Ground Zero GZCT 0500

WARNING: THIS PRODUCT CAN CAUSE HEARING DAMAGE! (See Editor review.)
A true compression driver with horn loading, this unit is identical to those used in medium to small sized professional sound reinforcement systems for live music concerts. It is made of a large rear magnet, metal diaphragm (Magnesium-Aluminium alloy) sandwiched beneath a turned Aluminium front horn-piece and with a narrow circular aperture to ‘squirt’ the output of the diaphragm through, formed by the presence of a clear plastic ‘phase plug’ mounted in the front of the diaphragm and curved geometrically/exponentially to complement the horn it is loaded into. Also, the diameter of this circular aperture is far less than that of the diaphragm it serves. Thus the output of the whole excited area of the diaphragm has to force its way out through the smaller aperture. This, along with the narrow dispersion of the horn results in a truly terrifying 106dB per watt efficiency.
The terminals are a small version of the classic binding post and are gold plated. A front ring of aluminium is supplied with the fixings. These enable mounting within a baffle with a front piece showing. This is engraved with the brand name. They are sold singly (c/w a single capacitor for use as a -6dB safety attenuator) and are unlike any ‘tweeter’ you will ever have seen described for car use.
– Diameter 42mm
– Magnet assembly 58mm diameter x 18mm deep
– Impedance: 3 Ohms
– Resonant Frequency: 2800Hz
– Frequency Response: 3kHz to 20kHz
– Power Handling: 25w RMS, 100w peak
– Efficiency: 106dB 1w/1m
– Mounting Depth: 35mm to 55mm
– Gold Plated Binding Post style terminals
– Front turned ring of Aluminium for mounting the product to the panel
– Billet-turned stubby horn front piece with 20mm throat
– Aluminium-Magnesium tweeter diaphragm 30mm including suspension
– Clear plastic phase plug that has rear piece shaped to pressurise the output
– Rear decal has protective film to be removed after installation.
Review by Adam Rayner
Let’s get this bit out of the way first. If you use these injudiciously, in car, on axis to your ears and at high level, YOU WILL HURT YOURSELF. The slogan runs ‘practice safe sound’ but all I can say is if your ears ring, they have been beaten up. If you do it enough the ringing will never stop for the rest of your life and that can be fatal, since Tinnitus has been proven to cause suicide. I kid you not, like your main sex bits, you only get one set of Cochleae, Basilar membranes, Hammer, Anvil, Stirrup etc. and you must care for your Organs of Corti! These tweeters go mind bending, metal-meltingly loud and HF is what rips ears apart. Too much bass makes you go potty but too much tweet will make you go deaf. In my book, these are show-blasters. Competition-slashers and full-range-at-long-range marvels. Fit these to your boot lid attract-system on the show car and you will pull punters from way further out than you ever did.
Match them to the Ground Zero GZCW 6-4Y midbasses if you will, but in honesty, they can be applied to just about any system you want to. They will take some serious depth to mount them and space to fit them and they weigh a whole load more than many six inch car speakers including full range coaxials! So they are far from a doddle to fit but if you are a mad nutter who wants to cut through and be heard or if your highs matter more to you than most, then fill your boots but while they are not desperately hi-of-fi (which is to miss the ruddy point of these) they do produce an incredible edge and definition to the high frequencies that will surely put you in mind of the last time you went to a live gig. I liked them rather a lot, although they scared me!
Their huge power and madness of efficiency makes them score hugely. So they get a Talk Audio Recommended flag but that comes with a caveat. These are recommended for nutters but ones with enough sense to handle dangerous things like scissors.
Overall 9.0
Sound Quality 7
Build Quality 10
Power Handling 10
Efficiency 10
Value For Money 8