Few understand how we come to hear the sounds of our daily lives. If you feel like you’re missing out, here is an easy-to-understand introduction to audio frequencies to get you started.
The pursuit of understanding Audio is a way of life. We love listening to it in a pair of headphones for some much-cherished audio nirvana. From Adele’s vocals that set fire to the rain to the distorted guitars of Metallica that make even bells toll, figuratively, of course; we love it all.
This beautiful thing called audio (music) is nothing but the movement of air molecules detected by the natural setup in our ears. Sounds travel through the air, water and even the ground. Once they reach our ears, they cause the delicate membranes in our ears to vibrate, allowing us to hear the voices of our loved ones listen to our favourite music or the calming sounds of raindrops and the distant sound of thunder. Admittedly, this is a simple explanation of a complex process.
It is known that human ears are susceptible to hearing sounds in the 20 Hertz to 20,000 Hertz range. This audio spectrum is the audible frequency range at which humans can hear, and a lot is going on in that spectrum. We’re sure you must have wondered if there’s more to it. This is what we plan on understanding and demystifying here.
We will be looking at the audible audio spectrum and its classification in terms of frequencies. Frequency, sometimes referred to as pitch, is the number of times a sound pressure wave repeats itself per second. A drumbeat has a much lower frequency than a whistle, and a bullfrog call has a lower frequency than a cricket. The low frequencies have fewer oscillations, and higher frequencies produce more oscillations of waves compared to low frequencies. The audio that we hear is broadly divided into 3 parts - Low, Mid and High Frequencies. Every sound you hear can be attributed to these ranges. The thump of a kick drum, vocals of a singer and the sound of a piano, all contribute their frequencies to form a beautiful song or music we hear.
Not just music but even the rustling of leaves in the wind, the noise of a bus in traffic blowing its horn - all come under these three frequencies. Here, we’re talking about the high and mid frequencies in particular.
Any object that produces a sound, vibrates air molecules at a particular frequency. It is indeed quite possible to differentiate between them. All you need to do is to pay attention while listening. For example, you might’ve noticed the different sounds the thump of a bass drum makes, say as compared to a flute. That’s because a bass drum is an instrument that produces sound in the Low frequencies while a flute usually produces a sound between Mid to High frequencies.
Good so far? Great, you now know that you can indeed differentiate between frequencies.
Now, there’s indeed a slightly tricky part to all of this. When listening to a sound, sometimes there’s no clear distinction between two immediate frequencies. There’s a bit of a grey area or overlapping. To keep grey areas like these into consideration, two sub-classifications were introduced, namely Lower mid-range (aka Mid-Bass) and Higher Mid-Range (aka Mid-Highs). Mid-Bass is the area where bass frequencies transition to mids and vice-versa. The same is applicable for Mid-Highs where transitions between mids and highs occur.
This might seem a tad bit confusing but let’s take a look below to understand it better.
LOW RANGE (20 HZ TO 200 HZ)
The lowest notes you hear in a song sit in this range of the spectrum, known as the low range. The kick drum or 808’s, in general, are the most recognised instruments in this range. As far as the impact of this range is concerned, this is the bedrock on which other sounds form a base over. The bass range is a range that many people are passionate about and has seen the most advancement in recording and reproduction technology. For music to sound whole, you need all the elements, and the bass is crucial as it can change the balance of the tracks, making it sound thin or fat. Hear some bass-heavy songs here.
LOWER MID-RANGE (200 HZ TO 1000 HZ)
The best example of an instrument for this range would be a bass guitar, brass instruments, and mid woodwinds, like alto saxophone and the middle range of a clarinet. Bass guitars sound low if you get our meaning. For example - the starting notes of bass in Queen’s iconic Another One Bites the Dust, are from a bass guitar and part of the mid-bass frequency range. Some male vocalists, cellos, and the crazy drops you hear in Dubstep (Skrillex - Scary Monsters and Nice Sprites) are some examples of sound in the lower mid-range.
Read more about bass here.
MID-RANGE AND HIGHER MID-RANGE (1000 HZ TO 5000 HZ)
This is the most audible range of the frequency spectrum. Vocals, guitar and many other sounds are the features here. It is this range that adds clarity and detail to the music and makes our listening experience engaging. The higher midrange is the range where your ears are the most sensitive. Consonant sounds in the voice, such as k, p, s, and t, are found in this range. Due to the design and evolution of our ears, the ear canal (the section that goes from the outer ear to the eardrum) naturally resonates in a range of around 3.5kHz. Whether you’re falling in love with A.R. Rahman’s 'Dil Se' or Michael Jackson’s 'Thriller', you get the meat of the most easily recognisable frequency here. Now, the next time you listen to a song, try and see if you can figure out and differentiate between the frequencies covered so far.
HIGH RANGE (5000 HZ TO 15000 HZ AND ABOVE)
Last but not least is the High frequency, also known as Treble. This is the sharp and shrill end of the musical spectrum that cuts across the others. As the name suggests, this range adds high-end clarity and brilliance to music. Flutes, bells and whistles, chimes and sometimes vocalists who can hit high notes, are all features under this range. The catchy flute tune you hear in Future’s 'Mask Off' is a lovely example of highs. Even when the song is playing, you can still hear the melody of the flute throughout.
Now that you have an understanding of the various frequency ranges in audio and how they react with other frequencies perceived by humans, do pay attention to any music you listen. See if you can differentiate between the various ranges. Do note that all frequencies must always be in balance otherwise the music tends to sound imbalanced. When listening to a song, keep the volume between medium and high, or at an appreciable level and listen. Try and isolate an instrument and try keeping track of that instrument throughout the track, this will help your listening skills and help you grow as an audiophile too. Lastly, we leave you with a song considered to indulge in all the frequency ranges wonderfully - Queen’s 'Bohemian Rhapsody'. See if you can keep track of the various frequencies independently. Once you do that, listen to the song while paying attention to the overall experience. We’re sure you’ll have fun.