It is widely known among musical technicians, audio engineers, and enthusiasts that amplifiers can cause damage to speakers. Overpowering or underpowering your speakers at the amplifier stage can lead to unnatural movement of the speakers’ cones and coils, causing them to get damaged.
In as much as amplifiers are known for their ability to cause damage to speakers, can speakers cause damage to amplifiers?
Speakers can damage an amplifier. When the speaker’s impedance is below the amplifier’s impedance range, the speakers will draw more power than the amplifier can deliver. This will cause the amplifier to overheat and damage over time.
Let’s take a look at all of the different ways speakers can actually damage a power amplifier. And then we’ll follow that up with how to prevent it from ever happening.
How Speakers Can Damage Amplifiers
Amplifiers break down from time to time. Damage to amplifiers by speakers is very rare but it does happen sometimes. Here are the different ways an amplifier can be damaged by a speaker.
Impedance mismatch is quite a popular term in the audio world. And expert audio enthusiasts are quite familiar with it. But I’ll try and simplify it the best possible way.
What exactly is impedance mismatch?
An impedance mismatch occurs when a set of speakers’ total impedance is either greater or less than the impedance range of the power amplifier they are connected to.
When speakers with low impedance are connected to amplifiers with relatively high impedance, we can term their impedances as mismatched. This simply means you are running an amplifier that is far too weak to drive the speakers connected to it. Similarly, when the speaker impedance is higher than the amp’s impedance, you can also call that impedance mismatch.
For speakers to damage an amplifier, the speaker’s impedance must be lower than the amplifier’s impedance. Most power amplifiers are designed to drive speakers with an impedance between 4 to 16 ohms. However, several factors can cause a speaker or a set of speakers’ impedance to fall below the amp’s acceptable impedance range.
Firstly, when you connect multiple speakers in parallel to the amplifier, their total impedance can easily go below 4 ohms.
For instance, let’s say you connect a pair of speakers, both with an impedance of 4 ohms, in parallel. Using a speaker impedance calculator such as this one, the total impedance of this pair of speakers will be 2 ohms.
2 ohms impedance is below most amplifiers impedance range. For this reason, there will be an impedance mismatch.
In connections with impedance mismatch, the amplifier is not strong enough to power the speakers effectively. Since the amplifier is not designed to drive speakers with such low impedance, the amplifier may overheat with time.
This causes the integrated circuit located inside the amplifier to heat faster, causing them to stop working after a while.
Impedance mismatch of speakers and amplifiers can lead to excessive power use, distortion, and noise problem as well.
Faulty or Blown Speakers
This ties into the previous point, but I had to talk about it separately.
Although speakers can last for decades without any signs of damage, some essential speaker parts wear out over time. After using your speakers for many years, some of the parts will wear out and lead to speaker faults. I discussed this, in detail, on how speakers wear out. Feel free to check it out.
I brought this up because impedance mismatch can also occur when good speakers become faulty. What do I mean? Well, when these speakers become faulty, they can present a wrong impedance to amplifiers. And if this new impedance presented by the speakers falls below the amplifier’s impedance range, it can easily damage the amp.
And it’s not only faulty speakers that can damage an amp; blown speakers can also easily damage an amp.
Here is how this happens.
When you turn up the amplifier’s volume to the point where it’s excessively loud, it causes the amplifier to start sending distorted audio signals to the speakers.
This distortion causes the driver coil of the loudspeakers to extend further and faster. This increase in movement causes heat to form inside the speaker. At a certain point or temperature, these coils start melting, and eventually, the speaker blows. Check out my post on how bass damage speakers to learn more on this subject.
Once the speaker blows, it causes its impedance to reduce drastically, and this will instantly increase the load demand on the amplifier.
The sudden increase in the load demand on the amplifier places a strain on the amplifier. This causes the amplifier to also heat up and crack. Simply put, if an amplifier is turned too loud and blows the speakers, the damage to the speakers can cause the amplifier to get damaged as well. Karma 😀
Loosely-connected speaker wires
Loosely connected speaker wires to the amplifier can cause sparks, which may damage amplifier terminals, or worst-case scenario, cause a fire outbreak. The chances of this ever happening are quite low, but it’s definitely possible.
Tampering with connected speaker wires while the amplifier is powered on can also cause damage to your amplifier.
Although this is not the case for every amplifier out there, making sure your speaker wires are well connected will do you a world of good. Therefore, before powering up the amplifier, it is important to ensure that the speaker cables are properly connected.
Speaker wires short-circuiting
Short-circuiting can occur under varied circumstances. In general, bad speaker wires can short and fry an amplifier. These speaker wires can damage your amplifier by shorting the output transistors of the amplifier.
Loosely screwed speaker wires (red and black wires) whose ends touch while connected to the amplifier can destroy the transistor. This will cause the amplifier to get damaged. Also, touching one loose hanging speaker wire to another wire can damage your amplifier. This can occur when care is not taken while disconnecting the speaker wires.
Short-circuiting can also occur when high current drawing speakers are connected to amplifiers that cannot handle them.
These high current drawing speakers usually have a low resistance of about 4 ohms and below, causing them to draw a lot of currents. Amplifiers that do not have circuit protection will overheat. This will cause their cables to short out. However, most amplifiers have protection circuitry like fuse or relay protection to prevent this damage from occurring.
How to identify if your amplifier is damaged
Being able to tell whether your amplifier is probably damaged might not be easy to do for many. However, if you notice any of these signs in your musical setup should give you a hint that there is probably something wrong with your amplifier.
If you notice any of the signs I will talk about, you should definitely check out your amplifier for any signs of damage. However, these signs can be caused by the malfunctioning of other components or equipment as well. So keep that in mind.
This occurs when all your connections have been properly made, but there is no sound after you have turned on your musical system. If your amplifier is on but you do not hear any sound, the chances are that the amplifier is damaged.
There is a noticeable distortion in the sound.
When your amplifier powers on normally but does not sound right to the ear, we can say the sound being generated has been distorted. Distortion of sound occurs when the speaker’s power demand is far greater than what the amplifier can supply.
In this situation, it becomes impossible for the amplifier to send a signal to the speakers without compromising its form. This means that the signal will be amplified by the amplifier but in a very distorted form. Sound distortion can also be caused by loose wiring.
In this scenario, the stereo system begins to make a fuzzy sound. The sound starts out normally by sounding fine, then gradually deteriorating into a flabby, fuzzy sound after long use. Sometimes, this distorted sound is generated when the amplifier volume is increased to a high level.
How to prevent Speakers from Damaging an Amplifier?
Power amplifiers can be quite expensive. And I’m sure you don’t want to spend extra cash repairing or even replacing them from time to time. By following these simple instructions, you’ll be able to prevent your speakers from ever damaging your amp.
Let us take a look at some measures that can help prevent speakers from damaging amplifiers.
Match the speakers with the right amplifier
When setting up a musical setup, it is essential to consider the relationship between the various components and equipment and how they match with each other. The relationship between the speakers and the amplifiers to be used is one of such relationships.
It is not just any amplifier out there that can power any speaker; there is the need for them to match. Most amplifiers and speakers operate on the same principles. However, you may end up causing damage to your equipment or getting poor sound if you choose incompatible speakers and amplifiers.
The following video gives a good summary of what to do when you are planning to acquire a speaker and an amplifier.
Do not tamper with speaker wires when connected to the amplifier.
As a general rule of thumb, do not tamper with a speaker wire which is connected to an amplifier that is powered on. Whenever there is the need to make adjustments to connections, you must turn off the amplifier first.
This is because brief accidental touching and crossing of speaker wires can lead to output failure of the amplifier when it is powered on. Therefore, if the amplifier is driving a speaker and a short in wiring occurs, the amplifier ends up frying.
Speakers can damage amplifiers that cannot provide sufficient power to drive them. Due to this, in choosing amplifiers and speakers, you will need to choose an amplifier that can provide sufficient power for your system. Combining the right amplifier and quality speakers will ensure your musical system is equipped to handle music at any volume.
After acquiring the right speakers and amplifier, make sure that the operator is competent enough to handle them. Some of these problems and damages are avoidable. Getting someone who knows what they are doing will help prevent some of the damages that can occur from the use of speakers and amplifiers.
Finally, I’ll recommend that you hear your selected type of amplifier and speaker in action together before you purchase them.