Subwoofer by Room Size – Easy Calculator & Recommendations


Subwoofer by Room Size - Easy Calculator & Recommendations

There is a difference between trying to pressurize a space to a certain pressure level and getting good bass performance within a particular listening area. And good bass performance within a given area is probably why you’re here.

When looking for a suitable subwoofer for your room size, you need to consider elements like room volume and concept, subwoofer size, power output, frequency range, explosiveness. The goal is not to have the cleanest bass; the goal is to have the best bass for you

No one has come up with a general rule of thumb for subwoofer by room size because there are too many variables for making this an exact science. 

But our test data should definitely help in determining just how much output you need in your room to hit reference levels.

We hope that the methodology we chose in defining the room size capability for subwoofers can be a helpful subwoofer room size calculator for an end-user striving to decide which subwoofer is best for their listening space.

These are “rule of thumb” calculations intended to let you make quick decisions based on a few numbers. Let’s dive right in!

How to Determine Room Size and How Did We Categorize Rooms?

When talking about subwoofers, cubic feet are a much more useful measurement for room size than square feet. A 25×15 room with a 10-foot ceiling might be easier to drive than a 20×10 room with a 30-foot ceiling. Also, if your room opens up into another room, that additional room’s volume (in cubic feet) needs to be taken into account as well.

Cubic feet (ft^3) = length (ft) × width (ft) × height (ft)

In this article we’ll use cubic feet, so if you’re using the meter as a unit, divide the number of cubic feet by 35.3 to get cubic meters.

Example: 1000 ft^3 = 28.3 m^3

Categorizing rooms

Most rooms are considered small compared to dedicated listening spaces like concert arenas or commercial movie theaters.

However, the aim for a small listening space is no less significant than for a large listening space.

We want to be able to hit reference levels with little to no distortion or compression. The larger the room, the louder the speaker or subwoofer needs to work to hit reference levels.

We have divided room sizes into five categories that seem most suitable based on feedback from industry audio pros.

  • Extra-small: under 1200 ft^3
  • Small: 1200 – 2000 ft^3
  • Medium: 2000 – 4000 ft^3
  • Large: 4000 – 6000 ft^3
  • Extra-large: over 6000 ft^3

Subwoofer Room Size Calculator (Table)

Recommended subwoofer specs by room size:

Room size (cubic feet)

Under 1200

1200 – 2000

2000 – 4000

4000 – 6000

Over 6000

Number of Subwoofers 1 2 2 2 4
Subwoofer Size 12″ 10″ (x2) 12″ (x2) 15″(x2) 13″(x4)
Wattage (RMS) 325W 400W (x2) 550W (x2) 800W (x2) 800W (x4)
Frequency Response 20-270Hz 19-270Hz (x2) 16-290Hz (x2) 18-270Hz (x2) 18-270Hz (x4)
Max Acoustic Output 116dB 118dB (x2) 128db (x2) 124db (x2) 125db (x4)
Subwoofer Example SVS SB-1000 MartinLogan Dynamo 800 SVS PB-2000 Pro REL Acoustics HT/1508 SVS SB-3000

Extra-small room (under 1200 cubic feet)

If your room is pretty small – less than 1200 cubic feet, your listening position is probably only about 8.5 ft from the TV. No matter if you’re looking for a subwoofer for gaming, listening to music, or watching movies, you can’t go wrong with subs in that small space.

Sealed subwoofers are the way to go here. With that in mind, your best choice is the SVS SB-1000 (Amazon link). You can also look at other subs in the price range, like the RSL Speedwoofer.

If you were to go with the SB-1000, you could go dual subs eventually due to the small size.

With this room size, you’re probably less concerned with super low bass and more with sound quality and the subwoofer working well with the rest of the speakers.

Likewise, by spending no more than $300, you can get a budget-king Jamo C912 and have the subwoofer sink into the space instead of earth-shaking bass.

Small room (1200 – 2000 cubic feet)

With 1200 – 2000 cubic feet, you’d get excellent results from a pair of sealed subs in that size space. I can pressurize my room of that size with just my PC12+ in sealed mode.

If you’re on a hard budget, it’s pretty hard to beat a pair of Klipsch 12”.

If you’re not on a budget, then a pair of MartinLogan Dynamo 10’s would be perfect. It seems the MartinLogan subs have the least amount of reported chuffing even when purposely trying.

Several of my colleges who have tested the MartinLogan have stated it was the best 10″ sub they have heard in extension/low distortion and been the most difficult to chuff. All ported subs will chuff at some point if not set up right and or really pushing their limits.

I’m not sure you would see any benefits from buying more powerful subs in this room size and might even have some negatives like possible port noise.

For example, a pair of HSU VTF3, VTF15, or one of the 15″ PSA subs would have enormous headroom, and I don’t believe you’d ever get either to chuff if the placement is solid and response at the listening position maximized.

Medium room (2000 – 4000 cubic feet)

When my friend bought a house where he got his own decent-sized man cave (about 15 by 14 by 12 feet), he was totally free to do treatments for better acoustics, install bass traps, and get new subs.

He wanted to get multiple subs for music and movies. Also, he wanted the setup to be capable of decent levels down to sub 20 Hz.

Also, he didn’t know much about subs and leaned toward the sealed variant over the ported because it’s smaller.

I recommended him two decent ported SVS PB-2000 Pro 12″ subs that can play deeply while additionally smoothing out the frequency response better than a single large sub in a decently treated room.

If you fancy sealed subs for the form factor, get dual Rythmik F12’s. They reach 20Hz at -1dB (14Hz at -2dB; the SB16 gets to 16Hz at -6dB), but they’re also costly due to their massive output and internal DSP.

Large room (4000 – 6000 cubic feet)

First, more than a 4,000 cubic feet room will take a lot of subs to pressurize if you want crazy bass.

Second, with a room that large, you also want to look at room dimensions in terms of bass modes.

For example, if your room is square and the height is evenly divisible by the other dimensions, it means you are going to get some severe variation with boomy spots and dead spots around the room.

That indicates you need at least two really good subs to have a chance of getting a reasonably even response around the listening area.

If you’re on a budget, forget about pressurizing the whole room and go with a nearfield approach which will be a cheaper way of making your bottom jiggle.

If your room is normally shaped and you’re not on a budget, it would be perfect to get a pair of 15” REL Acoustics HT/1508 Predator.

For “bang for the buck,” concentrate on the best-performing, largest subwoofer you can get. Not the biggest cheap sub, but the largest great sub. I would get a pair of 13″ from SVS or HSU over a 15″ Klipsch. “Big” is important, but “great” is much more relevant than size.

Extra-large room (over 6000 cubic feet)

I also have a huge living room at approximately 25×35 with 12-foot ceilings (an open floor plan is excellent for us but terrible for listening to music and home theater).

If you love deep bass and prefer sub 20 Hz, you might want to go quad subwoofers to manage the room modes. Two is good, four is great.

I’ve currently got a pair of SB16 Ultra that cost around $4500, but I wouldn’t recommend them for a room this big. Around $4500 gets you four of SVS 13” SB-3000.

For extra 350 bucks, you could grab a miniDSP 2x4HD and calibration mic. Then you’d optimize each subwoofer separately, better than anything your receiver is capable of doing.

What Matters Most When Deciding What Subwoofer for Your Room Size?

Subwoofer wattage

Almost every subwoofer you’ll see is active, implying it has its own internal amp instead of an external amplifier. 

The internal amplifier that’s powering the speaker driver is your subwoofer’s beating heart.

That power(ing) is measured in watts, and knowing what it does is the key to picking a suitable subwoofer.

Subwoofers normally have two sorts of wattage listed on their specifications: RMS and Peak.

You can disregard Peak. It’s a measure of the total maximum power a subwoofer can put out when you turn the volume to the max. Believe me when I say: you’re not going to be doing that frequently, primarily if you appreciate your ears. 

You want to look only at RMS wattage. RMS stands for Root Mean Square and is seldom addressed as continuous wattage. Basically, it gives you a concept of how much power a subwoofer can give when driven to a moderate volume over extended periods. 

I explained the math in this article.

So, as an illustration, let’s take the cheap Monoprice 9723, which is sold for under $130 and sounds splendid. It has 150 watts (RMS), which is expected for that price range and powerful enough for most folks.

The key point here is that wattage isn’t the same as volume. It doesn’t mind how strong a subwoofer is. We can always turn the volume down, right? Rather, think of wattage numbers as a range in which you can drive the subwoofer. 

The greater the wattage, the more probable the subwoofer can pump clean, distortion-free audio at loud volumes. 

Clearly, you will spend more for higher wattage values. As a common rule, most people will be completely satisfied with wattage from around 250-600 watts, which equals good power output with budget-friendly expenses.

Does wattage impact the loudness and clearness of a sub? When buying, do we just look for the highest-rated sub in terms of wattage in our budget? How many watts make a good subwoofer? Find out in the linked article.

Frequency Range

All sounds possess a frequency – how high or how low they are. A measure of frequency is Hertz (Hz), and for subs, knowing frequency is pretty necessary. 

Bass notes have a low frequency, meaning that a sub competent to reach the lowest possible frequency is, by definition, an excellent subwoofer.

Human beings can hear down to around 20Hz, and we can feel down to 10Hz, which is the frequency spectrum that makes your stomach rumble. 

The closer a sub can reach those, the better. Most recent subwoofers handle depths of 25Hz, although some extremely costly ones, like this SVS PB16-Ultra 1500 Watt, can sink to around 13Hz. 

You should always try to purchase a subwoofer that reaches 25Hz, but you can get away with 40Hz if the bass isn’t your thing. You’ll spend more for a lower frequency floor, so consider that when purchasing a subwoofer.

When installing up your subwoofer, please have in mind the highest frequency it can run. This point is termed the crossover and is where your usual speakers stop playing sound, and your subwoofer starts. 

Most A/V receivers will enable you to manually establish the crossover, which all but ensures a more solid bass sound. I haven’t seen this characteristic on many hi-fi amps, but it does exist.

Explosiveness

Explosiveness is the principal difference when it comes to choosing a bigger or smaller subwoofer for your room. And it’s not quite the same across brands. 

If you go from a 10-inch to a 12-inch subwoofer, you’re not necessarily going to get more explosiveness because some labels are more explosive than others. 

It all depends on how brands think their response curve needs to be shaped. And that’s a personal tuning choice. 

Usually, within the same brand, the explosiveness increases with the larger and more amplifier power (RMS watts in subwoofers) that you have. 

Typically, a 10-inch deep bass subwoofer may be more explosive than a shallow run-of-the-mill, 15-inch sub. It does make all the difference in the world. 

How Many Subwoofers do You Really Need?

Dual (two) subwoofers are undoubtedly necessary for rooms larger than 2000 cubic feet.

I only have the personal experience to back that up. But it’s my experience nevertheless.

Dual subwoofers break down a standing wave present in any sized room. So if you have a single subwoofer, you’re going to get peaks and valleys and loud spots and dead spots.

In a small room, it works the same as it does in a large room. You will have those problems if you run a single subwoofer. Duals matter.

But using very large numbers of subwoofers would result in the cancellation of room modes. For practical numbers of subwoofers, there appears to be no obvious correlation.

There is certainly no excuse for using more than four when you consider the additional expense of using more subwoofers. On the contrary, it was recognized that the LF factor went down for greater numbers of subwoofers.

Four subwoofers are sufficient to get the best results of any configuration.

When I ran a single subwoofer in my house, immediately I was not too fond of it. There was way too much variation. Way too many dead points and loud points. It wasn’t proper-sounding bass, as I appreciate it.

How Much Room Does a Subwoofer Need?

The bigger your subwoofer is, the more volume of space is required around it.

The suggested volume space for a 12-inch subwoofer is 1.25 cubic feet. For a 10-inch woofer, the volume guidance is 0.625 cubic feet, and the suggestion for an 8-inch sub is 0.375 cubic feet.

You can build a bigger enclosure to provide more space inside to allow a flatter sound, which is more suitable for less bass-heavy music.

A smaller-than-recommended box would not provide proper acoustics and significantly restrict the sound quality and wear out the speaker more swiftly than usual.

Subs with bigger drivers and more efficient amplifiers don’t need to lean on our walls for help.

High-quality subwoofers manage to sound their best when drawn at least 8 to 12 inches from any wall.

Subwoofers also run better in the front half of your listening space, located closer to your front-channel loudspeakers to reduce timing delays and phase cancellation.

Can a Subwoofer be Too Big for a Room?

Only because you have a small room doesn’t mean that you’re bound to small subs. 

Not saying you need them, but you can have the big boys if you want.

It’s just a matter of can you fit them in your space and can you deal with boundary gain problems.

I did it. I’ve put PB 4000s in a pretty tiny room. And it sounded remarkable. So I know what I’m talking about. This isn’t something I guess on.

If you’re running subs in an extra-large room, you might even be required to go bigger than recommended, just so your subs aren’t working as hard. 

You don’t want your vehicle to be revving at 9000 RPM all the time. Right? The same kind of concept applies to subwoofers. You don’t want your woofers working at their maximum level all the time.

So a larger subwoofer might make sense if you have a huge room. But from there on, down anything under 5000 cubic feet, you get what you want, as long as you can fit it physically.

What is Subwoofer Room Gain?

Room gain is a naturally transpiring jump in deep Bass energy produced by the acoustics of the listening room according to its size. 

This allows a subwoofer to play lower frequencies and deliver greater output relative to the rated output by gaining room control.

Room gain happens in rooms of all sizes but is most pronounced in smaller, enclosed rooms. 

It is related to the room’s longest dimension, which is normally its length or width.

If the room’s longest dimension is less than 20 feet, it can provide a truly significant increase in bass output levels. 

What’s so unique regarding 20 feet? It’s because of the length of low-frequency sound waves. The thing is that room gain begins at the frequency whose wavelength is twice the room’s longest dimension. 

Twice 20 feet is 40 feet, wavelength being 28 Hz. Therefore, in a room where the longest dimension is 20 feet, room gain kicks in at 28 Hz and below.

Of course, the longest dimension in many rooms is less than 20 feet, so room gain starts at a higher frequency. 

For instance, if a room’s longest dimension is 16 feet, room gain begins at 35 Hz (wavelength = 32 feet); with a room’s longest dimension being 12 feet, room gain starts at 47 Hz (wavelength = 24 feet).

Open vs. Closed Room Concept for Subwoofers

Understanding the layout and how your space opens to other spaces would be helpful when choosing a subwoofer for your room.

Subwoofer audio doesn’t care about the “listening area” if there isn’t a door to close off the space, then you have to contend with the space in total, no way around it.

If you have a sealed/closed room, you need to consider the furniture and walls. If you have open-concept space, you need to consider the WHOLE space, including open doorways, hallways, adjacent dining room, kitchen, etc. Essentially any space that isn’t closed of with a physical door.

Altough the dilemma between sealed vs. ported is more about room size and specific performance requirements than whether a room concept is closed, a room that is open to other spaces may need to have the more inherent capability, which usually means ported subs. 

Your personal listening preferences (e.g., how much bass you like, movies vs. music, at what master volumes) aren’t that important when the subwoofer fits your room size.

For example, for an open-concept 3000 square feet room with an additional (smaller) open-concept room, a single ported 12” PB-2000 could be sufficient. But, when talking about optimal, that’s a whole different story.

Optimal Placement for Subwoofers

Single subwoofer at each wall midpoint is the most beneficial in terms of Std, Max-ave, and Max-min but doesn’t support low frequencies especially well.

At facing wall midpoints, two subwoofers perform almost as well as four at the midpoints and provide a much better LF factor.

One subwoofer in each corner additionally has good low-frequency support but doesn’t play quite as well as one sub at each wall midpoint in terms of Std, Max-ave, and Max-min.

If price and aesthetics are analyzed, subwoofers at two wall midpoints are better.

optimal subwoofer placement

As a common rule, setting your subwoofer in a corner or close to the wall will result in more bass, but not necessarily the best bass.

Small, low-powered subwoofers similar to those you normally get with home-theater-in-a-box systems and soundbars tend to utilize small drivers matched with low-powered amps and, thus, profit from some boundary reinforcement.

Sadly, all you’re getting is more of the same crappy bass. While I concede that a corner is often the most suitable option, it is rarely perfect.

Tray Fiddy

Tray has come to terms with the fact he will probably never be a famous DJ.... but that hasn't stopped him from mixing and throwing parties around the town. Tray has over 10 years experience of DJing at home and events.

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