Ground Zero GZNW 6.5 Subwoofer

Product Details
Manufacturer: Ground Zero
Distributor: Car Audio Direct
Website/To Purchase: ground zero
Typical Suggested Selling price: £199.00 (GZ Audio UK Price £159.99)
In a Nutshell
Like a young Esox lucius or European Pike fish, the Ground Zero GZNW6.5 subwoofer looks bad as hell and beautiful with it, but is very delicate and easy to harm. Once fitted correctly and fed the right signal, this is a remarkable and clean woofer that has a dropping ability that quite utterly belies its size. With the right installer, the Ground Zero GZNW6.5 subwoofer could be used for Front Bass installations for sound off use. Clean, tight, deep, richsurprising as hell!
Overall 8.8
Sound Quality 9
Build Quality 10
Power Handling 10
Efficiency 7
Value For Money 8


Description
A 6.5 inch diameter subwoofer. Not a midwoofer, not a HiFi driver, this is a woofer that has gone through Wonka Vision and shrunk! Well in truth it is a dense spud of a cast chassis with a massive rubber-armoured Ferrite magnet on the back and one hell of an Aluminium piston in the middle with lots of suspension. Fully three layers, with a really big genuine rubber (not foam) top suspension and dual linen spiders beneath. The terminals are fit to accept a smallish wire and are a screw type that you will need a precision tiny screwdriver to use. The power handling is prodigious, for its size, as is the travel of the cone. It needs a small ported box and requires a steep -12dB per Octave subsonic filter at around 30Hz when boxed. When played ‘˜free air’ (as I did in the test rig, really) it should be subsonic filtered at 50Hz. (Which I failed to.)

Editor Review : Ground Zero GZNW 6.5 Subwoofer
Far more cathartic even than a damn good poo when you need one is the confession. Catholics love a bit of that and I can tell you that Jews do as well, but do it wholesale. Not weekly but annually by being REALLY sorry for being baaad earlier in the year. And I owe both apology to product and to the reader for being guilty of preconception and abject failure. After all, it’s a subwoofer, it’s small, it says it does 250 watts and I have a 250 watts amplifier in mono just for that purpose. What’s wrong with that picture? Well there were two things
One was, that just like the most beautiful driver that competing speaker maker Midbass ever produced, (a metal-coned eight) the GZ Nuclear 6.5 may have an evil name and a badass reputation and looks, but like a Pike fish, it is a delicate creature really and if treated badly can very easily die. It has a delicate cone. Now that eight from Vibe was supplied with a grille built-in, so you could not cock up its incredibly delicate cone when installing it. It was a costly thing to develop and is the pinnacle of proof that a single talented designer can lay golden eggs and create a speaker company. An uneconomic item, it never sold anything like its development costs when compared to most of their other big seller speakers but it has the DNA of the brand in its every pore. As does the Ground Zero GZNW 6.5 subwoofer. And I had hurt it somehow
And that Ground Zero DNA is what has taken one Edd Elson to the status of UK Bass King 2012. For his Audi, the one that needs a strut brace of steel from floor to roof brow to stop the damn monocoque from bulging with his 163dB 25Hz bass, is entirely Ground Zero driven. They are as extreme a set of bass heads as exists on the planet. So I expected a lot from this driver. And secondly, I had ‘˜boxed’ it in what was far too big an enclosure and not crossed out the deeeep stuff with a set-high (50Hz) ‘˜subsonic’ filter.
Thus I treated it far too casually and at some point after installation or maybe during it, I must have bumped up against the edge of the thin metal cone where it is glued securely to the rubber top roll surround. It is Aluminium, so it bent, taking the top roll from perfectly round and concentric to not quite so. The result was that as I ran it up gently on the delicious DLS RM10 250w monoblock amplifier, made as like to be born for the driver, it suddenly started to make a nasty ‘˜clack’ and I thought immediately about it being someone else’s fault rather than my own. Like you do
I put it down to the huge Xmax being asked of the cone’s voice-coil former and the serious linearity being asked of that in turn, then wondered at last and at worst if I had dropped the thing and had that huge ferrite magnet exert an angular force shearing it away from the chassis was it bent? But I could not recall dropping it. Later on, I sadly removed it from the enclosure it is filmed in and saw that the suspension was a bit crinkled. Upon removal, I could finally see the cone was just slightly bent at the edge and with real care, as delicately as possible, I gently eased it back until it looked properly circular and concentric again. Then, laboriously, I refitted the speaker wire, screwed it back into the baffle and tried it again. Trouble is, it still wasn’t properly boxed and in a full cubic foot, rather than the recommended 0.39cu ft and a port to acoustically suspend it a little, it should have been crossed over at 50Hz with a reasonably steep -12dB per Octave. (By comparison, the sweet smooth transition from mid to tweeter can be as gentle a slope as 6dB per Octave, as the Clarion components recently reviewed, prove.)
However, while I did apply some sanity and care, I was able to play a really phat bass line through it well the title track from the absurd More Bass, More Boom, More Bottom bass CD and it played the lot. MeJulie was downstairs and told me that the subwooferingness floating down the stairwell and wobbling things around in the air was proper profound-grade.
But the odd thing was that while the Ground Zero GZNW6.5 subwoofer’s cone had to travel in and out like a mad thing, the bass was rich and accurate. It tracked the changes and was even melodic. If you have no space and need bass, then the Ground Zero GZNW6.5 subwoofer is not a weedy impersonation but a real low end system. I was mightily impressed and of course kept on trying to overdrive it, indeed making a brief BURR on the video, which I rapidly wick back from. But even unsupervised or crossed over, or even given an IOTA of acoustic suspension as a full cubic foot when far less than half that ported is what is needed does simply not count as anything other than ‘˜free air’. All that taken into consideration, watching the subwoofer go in and out as far as it does and hearing how tight and sweet the bass was, was impressive as hell. The Ground Zero GZNW6.5 subwoofer is a Talk Audio Recommended product.
I would really like to hear the box design in the excellent pan-European manual for two of these in one shallow enclosure. The designs are all in the manual, as are the full Thiele-Small parameters published here. So, the Ground Zero GZNW6.5 subwoofer needs careful handling and installation but this is a remarkable bass product for those with both taste and limited space. The DLS RM10 amp that it was run upon is also excellent and shall have a review of its own in due course.
FULL Specifications
Ground Zero Nuclear 6.5in Subwoofer
– Frequency response: Not quoted
– Two-piece inverted-dome Aluminium metal cone
– Large diameter rubber top roll surround
– Die cast Aluminium chassis
– Diameter: 16.5cm/6.5in
– Nickel plated screw terminals
– Power handling: 250W RMS
– Impedance: 1 x 4 Ohms
– Voice coil Diameter: 38mm/1.5in on Aluminium former
– High X-max, Long Excursion Surround
– Double lower spider suspension
– Efficiency: : 83dB @ 1w/1M
– Fms: 48.2Hz
– Qes: 0.41
– Qms: 4.33
– Qts: 0.37
– Xmax: 18mm/0.7in
– Vas: 4.9 Litres
– Mounting depth 95mm
And the two-parter video