4) Runtime correction

In virtually all conventional center speakers, the tweeter is located between two low-midranges; the result is that a well-balanced sound is only heard if the listener is positioned directly facing the axis formed in this way. Sitting laterally to the tweeter axis means a considerable loss of acoustic pressure in the presence range (between 1 kHz and 4 kHz), and voice reproduction is not the only aspect to be audibly impaired.

Most manufacturers simply accept these restrictions with a shrug, whilst a few counteract them with a fourth chassis - a mid-treble unit - positioned below the tweeter. But all this does is to shift the problem from horizontal to vertical level, i.e. the center speaker may no longer simply be positioned on top of or below the TV set, but rather exactly at ear level, for example tilted, in order to obtain a decent sound. And that is certainly a rather questionable compromise.

quadral has quite consciously taken a different path here: delay or phase control in the crossover network ensures that the inevitable drop of acoustic pressure in the presence range is far less marked than customary - and hardly even verifiable in the vertical axis. quadral center speakers do not therefore need to be aligned to suit listeners sitting to the side of them, nor do they have to be aligned to ear level in order to sound clear and well-defined throughout the listening area.

The thick line shows the axial frequency response of the ARGENT BASE Mk ll, whilst the thin line shows the acoustic pressure curve 30° lateral to the main axis. The dotted line shows the area in which conventional center speakers lack volume.