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The term impedance is not one that most people are familiar with, regardless of whether they are heavy users of sound equipment. Similarly, the term ohm is not the most common in a conversation around sound equipment, or one that someone immediately thinks of when deciding which speaker would be the best to buy.
However, both concepts are very important to understanding in the best possible way how our sound systems work. If you want your equipment to offer great performance and last for a long time, without problems or breakdowns, this new Genius Audio article is for you. Today we will learn more about speaker impedance. Keep reading!
It is a concept that explains how speakers or headphones behave. All electrical circuits resist the current or the flow of electricity to some degree and the way we measure that resistance is impedance. Frequency is an important factor to consider, as it frequently causes this indicator to vary. In other words, as sound reproduction progresses and the frequency evolves, the impedance changes. It doesn't stay constant.
The unit of measurement of impedance is ohms.
In general, sound equipment manufacturers offer their commercial loudspeakers with an impedance whose nominal value is usually measured at a frequency of one kilohertz (kHz) ranging from 4 to 16 ohms.
The first thing to understand is that the ohm is a rating related to power resistance. The impedance applied to the power force will be higher as the device has a higher Ohm rating. When synchronizing the speaker with an audio and video receiving device, we must check that the Ohm rating of the speaker is the same –or greater– than that of the receiving device.
There are certain receiving devices that have an impedance range, while others may include a specific switch for it. Setting that switch to the correct impedance will allow us to connect lower impedance speakers without having a risk of damaging the receiving device.
A good amplifier will always be able to work with the various impedance variations that loudspeakers can have. When these variations start decreasing, it's important for the amplifier to be able to deliver more current and, therefore, supply more power to the speakers.
If these conditions are not met, there will be fluctuations in the sound pressure level, which will negatively affect the sound quality. Furthermore, if we have an amplifier that cannot deal with impedance variations, it will be overloaded. This would considerably affect the useful life of the device and could even break it down.
Second of all , a good amplifier comes with a proper power supply. This way, it will be able to "attack" any loudspeaker regardless of its nominal impedance, and it will not cause major problems if this parameter registers very abrupt drops.
Finally, a good amplifier has the ability to drastically increase the current delivery and double the power in case the impedance drops to half. Although it is an important condition, it is not essential, since some amp models do not adhere to it strictly, and despite that, their performance is quite good.
For an easy review of our equipment, it is enough to check the label to know the nominal impedance. It is common for manufacturers to include on the speaker label or on it´s box a listed impedance rating that can span the ranges mentioned above (4 to 16 ohms).
Another way of knowing is by measuring the impedance with a multimeter. This device is responsible of sending continuous current to measure resistance. You can set your multimeter's resistance setting to the lowest range (on most multimeters, this means 200 ohms). However, with a lower setting, it is possible to achieve more accurate results.
For more precise measurements there are special tools such as audio frequency oscillators. These devices generate sine or sweep wave signals. It would be a good choice to try this type of measurement in cases where the loudspeakers impedance varies with the frequency.
With this information it will be easier for you to choose a good quality car sound system, and if you´re ready to shop around, you must go with Genius Audio. We have a wide range of amplifiers, speakers, subwoofers and more for you, with the best quality. Contact us or browse our site and enjoy the Genius Audio experience!