The Signa S4 is a 3.1.2 soundbar consisting of a 25mm full-range center speaker, two tweeters 25mm and two 120 x 40mm midrange drivers for the stereo channels, and two 66mm vertical diffusers. The box itself is equipped with a woofer 150 mm and a vent bass-reflex. The bar has 3 listening modes (Movie, Night and Music) and three levels of voice emphasis (VoiceAdjust).
Let’s first look at the Movie mode. As its name suggests, this mode is particularly suitable for films and series, because it allows you to extend the scene in a rather surprising way horizontally. Indeed, although the bar offers a 3.1.2 format, it manages to reproduce side surround effects admirably without any dedicated speakers. The voices however seem a little distant, but remain sufficiently intelligible not to have to act on the volume constantly between the calm scenes and the more punchy action scenes. The use of VoiceAdjust is therefore of no real interest, especially since to highlight the voices, this mode lowers the level of the bass and treble, which distorts the sound a little too much.
The two vertical channels, dedicated to Atmos effects, are on the contrary a bit disappointing. The verticality of the sound stage is very discreet and it is difficult to really feel the elevation of certain effects. In addition, the bar constantly performs a upmix in Dolby Atmos, which cannot be deactivated, when it is in Film mode and creates a kind of reverberation which does not suit musical content, for example. Fortunately, the Music mode allows you to transform the bar into a simple stereo speaker. The left and right channels are then totally independent, which gives a much more natural rendering to musical content.
The Signa S4 has a V-shaped sound signature emphasizing bass and treble at the expense of mids and high mids. The warm aspect is provided by the subwoofer which provides a good extension in the bass. However, its cut-off frequency is particularly high (200 Hz) and the crossover is quite steep. This creates a dichotomy between the bar and the box: the officiating instruments in the bass register seem to come from the box while the rest comes from the bar.
The withdrawal of the mids and high mids creates a lack of presence and a distance from the soundstage: many instruments, including the vocals, can indeed seem distant. The general precision is also quite average, with overflow effects in the bass and fairly recurrent sibilance effects.