If you’re an audiophile or home theater enthusiast, you are probably familiar with watts and RMS ratings. It is one of the most important specs you should consider when selecting audio equipment such as speakers and amp. But at the same time, it is one of the topics that confused a lot of people.
There are different questions asked about watts and RMS, such as what RMS in speakers and amp means, what good RMS for speakers, and most importantly should speaker RMS matches amp RMS.
In this article you’ll find all the answers to your questions; let’s start the things answer the main question:
Should speaker RMS match amp RMS?
It’s not necessary for your speaker’s RMS to match your amplifier’s RMS. The reason is that the peak power output of an amplifier is much higher than its RMS power rating. For example, an amplifier with an RMS power rating of 100 watts per channel can easily produce 200 watts or more of peak power.
However, there are a few things you should keep in mind when matching your amplifier and speaker.
First, make sure that the amplifier can handle the speaker’s RMS power rating. If the amplifier is not powerful enough, it will clip (distort) at high volumes. Second, keep in mind that the speaker’s RMS power rating is its continuous power rating. The speaker can handle short bursts of a higher power, but it will sound better if you don’t push it too hard.
In general, it’s best to err on the side of caution and choose an amplifier that is slightly more powerful than the speaker’s RMS power rating. This will give you plenty of headroom to prevent clipping, and it will also allow the speaker to reach its full potential.
What is RMS for speakers?
RMS is short for Root Mean Square and it’s a way to measure the overall power output of a speaker. It’s usually expressed in watts and it gives you an indication of how loud a speaker can get.
The higher the RMS rating, the more powerful the speaker and the louder it can get.
When choosing speakers, it’s important to look at the RMS rating to make sure you’re getting a speaker that’s powerful enough for your needs.
Assume you are looking for a speaker that can fill a large room with sound, you will need a speaker with a high RMS rating. And on the other hand, if you need a speaker that just provides the background music in a small room, you can get away with a lower-powered speaker.
One more important thing, you should not mix up the RMS rating with Peak Power output.
The peak power output is the maximum amount of power that a speaker can handle for a short period of time. It’s not a continuous rating like the RMS.
So, when looking at speakers make sure to check both the RMS and peak power output to get an idea of the overall power and loudness a speaker can achieve.
What Does Amplifier RMS Mean?
The RMS value for an amplifier is the root mean square voltage that the amplifier can produce. It is a measure of the power that the amplifier can generate and is usually expressed in watts.
Just like mentioned early in what RMS for speaker section, the RMS value is a continuous power rating. So, it’s the amount of power that the amplifier can generate without distorting the signal.
The peak power output of an amplifier is the maximum amount of power that the amplifier can generate for a short period of time.
So now I hope you have a clear answer to what RMS in speaker and amp means and you also have no need to worry about matching speaker RMS and amp RMS.
Let me give you an example; Assume you are watching a movie on speaker with full volume at RMS power of 200 watts and amp power rating of 200 watts.
And as I explain above RMS for the speaker means the power handling capacity of the speaker on a continuous basis whereas RMS for the amplifier is the power output rating of the amplifier.
If both have the same RMS rating you can play the music or watch a movie at any volume all day long without any problem.
Now, in this case, your amplifier is just enough to power your speaker. But what if you are playing music on the same system and the volume is increased or there is a scene with lots of explosions and bass? Here comes dynamic power or peak power into the picture.
If you read the speaker and amp specification page carefully you will notice that most of the manufacturers mention two numbers for RMS power rating; one is the continuous RMS power and the other is peak power. And that peak power is always greater than continuous RMS power. It could be 400 for a 200 RMS rating speaker/amp or even 800.
Now, if you go back to our example and play the music on the same system with increased volume or there is an action scene in the movie, your speaker will demand more power than 200 watts to produce the sound at that increased volume or to handle those bass frequencies. And at that time if you have 400 watts peak power amplifier it will provide the required power to the speaker without any distortion and you will get a clear and crisp sound.
But if you have only a 100 watts amplifier and the speaker has a 200 amplifier RMS power rating then you will get distortion in sound as your amplifier is not powerful enough to provide the required power to the speaker.
In this case, you can either play the speaker at lower volumes or get a more powerful amplifier.
How to match speaker RMS to amp RMS?
Matching speaker and amp RMS ratings are not always a good idea. Sometimes the speaker RMP is too high for the amp and will cause distortion. Also, some amps can have an RMP rating that a speaker cannot handle and will lead the speaker to damage.
It is best to always check the RMP rating of both the speaker and the amp. The good rule of thumb is the amp RMP should be 50% higher than the speaker RMP. This will give you a much clearer and louder sound.
For example, if you have a speaker with 200 RMP, the amplifier should be around 300 RMP.
Also, make sure the ohm rating of the speaker and the amp match. Most home theater systems will have an 8-ohm speaker. If you have a 4-ohm speaker, you need to make sure your amp can handle that as well.
In order to match speaker RMS To amp RMS, you need to know the following things about your system:
- The power handling capability of your speakers
- The RMS power output of your amplifier
With that information, you can use the following equation to determine how to set the volume on your amplifier:
For example, if your amplifier has an RMS power output of 50 watts and your speakers have an RMS power handling capability of 100 watts, you would set the volume on your amplifier to 50%. This would result in your amplifier providing 50 watts of power to your speakers, which is the maximum amount of power that your speakers can handle.
How do you determine the RMS ratings for a speaker and an amplifier?
The first step is to just read out the manual that is provided with your speakers, the manual should have the RMS value listed in the manual for example 120Watts RMS. If the manual does not have the information, the box of your speaker will have that information listed for you or the back of your speaker will help. Similarly, you can try to search on the internet for it.
Does the RMS value affect sound quality?
As we have discussed above, the RMS value of the speaker reflects how much power the speaker can handle without breaking. Therefore, it does not have a direct correlation with its sound quality. However, speakers with a higher RMS value have a higher SPL rating for the speaker.
The SPL of a speaker determines how loud the speaker sounds. Therefore, the bottom line is that the RMS value of a speaker will not affect the sound directly as the loudness of sound is not an indicator of a “good” sounding speaker. So you should look out for other indicators to choose a speaker for yourself rather than focusing on the RMS value.
Which RMS value is best for your speakers?
There isn’t a perfect answer for which RMS value is best for your speakers. However, if you draw the correlation between the SPL value of your speakers and the RMS value, the higher the number of your RMS rating is, the better it will be for your speakers since it will produce a louder sound.
Therefore, you should not pay a lot of attention to the value of the speakers since it has little to do with how rich the speaker will sound. On the contrary, you should look at some other aspects such as the frequency response, and distortion of a speaker rather than how much continuous power it can withstand.
You should now have a better understanding of the RMS along with should speaker and amp RMS match.
In general, it’s a good idea to match the two as closely as possible. However, there may be situations where mismatched RMS levels could actually cause problems to your audio system.
In the above guide, I’ve put everything in detail so you’ll not only find the answer to the main topic, but you can also have a better idea of RMS rating, peak power, and how you can match both speaker and amp RMS power.