Whether you are talking about 4 ohms or 8 ohms, you are simply referring to the speaker’s impedance. This is an electrical property much like resistance. Speakers are designed in several different impedance ratings. Thus matching the impedance of your speakers to your amplifier ensures that your audio system runs efficiently and sounds its best.
What is Impedance?
Impedance just like resistance is a restriction of the flow of electrical current in a circuit. Resistance and impedance are quite similar. However, impedance changes for different audio frequencies and resistance are generally constant. Impedance stems from the interaction of the speaker’s voice coil as well as other electronic components. A speaker’s impedance rating is seen as an average taken over a wide range of audible frequencies.
4 Ohm Vs. 8 Ohm
When it comes to an audio loudspeaker, a 4-ohm speaker requires more power from an amplifier than an 8-ohm speaker. This is necessary if the speaker is to produce the same loudness of sound. This is a result of the relationship between voltage, current, and resistance in electronic circuits. For a given voltage, a lower impedance implies a greater current. Power is a combination of voltage and current, as such more current to the speaker, an amplifier must have a higher power rating.
Series and Parallel Connections – Speakers at 4 0hm Vs. 8 0hm
Understand that when you connect two or more speakers to the same amplifier output, you change the total impedance of the speaker set. You can wire speakers in series or parallel. How does it work? Here’s how it works – this series arrangement has the “hot” wire of one connected to the “ground” wire of the next, – where parallel wiring connects the “hot” wire of one speaker to the “hot” of the next, and “ground” of one to the “ground” of the other. Just understand that speakers connected in a series arrangement combine their impedance.
Impedance Matching – Speakers at 4 0hm Vs. 8 0hm
An amplifier’s outputs have an impedance rating much as a speaker does. 4-ohm speakers should be used with the 4-ohm speaker outputs of an amplifier. 8-ohm speakers on the other hand should be used with 8-ohm amplifier outputs. When there’s a mismatch of speaker and amplifier impedances, it can damage the amplifier’s circuits. It also results in distortion and poor sound quality. This issue is most important when you listen to loud music because the demands on the amplifier for power are greatest at high loudness levels.