The brain is an amazing thing. It can process sight and sound in unbelievably ways to create a mental awareness of the world around us which we unconsciously rely on to know where we are and the location of things around us which might be a threat or a treat. Our ears are placed wide on our heads to allow for stereo location which is enhanced by using our necks to move our heads around if we want to pinpoint a sound. Since our outer ears are essentially directional filters - focusing our hearing towards sounds in front of us - we instinctively turn to face a sound if we have cause to pinpoint its location in case we need to escape it, hunt it, or merely identify it with our eyes to determine what to do, if anything. This mechanism is amazing!
Stereo sound reproduction takes advantage of most of our physiological skills are judging location in front of us by one speaker not only feeding a signal to one ear, but by each stereo speaker also feeding sound to the other ear. Our brains measure the difference in distance from one ear to the other by the time delay between the two sound sources, but also based on the loudness of sound as it reaches each ear. That’s why a sound played equally loud from two stereo speakers in a well-aligned listening room will appear to be coming from directly in front of us – a phantom center speaker. That effect can allow a sound engineer to place a sound anywhere in the virtual soundstage in front of us with just two speakers, and in a great room with great speakers the virtual soundstage can even extend beyond the width of the physical speakers. With the application of fancy DSP algorithms, two stereo speakers can even fool us into believing the sound is to the side and even behind us. But that effect is only for the primary listener in the perfect location in the room.
Surround sound through the use of multiple speakers spread around the room can ensure multiple people experience the effect of sounds coming from anywhere in the 2-dimensional 360-degree plane at eye level and with new surround formats which place speakers above the listener some of the entire 3D audio environment can be produced in the room. But, there are a few issues which must be dealt with concerning the placement if speakers.
Several years ago, I wrote a long essay on the reasons a single rear surround speaker is inferior to having dual rear surround speakers, and I am recreating the basic knowledge today.
First off, we are pretty much incapable of holding our heads completely still while focusing on sound. We move our heads in tiny amounts all the time and sometimes quite consciously shift, tilt, and turn our heads when we are trying to understand what we are hearing. Our brains know how much we move our heads as we are doing it and comparing that motion to what sound is being processed to confirm or correct the mental mapping of the sounds being heard. This is why true binaural headphone recordings are not perfect at fooling a listener into believing they are in the audio environment of the recording (though some new VR technology which tracks head motion and adjusts the signal feeding the headphones is starting to solve the traditional binaural issues). So, fixed speakers in a room is often better than headphones at creating the impression of an ambient space with all the sounds seeming to come from their logical locations around a listener.
So, if you go with a traditional 5.1, 6.1, or 7.1 setup, where should you put the speakers?
Ideally, one would avoid a 6.1 setup if the money spent on the single rear surround speaker could easily be spent on two rear surround speakers in a 7.1 arrangement, or it could be applied to other parts of the system which are more impactful. I’ll get into that now.
Every comment below is based on direct radiating speakers. Using dipolar speakers for surround is a completely different conversation.
Stereo sound reproduction takes advantage of most of our physiological skills are judging location in front of us by one speaker not only feeding a signal to one ear, but by each stereo speaker also feeding sound to the other ear. Our brains measure the difference in distance from one ear to the other by the time delay between the two sound sources, but also based on the loudness of sound as it reaches each ear. That’s why a sound played equally loud from two stereo speakers in a well-aligned listening room will appear to be coming from directly in front of us – a phantom center speaker. That effect can allow a sound engineer to place a sound anywhere in the virtual soundstage in front of us with just two speakers, and in a great room with great speakers the virtual soundstage can even extend beyond the width of the physical speakers. With the application of fancy DSP algorithms, two stereo speakers can even fool us into believing the sound is to the side and even behind us. But that effect is only for the primary listener in the perfect location in the room.
Surround sound through the use of multiple speakers spread around the room can ensure multiple people experience the effect of sounds coming from anywhere in the 2-dimensional 360-degree plane at eye level and with new surround formats which place speakers above the listener some of the entire 3D audio environment can be produced in the room. But, there are a few issues which must be dealt with concerning the placement if speakers.
Several years ago, I wrote a long essay on the reasons a single rear surround speaker is inferior to having dual rear surround speakers, and I am recreating the basic knowledge today.
First off, we are pretty much incapable of holding our heads completely still while focusing on sound. We move our heads in tiny amounts all the time and sometimes quite consciously shift, tilt, and turn our heads when we are trying to understand what we are hearing. Our brains know how much we move our heads as we are doing it and comparing that motion to what sound is being processed to confirm or correct the mental mapping of the sounds being heard. This is why true binaural headphone recordings are not perfect at fooling a listener into believing they are in the audio environment of the recording (though some new VR technology which tracks head motion and adjusts the signal feeding the headphones is starting to solve the traditional binaural issues). So, fixed speakers in a room is often better than headphones at creating the impression of an ambient space with all the sounds seeming to come from their logical locations around a listener.
So, if you go with a traditional 5.1, 6.1, or 7.1 setup, where should you put the speakers?
Ideally, one would avoid a 6.1 setup if the money spent on the single rear surround speaker could easily be spent on two rear surround speakers in a 7.1 arrangement, or it could be applied to other parts of the system which are more impactful. I’ll get into that now.
Every comment below is based on direct radiating speakers. Using dipolar speakers for surround is a completely different conversation.
