As someone who has been obsessed with all things audio for most of my life, I always find it interesting to hear what people have to say about sound quality. I find it especially fascinating to hear the opinions of people who aren’t in the audio field themselves. A great live sound engineer once said to me, “Most folks know something doesn’t sound right; they may not be able to tell you why, but they know something sounds off the mark.” I think there’s a lot of truth to that statement. Just ask my wife, who’s heard a lot of the songs I’ve worked on since I first started engineering, in my early 20s. I’ve gotten reactions from her that range from, “Something doesn’t sound right” to “Please make it stop.” Then again, maybe she just can’t stand me. Sorry, bad example.
Anyway, there are myriad factors that go into the quality of a sound being reproduced, which may color that sound in some way before it gets to your ears. But, before it’s reproduced by whatever set of speakers you’re listening to, there’s the record itself, which, for the purposes of this article, we’ll assume is a commercial recording that sounds great on its own. Each voice and instrument was likely recorded professionally in a recording studio, and was subsequently mixed and mastered. During the mastering process, the final step of making a record, an engineer works in a perfectly tuned acoustic space that is designed to reproduce the audio as neutrally as possible. In other words, they are hearing the audio as it truly sounds. Mastering engineers look for areas in the frequency spectrum of the audio that are “out of balance,” so to speak. They use tools such as equalizers to correct these issues, with the aim of making the record sound as good as it possibly can on any given system.
But, the truth is, unless you’re listening to the record in a top-notch mastering studio, you’re never hearing the music exactly as it was originally intended. Whether it’s your favorite headphones, Bluetooth speaker, or home theater system, they all will color, or affect, the sound in some way. In addition to what you’re listening to the music on, where you’re listening to it makes a big difference, as well. If you’re listening to music on your headphones in the subway, your music has to compete with a ton of background noise, which impacts your overall listening experience. On the other hand, if you’re listening on the Bluetooth speaker in your kitchen, your car, or in your backyard, the acoustic environment itself will have a huge impact on what the music sounds like. This is because each untreated acoustic space will inherently have resonances, or “overloads,” so to speak, in particular frequency ranges. I think it’s perfectly fair to say that each sound system on which a piece of audio is listened to, and each acoustic environment it’s listened to within, is a completely unique listening experience unto itself. Whether the unique characteristics of a given sound system and room affect the audio in a way that’s pleasing or unpleasing is ultimately up to the listener. And luckily, as listeners, we have some agency over how the audio we listen to is experienced.
In the field of live sound reinforcement and acoustics, there is a concept known as “tuning the room,” which in simple terms can be described as an effort to compensate for the shortcomings of an acoustic space by altering the frequency response of the sound system using tools such as equalization. You can essentially do the same thing at home, if your Bluetooth speaker sounds too trebly or harsh in your kitchen, for instance, or if you have a particularly bassy set of headphones that tend to tire your ears during extended listening sessions.
The most essential tool in any sound system optimization is the equalizer. If you use a streaming service like Spotify, or Apple Music, they both come with equalization tools that allow you to customize the sound of the music you hear, whether you’re listening on your headphones, car stereo, or Bluetooth speaker. Spotify has a full graphic EQ, which is great for making easy, yet effective adjustments. Apple Music on iOS has a long list of well-labeled preset EQ curves that sound great, but if you really want to customize the sound to your exact taste, you’re better off accessing Apple Music through iTunes on your desktop computer and utilizing its graphic equalizer function.
Here are some general rules of thumb you may want to consider the next time things aren’t sounding the way you want them to sound.
Low End Theory
The low end, or bass, frequencies are what give the music its body and force. If the low end is tight and punchy, it can definitely “move the crowd” more so than any other frequency range can. But, too much bass can sound “flabby” and tiring on the ears. You may have a certain pair of headphones that tire your ears during long listening sessions. If that sounds familiar, try adjusting your EQ to slightly reduce the bass frequencies anywhere from 60 to 150 Hz until it alleviates that tiring in-ear pressure that can occur. On the other hand, if you’re listening to music on your phone using its internal speakers, you may want to boost this range to overcompensate for the lack of bass response from the tiny speakers. I find it especially helpful to boost this frequency range when listening to jazz and similar styles on my phone speakers to ensure that I catch all of the bass guitar and kick drum interplay.
The Mud Zone and Upper Midrange
If your music sounds “muddy” and seems to lack definition, try decreasing the level of the low-mid frequencies in the 200-400 Hz range. Try this on earbuds or car stereos that seem to lack clarity, and see if you can improve things. The upper midrange on a graphic EQ refers to the 2 to 4 kHz range, which is a great range to lower if the music sounds harsh to you.
The presence range is right in the 4-6 kHz area. This is a great range to boost when you want to increase vocal intelligibility, such as when listening to a podcast on a busy subway car with a ton of background sound.
I hope you have gained some knowledge from this general overview of using an equalizer. If you have any questions at all, feel free to leave them in the Comments section, below.