Gadgets and Reviews Daniel Redcliffos

I’m going to put this plainly: audio systems of all kinds need subwoofers—in the plural. The reasons for this I’ll get into later on, but understand that I’m talking about more than the wallop of home theater. I’m talking music. Subwoofers and TV caster are infamous for their inability to integrate in a 2-channel system. But is that a fault of the subwoofer or of the approach? Many people use subwoofers to extend the lower frequency spectrum, add more impact and weight, and obtain some texture that their conventional loudspeakers can’t portray. Often times this zeal creates an impressive sound that throws great punches, but calls attention to itself. So I offer a different approach. Subwoofers actually should NOT be used to increase bass output of the audio system. 

That’s not to say they won’t, but that’s not the reason they should be included. It’s all about loading. If you’ve ever played with port tuning of a speaker cabinet you know how dramatically the sound will change when you properly load the driver in the cabinet. This is precisely what a subwoofer is for. It loads the entire room. Rather than begin an in-depth look at room acoustics we’ll keep it simple. Constructive and deconstructive interference causes peaks and dips in the frequency response in a particular room. 

Because the wavelengths in the bass region are so long they tend to overlap wavelengths of higher frequencies. 

This is why bass trapping not only helps alleviate bass anomalies in a room, but also clears up phasing issues further up the spectrum equally as well. Subwoofers do a similar trick. With proper placement of the subwoofer in the room you have a more even distribution of bass. Frequencies below 120hz are basically omni-directional, so even if the woofer driver isn’t right next to your speakers it will still disappear when properly placed in a room. The key is proper placement and tuning. 

Using multiple subwoofers in a room allows you to eliminate the issues with room modes by having a more evenly distributed bass response.

 This also allows the subs to properly pressurize the room. When you read guides about subwoofer placement often times they describe placement either in a corner or slightly out from a corner. The intention is to take advantage of rear waves bouncing off the corners and creating constructive interference with the front wave to make the bass louder and more intense. The problem with this approach is that this interference is out of phase with the musical signal. So bass gets boosted in unintentional places. Not good. Further out from the wall gives more time before this interference occurs and presents a more even bass response from a single subwoofer, though perhaps with the perception of less bass. The lower frequencies are used to create the foundation of the music. 

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