HELIX M FOUR DSP | 4-channel amplifier with digital sound processor

HELIX M FOUR DSP

This rocks – the new M FOUR DSP

At first glance, the M FOUR DSP appears to be a four-channel amplifier – but despite its compact dimensions, it's actually a powerful control center boasting no fewer than ten processed DSP channels. And it delivers plenty of power, effortlessly producing 100 watts of continuous power per channel into both 4 and 2 ohms. This is complemented by a fantastic feature set that will make your eyes light up, especially when considering the price-performance ratio.

Sonic excellence through and through!

Sonic compromises have no place in a HELIX product – and that's why the M FOUR DSP is equipped with all the refinements for perfect sound. High-quality, separate AD and DA converters are standard features on the German-made DSP circuit board, as is the use of an extremely powerful DSP from Analog Devices. The six preamplifier outputs with 6 volts output voltage provide more than enough signal to drive any power amplifier. Textbook Flexibility: The M FOUR DSP's internal amplifier section is truly versatile – it can be operated in four-channel mode or, thanks to its bridgeability, configured as a three-channel or two-channel amplifier. But that's not all – in conjunction with the six preamplifier outputs, the system can be expanded in a variety of ways and upgraded to up to ten channels. Even just combining it with the other amplifiers in the M series (M ONE X, M ONE, M FOUR, or M SIX) offers more than enough options to increase the number of power channels. This makes complex yet affordable and, above all, space-saving multi-channel systems with enormous performance easily achievable.

Virtual Channel Processing – this is how signal routing works today

Many DSP channels need to be managed and configured properly – therefore, it was a given that the M FOUR DSP would also be equipped with Audiotec Fischer's innovative Virtual Channel Processing.
Adapting to modern OEM sound systems via an increasing number of signal inputs makes increasingly complex signal routing within the amplifier unavoidable. Especially when multiple input signals are mixed together and then split again into multi-way systems, conventional routing concepts quickly reach their limits in terms of both implementation and usability. The multi-stage "Virtual Channel Processing," in conjunction with the renowned user-friendly DSP PC-Tool software, makes it easy to map even highly complex system configurations and to freely assign proprietary FX sound features such as "RealCenter" or "Augmented Bass Processing." The added speed – thanks to ACO: Faster is better – the particularly powerful 32-bit ACO platform handles all control tasks and ensures significantly more speed, especially in data communication with our DSP PC-Tool software, but also in lightning-fast switching between up to ten possible sound setups. But ACO offers much more – fantastic sound effects such as Augmented Bass Processing, StageXpander, and RealCenter are implemented, as well as a channel-separated input EQ with Input Signal Analyzer (ISA) for easy analysis and compensation of the input signals from OEM radios that already include a factory-installed sound setup.

Compact, cool, and extremely practical

Despite its enormous range of functions and ample output power, the M FOUR DSP, with its typical HELIX design and clean lines, is just as fantastically compact as an M FOUR or ONE. Thanks to its Class D amplifier technology, it remains cool even at full power. And thanks to features like start-stop capability, ADEP.3 circuitry, and power save mode, it is also ideally equipped for the now commonplace challenges of integration into OEM systems.

Features

• Up to 135 watts RMS maximum power per channel at 4 & 2 Ω
• Extremely powerful 64-bit "fixed point" audio DSP and state-of-the-art 32-bit AD and DA signal converters from AKM
• ACO – Advanced 32-bit CoProcessor platform for advanced system and DSP features:
  • ISA (Input Signal Analyzer) and InputEQ for easy analysis and compensation of input signals
  • SFX sound effects – Augmented Bass Processing, StageXpander, RealCenter & Co.
• Intelligent 6-channel high-level input with ADEP.3 circuit
• Six RCA outputs with a maximum output voltage of 6 volts
• Virtual Channel Processing (VCP) allows for even more flexible configuration of highly complex sound systems
• Bridgeable amplifier channels for powerful control of a woofer or subwoofer
• DSP circuit board manufactured in Germany

Special Features:

ACO – Advanced 32-bit CoProcessor

The HELIX M FOUR DSP amplifier uses a particularly powerful, latest-generation 32-bit coprocessor for all internal and external control and communication tasks. In contrast to the previously used 8-bit processor, this results in significant speed advantages, not only when switching between different sound setups but especially in data communication with our DSP PC-Tool software. Another key advantage is the integrated, native bootloader of the CoProcessor. This enables software upgrades for all components of the integrated DSP, allowing, for example, the microcontroller-controlled ADEP.3 circuit to be adapted to future changes in the diagnostic systems of factory radios or the device to be expanded with additional interfaces. Furthermore, thanks to the new flash memory, the ACO offers space for 10 sound setups instead of the usual two. Modern, factory-installed car radios are becoming increasingly intelligent in terms of diagnosing the connected speakers. The latest generation, in particular, is equipped with additional monitoring functions, so that error messages or even malfunctions can occur when an additional amplifier is connected. The new ADEP.3 circuit (Advanced Diagnostics Error Protection Generation 3) prevents these problems without unnecessarily straining the radio's speaker outputs at high levels.

Power Save Mode

Power Save Mode is enabled in the basic settings of the DSP PC-Tool software. It allows the power consumption of the M FOUR DSP (and any additional connected amplifiers) to be drastically reduced when no input signal is present for more than 60 seconds. Once Power Save Mode is active, the internal amplifier stages of the M FOUR DSP and the Rem Out are switched off, thus significantly reducing power consumption. The amplifier returns to normal operation within 2 seconds as soon as a music signal is present at its input. The shutdown delay can be varied or completely deactivated via the DSP PC-Tool software.

Start-Stop Capability

The power supply in the HELIX M FOUR DSP amplifier ensures a stable internal voltage supply even during brief voltage drops down to 6 volts. This guarantees that the HELIX M FOUR DSP remains fully functional even when the engine is started.

DSP Features

RealCenter

The "RealCenter" function is a proprietary algorithm from Audiotec Fischer that emphasizes the monaural information of the left and right front channels to create a unique center signal. Unlike conventional methods that simply sum the channels, this method also dynamically controls the center signal based on the stereo information content of the left and right channels. This means that the center channel does not reproduce a signal if only the left or only the right channel is supplying an audio signal. With conventional algorithms, the center channel would only be 6 dB quieter in this case. Audiotec Fischer's "RealCenter" thus enables a unique, wide soundstage – and is equally optimal for the driver and passenger! The disadvantages of a conventional center channel, such as an intrusive, narrow spatial sound reproduction, are finally a thing of the past. Augmented Bass Processing Audiotec Fischer's proprietary "Augmented Bass Processing" consists of two revolutionary sound features: "Dynamic Bass Enhancement" and "SubXpander." These have been specially developed to dramatically improve the bass reproduction of subwoofers. "Dynamic Bass Enhancement" ingeniously combines maximum deep bass foundation and high maximum sound pressure – regardless of the music genre being listened to or the sound settings on the radio. Depending on the input signal, "Dynamic Bass Enhancement" amplifies the lower frequency range and simultaneously varies the cutoff frequency of the subsonic filter. The result is significantly more powerful, deeper bass reproduction at low and medium volumes without the risk of mechanically or electrically overloading the subwoofer at high volumes. It's simply fascinating what kind of bass performance is suddenly possible. For those who want the low frequencies even deeper and "blacker," the "SubXpander" can also be activated. This adds subharmonic tones to the fundamental frequencies in the 50 to 100 Hz range. StageXpander: Depending on the speaker arrangement in the vehicle, a more or less wide stereo image can be created for the front seats. If a center speaker is also installed, it can sometimes further limit the spatial imaging of the music. This is where Audiotec Fischer's new "StageXpander" comes into its own – a sound feature that seems to dissolve acoustic boundaries, thus enabling a significantly wider stereo base without negatively impacting the precision of voice or instrument localization. The effect can be adjusted to personal taste in four stages. ClarityXpander: Want more transparency and substance in the treble reproduction? Audiotec Fischer now offers just the right tool with the "ClarityXpander." When used correctly (and therefore selectable in three stages), it gives the overtones additional brilliance – particularly useful if the original speakers lack the necessary sparkle in the high frequencies. This extra treble boost is available not only for the two front channels but also separately adjustable for the center channel. And because even a tiny bit too much of the latter, especially in combination with overtone-rich music, can tire the ear, an automatic, dynamic control of the additional overtone content can even be activated here.

Technical Data

RMS Power ≤ 1% THD+N
- @ 4 Ohms	4 x 100 Watts
- @ 2 Ohms	4 x 100 Watt
- @ 1 Ohm	-
- bridged to 4 Ohm	2 x 200 watts
- bridged to 2 ohms	-
Max. Power per channel*	Up to 135 watts RMS @ 4 / 2 ohms
Amplifier technology	Class D
Inputs	6 x RCA 6 x high level speaker input 1 x Optical SPDIF (12 - 96 kHz) 1 x Remote In
Input sensitivity	RCA 1 - 4 volts High level 5 - 20 volts
Input impedance RCA	22 kOhm
Input impedance high level	9 - 33 Ohm or 20 kOhm
Outputs	4 x speaker output 6 x RCA 2 x Remote Out
Output voltage RCA	6 Volt RMS
Frequency range	20 Hz - 22,000 Hz
DSP resolution	64 bit
DSP computing power	295 MHz (1.2 billion MAC operations/second)
Sample rate	48 kHz
DSP type	Audio signal processor
Signal/noise ratio digital input	105 dB (A-weighted)
Signal/noise ratio analog input	102 dB (A-weighted)
Total Harmonic Distortion (THD)	< 0.03%
Damping factor	100
Operating voltage	10.5 - 16 volts (max. 5 seconds down to 6 volts)
No-load current consumption	1500 mA
Max. Remote output current	500 mA
Fuse	2 x 30 A Maxi plug-in fuse (FK3)
Additional features	ADEP.3 circuit, Auto Remote switch, 32 Bit CoProcessor, Control Input
Dimensions (H x W x D)	50 x 230 x 154 mm

*In typical multi-channel applications (2-/3-way system + rear speakers + subwoofer)

Scope of delivery

1 x HELIX M FOUR DSP amplifier
1 x Line output-to-RCA cable
1 x USB data cable
1 x Mounting hardware
1 x User manual