Speakers with multiple drivers need a way to divide up the 20 to 20,000 Hz frequency range to the individual drivers. The points where they are divided up are called crossover frequencies. There may be 2, 3, or 4 bands depending on the need of the speakers.
Speakers use components such as capacitors and inductors to set the crossover frequencies. Therefore, the crossover frequencies are set and cannot be changed. It’s also important to note that the speaker’s crossover points are not a perfect point. For example, the tweeter does not only produce sounds at a crossover point of 2000 Hz and up. There is slope and the tweeter will also produce some sounds below 2000 Hz. The sharpness of these slopes will determine the quality of the speaker.
Impedance is a unit of measurement that directly affects how much current (or power) a receiver/amplifier has to produce to source a speaker. The lower the speaker’s impedance is, the more current (or power) the receiver or amp will have to provide. Eight Ohm speakers are typically easy to drive and can be powered by most receivers or amplifiers. Four Ohm speakers are harder to drive and should be connected to receiver/amplifier that has enough power output. A lower impedance does not mean a four ohm speaker is at a lower or higher quality than an eight ohm speaker. Impedance does not affect speakers quality, but does affect the power required to drive it.
Speaker sensitivity is used to measure a speaker’s efficiency in producing sounds. Sensitivity ratings in speakers typically range from 88db to 92db. The difference between 89db and 92db is significant because 89db requires twice the amplification as 92db. For example, a speaker with a rating of 89db needs 100W to produce the same volume of sound as a speaker with a rating of 92db that is using 50W of power. A lower speaker sensitivity doesn’t mean a lower quality sound, it just means an amplifier needs twice the power to produce the same sound.
- Except for a subwoofer output, receiver/amplifier speaker outputs provide the full 20 to 20,000 Hz spectrum to each speaker. It is up to the speaker to divide up the full range into specific frequency ranges for each driver.
- See the cables and audio Connections page for more details on connecting your speakers.
- Tower speakers are top–notch in room filling sound, but they do take up more floor space.
- CRT TVs are sensitive to the magnetic field produced by speakers. Make sure your speakers are shielded if you plan to place one next to a CRT.
- Picking speakers from the same manufacture and the same family will ensure the best surround sound effect.
- Beside the speaker’s drivers, the quality of a speakers housing and its grills can affect the quality of sound.