After collecting detailed experience in SQ performance and general in-car audio reproduction for more than 25 years during the development of loudspeakers, subwoofers and amplifiers for highly demanding customers and having launched a wide range of car audio products used for sound quality competitions all over the world, GROUND ZERO had started to take advantage of all these gathered skills devising a very new and super high-end product line. For the most sophisticated demands, GROUND ZERO introduces an extraordinary two-channel amplifier and matching loudspeakers now! REFERENCE ULTRA series products are developed by highly attentive engineers from England, Sweden and Germany creating products for the most demanding customers without accepting any compromise in overall quality and SQ performance.

Ultra Amplifier

The results of three years of development, uncountable listening sessions, comparisons, tuning and testing led to the GZ ULTRA A-2, the most advanced analogue amplifier on the market uniting perfectly selected components reduced to the minimum of distractingly influencing aspects creating a masterpiece of an amplifier, matching our very own intention and everybody´s uncompromised expectations, worth to be called ultra-high-end.

Not a huge surprise but a great honour, the performance of the GZ ULTRA A-2 charmed the members of the EISA, a group of international car audio trade journalists, right from the very first listening sessions that much that there was any doubt about the decision to award this amplifier as


The designation of the REFERENCE 2PURE and 4PURE amplifiers reveal the essential idea behind: Pure Sound Quality! By omitting strictly any kind of signal affecting filter, the result is a completely new and impressing high-end audio performance never heard before.
Only the best components ever have been considered good enough to find their way to the REFERENCE amplifier line-up.
Cooled by a high-quality copper-anodized aluminum heat sink, each model has been equipped with a slightly toned acrylic bottom allowing a glance on the selected components accurately arranged on the discreetly white illuminated and copper-plated double-layer pc board.
The PLUTONIUM series contains two sound quality amplifiers which simply leave no wish unfulfilled.
The 4-channel version has been awarded by the EISA organization as the world´s best in-car amplifier 2018/2019.
Massive class A/B multi-channel amplifiers and an impressively powerful and low-impedance stable class D mono version featuring dual high-current power supplies, enabling an excellent performance, can be selected from the NUCLEAR line.
The distinguished URANIUM amplifiers point out the main purpose by their designation already. Particular features like the unique BIAS setting increase the sound quality to the next level while highly accurate and variable wide band filters allow various combinations of full active speaker setups.
Especially for limited installation space, GROUND ZERO offers the HYDROGEN MINI full-range class D amplifiers. Meeting all requirements 2- and 4-channel models, a full-equipped 5-channel amplifier and last, not least, two powerful mono amplifiers in compact-sized, black-anodized aluminum heatsinks are available. Furthermore, the line includes a 4-channel and one mono amplifier for 24 V applications, as well.
The RADIOACTIVE series amplifiers offer an amazing high power output up to 6000 Watts in Link-Mode wrapped in a stylish titanium color heatsink containing a wide range of appropriate features for perfect audio adjustment. In a modern car environment, the installation space for an audio system could be very limited, as well. For this reason, the RADIOACTIVE line includes the smallest amplifiers GROUND ZERO ever built. The GZRA MICRO series amplifiers allow uncomplicated and space-saving installation and offer all necessary filters for the sound setup.
The products of the TITANIUM line combine premium quality and high efficiency. The amplifiers are equipped with sophisticated technology and encased by a posh heatsink with brushed titanium color surface. Especially for trucks, GROUND ZERO offers two models of the TITANIUM amplifier line-up as a 24-Volt version.
The range of amplifiers contains a variety of affordable models for the daily use and for SPL purpose. The feature list includes the most important functions like high-level input with auto turn-on or a remote control for the low impedance stable mono amplifiers.
Each of the new full-range class D amplifiers offers a huge amount of output power for any kind of open show or SPL application. At the top end, the COMPETITION line includes one of the most powerful amplifiers in the world – delivering the unbelievable power of 35.000 Watts RMS!



Ultra-high-end analogue 2-channel amplifier

Ultra Speaker Components

ULTRA speakers are designed for the most demanding music lover.

Carefully built by hand with the best materials and selected in pairs, they are delivered in fine wooden boxes.

The mid-bass driver ULTRA K-165 uses a high-tech fabric cone “Made in Germany” in conjunction with linear suspension and a narrow-tolerance copper voice coil with a linearized NEO motor. Built in a filigree aluminum basket for optimal air flow, these are the ingredients for outstanding neutrality and sound quality.

The tweeter ULTRA T-30 with its 30mm coated silk dome is characterized by a particularly low resonance frequency and extreme neutrality. The linearized NEO magnet system with the complex rear ventilation of the cone in the solid aluminum housing enables the wonderfully spatial and precise audio reproduction with an extremely wide frequency range.

REFERENCE speakers are designed for demanding high-end music lovers. Accurately hand built in Europe, selected in corresponding pairs and delivered in classy wooden boxes. Midbass and midrange speakers are made from hand-coated, pressed paper cones and hand-spooled copper voice coils, inserted into manually machined aluminum parts of the basket, forming the basis for outstanding high-end sound quality. The tweeter features a particularly low resonance frequency. The usable wide frequency range of the hand-coated silk dome thus enables astonishingly spatial and precise audio reproduction.

In order to compile an individual sound quality setup at highest level, the speakers of the PLUTONIUM line are available in pairs as components separately.
In order to compile an individual sound quality setup, the speakers of the NUCLEAR line are available in pairs as components separately.
Using outstanding materials for the cones and accurate tuning, these speakers provide an amazing sound quality performance. The drivers are available for active setups, separately.
For some years customers were missing matching loudspeaker components and systems belonging to the GROUND ZERO HYDROGEN series to be combined with its amplifiers and subwoofers. Based on a particularly designed aluminum cast basket the engineers have realized a powerful 6.5” midwoofer with a strong ferrite motor and oversized CCA voice coil. In combination with a vented silk dome tweeter equipped with a coupled chamber and a passive crossover, the new HYDROGEN series 2-way system is born for customers looking for an extraordinary performance. The loudspeakers are available separately for active setups, as well.
Some components of the RADIOACTIVE loudspeaker systems are also available separately.
The TITANIUM line includes a wide range of coaxial and component speaker systems in the favorable price segment and a separately available tweeter.
The IRIDIUM line includes a wide range of coaxial and component speaker systems in the favorable price segment and a separately available tweeter.
For high-frequency and mid-range reproduction, the COMPETITION series offers a variety of high-efficient far-field compression tweeters and various midrange speakers. The latter can be used in free-air applications as well as in horn or bass reflex systems.
Speaker components of the COMPETITION PRO series are specially designed for a long distance to the listener and are particularly suitable for show and demonstration purposes with high sound pressure levels.



Ultra-high-end 30 mm / 1.18″ tweeter


32210010: Ultra-high-end 80 mm / 3.15” midrange speaker



Ultra-high-end 165 mm / 6.5” midwoofer

Ultra Accessories

In this category there are crossovers for loudspeakers. These can be used to combine individual components into a passive system.
In this category there are crossovers for loudspeakers. These can be used to combine individual components into a passive system.


32010010: Precisely machined massive aluminum mounting ring


32010015: Precisely machined massive aluminum mounting ring