It's no surprise that the world of hi-fi audio and surround sound is complicated. There are many popular beliefs about surround speaker systems that are misleading, or are simply not true. As experts of the craft, we're here today to break down these hi-fi myths and uncover the truth:
Subwoofers are often considered the optional component of a speaker system, but if you're talking about real high fidelity surround sound, this is far from the truth. A subwoofer is specifically designed to handle the low bass frequencies that can't be reproduced by satellite speakers. While large floorstanding speakers are better able to produce low frequencies compared to bookshelf speakers, neither of these can produce a proper bass sound the way a subwoofer does. A typical AV receiver has a bass management circuitry that directs all low end frequencies to the subwoofer, which lightens the load on the satellite speakers, keeping the overall sound clean and well-rounded.
Additionally, subwoofers receive the Low Frequency Effects channel in a surround mix. This means they are not just producing the low frequencies; surround sound mixes are specifically designed with a channel for a subwoofer, equipped with effects and nuances that can't be properly reproduced by other speakers. So, not only is a subwoofer essential, but having multiple subwoofers can fill out the sound even more, depending on the size of the system and the room.
Inherently, surround sound systems have the potential to create more immersive sound than a stereo system, but that doesn't mean they make everything sound better. The surround mix has the biggest impact on how audio is played back -- a bad mix means bad sound, and there are many factors that go into the quality of a surround mix.
Of course, the skill of the audio engineer plays the largest role in the quality of a mix. The setup of the audio engineer is important too. If the room and speakers are not properly calibrated then the mix will have maladjustments. The same goes for your setup at home -- poor speaker placement will impact how your surround system sounds.
Not all surround mixes are even created by an audio engineer, but are created using software. This is referred to as "upmixing", and involves using audio signal processors and other software to build a surround mix. These programs automatically convert a stereo mix into a multichannel mix using phase manipulations and other digital algorithms. While this is sometimes the only option if original surround mix files aren't available, upmixes generally don't sound nearly as good as professional engineered multichannel mixes.
When it comes to the optimal listening position, the sweet spot is actually smaller in surround sound systems. In a stereo system, you can hear accurate audio playback from multiple positions, even during audio engineering and mixing in a studio. When more speakers are added to a system, it becomes more difficult to properly align the speaker positioning. In a professional mix room, the space is treated acoustically and the speakers are accurately calibrated within the room to a fixed location in front of the console. The dimensions of the room also play a role in the perfect speaker positioning.
Most home theatres aren't set up in such ideal conditions, as they typically are placed in living rooms or spaces that are't designed for hi-fi listening. With so many variables affecting the actual sweet spot in a home theatre, using a calibration technology such as the Yamaha Parametric room Acoustic Optimizer can be extremely helpful.
Going along with the last myth, as the sweet spot becomes smaller, speaker positioning becomes more important for creating a location where the audio is perfectly calibrated. Here are some of the most common positioning limitations or mistakes in home surround sound systems:
Positioning errors like these can cause the audio to be muffled or improperly distributed throughout the room. Most casual listeners don't require perfect placement to get a satisfying sound, but many try to get as close as possible. Speaker positioning is an exact science, and you can read more about it here.