Audio enthusiasts, many of whom self-identify as audiophiles, are constantly in pursuit of perfection. Oftentimes, that starts with chasing the best gear. But after learning the basics of Hi-Fi, getting the best equipment is only half the battle. Setting that equipment up is just as critical and can make all the difference to the listening experience.

One of the most finicky aspects of a setup is knowing where to place your speakers. The goal for a two-speaker stereo setup is to find the so-called sweet spot — that is, the best distance from the listening position to the speakers, and the best angle for the speakers relative to one’s ears. When placed correctly, a pair of loudspeakers should provide great stereo imaging. When done well, this can offer a wide, focused sound. But finding the sweet spot is a Goldilocks affair. Place the speakers too far apart, or get the listening position wrong, and frequencies may sound unbalanced with a collapsed stereo field, making the music sound flat.

One audio expert claims to have found the golden ratio for speaker placement, and it’s become known as the 83% rule. This rule of thumb dictates that the distance between the two tweeters of one’s speakers  — the portion which outputs higher frequency sounds  — should equal 0.83 when divided by the distance to the listener’s ear. Here’s what you need to know, and what else you may need to do beforehand to make this formula work for your personal Hi-Fi setup.

In a video on YouTube channel The Absolute Sound, audio setup expert Jim Smith claims to have concocted a clever yet simple formula that can help determine where stereo speakers should be placed. The formula involves measuring the distance from the center point between two loudspeakers, which we’ll call “X.” The ‘Y’ variable is the distance from the left or right speaker to the listener’s corresponding ear. This rule states that dividing X by Y should equal 0.83. Expressed another way, the distance between one’s ears and the speakers on either side should be 83% of the distance between the two tweeters of your speakers.

Smith does make clear that this is just a rule of thumb, and that some placements work at slightly lower or higher ratios. He also clarifies that this formula assumes a room that’s already treated for quality audio, with the listening position fixed in place before the speakers are positioned. Even so, he insists that most listening set-ups that fit those criteria he’s encountered over the years have measured within at least a couple of percentage points of his formula. So, if you’re struggling to get great sound from your loudspeakers or the best studio monitors, it might be worth busting out a measuring tape and giving this formula a shot.

As noted, Jim Smith’s 83% rule for speaker placement should be the final step in setting up a great stereo playback system. On top of requiring the room to be conducive to audio and treated to eliminate reflections that degrade sound quality, the equation also needs a listener to have a pretty fixed listening position.

Smith notes that the speakers’ toe-in must also be adjusted. This refers to the angle of the speakers, since stereo loudspeakers are not placed head-on to the listener, but are angled toward them from either side. Because speakers push out audio waves in a cone-shaped pattern, the toe-in of the speakers determines the angle at which those waves enter the ear. These are the sorts of details that much more than wasting money on overpriced audio cables or other audiophile red herrings

Another thing to be aware of is that this ratio is only meant for music listening, not for studio production. It is meant to create a dynamic sound, but it will ruin the more neutral sound that’s necessary for technical studio work. If you’re listening back to your music after a production session, using the 83% rule may help you understand how your listeners will hear your music, but it should not be used while actively composing or mixing.