Proper speaker placement is one of the most important aspects of setting up an audio system. According to Jim Smith, the author of Get Better Sound, speaker placement alone accounts for 50% of the overall system performance. My own experience confirms that notion. The most important factors are the distance between the speakers, the distance from the speakers to the wall behind them, and the distance between the speakers and the listener. One should not compromise on the distance from the back wall. I believe that a minimum distance of 20 centimetres is necessary to achieve proper soundstage reproduction and the right tonal balance.
What one has to listen for while adjusting the distance from the back wall is not only bass quality and tonal balance, but also the width and depth of the soundstage. A proper three-dimensional soundstage is very important when it comes to realism in sound reproduction. When the speakers are placed too close to the back wall, the soundstage often feels compressed, the performers seem to overlap, and the whole presentation becomes flat and lacking in depth.
The same sense of spatial compression can be observed along the horizontal axis when the distance between the speakers is too small. The placement of the performers within the soundstage starts to feel unrealistic. I suggest leaving the toe-in angle adjustment until the very end because, even with the speakers pointing straight ahead, the overall image quality and tonal balance should already be in place. Trying to adjust both toe-in and speaker distances simultaneously makes the task much harder because the number of variables increases significantly. It is always a good strategy to break one complex task down into several simpler ones and follow a step-by-step adjustment process.
In my room, for example, the speakers are almost parallel. This is partly because they have wide dispersion characteristics, but also because of the room itself. The distance between the speakers and the listening position is around 1.8 times greater than the distance between the speakers themselves. This is simply due to the room’s limitations. I cannot move the door one metre to the left or place my sofa in the middle of the room. Most listening rooms impose similar constraints, and one does not have complete freedom to position the speakers and listening seat exactly as desired because the room still has to serve its everyday purpose. Unless you are one of the lucky people with a dedicated listening room, compromises are inevitable. The goal is to get the best possible sound without sacrificing the room’s practicality. Especially in a living room like mine, it should remain a comfortable place to live in.
In summary, the toe-in angle is a very fine adjustment tool for optimising the soundstage dimensions and the final tonal balance. However, even with the speakers positioned parallel to each other, the soundstage should not feel compressed but should fit naturally within the room. I would also like to mention that even very small adjustments of half a centimetre can make a surprisingly large difference. This may sound strange at first, but one has to remember that in an average 25-square-metre room an audio system is reproducing the sound of an entire band or even an orchestra. The acoustic space of the original recording venue has effectively been compressed many times to fit inside a domestic listening room.
We can think of this spatial compression as a scale of 1:5, 1:10, or even greater. Accordingly, moving the speakers just one centimetre farther apart may result in what feels like a five- or ten-centimetre increase in the perceived width of the soundstage. In situations where one speaker is close to a side wall while the other is not, treating the nearby side wall should also be considered in order to restore the natural balance that symmetrical spaces provide.
One should not take speaker placement recommendations for granted either, because every room is different. The placement guidelines published in magazines such as the German Audio, where speakers are categorised according to their minimum back-wall distance, can be useful as a starting point, but they should not be followed blindly. In Hobby HiFi, for example, Bernd Timmermanns recommends placing the Fostex BK108 horn speakers no more than 10 centimetres from the back wall. In my room, however, placing them 10 or even 15 centimetres from the wall produces a rather poor soundstage compared to what they deliver at distances of 20 centimetres or more.
Finally, don’t assume that once the setup is complete, it will remain that way forever. Every component change also changes the tonal balance of the system, which means that small placement adjustments may become necessary. Even changing an interconnect cable can alter the tonal balance enough to require further optimisation. For example, after my latest notch filter experiment, the speakers’ frequency response changed slightly, and I had to increase the distance from the back wall by about 2 centimetres to restore the full soundstage depth and tonal balance.
Thank you for stopping by!