Speaker Positioning Advice for Stereo Systems

When buying a home audio system, you have to remember that your acoustic environment is critical to the performance of your sound system. If you want to get the very best out of your hi-fi setup, you will have to take this into consideration. Below is a professional guide to mastering your room’s acoustics through placement, covering the most common home scenarios.

1. The Foundations: Stereo Geometry

• Identify your Main Listening Position. This is going to be a focal point for your listening. Whilst most home speakers can perform off-axis ( some better than others), there is always going to be a sweet spot for optimal performance and it is important to focus your system around it, even if practicality limits your options.
• The Equilateral Triangle: a great basic rule to follow is to have your left speaker, right speaker, and listening position aiming to form a perfect equilateral triangle. For example, if the speakers are 2.5 meters apart, you should be 2.5 meters away from each. If your speakers are too narrow, your performance can lose scale and separation, too wide and it becomes uncentered and disjointed.
• Ear-Level Height:The tweeter must be close to ear level in most cases, unless the speaker is specifically designed otherwise. This is due to the fact that high frequencies are highly directional and if they are firing at your chest or over your head, you lose a lot of clarity and detail. This can also lead to an unbalanced performance, due to using the speaker not in its intended setting.
• Symmetry: The distance from the left speaker to the left side wall should ideally match the distance from the right speaker to the right side wall. Asymmetric reflections cause the sonic imaging and the illusion of a realistic and centered soundstage to become unbalanced and blurred.
• Toe-in:  In most cases, aiming the speakers directly at your ears or just slightly wider is the way to go, however there are speakers that are designed to be placed facing straight at the opposite wall ( such as certain hybrid, ribbon, horn-loaded and point-source driver models)

2. Managing the Walls

Speaker-Boundary Interference Response happens when low-frequency waves bounce off the wall behind the speaker and cancel out the direct sound. Getting this right is absolutely essential for the correct representation of the low frequencies and creating depth in the soundstage.

Please note that the speaker design and size as well as the material and the thickness of the walls will affect this response, so it is always necessary to experiment to get the correct feedback.

In general, try to avoid placing the back of your speakers very close to the front wall. A short distance often causes unwanted reverberation which will result in a boomy and uncontrolled bass response.

Aiming for a distance which is 1/5th of the length of the room is a great place to start in most spaces where it is possible. However if practical concerns do not allow that, moving the speakers inch by inch off the wall will allow you to find a point where the reverberation is minimised. Every speaker will have its own optimal distance. However, for back-ported speakers, a distance of at least 15-20cm is generally recommended.

Last but not least, the distance from each speaker to the back wall and side wall next to it should not be equal, as this can create unwanted wave interference at that particular wave length.

3. Additional tips

• The L-Shaped or Open Plan Room

These are considered a challenging environment because one speaker usually has a wall next to it while the other fires into a much larger open space. To address this use more toe-in on the speaker near the wall to minimise side-wall reflections. If possible, use a heavy rug or a bookshelf on the “empty” side to act as a pseudo-wall to balance the acoustic pressure.

• The Subwoofer Advantage

Adding at least one subwoofer to your system can be a huge advantage. Not only does it add low frequency information, it helps ease the load on the speaker woofers and creates better sound pressure levels in your listening space. All of this can act almost as a form of room correction, as more of the direct higher frequencies will reach your ear and thus the effect of reflections will be lowered. 

Most of the lower bass frequencies will emanate omni-directionally around the subwoofer/woofer, but it accumulates in certain spots of the room, particularly around corners and along the boundaries. Hence a correct setup is absolutely essential to be able to take advantage of these benefits. Adding a second subwoofer can stack and amplify these positive effects, and also minimise the uneven spots for a more balanced sound distribution and a stereo effect.

• First lines of reflection

As you can see, minimising and controlling for reflections is the main challenge for achieving optimal in-room response. Apart from placement, acoustic absorption on first lines of reflection is the best way of keeping them in check. A simple trick to find those points is with a mirror:

1. Sit in your focus position..
2. Have a friend slide a mirror along the side wall.
3. The moment you see the tweeter of the speaker in the mirror, mark that spot.
4. This is yourFirst Reflection Point. Placing a rug, a curtain, or an acoustic panel here will instantly improve your soundstage.

The same principle applies to floor and ceiling reflections, which should also be absorbed.

This first  reflection point is going to mark the reflection of the very highest frequencies. Moving the absorber closer to you will cover lower octaves. Small movements (even 5cm) can result in audible changes. Don’t be afraid to experiment.