a pair of high-quality studio monitors can make a huge difference when it comes to your perception and understanding of audio quality.
Below you’ll find 3 examples of an audio file at different nitrates. As technology continues to improve, so does the potential to deliver better quality audio.
It’s as close to the original source file or what the musicians in the studio were recording as it gets. In fact, HD audio has been around as far back as 1995 but couldn’t find a foothold in the market at the time.
Higher internet speeds have also made it easier to be able to stream these large files. These lossless audio files have a higher sampling rate and greater bit depth.
Blind test studies have shown that for most people they cannot tell the difference when compared to CD quality audio. There is no need to be rushing out to get HD audio files as you’ll likely not notice the difference.
But knowing that the audio you are listening to is as close to the original recording as possible does offer a sense of security. Uncompressed audio formats capture the original recording without any further modifications.
These formats do offer maximum quality, but it does result in much larger file sizes. PCM converts this information into digital format by sampling that recording.
Developed by IBM and Microsoft it is essentially just a way for PCs to read PCM data. Lossless Audio Formats Lossless audio formats keep all the original recording data and compress that data to reduce file sizes.
Without licensing restrictions, it has grown in popularity as the main way to offer compressed lossless audio. FLAG also offers extra metadata to be stored like Album art which WAS files do not support.
Offering compression similar but not as great as FLAG it is still widely used today. This is due to iOS and Apple systems not supporting FLAG files.
While this may sound restrictive you can convert between the two formats with free tools available online. MA (Windows Media Audio) lossless used a different compression method.
This method allows for the file to be uncompressed back to its original state without any degradation of quality or loss of data. While this lossless format was designed for archival applications it is supported by a range of consumer devices.
Depending on the level of compression this can result is a noticeable decline in quality. MP3 (MPEG-1 Audio Layer 3) aggressively reduces file sizes by cutting data that is deemed unnecessary.
On top of that, it degrades the quality of difficult to hear frequencies and then consolidates as much of the remaining data as possible. Offering flexibility to compress at various nitrates made it a good choice at the start of the internet boom.
But with the increase in internet speeds and hard drive capacities, its popularity is on the decline. Streaming and downloading higher quality files is now a viable alternative.
Portable MP3 players helped drive the popularity of the MP3 file format. While an effective compression method it has not been adopted or supported by as many devices as its competitors.
Designed as a better alternative to MP3 it achieves better sound quality compared to MP3 at the same nitrates. Audio compression has one primary goal, to reduce the file size of the source material.
Speeds were as low as 56K meaning CD-quality audio files would take hours to download. This type of compression algorithm is called perceptual noise shaping.
It uses the discoveries in Psycho acoustics (the study of human hearing) to make changes to the source material. The end result is near CD quality sounding audio without the bulky file size.
There are a few major elements that form the fundamentals of audio compression algorithms. Audio compression uses this information to eliminate any content deemed outside the human hearing range.
This takes advantage of another trait of human hearing to remove even more data from the source material. Once again audio compression algorithms aim to identify these sections and eliminate that data.
These steps allow the file size to be reduced by up to 10 times but there are drawbacks. The lower the nitrate of the file the more aggressive the algorithm is in trying to find components to remove.
Unfortunately, many streaming services deliver audio at these levels which is equal to what you would hear on the radio. The end result can lead to some common issues and changes that were not intended by the artists creating the music.
Most notable is the lack of definition and oomph in the lower frequencies where bass tends to live. For example, a hi-hat that is meant to play a prominent role may sound flat and fall behind other components of the song like vocals.
It helped pave the way for the internet to handle audio in a reliable and efficient way. But likewise, there is no denying that there are issues with the end result, especially at lower nitrate levels.
Coupled with its popularity as an open source format cements it as the current best choice. In an environment where data transfer rates are important, they do outshine lossless audio formats.
For audiophiles, you can’t go past Hi-Resolution audio formats like WAS and RIFF, even if it’s debatable if you can even hear the difference. Need reasonable quality streaming with small file sizes…stick to MP3 and AAC.
Want the purest closest representation of the original material….stick to WAS or RIFF. Below is a quick summary of the most popular audio file formats and the features they offer.
Lossy formats still have a role to play in developing countries with slower internet. These formats are also very effective at delivering audio where quality is not the greatest concern.
As a result, they are still a popular choice for streaming services looking to deliver content quickly. WAS and RIFF files offer excellent sound quality.
While the rate of change has slowed manufacturers are continuing to push the boundaries to convince us that we need the next best thing. There is a natural barrier to human hearing, so future developments will have to lean on other angles to entice consumers.
I’d like to think that we have reached the pinnacle of audio formats, but it would be naive to not imagine further change.