home stereo: Hi-Fi FAQ
How should I position my speakers?
In an ideal world once the carpet is down in your room you should position your speakers, then the rest of the furniture around your hifi.
For a variety of reasons (or people) this isn't practical. You may have no choice in the matter but ideally try and position the speakers in a triangle. Preferable an equilateral triangle (helps if you did geometry) where you are at the apex of this triangle. If the speakers are too far apart you will get a left and right sound with no centre stage. If you are too far away you will also not have a wide sound. The distance apart depends on the dispersion characteristics of the speaker. Your ideal listening position is also determined this way as well. Better quality loudspeakers have greater flexibility in listening position. This is quite often forgotten in the decision making process of buying.
Remember that the room and furnishings will have an effect on the sound, so be brave and experiment.
Why do my speakers keep blowing when the power output is above the amp?
Speakers have drive units in them. These are the electro-mechanical parts which produce the sound. Each drive unit is designed for specific frequencies and has a different power rating. If your amplifier is say 10watts and the speaker is rated at 20 watts, the high frequency unit may only be rated at 5W. So it is still possible to overdrive it. More likely the reason the speakers have been damaged is that the amplifier has reached its peak output power and instead of sending out a nice sine wave music signal, for which speakers are designed, it has sent out a square wave spike. Speakers don't like this and basically it burns the fragile wires at the back of the drive unit. It is Hifi Corner's experience that more speakers are damaged by amplifiers having too low a power output rather than the reverse. Melted or fused wires at the back of the speakers are not under guarantee, so take great care. Overdriving of amplifiers often happens under the following conditions:- when the tone controls are turned up (this demands more power even at same volume levels); wild parties (the more you have to drink the harder of hearing you become); and when no-one was in the house (except the children/cleaner who deny ever touching the hifi).
How many drive units should I have?
The working parts of a loudspeaker, the drive units, come in a variety of shapes and sizes. Like the size of the speaker itself, a good speaker with two drive units will sound better than a bad speaker with five. The more drive units the harder it will be for the designer to make it sound good. So be wary of inexpensive designs with multiple drivers. Speakers sold on specifications tend to be aimed at the less experienced buyers. Hifi Corner have superb demonstration facilities and there is no substitute for listening yourself.
What is "in phase"?
Terminals at the back of the speaker are marked 'plus' or 'positive' and 'minus' or 'negative' . Amplifiers also have at the back 'positive' and 'negative' terminals. They may be colour coded. If one of the terminals is misconnected then the speaker is said to be out of phase.
Basically when one of the drive units is moving out on one speaker, it will move in on another. The net effect is that bass is lost as the speakers are working against each other.
Stereo becomes diffuse and it is difficult if not impossible to localize sounds in the middle of the speakers. Correcting this balance means the speakers are 'in-phase'. This is a common problem which if careful connections are made should be avoided.
If you are not sure if your speakers are 'in-phase', reverse the polarity of one of your speaker terminals, and listen to which setting gives you the most bass. Be careful to switch the amplifier off before changing and do not let the terminals cross (or short circuit) each other.
http://www.hificorner.co.uk/tips/loudspeakers.htm
In an ideal world once the carpet is down in your room you should position your speakers, then the rest of the furniture around your hifi.
For a variety of reasons (or people) this isn't practical. You may have no choice in the matter but ideally try and position the speakers in a triangle. Preferable an equilateral triangle (helps if you did geometry) where you are at the apex of this triangle. If the speakers are too far apart you will get a left and right sound with no centre stage. If you are too far away you will also not have a wide sound. The distance apart depends on the dispersion characteristics of the speaker. Your ideal listening position is also determined this way as well. Better quality loudspeakers have greater flexibility in listening position. This is quite often forgotten in the decision making process of buying.
Remember that the room and furnishings will have an effect on the sound, so be brave and experiment.
Why do my speakers keep blowing when the power output is above the amp?
Speakers have drive units in them. These are the electro-mechanical parts which produce the sound. Each drive unit is designed for specific frequencies and has a different power rating. If your amplifier is say 10watts and the speaker is rated at 20 watts, the high frequency unit may only be rated at 5W. So it is still possible to overdrive it. More likely the reason the speakers have been damaged is that the amplifier has reached its peak output power and instead of sending out a nice sine wave music signal, for which speakers are designed, it has sent out a square wave spike. Speakers don't like this and basically it burns the fragile wires at the back of the drive unit. It is Hifi Corner's experience that more speakers are damaged by amplifiers having too low a power output rather than the reverse. Melted or fused wires at the back of the speakers are not under guarantee, so take great care. Overdriving of amplifiers often happens under the following conditions:- when the tone controls are turned up (this demands more power even at same volume levels); wild parties (the more you have to drink the harder of hearing you become); and when no-one was in the house (except the children/cleaner who deny ever touching the hifi).
How many drive units should I have?
The working parts of a loudspeaker, the drive units, come in a variety of shapes and sizes. Like the size of the speaker itself, a good speaker with two drive units will sound better than a bad speaker with five. The more drive units the harder it will be for the designer to make it sound good. So be wary of inexpensive designs with multiple drivers. Speakers sold on specifications tend to be aimed at the less experienced buyers. Hifi Corner have superb demonstration facilities and there is no substitute for listening yourself.
What is "in phase"?
Terminals at the back of the speaker are marked 'plus' or 'positive' and 'minus' or 'negative' . Amplifiers also have at the back 'positive' and 'negative' terminals. They may be colour coded. If one of the terminals is misconnected then the speaker is said to be out of phase.
Basically when one of the drive units is moving out on one speaker, it will move in on another. The net effect is that bass is lost as the speakers are working against each other.
Stereo becomes diffuse and it is difficult if not impossible to localize sounds in the middle of the speakers. Correcting this balance means the speakers are 'in-phase'. This is a common problem which if careful connections are made should be avoided.
If you are not sure if your speakers are 'in-phase', reverse the polarity of one of your speaker terminals, and listen to which setting gives you the most bass. Be careful to switch the amplifier off before changing and do not let the terminals cross (or short circuit) each other.
http://www.hificorner.co.uk/tips/loudspeakers.htm
