Paring your pair of speakers to an amplifier can be stressful when you are new to basic acoustic jargon, like watts per channel, speaker sensitivity, and ohm rating.
How to choose an amplifier for speakers is no mystery, but users are in so much of a hurry that they overlook basic matching and just pick whatever amp looks good or fits their budget.
An amplifier is not just a fancy-looking box that audiophiles like to put on display. It significantly improves the audio signal sent to your speakers while reducing any residual distortion and noise produced.
If you want a robust sound output, and want to make the most of what an amplifier offers, you will need to do some basic matching.
This guide focuses on the main factors you should look out for when you have to choose power amplifiers to pair with your speakers, wherever they may be.
How To Choose Amplifier for Home Speakers
The factors that affect how to choose amplifiers for speakers are the same you should look out for whenever you have to match speakers and subwoofers to any rated channel amp: power, impedance, and speaker sensitivity.
If you match these carefully, you’ll know exactly where to use your speakers, maximize the sound produced and never have to worry about damaging your amplifier.
To keep things simple, we will stay away from difficult technical jargon. Instead, we will keep you focused on ratings to watch for and how to match a new amplifier to your speakers.
Speaker impedance is a measure of the resistance of your speaker to the electrical signal of your amplifier. It’s an electrical quantity and is measured in Ohms, denoted by the omega symbol.
You can easily find the nominal impedance of your speaker and amplifier on their respective spec sheet, online, or on the equipment itself.
All you need to do is to check if the impedance of the speaker is compatible with the impedance of the amplifier.
A good rule of thumb is to ensure that your speaker and your amplifier impedance fall within the range. We recommend checking the spec sheet before purchase as it shows the compatibility rate for both speakers and amplifiers.
Most speakers usually have an ohm rating between 4 and 16. Amplifiers will cover that range most of the time or come with ratings between 6 and 12-ohm.
If you can’t get access to the spec sheet or if you don’t see any compatibility information, verify that the amplifier ohm rating is equal to or lesser than the impedance of the speaker.
Low resistance from the speaker can produce richer and clearer audio profiles more easily.
Power is measured in Watts and refers to how much energy the equipment can handle without damage.
The power of your amp does not necessarily affect the volume level of your speaker, but rather the sensitivity, which we will get to later in this guide.
You must pay attention to the continuous steady-state power or RMS as designated by most manufacturers. Continuous power rating drives a fixed wattage into specified impedance loads. For example, an amplifier can be rated at 700 watts and will drive those Watts of power into an 8 Ohm impedance speaker load constantly.
To make the best choice, check the wattage level of the speaker and ensure the amplifier has at least twice the rated wattage levels of the speaker.
If you have a 250 Watts rated speaker, it’s best to use an amplifier rated 500 Watts. This gives the amplifier enough room to easily maximize the power of the speakers without distortion.
A 500 Watt speaker will work best with a 1000 Watt size amp, whereas a 1000 Watt speaker will work best with a 2000 Watt size amp.
Some speaker specifications will also display recommended wattage levels. If that is the case, compare the wattage levels of the speaker and the amplifier to ensure they match.
The sensitivity indicates how loud the speaker can get. It is measured in Decibels and can be found on the spec sheet of your speaker. It’s important to pay attention to speaker sensitivity if you are looking to match your speakers to a proper amplifier.
If your speaker has a high sensitivity, you will need less amp power, whereas if your speaker has low sensitivity, you will need more power from the amplifier to increase the loudness.
Generally, you have to double the amplifier power output from a base level of 1 Watt to increase the speaker sensitivity by 3 dB from a distance of 1 meter.
If your speaker has a sensitivity of 120 dB and you want to amplify it to 150 dB It would take 2 watts to increase it from 120 to 123 dB, 4 Watts to increase it to 126 dB, 8 Watts to increase it to 129 dB, and 1024 watts to increase it to 150 dB
Depending on how loud you want the speaker to get it’s important to pay attention to the sensitivity and the power rating of your amplifier.
Choosing an Amplifier for Speakers: The Bottom Line
If you care about the sound quality of your speakers and the integrity of your setup, then you should care about how to choose an amplifier for speakers.
All you need to do is follow our instructions above and pay attention to the physical space you’ll place your speakers, as this can also affect the type of amplifier you need.
Make sure to pick a powerful amplifier for large rooms and smaller amplifiers for small spaces.
Can An Amplifier Be Too Powerful For Speakers?
Yes, it certainly can. This is why most home amplifier not matched correctly to a speaker can quickly get damaged. Not matching amplifiers to speakers will cause your speaker to burn out due to excess wattage before even reaching peak loads.
We have talked about the importance of choosing the right amplifier, and the many benefits of doing so. But what happens if you decide to go ahead and pick an amplifier without checking any specifications? Below are three common scenarios:
- You get lucky and manage to pick the right amplifier without any consequences. Yes, you could disregard all the information here and end up choosing the perfect amplifiers for your speakers. One with just the right power to ensure plenty of headroom, and good audio output with no distortion.
- You could end up with a sorely mismatched amplifier that is far too weak to power your speakers. At first, you’ll notice that the amplifier is not increasing the output too much. Even if you keep turning up the volume, the only result you’ll get is distortions and an amplifier that heats up way too fast, causing overheating.
- Lastly, you could end up with an overly powerful amplifier, way too powerful for your home speaker. This also causes overheating but not as much as in the previous scenario. It would still end up damaging your speakers eventually.
By now you would have seen that learning how to choose amplifiers for speakers may require some extra attention.
Simply keep your eyes focused on the specifications of the amplifier to make sure they match the features of your speakers. You do that and your speakers and amplifiers will last for decades. You will also enjoy high-quality audio output, low noise levels, and no distortion problems.
Don’t hesitate to read similar guides that can help improve your audio experience.