Adjusting the TV equalizer for speech

What is an equalizer

An equalizer is a tone control that divides the audio signal into several frequency ranges. Each range can be made louder or quieter on its own. In the TV’s sound menu, besides the equalizer, there are usually sound modes that work similarly but are fixed presets.

Frequency bands and sliders

Each slider of an equalizer is responsible for a frequency range, a so-called band. In the TV menu, a frequency in Hertz is listed at each slider, for example, 100 Hz, 300 Hz, 1 kHz, 3 kHz, and 10 kHz. The slider primarily changes this frequency and, to a decreasing extent, the frequencies below and above it. The low values represent the bass, the middle ones the vocal range, and the high ones represent noises, sounds, or fine details.

Many TVs offer five such sliders, some even more. They can be moved up or down in steps. In the center position, the sound remains the same. The frequency and width of the bands are fixed on the TV. In contrast, with a parametric equalizer, as found in some AV receivers and apps, the frequency and width of a band can also be changed. Some devices have only two sliders for bass and highs instead of an equalizer. Voices can only be influenced indirectly with these, as there is no dedicated slider for the mids on these devices.

Equalizer and sound mode

Sound modes such as Standard, Movie, Music, or Speech are ready-made settings from the manufacturer. In speech mode, the mids are usually emphasized and low frequencies are reduced—similar to an equalizer setting for voices. Often, the difference between quiet and loud passages is also reduced.

The equalizer, on the other hand, is freely adjustable. On many TVs, however, it can only be changed in certain sound modes, such as Standard or User mode. In that case, you cannot use the speech mode and your own equalizer values at the same time.

The sliders and their effect on voices

Voices are spread across a large part of the audible frequency range. The lows give them fullness, the mids make the words understandable, and the highs bring sharpness. On a TV, the sliders around 100 and 300 Hz, around 1 and 3 kHz, and around 10 kHz are usually responsible for these three areas.

For speech, a little less bass and slightly boosted upper mids help most; the highs should only be changed carefully.

Bass and fundamental tone

The fundamental tone of a voice lies in the transition from bass to the lower mids—on a TV, this is in the range of the sliders around 100 and 300 Hz. It gives the voice fullness and volume but contributes little to understanding individual words. If you boost the 300 Hz slider too much, voices will sound muffled rather than clearer.

In the deep bass, on the other hand, you mainly find movie music, explosions, and other loud scene elements. If you lower this range slightly, the noises become quieter and mask voices less. The small speakers in flat-screen TVs only reproduce deep bass to a limited extent anyway. With such devices, the difference after lowering is therefore less noticeable, but the speakers are relieved at higher volumes.

Mids and highs

For intelligibility, the range between approximately 1,000 and 4,000 Hertz is most important. Many consonants have large components in this range. Therefore, it primarily determines whether you can distinguish between similar-sounding words. A classic telephone, for example, only transmits frequencies between about 300 and 3,400 Hertz. Voices are still easy to understand because the most important part of speech for intelligibility lies in this range.

The highs mainly contain S-sounds and other sibilants. If you boost them strongly, S-sounds sound sharp and the hiss in older recordings becomes louder. If you lower them too much, voices sound muffled. Therefore, you should only change the slider for the highs in small steps.

Adjusting the TV equalizer

You operate the equalizer on the TV via the sound settings. For testing, a program with a lot of speech and a movie where music and voices can be heard simultaneously are suitable. This allows you to check whether the setting works well in both cases.

To the sound menu

In the TV menu, open the sound settings and look for the equalizer under Expert Settings or Advanced Settings. On some devices, you must first set the sound mode to Standard or User, otherwise the menu item is grayed out.

Often, the equalizer is also locked when the sound is played through a soundbar, an AV receiver, or headphones. In this case, the TV leaves the tone control to the connected device. On some models, the values can also be saved separately for each input, such as for the TV program and for a game console.

Setting for speech in six steps

You don’t need measuring devices for a simple setup. However, you should proceed in individual steps and listen briefly after each change. The following sequence has proven effective.

1. Set all sliders to the center position and turn off sound effects like virtual surround sound.
2. Turn on a news program or a talk show at normal volume.
3. Lower the bass slider by two to three levels.
4. Boost the 3 kHz slider by one to two levels, and the 1 kHz slider by one level at most.
5. Play a movie with music and noise and check if the voices are also easier to understand there.
6. If S-sounds sound sharp, turn the highs down one level. If voices sound muffled, lower the 300 Hz slider by one level.

Lowering instead of boosting

Boosting the mids strongly does not automatically make voices easier to understand. The sound then quickly becomes tinny and strenuous over time. The TV’s built-in speakers and amplifiers also reach their limits sooner because the boosted ranges require more power. At higher volumes, the sound can distort more easily.

Therefore, it is often more sensible to lower the disruptive ranges instead of strongly boosting the voice. If you turn the bass down slightly, the mids seem louder in comparison without the speakers having to work harder. You can then adjust the overall volume using the remote control.

Equalizers on soundbars and AV receivers

If an external audio device is connected, you usually adjust the sound on that device. Soundbars often offer only a few sliders for this, while AV receivers offer a whole range of settings, including automatic calibration. In many cases, the sound can no longer be changed on the TV itself.

Soundbar

Many soundbars do not have a multi-band equalizer, but only sliders for bass and highs. These can be accessed via the soundbar’s remote control or the manufacturer’s app. In the app, there is sometimes an equalizer with more sliders. In addition, there is often a speech mode or a dedicated button to emphasize voices. They sound a bit clearer with this, but they usually cannot be completely separated from music and effects in this way.

For soundbars with their own subwoofer, the bass can usually be adjusted separately. If you turn the subwoofer down, movie music and effects become quieter in relation to the voice. This works similarly to lowering the bass slider on the TV.

AV receivers and automatic calibration

Many AV receivers have a small microphone for automatic calibration, which you position at head height at the seating position. The receiver then uses test tones to measure how each speaker sounds in the room and determines an individual sound correction for each. In doing so, it primarily compensates for excessive bass caused, for example, by high walls.

The goal of the calibration is a balanced sound; the focus is not on voice or dialogue optimization. If you want to emphasize voices, you can also turn up the center speaker on the receiver. With multi-channel sound, a large part of the dialogue usually runs through it, but also music and noise, which then become louder as well. On many devices, you can then additionally set your own equalizer values.

Limits of the equalizer

An equalizer changes frequency ranges and does not distinguish between voice, music, and noise. Whatever lies in the boosted range becomes louder.

Voice and music in the same frequency range

Voices, dialogue, and many noises lie largely in the same frequency ranges. If you boost the mids, voices become clearer, but the music in this range also becomes louder. If the music in a film is mixed very loudly in relation to the voice, the equalizer can do little to change that.

To actually separate voices from music and effects, you need processing that recognizes what is speech in the audio signal. Such a process is behind the additional audio track “Clear Speech” offered by some public broadcasters. With a TV speech amplifier like OSKAR, a specially developed algorithm separates speech from music and effects and highlights it. The device is placed close to the seating position so that the voices arrive over a short distance.

Programs and speakers

A setting that works well for news, for example, can sound significantly too thin or too sharp for a movie. In news, there is hardly any background noise, whereas movies often have loud music and strong effects. If movies run via a streaming stick or player on a separate input, some TVs allow separate values to be saved for that input.

The TV’s own speakers also have their limits. If they fire downwards or backwards, the upper mids in particular are partially lost on the way to the sofa. The equalizer can compensate for this to some extent, but it does not change the direction in which the sound is emitted.