The Harman Kardon GLA-55 is a striking two-way speaker system featuring transparent cabinets and bi-amped drivers with digital crossovers.
Some speakers are destined to blend discreetly into your environment. Not so the Harman Kardon GLA-55, whose multi-faceted-diamond looks are positively shouting for attention.
Each Harman Kardon GLA-55 speaker is based on a traditional two-way driver design, comprising a concave metal 52mm mid-bass driver and metal-domed tweeter, shoehorned into a totally transparent case resembling an alien crystal skull.
The tweeters carry chromed bars to discourage idle prodding of the delicate domes. And built into the case are the system’s amplifiers, hidden away in the base plate.
You connect the speakers to a computer or iPod via a 3.5mm stereo jack plug in the right-hand speaker. Electrical power also comes into this master speaker from a laptop-style power supply. Under the main drivers is a reflex port which helps improve acoustic efficiency and low-frequency response.
As well as the usual volume control on your music player, there are touch-sensitive + and – buttons on the right Harman Kardon GLA-55 speaker, sat between drive units. White LEDs are hidden in each speaker’s base, pulsing when in standby mode and steady-on when in use.
Try to lift a Harman Kardon GLA-55 speaker and you may be surprised at their weight. They really are very solid and hefty feeling. If you peer inside the transparent sides you can see the U-shaped reflex port curving through the bodies up to the tweeter, as well as polished metal internal parts of all the drive units. What you can’t see is any obvious cable wiring, as this seems to be handled by thin metallic rods that join the drivers.
The GLA-55 speakers not only look but feel like no traditional hi-fi speaker. They are incredibly dense and seem non-resonant. The absence of wood cabinet and parallel internal walls means the familiar colorations of a hi-fi box speaker are entirely absent. In fact, the crazy shape with faceted external sides and curved interior really should reduce the usual resonances that can cloud the sound.
Digital Signal Processing
To optimise sound quality, the GLA-55 system uses digital signal processing (DSP).
Analogue audio signal input is converted to 24-bit/48kHz digital, then passed to a 24-bit DSP, responsible for equalisation and dynamic limiting, gently contouring bass and treble levels to suit the speaker’s limited size.
Some compression and limiting here also serves to prevent either the amplifiers or drive units from being overdriven into gross distortion at high volume levels or when presented with high levels of bass.
Four separate channels of 26-watt MOSFET Class D amplifiers are included, two for each speaker and dedicated to each treble and mid-bass drive unit, with active crossovers to split the signal at the DSP stage.
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