When we say "full range speakers", we really mean "wide range single driver speakers". For one loudspeakers that contain multiple drive units may well be full range. On the other hand, full range must be defined as some range other than the entire audible spectrum, because no loudspeakers covers all frequencies we can hear. So for the purposes of this post, we will define "full range" as a loudspeaker using only one drive unit and "full" as the frequency range expressed by real musical instruments. We also need to look at the loudness at which the loudspeakers can express the "full range" of frequencies.
Such full range speakers like the Sound Sommeliers are not for everyone. Single driver speakers are most suitable for the more intimate genre and at moderate volume levels. This includes solo voice, small group jazz and 18th century classical and chamber music as well as classical rock. Really anything expressed by real musical instruments and played no louder than would be considered just a little too loud for most people in an average sized listening environment. In technical terms we are talking about 80dB at the listening position. In non-technical terms this is the noise level of a freight train at a distance of about 15m. Anything louder than that and a full range driver might not be for you. Now, if you are into very loud heavy metal, techno or Mahler symphonies at full concert volume, you may not be in the right place.
What are the advantages of single driver speakers? Well for one the completely unique sound that comes by the elimination of all electronics from the system after the amplifier. A speaker employing more than one driver uses a device called a cross over that divides the musical signal up between the different drive units. This crossover has two problems. For one it adds complexity and hence distortion. Second, all but the rather difficult to design, "first order cross-overs" have a problem; at the frequencies where they hand over from one driver to the next, the phase switches. This means that the membrane of one drive unit might rise while on the other drive unit it will fall. This is important because it leads to cancelations of frequencies making the listening position and speaker setup of such system a distinct art requiring constant tinkering. On the other hand, the human ear uses phase as a cue where a sound is coming from and since a "normal" speaker has a crossover that switches phase the sound stage or stereo image will become blurred and messy.
By not using a crossover the SoundSommeliers like select few other full range systems often available at much higher prices have no electronics at all. A high purity copper wire runs from the binding posts directly to the driver. This leads to reduced distortion and thus provides a sound stage and a stereo image that is more precise and natural with depth that is not possible with speakers that have several drive units. In simple words: It sounds like the music was just happening.
Another advantage of full range designs comes from the fact that in a multi driver set up the sound around the crossover point which usually spans as much as an octave, actually comes from two different areas leading to interference patterns and again a smeared stereo image.
And finally, a well designed single driver speaker using quarter wave technology is much more articulate and precise in the bass with better transient responses coming from a lighter cone. These bass notes extend well bellow the capabilities of the drive unit itself and are always in phase with the sound coming from the cone. Congruency might not be something many have thought about, but there is something to be said about the bodily experience when the fundamental bass note of a musical instrument is in tune with its over-tones. We at KVART & BØLGE experience this bodily experience as "Goosebumps". Call it what you may, it is only a full range system like ours that can provide headphone-like soundstages and stereo imaging and the bodily experience of a deep congruent bass.
Now due to the intrinsic limitations of 3inch drivers to go to the very deep basses, compared to woofers, some "tricks" are necessary. First off: Consider that our tiny ear drums, aren´t really that good at picking up bass notes either and human hearing in the basses is terribly logarithmic. The human brain uses an equalizer of sorts that lets us perceive loudness of lower notes of a harmonic or subharmonic tone at the same loudness at its over-tones. The brain then adjusts the perceived loudness for both to match in the wondrous world of psychoacoustics. For this to work, a smooth bass roll off is required that keeps the overtones congruent with the bass. A well-designed quarter wave speaker can do just that and the results are outright surprising for many.