The left and right speakers up by your TV are collectively known as your ‘fronts’, and together they handle the vast majority of music played with any system. The human ear can detect frequencies from 20Hz on up to 20kHz (20000Hz), and your front speakers are going to be responsible for anything above 60-100Hz. The lower stuff matters a lot too, but we’ll get to that later in my Subwoofer Guide.
Driver Types
Speakers contain two types of drivers, tweeters and woofers, with the tiny tweeter handling the higher pitches and the larger woofer handling the middle and low-end. As a rule of thumb, larger woofers equal greater low-end extension, as in they can reach deeper frequencies and at greater volume with less distortion. They’ll also move more air, making it easier to fill your room with sound, giving the sound-stage more depth and immersion potential. Another rule of thumb is that a larger speaker enclosure is going to create a fuller sound, and that’s where the floor-standing vs bookshelf speaker debate enters the stage.
Floor-standing Vs Bookshelf
Floor-standing speakers tend to be large, obviously stand on the floor, and have multiple woofers. They’re better suited to enormous spaces than bookshelf speakers, which are smaller, tend to have one woofer, and generally provide better value. As the name implies, bookshelf speakers need something to sit on, preferably dedicated speaker stands which can add slightly to the cost.
“I want my speakers to be loud, so I want the biggest floor-standers possible!” Not so fast pal. Take a look at this chart: Comparative dB Levels
Almost any speaker is going to get loud enough to push up into the areas where hearing damage is imminent, to the extent that a lot of manufacturers don’t bother listing the maximum output level. In reality absolute volume is unimportant, what’s important is whether your speakers sound good when the music is really loud and how filled out the sound-stage is. Above 85dbA will begin to cause hearing damage after eight hours of listening, above 91dbA after two hours (Dangerous Noise Levels). So don’t worry about output capacity, focus more on the sound quality when deciding on speakers.
Ninety-five percent of people will be perfectly happy with a pair of large bookshelf speakers, so unless you live in a massive cave or just love the look of floor-standing speakers you’ll likely get better value out of the bookshelves. If you don’t believe me, read my glowing review of my very own bookshelf speakers here. There are also many DIY speaker kits available that can offer great sound for the price, so if you don’t mind getting your hands dirty take a look into that.
Active Vs Passive
Moving on, speakers generally draw power from one of two sources. Speakers that require power from a receiver or external amplifier are known as passive speakers, whereas those with a built-in amplifier (they have a wall plug) are active speakers. Active speakers are generally more expensive and often have a direct input such as an aux-cord. In general passive speakers are the way to go for any significant investment as they are much more modular and can be reorganized for any changes down the road.
Sensitivity
Now that you know to get passive speakers, speakers in general have a number of specs to consider when you’re buying them. Sensitivity is the efficiency of the driver, i.e. how loud it can be driven by a standardized amount of power. The higher the sensitivity the better, as you require less power from your amplifier to get to higher volumes, minimizing your electricity bill, the strain on your amplifier and the chances of encountering clipping.
Frequency Response
Frequency response is another factor. Larger woofers and enclosures can help drive the low-end deeper, but in general a subwoofer is going to handle anything below 80Hz and do it better than your fronts. Still, the closer a speaker gets to the extremes of its claimed frequency response range the worse it is likely to perform, with large drops in volume and increases in distortion as you approach the limit. It’s best to have at least 15-20Hz of lee-way between the low-end limit of your front speakers and the cut-off where your subwoofer takes over, so speakers that can manage 65Hz and lower are ideal for a crossover of 80Hz. If you have speakers that can’t make it that low it’s possible to set the crossover higher, say 100Hz, to try and mitigate the poorer quality audio of small speakers trying to dig deep.
Impedance
Remember impedance from my A/V receivers section? Again, make sure to check that your receiver can handle the impedance of the speakers you’re looking to pair with it.
Subjective Qualities
Beyond specifications, all speakers have slightly different designs which produce different sounds, just like receivers. For example, Klipsch’s horn-loaded tweeters have a reputation for being rather ‘bright’, and can be divisive in a love-it or hate-it way. They seem to have reined it in with recent models, and personally I love their sound, but for that reason it can be difficult to buy speakers without first hearing them. Sound preference is completely subjective.
Generally it’s a good idea to visit a physical location that stocks the speakers you’re looking to buy to ‘audition’ them in store. If you can find somewhere to buy them with a solid return policy so that you can audition them in your own home then even better, the room is going to play a big part in how the speakers sound. Speakers can also sound different as they break in over time, so the sound you hear from the floor model can be off if they’re brand new rather than hundreds of hours of playtime in. I always give my new speakers about 10 hours of playing at low/medium volume overnight before I really try them out and form an opinion.
So, if you listen to a lot of music and have a huge listening space with vaulted ceilings, you’re going to want to have some floor-standers with multiple 8” woofers to get the best effect (though they are not at all necessary to get perfectly acceptable sound). If you only watch movies and have a 10×10 foot room with a quality subwoofer, you can get away with some high-quality bookshelves as your fronts running 4” woofers and probably not be missing much.