If you’re looking at buying new speakers, you’re likely wondering what size you should get, particularly concerning your room.
You may be glancing at a five-inch woofer, a five-inch or six-inch, or a three-way system. And then there are horizontal ones and vertical ones.
You probably also heard somewhere that you need to match the speaker size to your room because otherwise, you might overpower your room and cause all sorts of problems.
So in this article, I want to look at the science behind matching the speaker size to your room, explain what’s going on, and provide a better strategy to calculate what size speaker is suitable for you.
Overpowering the Room is a Myth, Here’s Why
Let me begin by stating that you can’t overpower your room. There’s no scientific relation between speaker power and room size as, essentially, speaker power translates to volume, right?
So, more power only means higher volume from your speakers, while a higher speaker volume or higher SPL (Sound Pressure Level) doesn’t provoke new problems in your room.
But even if higher volumes caused problems, you could always turn the volume down. It’s relatively simple.
There’s no real issue here. Higher-potential speaker power or higher-available power from your speakers doesn’t indicate that it causes problems in your room.
Having higher power obtainable from our speakers suggests we have more headroom, or in other words, less distortion for the same volume.
Headroom and Speaker Power
I made the following graph to illustrate the point:
This graph shows that for a specific driver size and a particular amount of power available, there’s only so much headroom the speaker can deliver outside the average listening level you’re operating at.
But with uncompressed audio with waveforms with genuinely high peaks, you require a lot of headroom for the speaker to recreate those high peaks without distortion.
From a power standpoint, in a studio, you want a speaker with the highest power you can get, which correlates to getting the most prominent speaker you can get.
And it doesn’t matter what the size of your room is. That has nothing to do with the size of your room. That is only about speaker power and available headroom to represent the waveform, the energy in the waveforms, correctly without distorting.
Everything there is to know about the watts you need for your speakers, you can find in my article Speaker Wattage & Room Size – How Many Watts Per Square Foot.
Limiting Low-End Extension
Another reason that often gets mentioned for limiting speaker size in a small room is to restrict low-end extension, which also usually comes along with restricting the driver size.
Practically, it’s all about how low down in frequency a speaker can play. But I think this is not a good idea unless you’re a beginner. Let me illustrate why.
The concept here is to put less low-frequency energy into the room not to cause standing waves. Standing waves are the leading cause for the significant peaks and dips you’ll encounter in your room and at your listening position, making it so hard, for instance, to offset the kick and the bass in the mix.
They also ring out in time, generating a lot of that mush that might happen in the low end in an acoustically untreated room.
So technically, this is correct.
You could limit the low-frequency extension of your speaker never to produce these standing waves, which will, in turn, never cause those problems.
But that also implies that you can’t really work with those frequencies in your mix. So you’ll never hear them, and it’s entirely out of your control.
An analogy to limiting the top speed of a car in a race [for beginners]
You can think of it as car racing. So you’re entering this car race and limiting your vehicle’s top speed to 68 miles per hour (110 kilometers per hour).
If you do that, you can never win the race. You won’t be capable of going fast enough. Again, this can be beneficial if you’re a beginner or want to learn to drive in this analogy or mix in relation to speakers. At that point, it could make sense.
But if you want to take driving seriously in this analogy or take mixing, recording, and working with music seriously, you have to deal with these issues. You have to learn how to deal with these low frequencies regarding how they interact with the room and what that implies for you while you’re mixing.
When we’re talking about limiting the speaker’s low-frequency extension by choosing a smaller driver, we’re talking about 5 inches or less. Because modern 5-inch woofers quickly go down to about 50 Hz, which is a direct hit in standing wave territory in just about any room. So if you want to make this work by choosing a smaller speaker, you’ll need to choose a tiny speaker.
And as I just explained, that means typically very little power, which means very little headroom and more distortion. So it’s basically a poor idea.
Why Limit Speaker Size?
One pragmatic reason you would like to limit the speaker size when you’re working in a small room is that you need to be able to position your speakers precisely in reference to your listening position.
It’s all about how far apart your speakers are and how far away they are from your listening position. Depending on where your listening position is to get a level low end, you’ll have a very narrow amount of space open to position your speakers to get that appropriate complex balanced stereo image.
You don’t get to choose your listening position yourself! Your listening position must be placed at your room’s low and sweet spot, which depends completely on your room’s shape and measurements.
This means that your room decides where your listening position is. You must find it and ensure you get to sit there when you set everything up.
Prioritizing Positioning Over Speaker Size
Positioning is absolutely critical to get right. It’s not something you can compromise on just because you want a more prominent speaker.
Depending on your listening position, you’ll have limited space on the front wall. And if that’s only maybe 4-5 feet, you can’t put in a massive midfield speaker that must be placed, let’s say, 7 feet away. It’s never going to work.
Instead, referring to the example above, you need a smaller near-field monitor constructed to work at those distances. So it would be best if you had a speaker small enough so you can experiment with the same positioning, so you can identify precisely that stereo image.
You always have to prioritize positioning over speaker type, shape, or size.
This is why I’m not too fond of these horizontally laid out three-way or 2.5-way systems. For instance, if you want to use them in small rooms, they’re normally just too bulky to test with the positioning correctly and actually get that stereo image that you need to work properly.
They’re excellent for bigger rooms if you have the luxury of space between your listening position and the front wall, but in small rooms, they’re just more of a concern than they’re worth.
Choosing speakers based on their power and headroom capabilities
…rather than matching them to the size of the room.
In terms of power, you want to get the speaker with the highest power, the largest speaker possible, to maintain that headroom available.
It’s also not a good idea to get a smaller speaker to limit low-end extension unless you’re a beginner. Rather, you should understand how to deal with it.
What you actually want to do to figure out the proper size speaker is to calculate how much space you have available between your listening position and the front wall and then get the largest speaker you can but without compromising placement.
That’s the crucial part. Go as large as you can, as long as you still have the flexibility to change the placement, test it, and really precisely identify that stereo image.
The first step is to know where your listening position is first. And as I mentioned, you can’t just choose your listening position yourself if you want to have any luck at a balanced low end.
The room decides where the low-end sweet spot is, and when you find it, it will determine your available space.
Now, you can do all this with complex and time-consuming measurements. Still, a much faster and simpler method is to use a systematic, structured listening test explicitly developed for this objective.