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Ground Zero GZCF 7104SPL 7x10 Oval Speakers

Product Details
Manufacturer: Ground Zero
Distributor: Car Audio Direct
Website: http://www.caraudiod...ompetition.html
Typical Selling price: £129.99 (CAD £99.99)

High power handling, four-transducer oval speakers in 7x10 inch size, built to fit (with adaptor rings) into a standard 6x9 aperture if the installation cannot have its ‘own size’ holes cut to 7x10in. The pressed steel chassis is powder coated yellow and has a large magnet on the rear, certainly big enough to drive a decent eight inch woofer, let alone a six. These do not have motors the size used by ten inch woofers like the much more costly and now long-gone-legendary (In the UK at least) DLS 7x10s. The midband driver is a very unusual Ferrofluid-equipped device, since very few mids in car audio get Ferrofluid, even if some tweeters do. This allows hugely increased linearity and massively raised power handling as the magnetically-attractive Iron-based liquid both cools the voice coil and damps its motion. The outer edges of the midband driver are flanked by two Piezo-electric tweeters, one 19mm in diameter, the other 10mm. Described as a four-way as it has four drivers, I feel this is more correctly labelled as a three-way, high-power design with the twin tweeters used for extra level and the mid being Ferrofluid-loaded for high power use. Indeed, they have the letters standing for ‘competition’ and SPL in their part number/names.


- High Power Coaxial 4-Way Speakers in 7x10in oval size
- Power Handling: 150W RMS/250W Peak
- Impedance: 4 Ohm
- Resonance-free pressed steel basket, grilles supplied
- Injection Moulded Polypropylene (IMPP) bass cones with rubber surrounds
- Ferrofluid- cooled PEI midrange with basic 6dB slope passive crossovers built in
- 2 x Piezo Tweeters, one is 19mm Ø, the other 10mm Ø
- Passband: 35Hz to 20kHz
- Sensitivity (1w/1m): 92dB
- Mounting Depth:84mm
- Includes 6 x 9in to 7x10in converter rings/mounting bracket with fitted brass insert bushings

Editor Review : Ground Zero GZCF 7104SPL 7x10 Oval ‘Competition’ Series Speakers

OUCH! These are not for tinkly audiophiles but for raving rip-snorting audio bass-and-tops hounds who love drum an’bass better even than dat Ali G character, innit. As subtle as a flying mallet, as unapologetically penisoidal in their protuberance into your consciousness as a stallion’s erection, these are NOT speakers for the playing of nice chamber music to your grandma.

Unless grandma is Suzi Quatro, in which case, crank some guitar-based rock right up and let her have it hard for these will keep up with an astonishingly loud SPL system of monster subs and just on their own can be used to raise some seriously offensive levels of everything that makes you feel good with your windows open and your breastbone thumping gently along to the bass line.

For yes, more does mean more, when it comes to seven by tens. These are not some kind of super-stretched-out 6x9 cones as some of the so-called 7x10 products have been, nor is it a Boo-Yah sawn-off shotgun of a ten inch woofer with the edges chopped off, but rather a very well designed oval from the ground up, just specifically made in the bigger 7x10 size. In my stock oval test enclosures, (now having had something like 70 or 80 different models of 6x9 in them and several 7x10s) the GZCF 7104SPLs needed some speaker gasket foam fitting around the 6x9 apertures, then screwed down nicely into the holes with some (solid, thus sealed) chassis sticking up. I also sealed the remaining ‘normal’ 6x9 screw holes up with BluTack and cranked the hell out of the speakers. The adaptors are well made and even have a set of brass bushings to really snug the speakers’ mounting screws into, once you have screwed the regular 6x9 fixings into your install. They fill the space and support the chassis in the tiny-bit-protuberant position they needs must live in. This also means the grilles are fat. Like the tail of a cat sniffing cream they are just a bit ‘puffy’. But they don’t look too flash-come-nick-me, so most owners will be OK with this.

The bass output is stupefying and just so very good for the soul. It has nearly all that ridiculously sweet bass control and edge of a six by nine that so few in car audiophiles will acknowledge (and seem to hate taking on board from behind them) and yet also a fat lump of the sheer scale, weight and breastbone thump-bass of proper subwoofers. So much so, that the tasty Alpine MRX-F30 amplifier, fully capable of a fat 100 watts RMS was not powerful enough to stretch these puppies. I could feel almost no excursion at all to a finger-tip on the midband’s edge (do NOT do this at home…or on the road for that matter folks.) and yet you can clearly hear it working.

Quick aside…the professional way to hear if a tweeter is on or not, or a midband driver for that matter, is to set the volume quite low, enough to put your ear up to the speaker and then cover it with a hand in between the driver and your ear, without touching the speaker. Then simply move your hand in and out of the way and the change in the SPL of the output will be clearly audible. It is surprisingly hard to do this without otherwise sticking your Pinna literally inside the cone of the driver.

I suspect from what I know of Ground Zero, that the GZCF 7104SPL would be happy to live on an amp, set well, that had as much as a quarter kilowatt rating per channel, for they were raising a mad bass hellaciousness in my test area (the landing) without raising a sweat and yet revealing where the amp was being overdriven if I just did silly levels to see. The 150W RMS rating, with its mad peak power handling rating, is nothing but a simple truth. Which is quite, quite mad, really.

The only sad thing is that the Piezos are a breed of tweeter that has never sounded all that sweet. Even the great big Motorola Piezoelectric tweeter horn-drivers (they weighed very little) that had their time being fitted to cars as a super-duper stereo imaging fad for a while, were a bit sad sounding to me. They are shrill, they shriek and they can HURT. You get a shouty little 10mm diameter job and a bigger and even shoutier 19mm diameter one on these 7x10s. They have no magnet behind their arses and there is certainly no big super passive box hiding away somewhere to call these four-way via a complex three-crossover-point pile of capacitors, coils and resistors. The specification does boast of a 6dB crossover, meaning that a capacitor is secreted somewhere in the innards, just to keep the bass out of the mid/high assembly (eventually). The rest simply relies on the midband not playing bass and tops and the two shrieky Piezos not doing anything but their own thing. I ache for knowing the technical specifications of each of the components within these ovals to be able to relate them to you. But no matter.

Imagery and subtlety may not be their forte but if you were to be one of the True SPL Brethren and wanted a simple single set of speakers to cut through a wall of mayhemic lows, then these are they. Sold at £99, they are a simple no-brain five pointer for VFM and for those who want max output for the money are currently unassailable in the market for sheer bang for the buck. They play edges of stuff like guitars very well and at low levels, the linearity can be quite good. Yet I feel they were really designed for quantity and dispersal, meant to be splashing the hell off your rear screen and pumping the cabin with energy of stuff you might like to move ‘yo ass to….they sound nicer sat at my desk in the next room, after a reflection or two, after all.

So, although as refined as a ruffian at a black tie do. I adored these speakers for their purity of purpose, their affordability and their sheer in your face attitude. That and the giggly-silly most-bass-ever-made-in-those-boxes (NB also see earlier note) levels of throbular output. Great fun and easily a Talk Audio Recommended earner.


In a Nutshell
Probably the best value for money boom product on the UK Ice Market right now. Not posh HiFi but really serious amounts of genuine power handling for the 6x9 slot and able to make far more bass than a pair of sixes plus a ten inch woofer. You can feel the bass in your chest and you will be heard coming with the windows open. Proper offensive in the right hands, proper bass, lots of tops. BOOM!

Overall 9.0
Sound Quality 8
Build Quality 8
Power Handling 10
Efficiency 9
Value For Money 10

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