Ground Zero Competition Separates

Whereas the Hybrid Audio Legatia speakers and the Morel components are made and sold primarily for active use, (that is with a separate amplifier channel for each loudspeaker driver and active electronic control of the passband of the sound sent to each driver) both the Morels and the Hybrids are full range designs meant to play all the way down to the bass zone and in fact work beautifully when used with a passive crossover made for a ‘near relation’ or in the case of the Hybrids, made to order according to the musical taste of the buyer in a bespoke style.
These drivers, though, the GZCW 6-4Y and the GZCT 2500 are not just sold as utterly user-configurable separate products but are even sold singly.
As in ‘each’
This caused some confusion as the distributors had never ordered them before and sent me single examples of these and also the three sets of their other tweeters. This is because the midwoofers have got a choice of four very high power high frequency drivers to select from.
There is no passive made for these at all, nor related product to pinch one from.
The midwoofers themselves are very heavy duty and made with cast chassis painted Hammerite style and a sexy woven fibreglass cone around a very Focal-esque solid aluminium turned phase plug. They are built with big magnets and are rated to high power but only down to 65Hz. Which is a whole load of bass less than normal speakers. In fact the ‘midwoofers’ in this line up include eight inch and ten inch models. Not woofers, again they are only rated down to 150Hz for the eight and the same 65Hz for the ten inchers! This makes them utterly unique in car audio.
Tens were used as midrange drivers in the MTX 2 x 22 inch MTX Jackhammer pickup truck (see Installations ‘Hammer Your Brains Out’) and they thought they were being extreme. Ground Zero think this is normal.
The tweeters I chose of the selection offered as partners to the 6-4s are very heavy duty in build versus more normal types. With turned-from-billet style Aluminium housings that afford a degree of horn loading to the Titanium silk suspended dome. They have a wire affixed with colour marked terminals and come with fixings and a single capacitor to place in line with the positive feed to make a simple -6dB protective capacitor. These were fitted to the test rig and while the midwoofer and this, the smallest and most-like-normal-HiFi tweeter were tested together as a collected set, the other three models of high power heavy duty high frequency transducers were reviewed each to their own section as they are complex and neo-professional items.
The GZCW 6-4Y speakers are supplied with grilles with plastic Ground Zero badges on them (also in miniature on the tweeters’ grilles) and their rear decals are clear plastic protected until the last thing before installation intended for those with clear view windows in their installations, so competition-intended
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GZCW 6-4Y Midwoofer sold singly @ £42 each
– 6.5 inch 4 Ohm
– Fibreglass woven cone, solid anodised Aluminium phase plug in centre
– Rubber top suspension, heavy duty tinsel leads
– Cast Aluminium chassis with Hammerite style paint
– 1.5 inch high temperature voice coil
– Mounting depth: 75mm
– Frequency Response: 65Hz to 7000Hz
– Power Handling 100w RMS, 200 peak
– Efficiency: 92dB 1w/1m
– VAS: 9.9 litres
– QTS: 0.35
– Comes with grille, mastic and fixings
– Rear decal has protective film to be removed after installation.
 
GZCT 2500 Titanium tweeter sold singly @ £30 each
– Titanium dome with Silk suspension
– Aluminium housing affording slight horn loading to output, integral grille
– One inch high temperature voice coil
– Diameter: 55mm, dome 25mm
– Impedance: 3 Ohms
– Resonant Frequency: 1450Hz
– Frequency Response: 2kHz to 22kHz
– Power handling: 25w RMS, 60w peak
– Efficiency: 95dB 1w/1m
– Mounting Depth: 21mm
– Rear decal has protective film to be removed after installation.
Single capacitor supplied as basic 6dB per octave attenuation crossover for protection, no passive crossover supplied or exists for this range.
Review by Adam Rayner
I’ll be honest, it took me some time to get to grips with the Ground Zero approach to mids and highs and finally realised sheepishly that GZ have simply taken a very direct view on something that I have been going on about for years. Car HiFi has more in common with professional live music reproduction than it does with recording studio monitors that’s what HiFi indoors is trying to achieve. On the road, you need power and intelligibility and clarity and above all extension! Ground Zero are good at extension and make some of the nuttiest subwoofers and have garnered a lot of respect in their own German market for their heavy bass. These components are about full range power in the face of Brobdingaggian bass.
My background is in professional Public Address systems or flipping great huge speaker systems for live concerts. (As well as recording studios, rehearsal rooms and studio hire equipment and being Acoustic Energy’s very first production manager, while we are at it) It’s great fun and they go seriously loud. They use kinds of speakers we wouldn’t even recognise in car audio, let alone home HiFi. For explanation of what a compression driver is, you need to read the rest of the reviews of the crazed pro-audio style tweeters that are also offered to marry up to the 6-4Y midwoofer drivers, here.
First, I made some wires and soldered the supplied 6dB passive capacitors in line (in the positive feed) and fitted the midwoofers to the test enclosures. I had an idea that I could use the eighteen different four channel amplifiers I am collecting for review to drive these components actively and see which amps were the best. However, only a few amps can do this (the SPL Dynamics, and Diamond Audios were cool and oddly enough, the Mutant Ascension. I had to rewrite a mental brand-image for that one but you can read about it in the four channel amp review when it’s out.) as most are made to run say a subwoofer and full range, rather than do complex bandpass stuff. Anyway, I then hooked them quickly up to the Genesis SM100 and ran the tweeters straight out of the backs of the test boxes’ terminals so they ran parallel to the mids to try them out for function checking. This did not faze the amplifier but didn’t sound satisfying at all.
So I checked through the amps I have and found the SPL Dynamics example to have 4kHz capable crossovers for both highpass and lowpass, so I hooked that up and spent some time tweaking the settings.
The GZCT 2500 tweeter is intense and has that characteristic pro-audio cut and impact with real edge to it. Very efficient, too, it made major output from only a small setting on the dedicated amplifier channels’ gain control.
At first I was rather disappointed at the lack of perceived richness of the sound and was puzzled. Then it sank in that I really truly needed some sub bass. So I got out the active Fusion woofer tube I also have here for review and hooked that up using the line out from the versatile SPL Dynamics amplifier.
It is clear that the GZCW series really are simple midrange drivers. The sort that we in in-car think of as being up to four inches across. Once hooked up and working, the whole sound snapped into focus and all I wanted was to have around ten times more bass power to play the Ground Zero Competition component speakers against. The tweeters look almost normal but they can cut like a knife. Serious output. I was not as pleased with the subtlety of the sound overall but again I had slightly missed the point that the sort of ‘competitions’ that the series’ moniker is referring to simply have to be Sound Pressure Level ones!
It’s unusual for a speaker company to be terribly good at both bass and the rest of the frequency spectrum but with these Ground Zero have a set of speakers every bit as hooligan-struck as their baddest woofers. They go together like T & A!
(all puns intended)
Overall 8.4
Sound Quality 8
Build Quality 9
Power Handling 9
Efficiency 8
Value For Money 8