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Speakers are the safest and least invasive audio listening devices. In an ideal world, everyone would be using speakers to listen to music while commuting and hanging out in public. Unfortunately, not everyone is so accomodating; hence, you’ll most likely be limited to using speakers in your own home, studio, or outdoor picnic spots.
Nonetheless, it’s always better to understand the different types of speakers and their sound quality. One of the most important indicators of this (and often times overlooked) is the frequency curve.
So, what is a good frequency range and graph that’s good for speakers?
The short answer: most good speakers will deliver quality sound if the frequency range falls within 20Hz-20kHz (audible frequencies) and has a frequency response graph that matches the ideal frequency response curve (flat curve) as much as possible, despite having constant fluctuations.
Flat curve? Audible range? If any of these don’t make sense. Don’t worry because I’ll go over everything you need to know in order to understand the frequency ranges and response curves of speakers in the following sections:
Understanding frequency response when it comes to good speakers
Common questions regarding frequency response in speakers
Table of Contents
What is a Good Frequency Response For Speakers?
We’ve already established that the frequency response and the frequency range are significant factors in determining the quality of sound. However, we have yet to understand how it impacts our listening experience.
So in this section, we’ll talk about the frequency range and frequency responses of speakers. On top of that, we will discuss how they differ based on sound quality, form factor, and intended applications.
The Frequency Range Specification of Speakers
Sound travels through the air as a wave, and because of this, they have certain frequencies. Since speakers are used to translate the input audio signal and play sounds, they have to recreate the frequencies accurately to create a more authentic and enjoyable listening experience.
However, speakers cannot recreate sounds in the entire frequency range. Their hardware is limited (or intentionally designed) to deliver a range of frequencies that fall within the human audio spectrum range of 20Hz-20kHz. (Even if the input signal contains these frequencies.)
So if the speakers have a limited frequency range, they won’t be able to reproduce frequencies that don’t fall under this limit. For example, a subwoofer, which is designed to reproduce lower frequencies has a limited range of around 20Hz-200Hz. Frequencies that don’t fall into this range are sent to the supplementing drivers (woofers or tweeters).
How Manufacturers Specify the Frequency Ranges
Most manufacturers will list the frequency range in the speaker’s spec sheet, and the majority of speakers on the market will offer a frequency range that covers the human audio frequency range of 20Hz-20kHz.
So if you are thinking of buying new loudspeaker audio system, audio device, or karaoke speaker, I always recommend checking the frequency range spec in your desired speakers. If that spec is missing, it’s best not to spend your money on those speakers because they will definitely be low-quality speakers with a limited range.
Some speakers will also have a frequency range that’s outside of the audible range (such as 6Hz-51kHz) these devices have such an extended range to create a more stable 20Hz-20kHz frequency response. Also, devices with extended frequency response can make you “feel” the musical instruments on either end, whether it’s booming bass frequencies or tinny high notes.
What is Frequency Response in Speakers?
Even though speakers will have an impressive audio frequency range listed in their spec sheet. The frequency range alone is not enough to size up a speaker’s quality. You need to understand (or visualize) how well this speaker is capable of recreating sound as accurately as possible, this is where the frequency curve comes in.
The frequency curve plots the frequencies that the speaker is capable of producing, along with their corresponding sound pressure level (loudness measured in decibels, dB) under constant power input. The curve starts from the bass frequencies, goes through the midrange frequencies, and ends up at higher frequencies, just after 20kHz.
However, the ideal flat frequency response in speakers and headphones is impossible to recreate in real life, mainly due to hardware constraints and use-case requirements; hence, you shouldn’t always go for the ideal flat response. Instead, look for one that fits your requirements, whether it’s a (somewhat) neutral or altered response.
What’s a Good Frequency Response Curve for Speakers?
Good frequency response can make or break a speaker system. With such importance placed on this measurement, you would think that brands would include this graph on their datasheet. Unfortunately, many brands and manufacturers don’t include the frequency curve. It’s up to tech reviewers to create this graph.
The best way to do this is to search for the frequency response of the speakers. Many third-party tech reviewers carry out frequency response measurements and produce the response graphs of many well-known speakers.
As a rule of thumb, if the compensated frequency response curve sits around the 80dB SPL level without deviating too much throughout the entire frequency spectrum, it can be considered a good speaker system. Also, if the frequency range covers the audible spectrum, you are good to go.
Let’s talk about a couple of examples so we can really visualize what a good frequency chart looks like by comparing a very common set of bookshelf speakers.
Undersdtanding the Frequency Response of the Fluance Elite SX6
For example, let’s consider the frequency response of the Fluance Elite SX6, a highly affordable 2-way bookshelf speaker system.
As you can see, the graph starts at 20Hz and ends at 20kHz. Even though it starts from a steep drop of 55dB SPL at 20Hz, it rises to 80dB SPL at 100Hz (where the majority of bass frequencies lie) and maintains a steady climb up to 20kHz. There are no rapid oscillations/fluctuations or intense peaks/drops.
It covers the entire human audio spectrum with only a slight drop in the sub-bass response. (It is very common among surround speakers, center-channel speakers, two-way and three-way speakers) Nonetheless, you can supplement this drop by adding an external subwoofer to the system. Even without one, the Elite SX6 does a pretty decent job with its existing woofer, and you would barely find music that uses these extreme ends of the frequency spectrum.
Therefore, the effective frequency response of this device is 60Hz-20kHz with 89±3db sensitivity, a very decent overall response for bookshelf speakers.
Common Questions Regarding Frequency Response in Speakers
Why Can’t Speakers Achieve a Perfectly Flat Response Curve?
There are a lot of factors that can affect the frequency response of most loudspeakers. However, it’s primarily due to hardware limitations such as enclosure materials and design, impedance matching, size of the drivers, etc.
On top of that, due to size limits and acoustics, most drivers can only achieve a (somewhat) flat response if they are designed to output a narrow frequency band. Therefore, to get a more overall flat curve, the speaker system utilizes multiple drivers that cater to different frequencies. This is why, in most loudspeaker systems, we have the woofer (or subwoofer) for low frequencies, midrange driver for the mids, and tweeters for the high frequencies.
For producing lower frequencies, you need a larger diaphragm and vice versa; hence, the reason for a surround sound setup would come with a dedicated subwoofer and usually include two drivers (a tweeter and woofer) in the main speaker enclosure.
Why is it better not to have a perfectly flat response?
Also, theoretically, if we managed to achieve a perfectly flat response, it is not guaranteed to provide an enjoyable listening experience.
A completely flat and neutral audio response is great for studio work, or professional applications, where you need to listen to the most accurate and raw sounds. However, when it comes to listening to music, you need a little emphasized bass response to enjoy it.
Also, a perfectly flat response is going to sound very different to different people. Not everybody prefers to listen to music in the same exact way, and some listener’s may consider the truly neutral flat response curve to be “boring.”
Which is better? 3-Way or 2-Way speakers?
Two-way speakers include a woofer and tweeter. As we saw in the case of the Fluance Elite SX6, the woofer handles most of the upper bass and mids, while the tweeters take care of the high notes.
Meanwhile, Three-way speakers (such as the Fluance HiFi 3-Way) have more accurate and flat curves than their two-way counterparts since they have a dedicated midrange driver.
So, in the debate of two-way VS three-way loudspeakers, three-way speakers are always superior in quality. However, it mostly depends on the internal components, materials, crossover setup, and frequency response; hence, a high-quality two-way speaker can beat an inefficient three-way.
Frequency response, which includes the range and response graph, is a very important specification that will determine the range and quality of sound. Even though most speakers cannot achieve a perfectly flat response in real life, they do a pretty decent job of recreating sounds accurately as possible.
So as long as the speakers can cover a wide frequency range of the human hearing spectrum (20 Hz-20,000 Hz) and have a more natural response graph, you have a better chance of finding speakers with the best frequency response.