Excerpted and adapted from the Fifth Edition of The Complete Guide to High-End Audio. Copyright © 1994–2019 by Robert Harley. For more information, visit hifibooks.com. To order call (800) 841-4741.
The single most important factor in getting the best sound from your system is the positioning of the loudspeakers and the listening seat. Just by moving your speakers you can dial-in the system’s overall tonal balance, the quantity and quality of bass, soundstage width and depth, midrange clarity, and imaging. As you make large changes in speaker placements and then fine-tune these positions with smaller and smaller adjustments, you’ll hear in the sound a newfound musical rightness and seamless harmonic integration. When you get it right, your system will come alive.
Here are four simple techniques that will make your speakers sound better than you thought possible—without costing you a dime.
1) The relationship between the loudspeakers and the listener is of paramount importance.
The listener and speakers should form an equilateral triangle; without this basic setup, you’ll never hear good soundstaging and imaging. The listener should sit exactly between the two speakers (called the “sweet spot”), at a distance away from each speaker that’s slightly greater than the distance between the speakers themselves. If you don’t have this fundamental relationship, you’ll never hear good soundstaging.
Setting the distance between the speakers is a trade-off between a wide soundstage and a strong center or “phantom” image. The farther apart the loudspeakers (assuming the same listening position), the wider the soundstage. As the speakers are moved farther apart, however, the center image weakens, and can even disappear. If the speakers are too close together, the soundstage narrows.
Speakers placed the optimal distance apart will produce a strong center image and a wide soundstage. A musical selection with a singer and sparse accompaniment is ideal for setting loudspeaker spacing and ensuring a strong center image. With the speakers fairly close together, listen for a tightly focused image of the singer exactly between the two speakers. Move the speakers a little farther apart and listen again. Repeat this move/listen procedure until you start to hear the central image become larger, more diffuse, and less focused, indicating that you’ve gone slightly beyond the maximum distance your speakers should be from each other for a given listening position.
2) Proximity of loudspeakers to walls affects the amount of bass.
The nearer the loudspeakers are to walls and corners, the louder the bass. You can reduce excessive bass by moving your speakers farther out into the room. How far into the room the speakers are positioned also affects the clarity of the bass because certain speaker locations don’t excite the room’s resonant modes as strongly. You can reduce these resonances by following the “rule of thirds” which states that, for the best bass response, the distance between the speakers and the wall behind them should be one-third the length of the room. This is often impractical, but one-fifth the room length is generally the next-best location.
3) The farther out into the room the loudspeakers are, the better the soundstaging—particularly depth.
Positioning loudspeakers close to the wall behind them can destroy the impression of a deep soundstage. Acoustically reflective objects such as a television or fireplace near the speakers can also degrade soundstaging. A deep, expansive soundstage is rarely developed with the loudspeakers near the front wall; pulling the speakers out a few feet can make the difference between poor and spectacular soundstaging.
4) Toe-in affects tonal balance, soundstage width, and image focus.
Toe-in is pointing a loudspeaker inward toward the listener rather than aiming it straight ahead. Toe-in is a powerful tool for dialing-in the soundstage and treble balance. There are no rules for toe-in; the optimal amount will vary greatly with the speaker and the room.
Toe-in increases the amount of treble heard at the listening seat. You can fine-tune a speaker’s treble balance by adjusting the amount of toe-in in small increments and listening after each adjustment.
Toe-in also increases soundstage focus and image specificity. When toed-in, many loudspeakers provide a more focused and sharply delineated soundstage. Images are more clearly defined, compact, and tight, rather than diffuse and lacking a specific spatial position. The optimal toe-in angle is often a trade-off between too much treble and a strong central image. With lots of toe-in, the soundstage snaps into focus, but the sound is often too bright. With no toe-in, the treble balance is smoother, but the imaging is more vague. You can find the best balance simply by listening and adjusting.
Toe-in also affects the sound’s overall spaciousness. No toe-in produces a larger, more billowy, less precise soundstage. Instruments are less clearly delineated, but the sound is bigger and more expansive. Toeing-in the speakers shrinks the apparent size of the soundstage, but allows more precise image delineation. Finally, identical (and I mean identical) toe-in for both speakers is essential to realistic soundstaging. There’s no substitute for a listen-adjust-listen process to realize ideal speaker placement.