If you enjoy making music or listening to it with headphones, you have probably heard of something called “hertz” (abbreviated: Hz) in the music and technology world before. Hertz is simply the unit that frequency is measured in. Everything has a frequency, but hertz are usually used in the case of measuring things that have more than just one frequency.
So what roles exactly do these measures of hertz play in the music and technology worlds, and what else is measured in hertz? Read on to find out these answers and more.
Hertz (Hz): understanding the basics
Hertz (Hz) is the smallest, basic measure of frequency. To represent thousands of hertz, we use kilohertz, or kHz. To represent millions of hertz, we use megahertz, or MHz.
To represent billions of hertz, we use gigahertz, or GHz. GHz is typically used more in the technology world, for example to describe computer processor speed (which we will get to in a little while), rather than the music world.
In general, hertz are most often used to describe musical and sound related frequencies rather than frequencies related to other subjects.
Hertz (named after German physicist Heinrich Hertz due to his work with radio waves) is a measure of one whole wave cycle per second in terms of frequency. Most commonly, the thing that is being measured is usually electrical changes. Music is made up of waveforms that oscillate (move at a constant rate) at different frequencies.
For example, if a sound wave completes one whole cycle in one second, its frequency is 1 Hz. If a sound wave completes 10 cycles in a second, the frequency is 10 Hz.
The faster a wave moves, the higher its pitch is. This means that different frequencies match the pitch of different musical notes. For example, the A note above Middle C has a frequency of 440 Hz.
Frequency doesn’t have an effect on the volume of music, instead what affects the volume of a waveform is the amplitude, or the size of the vibration of the wave. Frequency is more about speed and time.
Understanding hertz in music
In the 1880s, the Italian government’s Music Commission decided that all musical instruments should be tuned using a tuning fork that vibrates at 440 Hz.
This was so that all around the world, a song could be performed and it would sound the same as it would if it was performed elsewhere. Prior to this, tuning forks vibrated at frequencies of 435 Hz and 432 Hz.
In the 1900s, the American Federation of Musicians made it clear that they agreed with the Italian Music Commission’s declaration, and later they too pushed for a tuning standard of 440 Hz.
In 1953, it was agreed worldwide that the tuning of the first A note that comes after Middle C on the piano would be tuned to 440 Hz. This became the standard for tuning instruments that use the chromatic scale.
A human with a normal amount of hearing can hear between the range of 50 Hz to 20 kHz, and someone with very good hearing should be able to hear between 20 Hz and 20 kHz.
20 Hz to 20 kHz is also the average frequency range for most decent quality headphones.
The majority of human voices range between frequencies of 100 or 200 Hz to 8 kHz, so even if you lose a lot of your ability to hear high frequencies, you should still be able to understand human speech pretty well, even without the use of hearing aids.
As for singers, the different vocal ranges also are within limits of frequency. For example, a bass singer will probably have a voice that has a lot of low frequencies. The average bass vocal range in terms of frequency is 82 Hz to 330 Hz. The average soprano vocal range is from around 260 Hz to 1,050 Hz.
Because instruments and voices are much more complex than a simple computer generated sine wave, for example, they don’t just produce one single core frequency, they produce multiples of the core frequency. These multiples are called harmonics.
Since these are multiples of a fundamental, core frequency, that means that the fundamental frequency is multiplied by two, three, four, or higher to create the harmonics of a waveform. If a note is played at 440 Hz, the harmonics would be at 880 Hz, 1,320 Hz, 1,760 Hz, and more.
Let’s talk for a second about hertz and frequency within a more specific topic: speakers, headphones, and microphones.
Microphones, headphones, and speakers all have something called a frequency response or frequency response range.
Frequency response is the range of frequencies that a piece of audio gear such as a microphone, pair of headphones, or pair of speakers can reproduce.
Professional microphones, speakers, and headphones can easily reproduce sound waves, especially sound waves with frequencies beyond the extent of average human hearing.
For example, a Neumann U 87 condenser microphone has a frequency response of 20 Hz to 20 kHz. This means that it can reproduce sound waves that move at speeds of 20 wave cycles per second to 20,000 wave cycles per second.
Here is a chart of the frequency response of the Neumann U 87’s cardioid pickup pattern.
You can see that there is one line that starts at the 20 Hz mark and ends at the 20 kHz mark, and another line that starts at around 50 Hz joins the first line.
The line that spans from 20 Hz to 20 kHz shows that that is the frequency response range of the U 87. With the U 87’s high pass filter activated, more of the lower frequencies are cut out, thus why the second line starts at 50 Hz.
With speakers and headphones, there is also a frequency response range, and again, it is simply the range of bass, mid, and treble frequencies that can be reproduced by the audio gear. The Audio-Technica ATH-M50x closed back headphones have a frequency response range of 15 Hz to 28 kHz.
Another important topic that combines the music and technology worlds is something called sample rate. When you’re making music in a DAW (digital audio workstation) on a computer, once you are finished with your song and want to save it as an audio file, you export the song, and during the exporting process is when sample rate becomes relevant.
To understand sample rate, first one must understand how a computer processes analog sound waves and turns them into digital audio.
During the exporting process, your computer takes snapshots of things like the amplitude of your song’s sound waves. These snapshots are called samples. Your computer takes these snapshots at certain points in the audio file and then converts that information into binary information that is then stored elsewhere on the computer as your audio file.
There are thousands of samples taken per second in a single song, which then results in good quality audio reproduction.
The sample rate is the speed at which your computer takes snapshots of the song’s sound waves. Sample rate is measured in kilohertz (kHz).
In your DAW, you can adjust the sample rate in the settings menu. There are various sample rates to choose from, and they may seem random, but they’re actually not. Sample rate is what determines the range of frequencies captured in audio.
The most common sample rate is 44,100 samples per second or 44.1 kHz. In order to capture the full wave cycle of sound waves in a song during the exporting process, the sample rate needs to be at least double the range of human hearing (20 Hz to 20 kHz).
Technically 40 kHz would be a fine sample rate, but due to artificial frequencies being created by the analog to digital converter during this process, 44.1 kHz ensures that everything is captured properly, even the artificial frequencies.
Another popular sample rate is 48 kHz, which means there are 48,000 samples taken in a second, resulting in an even more accurately exported file and even higher quality audio.
Understanding hertz in technology
Hertz in technology is the same as in music – it measures frequency. However, with technology, hertz can be used to measure things like computer processor speed or refresh rate of a device’s display.
Refresh rate, or frame rate, is the speed at which a monitor’s display is renewed per second, and it’s also measured in hertz. Each time the display is renewed and redrawn, it’s updated with new information or images.
For example, a monitor with a refresh rate of 60 Hz will renew and redraw 60 times per second.
It is important to make sure your monitor’s refresh rate is set to something that works for you. If your refresh rate is too low, it can cause strain on your eyes after long periods of looking at the monitor, but if the rate is too high, it can decrease your FPS, or frames per second.
FPS is the measurement of how fast data is transmitted in the form of consecutive images, or frames, a computer or TV can modify or convert into another format and ultimately display. One hertz equals one frame per second.
Typically with computers or gaming consoles connected to a TV, a high refresh rate makes for a smoother image on screen and allows for the display of more frames per second. However, this isn’t always the case when it comes to gaming. If your game requires a refresh rate that is higher than what your monitor can do, you’ll likely have some lag or blur when playing or boosting games with a lot of action. Lag also depends on other things, like your computer’s graphics card, memory, and processor speed.
Hertz are also used as units of measurement when talking about smartphone screens and their refresh rates. The average smartphone will have a refresh rate of 60 Hz, although some phones that are especially made for gaming, like the Razer Phone, have a refresh rate greater than 60 Hz.
Hertz is also used to measure computer processor speed. Gigahertz, or GHz, is the measurement unit of the clock rate or clock speed. The clock speed rate of a CPU is a measure of the number of clock cycles a CPU can perform in a second.
An oscillator circuit sends electricity to a crystal, and when the electricity hits the crystal, the crystal vibrates, keeping time. So if a computer processor has a speed of 1.8 GHz, that means that the crystal in the main CPU vibrates to keep time 1,800,000,000 (1.8 billion) times per second.
The higher the clock speed rate for the processor, the faster the CPU can process data and change it into binary code to store, modify, or access files and perform tasks. This will result in faster overall computer performance whether you are running multiple programs at the same time, recording audio or video, exporting files, gaming, and more.
Hertz doesn’t have to be difficult to understand, and while it may seem daunting at first, it’s not as confusing as you probably thought it was going to be.
Now that the concept of hertz is not a mystery to you anymore, you can be comfortable changing the settings of your computer or DAW in order to get better computer performance, better quality audio, better quality graphics, and more.
If you are looking to purchase speakers or headphones for music production or listening to music, you now will also have a much easier time picking out something that has a good frequency response range that allows you to hear the full frequency range of your music.
When looking for a new computer, you can remember that hertz also has an impact on what your decision will end up being and you can make a better informed choice to get exactly what you are needing.
For more articles on music and technology, be sure to check back with us soon!