AUDioImages

Speakers in general
Speakers, as we've already noted, come in every shape, size and colour you can imagine and some you can't. But what's the difference between the technologies. Here is a rough guide. "A rough guide" you say, well yes, because we don't want to get to technical on how each system works, we'll leave that for the different manufacturers. Suffice to say they work in their own ways and this list will just give you some "rough" information so you're not completely in the dark.


Dynamic speakers 
these are speakers that use drivers that are like we are all used to. Generally a round (although they're not all that way) driver made from a choice of materials like Paper, Plastic, Carbon fibre, Silk, Beryllium, Aluminium, Fibreglass, Kevlar to name but a few. These are supported by a rubber type flexible surround to a basket which can be made of Pressed steel, Cast steel, Aluminium and many more besides. Behind this will sit a magnet, sometimes small, sometimes huge! These drivers are mounted in a box (cabinet) usually which may incorporate different designs. For instance a box that is completely sealed would be called an 'infinite baffle' design. A box with a round hole in may be called 'a ported' design. Some with a slot in the box and a labyrinth inside of the cabinet can be 'a transmission line' design. Some with an ever increasing tunnel behind the driver (or indeed in front) can be 'a Horn loaded' design. Sometimes they are just mounted on a flat panel with no box at all and this would be 'a fully open' design. And quite frankly this is just a start. Many manufacturers have their own designs which of course they swear as being the ultimate. The plain fact is that every design can offer a good sound depending on how good the manufacturer was at their job.

Electrostatic speakers
probably the most notable of these would be Quad, but they are by no means alone and may not be seen as the best. However, to some degree they may be seen as the originators of the most popular design. These are a flat panel design of speaker that use an electrostaticaly charged panel using high voltages (and therefore must be plugged into the mains as well as your amp) to energise a very thin material (in the case of Quads famed units, a material that looks like cling film, but that is up to ten times thinner) which produces the sound. Generally these speakers radiate as much sound out the back as they do from the front, this means they must be placed a long way (ideally 2 metres or more) from the back wall. But, they can sound fantastically open. By design they may have less bass than you may get from a dynamic speaker, but this is not necessarily a limiting factor depending on your taste in music.

Panel design
I guess the most famous of these may be Magnarplaners. A little bit similar in the way they work (in placing etc. not in mechanical terms) to electrostatics without the mains supply and high voltages.

Ribbon design
usually used for tweeters only. It uses what might appear to be a a Kit-Kat foil wrapper to produce the sound. Because of their large surface area ribbon tweeters offer a very open sound, but naturally other manufacturers will be quick to point out any faults they may have.

Now, we've just barely scraped the surface of what is available here. There really are many many more, including some very clever designs like Omnipolar and Martin Logans hybrid designs. But just to get you started the list above will do.

Which one is for me then?
So lets decide on a few principle things about your situation. The most notable is going to be - where are they going? Needless to say it's pretty pointless you listening to a huge pair of floorstanding speakers that must be sited away from the wall by three feet when you only have a tiny room to put them in. On the flip side listening to a pair of beautifully crafted delicate sounding bookshelf marvels when you live in something like the Albert hall would also be pointless.

How big is yours?
If the answer here is 'I'm not telling', then you've got hold of the wrong end of the stick! 

Your room size is the biggest determining factor on what speakers you should look at. If you need to put some kind of figure on it then let's say that a room that is ten feet by twelve feet would certainly be big enough for a small pair of floorstanders, but small enough to sound great with a good pair of stand mounts. 

Some speakers - especially rear ported design ones, may be very fussy about going to close to the wall. Most speakers will sound better when they are as little as six inches away, but some will boom terribly unless they have a foot or more. 

Putting a speaker in a corner is generally a big no no. It will cause the sound to seem like it's coming at you down a tube, funnelling the sound. 

If you having small speakers and want to mount them on the wall then don't go to high or two low. To high and all of the treble detail will become muffled, to low and they will only sound good if your ears are on your knees (my apologise if you are from the planet Klatoo, where I know this is your natural physical layout). A very basic but good rule is that wall speakers want to be sited somewhere between your shoulder and your pelvis when your standing up. (On the wall that is - not on your body!)

Ideally of course they want to be on the wall in front of you. Another handy hint is point them (cant them in) so that from the speakers themselves form a triangle that finishes about a yard (or a metre if you like) behind your head.

Wots the power of these ones gov?
This is probably the most asked question about speakers. Which is a shame because for most people it's almost totally irrelevant. Speakers have a power rating it's true, but it is not an indication of how loud they go. It is also not a limiting factor with regards to your amp. For instance if a speaker is rated at 100 watts, but your amp is capable of 150 watts then that really isn't going to cause a problem. When a speaker starts to struggle because it is getting to much power you'd have to be fairly deaf not to hear it. Most people who damage speakers do it by using amplification that is poorly built and cannot give out a distortion free sound at higher levels. As the amp distorts it passes this signal to the speakers which do their best to reproduce the sound they were given - which in this case is distorted. This makes drivers overheat and causes speaker damage.

Impedance
All speakers have a nominal impedance, usually it's somewhere between 4 to 8 ohms, although there are some 16 and some 3 ohm speakers that spring to mind. Quite often you see an amplifier has its power listed as lets say 30 watts RMS into 8 Ohms and 60 watts into 4 ohms. A good analogy for this would be that the ohms rating of your speaker is a bit like the weight of your car. If it has a 2 litre engine and weighs eight ton then it will go 30 miles an hour. If it has a 2 litre engine and weighs four ton then it will go 60 miles an hour. Some amplifiers really don't like low impedance speakers. It''s like revving your engine when it's not in gear, you can over rev it. 

Never be tempted to wire more than one pair of speakers up to your amplifier unless it has the extra outputs to support it or unless you are using a speaker switching box that was designed for the purpose. If you hook up two pairs of eight ohm speakers to you amplifier, the nominal impedance will drop to four ohms. Two sets of four ohms will drop to an almost certain amplifier destroying two ohms. 

A nominal impedance is the figure for the speaker at rest, during music reproduction this figure could well drop to half of that on some designs. So be sure that the amp you have will match the speakers you want.

Efficiency
Speakers have an efficiency rating. This is usually listed as db (decibels) as measured at one metre with one watt of input power. The more efficient the speaker the louder it will reproduce sound for a given signal input. For example, give a pair of speakers that are rated at 83db (low efficiency) a piece of music from your amp at a quarter volume position, now swap these for speakers rated at 92db (high efficiency). Without changing the volume control you will find that the sound is much louder. Change them once again for a pair rated at 102db (very high efficiency) and most likely you'll have to leave the room. 

Don't mistake efficiency as a measure of quality however as this would not be true. But for people who like pure class 'A' sound or the sound of valves where the power can be low, you will find that it is better to look at the medium to higher end of the efficiency level.

Too low an efficiency level and you'll need a Atomic power station to run them. Too much efficiency and the speakers will actually reproduce the background noise that most every amplifier makes.

HOW LOUD IS THAT THEN!!! 
Do yourself a favour and be honest when you buy your speakers. If your favourite thing of an evening is to listen to Motorhead at 11 on the volume dial, then make sure you can get something that's up to the job. Just don't expect it to have the detail, sound stage and subtleties of a speaker that was not designed for ultimate loudness. I'm afraid the two go together like Jam and Mustard!

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