Speaker Buying Guide

Speakers, or 'Loudspeakers' are the window to your sound system, the quality of the speaker will determine how much benefit you get from the electronics feeding them. You could have the worlds best CD player and amplifier, but if it is a $20 speaker you would never get the benefit of those upstream components.

Speakers are therefore, a vital component in any sound system. Over the years there has been a saying, that you should spend a third to a half of your system budget on speakers and in light of the above information, that is about right. This buying guide will not advise you on which  speaker to buy, the goal here is to help you understand the terminology and to understand why in many cases, a small speaker will do a better job than a big one! Read on....

Tweeters and Woofers

Possibly the two most often heard terms when talking about speakers: tweeters and woofers. A tweeter is the small driver usually at the top of the speaker responsible for the high frequency output of the speaker, things such as cymbals and violins etc. A woofer is the larger driver responsible for the lower frequencies, such as deep bass, bass drum and church organs etc.

On some larger speaker systems, there may be another driver that sits in between the tweeter and the woofer, called a midrange driver. The midrange driver will reproduce a lot of the musical content in your music, including the all important vocals.

Two Way, Three Way

Two way and three way refers to the driver array in a given speaker. A two way speaker will have a bass driver and a high frequency driver. (woofer and tweeter) And a three way speaker will have a bass driver, a midrange driver and a high frequency driver. Is three way better than two way? Depends on who's opinion you want to believe, but the argument for a good two way is pretty strong. More on this soon...

Crossover Network

A crossover network is a passive electronic device inside the speaker that takes the incoming signal from the amplifier, and splits it into frequency ranges and in simple terms and in reference to a two way speaker, sends the high frequencies to the tweeter, and the lower frequencies to the woofer. In a three way design the sound is split into three ranges with the midrange driver being the added extra range.

You will see on a speakers specifications sheet a term called crossover point, this tells you at which frequencies the tweeter starts at, and where the woofer stops. In a two way speaker it is typically around 2.5kHz.

Frequency Response

This is the term applied to the sound gamut that a given speaker can reproduce. Often times you will see a speaker has a frequency range of 45Hz- 20kHz (k = x 1000) and what this means is that the speaker is capable of reproducing sound from 45Hz in the bass region right through to 20kHz in the high frequencies. But what do these number mean?

To put these numbers into perspective, an electric bass guitar has a low frequency range down to 60Hz-80Hz depending on tuning, a bass drum is in a similar frequency space. A piano can go down to 80Hz also, but tops out at 10kHz with overtones. The human voice can range from 120Hz (for deep baratone voices) with the 2-5kHz region covering presence and sibilance in the voice.

This may lead you to believe that you only need a speaker to cover the 80Hz to 10kHz range but that is not the case. Classical music can have frequencies much lower than 80Hz particularly if it is church organ music, and in the top end harmonics can require reproduction way above 10kHz, and the 'air' around the human voice, acoustic guitar and even cymbals all require those very high frequencies. A speaker that does not reproduce frequencies up to 20kHz will sound quit dull and lifeless.

Ported or Sealed?

Some speakers you will notice have a 'ported enclosure' which in layman's terms means a hole in either the front or rear of the speaker cabinet. A ported speaker is using the cabinet to generate frequencies lower than the bass driver is capable of reproducing in a sealed box.

This is a great way of getting a smaller speaker to provide bigger bass output, but it is not without it's problems. Firstly, in a sealed box, the crossover will roll off the lower bass frequencies more gradually (6db per octave), than in a ported box (12db per octave), because the ported box does not have the 'cussion' of air to help 'support' the bass driver.

But one of the main considerations it placement. A ported speaker, and in particular I am referring to a rear ported speaker, needs some space behind it. So if you are looking at a small speaker to place on your bookshelf (not ideal but we all have considerations to make), make sure it is NOT a rear ported design. This is where a sealed box, or at the very least a front ported design is better suited.

Impedance

The Impedance of the speaker represents the 'load' it puts on the amplifier, and it is measured in ohms. Most speakers are 8 ohm loads, but more and more we are seeing lower impedance speakers rated at 4 ohms. This figure is a average measurement, and speakers will at differing frequencies present a different load to the amplifier.

This specification is important, as some classes of amplifiers do not like low impedance loads. Most low end amplifiers are fine at 8 ohm loads, but start to strain under a 4 ohm load, particularly given that the load is not flat across all frequencies. See our Amplifier Buyers Guide for more on the effects of impedance on the amplifier.

Power Handling

Power handling is a recommendation of how much amplifier power a speaker can handle. Most speakers can handle around 80-100 watts of power. Does this mean you can not use an amplifier of higher power than the rating? No, in fact it is safer to use a higher rated amplifier than it is to use a lower powered amplifier.

So long as you do not do anything stupid in terms of turning the amplifier up to ear shattering levels, a higher powered amp is a much better choice simply because it will always be operating within its rated specifications, namely the distortion specification. If you chose to use say a 20 watt amplifier and were constantly running it at the upper end of it's abilities, then it will be operating at higher distortion levels, and it is distortion that will kill the tweeter in the speaker. So, high power used sparingly, is the smarter choice!

Efficiency

Efficiency refers to the audible output of a speaker for a given amount of input power. Typically this measurement is listed in DB (Decibels) for a 1 watt input. An efficient speaker is around 89-90db, an inefficient speaker would be around 83-86db. What difference does it make? A huge difference actually!

To understand the difference it makes, you need to understand the difference between 86db and 89db. That 'small' difference of only 3db is in fact huge. To get the 86db speaker to be as loud as the 89db speaker requires a doubling of power! So the 86db efficiency speaker requires 128 watts to achieve a 107db of output, where as the 89db efficiency speaker only requires 64 watts to reach the same level.

So what is it that makes one speaker more efficient than another? A few things can affect the efficiency, primarily the crossover network, depending on it's complexity, can suck a lot of the power your amplifier provides, but individual driver efficiency, and even the cabinet itself can effect the efficiency.

The take away here, is to be aware of a speakers efficiency, so you know how much power you will need to drive it. And remember, an efficient speaker does not mean a better speaker, on the contrary most exotic speakers are less efficient than the average speaker, and that is primarily due to the complex crossover networks they have. 

A two or a three way?

This is the big question, along with, floor standing speaker or a stand mount? If you 'think' you want a stand mounted speaker because 'it takes up less space' then think again. Most speakers on a stand take up just as much space as a floor standing speaker in terms of their footprint. There is another reason why you would want a stand mounted two way speaker however....read on.

The thing to understand is that the crossover point of a speaker is where 'problems' arise because as the bass driver rolls off at say 2.5Hz, the tweeter has to take over frequencies above 2.5Hz and there is usually two problems with this.

The crossover of a speaker rarely crosses over perfectly, and you get phasing issues at and around the crossover point. So it stands to reason that a three way speaker is even more complex and has even more issue to overcome.

Conversely a two way speaker is asking more of it's drivers than a three way in terms of the frequencies they are being asked to reproduced. My personal view is that a quality two way will do a better job than an equivalently priced three way. 

Of course if money is no object, buy the best three way you can find. But if you are on a budget, look for the best two way stand mount you can afford, before looking at the biggest three way floor standing speaker you can buy. Quality over quantity!

A final thought: A bass driver has to push a lot of air to reproduce bass notes, and a smaller driver can move more quickly than a large one, so the dynamics of a good small two way for me at least outway the shortcomings in bass extension. But that's me...