What Wattage Soundbar do I Need?

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If you are looking for a simple, easily understandable, and measurable answer to this question, let me disappoint you from the start – There is none.

Most people buy soundbars because they are all-in-one esthetically pleasing, simple, and more or less affordable solutions that sound much better than TV speakers. But, when you go to buy one, you will be bombarded with all kinds of numbers:

– 100, 300, or 500 Watts of immersive sound

– 100, 120, or 130 dB of ear-piercing loudness

– 2.1, 3.1, 5.1, 5.1.2 channel system

– 40Hz – 20kHz frequency response

– Class D amplifier etc.

There isn’t a unified way of comparing different soundbars coming from various manufacturers, so it is essential to understand what those numbers and specifications represent to have some idea of what to look for.

Understanding the specs is the key to finding the right soundbar for your needs


Understanding the specs is the key to finding the right soundbar for your needs

What do all those specs mean?

Watts represents the amplifier’s output strength and how much of that strength a speaker can handle before breaking down or distorting the sound. They are critical if you have a passive speaker system connected to an amplifier. However, passive soundbars are very rare and usually very expensive, so you will probably get one of the most common ones – an active, integrated system.

With active soundbars, watts are not relevant because they will have minimal impact on the overall sound quality.

Other specifications, if published, are far more important. The first of them is SPL or Sound Pressure Level.

Speaker sensitivity

Speaker sensitivity is expressed in dB or decibels, and it represents the efficiency of speakers to convert power to sound. The higher the number, the louder and more efficient the speakers are. This value is measured at a 1m distance from the soundbar. The bar is fed with 1 Watt of input power and the SPL is measured with a calibrated SPL meter. A typical SPL of a good speaker is anywhere between 85 and 100 dB.

How loud is 100 dB?

For comparison, an average SPL of a normal conversation is around 60 dB, while a motorcycle produces around 100 dB. Pain threshold is usually between 120-125 dB, and anything above can be hazardous for your health.

If your speakers have SPL of, let’s say, 90 dB, you have a good starting point. The general rule is that doubling the power input increases the SPL by 3 dB (2W =93 dB, 4W =96 dB, 8W = 99 dB, 16W =102, 32W =105, 64W=108 and 128 W of power will give you 111 dB of SPL).

This is where we can start combining specs to figure out how loud a soundbar can be and how many watts you need to achieve a certain level of loudness.

Most recommendations say that 105 dB is a sweet spot for volume. Anything below that can be too quiet to enjoy all the effects to the full extent. And, as we’ve already said, higher volume levels can be potentially hazardous to your health.

So, how will we know do we have that 105 dB or not?

 Let’s assume that your speakers have an SPL of 86dB and a power rating of 100 Watts, and do the math:

As we can see, you can reach that recommended 105 dB value at a distance of 1m. However, almost all distances will be greater than 1m. How much do we lose over span? For every meter of space, the sound gets 6 dB quieter, and you should take that into your calculation as well. The soundbar from our chart will not produce sufficient volume at a distance of 2m or more, and you should be looking for the soundbar with either higher sensitivity or higher power output to get to that 105 dB sweet spot.

What about the channels?

Many, if not all, manufacturers will show you the number of channels their soundbars support. That number is usually formatted as 2.1, 3.1, 5,1 or less commonly 5.1.2, etc. But what does that number mean?

Let’s say you found a soundbar that has 2.1 channels. That means it has two front speakers (left and right) and a subwoofer. Or that it has multiple drivers arranged in two channels (L and R) and a subwoofer.

VIZIO SB362An-F6 soundbar is classified as 2.1

VIZIO SB362An-F6 soundbar is classified as 2.1 (because of two passive bass radiators) but it’s actually a 2-channel soundbar

3.1 means 3 channels (not necessarily just 3 speakers) – left, center, right, and a subwoofer.

5.1 means two front speakers (left and right), center, two rear speakers (left and right), and a subwoofer. This setup is also known as a surround system. Some soundbars will fake this by putting two speakers in the corners of the bar and directing them to bounce the sound of the walls, thus mimicking a real surround sound.

5.1.2 means you have all of the above + 2 speakers simulating height speakers. This can create a unique sound experience of overflying airplanes or raining.

VIZIO SB36512-F6 soundbar-based 5.1.2 surround sound system

VIZIO SB36512-F6 soundbar-based 5.1.2 surround sound system – in this case, the soundbar replaces 3 front channels (FL, C, FR) and two Atmos modules (those two up-firing drivers)

When it comes to channels, the general rule is – more is better. However, make sure your TV room is big enough to host such a large soundbar (and, in some cases, additional wireless speakers).

Frequency response

Frequency response represents the range of frequencies a soundbar (or a speaker) is capable of producing. It is expressed in Hertz (Hz). This frequency range and can be found in every specs list. You will basically find two numbers – the lowest and the highest frequency a speaker can reproduce. Sometimes, the frequency response is followed by a deviation – (something like +/- 3dB). This deviation gives you some info regarding the accuracy of sound reproduction. 

Frequencies between 20 Hz -200Hz are known as the low-end or bass, and they are produced by the subwoofer. Midrange frequencies are between 200 Hz and 2000 Hz (or 2 kHz), and they are generated by woofers or mid-bass drivers. High frequencies are those between 2 kHz and 20 kHz, and they are produced by the smallest drivers called tweeters.

Most soundbars are not large enough to house a good subwoofer, so you will not have a great depth out of the box. However, most of them will allow you to connect a separate subwoofer to provide you with those low-frequency bass tones.

So how will you know if the soundbar good or not?

Since there isn’t any universal system that would help you find a perfect soundbar and compare specifications, you could go by “more is better”. High SPL, at least 3.1 channels or more, and the widest frequency response you can find within your budget.

However, this won’t guarantee you anything because when it comes to sound, things can be very subjective.

The best and least practical way to find the perfect soundbar is to test it in the room it is intended for. However, since that will not be possible in most cases, any live test will be better than none.

If you’re looking for the soundbar online, try to find positive reviews from trusted sources. If many people like some product and have positive words about its performance, chances are you will like it as well.

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