Our Soundbar Sound Tests
Height (Atmos)

Updated
What it is: How accurately the soundbar reproduces audio with an Atmos file that has one object placed in the middle of the ceiling. When possible, soundbars are tested using a direct HDMI connection to the test PC. Otherwise, HDMI ARC through a TV is used for testing. Height is tested using the preset we selected and not with the full preliminary calibration.
When it matters: When a deep and powerful bass, clear dialogue/instruments, a large soundstage, and a loud and artifact-free sound is desired from the height (Atmos) channels. This only matters when the content is Atmos (like most recent movies and video games), but won't matter for stereo or surround content (older music and movies) since they don't have discrete height (Atmos) channels.
Score distribution

From Blu-rays to popular streaming platforms like Hulu and Netflix, you can find more and more movies that support Dolby Atmos. Dolby Atmos is an object-based surround sound format that allows sound engineers to more accurately place objects like voices and footsteps in pinpoint locations in the sound image, resulting in a more immersive listening experience. While down-firing speakers found in home theater setups are considered the standard for Dolby Atmos technology, you can also find Atmos-enabled soundbars designed to create the illusion of height.

We perform several tests to measure a soundbar's height performance, including localization, slope, standard error, SPL @ Max Volume, and weighted total harmonic distortion at 80 dB SPL and max volume.

Test results

When It Matters

If you like to listen to Atmos-enabled content, you'll want a soundbar that can offer an immersive listening experience. Most new movies and video games support Atmos, so fans of this content want a soundbar that can reproduce a large soundstage and accurately localize objects like voices and footsteps in the sound image. It's also important for those who want to feel the deep, thumpy bass in action-packed scenes and hear clear and accurate dialogue. You may also want to crank up the volume when listening to Atmos content for a loud sound without a lot of distortion. Surround and stereo content like older movies and music don't have height channels, so this won't matter for listeners who prefer those types of audio content.

Our tests

To test a soundbar's Atmos performance, we look to see how accurately it can reproduce an Atmos file with one object placed in the middle of the ceiling. We measure its frequency response by playing a sine wave tone at -6 dB FS between 20Hz and 20kHz and plotting its output, in dB, on a frequency response graph. Using our microphone array, we also measure how loud the bar gets on its height channels. Additionally, we apply a spectrally pure sine wave to measure the amount of total harmonic distortion, both at a normal listening volume and at max volume. While we only test for Atmos content, we expect similar results with DTS:X content.

 

We perform our Atmos channel tests with a similar setup to our stereo channel tests. We use a room that's 18' (L) x 16' (W) x 9' (H), with one couch and minimal sound treatment to represent a typical living room. We place the soundbar and the table it sits on 7.5 feet away from our microphone array. We also test the bar when it's 6.5 feet and 8.5 feet away from the microphone to get a better understanding of the sound profile from different places in the room. We use a laser measuring tool to ensure that the microphone array, table, and soundbar are at the appropriate distance from the side walls, as well as the subwoofer and the satellites if they're included in the setup. However, we test the Atmos channels using the same preset we selected for our stereo frequency response tests and not with preliminary calibration.

Localization

What it is: Whether the soundbar has dedicated height (Atmos) speakers (discrete), or uses up-firing speakers on the soundbar and/or satellites to represent an Atmos object in the soundstage (phantom). The soundbar may also lack any Atmos capabilities and play the Atmos content through the left/right surround speakers of the soundbar (downmix).
When it matters: When you care about an accurate and clear representation of Atmos objects in the soundstage. A phantom representation won't sound as clear and real as a discrete Atmos, and the objects may not feel as if they are located in the intended area. This won't matter for stereo or surround content (older music and movies) since they don't have height (Atmos) channels. However, most recent movies and video games have Atmos content.

While many soundbars support Dolby Atmos content, not all of them reproduce this content in the same way. Localization describes how the soundbar is set up to playback height content and can impact how accurately objects reproduce in the soundstage.

Home theater setups tend to come with dedicated or discrete height channels that you can screw into your ceiling, which offer the most accurate and focused soundstage performance. However, soundbars may have a phantom setup, meaning they use up-firing or side-firing speakers to bounce sound off the ceiling and back down towards you to simulate height. Unfortunately, a phantom setup can't reproduce objects in the soundstage like voices and footsteps as clearly or accurately as a discrete setup. Other soundbars that lack Atmos capabilities have to downmix this content into surround to play it, which doesn't sound as immersive.

Slope

What it is: The derivative of the logarithmic fit (regression line) of the frequency response. This value shows the overall tonal balance (tilt) of the sound as opposed to the std. err. value which shows the overall deviation. Negative values translate to a bass-heavy sound and positive values represent a treble-heavy sound. 0 (a flat slope) represents a balanced tone.
When it matters: When the overall balance between bass and treble is important to you.
Noticeable difference: 0.2

During our height tests, we measure the frequency response of the height channels by playing a sine wave tone at -6 dB FS between 20Hz and 20kHz and plotting its output on a graph. Ultimately, the frequency response graph shows us how accurately the soundbar can reproduce audio at each frequency, from the low bass to the high treble.

The slope of the frequency response describes the overall tonal balance of the bar's sound profile. If the slope is negative, the bar reproduces more bass than treble, resulting in a thumpy, punchy, or boomy sound. A positive slope represents a frequency response with more treble than bass, so your audio may sound bright, sparkling, or piercing. A slope closer to zero represents a more balanced sound.

TCL Alto 8i H Frequency ResponseOn its height channels, the TCL Alto 8i has a slope of -2.55
Vizio SB36512-F6 H Frequency ResponseThe Vizio SB36512-F6 has a slope of 0.01 on its height channels

As with our stereo frequency response tests, we don't score the slope for the height channels. Personal preferences play a role in determining the sound profile that you'll prefer. While a neutral, balanced sound is considered suitable for most types of audio content, some listeners may prefer a bass-heavy sound that adds more thump and punch to action-packed scenes.

Std. Err.

What it is: The average deviation of the soundbar's in-room frequency response from the in-room target response. This shows the amount of error in frequency response, as opposed to the slope which shows the tonal balance of the sound. Higher errors represent a less accurate frequency response and lower values represent a more accurate sound.
When it matters: When you care about accurate sound reproduction in a fine-detailed view.
Good value: <2.5 dB
Noticeable difference: 0.1 dB
Score distribution

Audio content like movies and video games are mixed to contain a wide range of frequencies, from the thumpy bass in action-packed scenes to the dialogue and lead instruments in the mid and treble ranges. Our standard error measurement shows the average deviation of the soundbar's in-room frequency response from the in-room target response, allowing you to see how accurately the soundbar reproduces audio at each of these frequencies.

For all of our sound tests, we use the Harman in-room response curve as our target response. Research has shown that this curve represents the sound most pleasing to most listeners, and it adds a little extra emphasis in the bass and a little less emphasis in the treble. Ideally, your soundbar will have a low amount of standard error, meaning that its audio reproduction is very similar to the target curve. This usually results in a cleaner, more even sound.

Sony HT-G700 H Frequency ResponseThe Sony HT-G700 has a standard error of 2.97 dB
Samsung HW-Q850T H Frequency ResponseThe Samsung HW-Q850T has a standard error of 8.68 dB

You can usually tell which soundbars have higher amounts of standard error just by looking at their respective frequency response graphs. A soundbar with a lower standard error will usually have a flat response that's close to the middle, while a response that deviates from the middle usually represents a higher amount of standard error.

Depending on where those fluctuations occur in the graph, you can get a better understanding of the bar's sound profile. The bass range is where the thump and punch in your audio reproduce, so an overemphasized bass could make your audio boomy, while an underemphasized bass could mean that you don't feel the rumble in action-packed scenes. Deviations in the mid-range can make vocals and lead instruments muddy or push them towards the back of the mix, while fluctuations in the treble range could make higher-frequency sounds either piercing and painful or dull and whispery.

SPL @ Max Volume

What it is: The SPL (sound pressure level) produced by the soundbar with its volume set to maximum. This value is measured and reported at 2.5 meters.
When it matters: When you want a soundbar for a large, crowded, or noisy environment, so it needs to get loud, but you don't necessarily care about how much the frequency response is degraded in the process.
Good value: >92 dB SPL
Noticeable difference: 1dB SPL
Score distribution

If you listen to audio in a large room or at crowded parties, you may want to crank up the volume for a loud sound. We measure the soundbar's Sound Pressure Level in decibels (dB) when it's pushed to its max volume. This measurement shows us how loud the soundbar can get on its height channels.

We consider a good value to be above 92 dB SPL since this gives you a lot of flexibility in selecting how loud your soundbar can get. Most of the soundbars we've tested measure between 80 and 95 db SPL, but your personal preferences play a role in how loud you want your soundbar to get. You can also find soundbars that get a bit louder than that, like the Nakamichi Shockwafe Ultra 9.2Ch, which reaches 100.2 dB SPL on its height channels.

Weighted THD @ 80dB SPL

What it is: The total harmonic distortion produced by the soundbar at 80dB SPL. To make the score more perceptually relevant, more weight is given to the higher frequencies. This value is measured and reported at 2.5 meters.
When it matters: When a pure and clean sound is desired at moderate listening levels. Harmonic distortion is relatively difficult to hear, so it should only matter to those who really care about the fidelity of sound reproduction.
Good value: <0.7
Noticeable difference: 0.1
Score distribution

 

Total harmonic distortion, or THD, is a measurement that shows the number of unwanted frequencies that the soundbar reproduces alongside the intended frequencies. Essentially, it compares the input, or the audio that you're listening to, with the output reproduced by that soundbar. Ideally, a soundbar has a low amount of distortion since that means that your audio content reproduces the way it was meant to be heard by whoever mixed it.

We use an SPL meter to set the soundbar to a normal listening volume of 80 dB SPL. Then, we apply a spectrally pure sine wave and measure the output produced by the bar using our microphone array. By comparing the input to the output, we can determine the amount of total harmonic distortion. Our measurement applies more weight to higher frequencies since those are more likely to be audible. THD can be difficult to hear with real-life content, so it's mostly important for listeners who care about the fidelity of audio reproduction.

Weighted THD @ Max Volume

What it is: The total harmonic distortion produced by the soundbar at its maximum volume. To make the score more perceptually relevant, more weight is given to the higher frequencies.
When it matters: When a pure and clean sound is desired with the soundbar set to its maximum volume. Harmonic distortion is relatively difficult to hear, so it should only matter to those who care about the fidelity of sound reproduction.
Good value: <1
Noticeable difference: 0.1
Score distribution

If you like to listen to your Atmos content at loud volumes, you'll want to see if your soundbar can maintain clear and pure audio reproduction when it's pushed to its max volume. We measure the amount of total harmonic distortion, or THD, reproduced by the soundbar at its max volume on its height channels. Our testing procedure is the same as above, only we set the volume to its maximum instead of 80 dB SPL.

Most of the soundbars we've tested see a jump in total harmonic distortion at their max volume. However, THD can be difficult to hear with real-life content, especially if the weighted total remains below one.

Conclusion

If you enjoy Atmos-enabled movies and video games, you'll want a soundbar that offers an immersive height channel performance. Our Atmos tests give you a better understanding of how accurately the bar can reproduce the thumpy bass and the dialogue in your movies and whether or not objects like voices accurately localize in the soundstage. You may also want a soundbar that can get loud on its height channels without a lot of distortion. However, if you only want a soundbar for listening to stereo and surround content like music and older movies, this may not be very important to you.

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