Our Soundbar Sound Tests

Height (Atmos)

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.

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.

On its height channels, the TCL Alto 8i has a slope of -2.55

The 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.

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.

The Sony HT-G700 has a standard error of 2.97 dB

The 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.

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.

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.

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.