Features

• Up to 135 Watts RMS max. output power per channel into 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 enhanced system and DSP features like:
  - ISA (Input Signal Analyzer) and InputEQ for easy analysis and compensation of input signals
  - SFX sound effects – Augmented Bass Processing, StageXpander, RealCenter & Co.
• Smart 6-channel highlevel input with ADEP.3 circuit
• Six RCA / Cinch line outputs with max. 6 Volts output voltage
• Virtual Channel Processing (VCP) allows even more flexible configuration for highly complex sound systems
• Bridgeable amplifier channels for driving powerful woofer or subwoofer
• DSP-board manufactured in Germany

Special features:

ACO – Advanced 32 Bit CoProcessor

The HELIX M FOUR DSP incorporates an extraordinary powerful 32 Bit CoProcessor of the latest generation for all monitoring and communication tasks, both internally and externally. In opposite to the 8 Bit predecessor generation this MCU achieves way higher speeds with respect to setup switching and data communication with our DSP PC-Tool software. A further significant advantage is the integrated, native boot loader of the CoProcessor.
It allows software upgrades of all components of the integrated DSP in order to adjust the microcontroller-controlled ADEP.3 circuit for example to future requirements of the diagnostic system of factory radios or if the device will be extended with additional interfaces. In addition, thanks to the new flash memory, the ACO offers 10 memory locations for sound setups instead of the common two.

Smart highlevel input ADEP.3

Modern, factory-installed car radios incorporate sophisticated possibilities of diagnosing the connected speakers. In particular the latest generation of car radios are equipped with additional monitoring functions so that failure messages and loss of specific features (e.g. fader function) quite often appear if an amplifier will be hooked up – but not with the M FOUR DSP.
The new ADEP.3 circuit (Advanced Diagnostics Error Protection, 3rd Generation) avoids all these problems without loading the speaker outputs of the OE radio during high volumes unnecessarily.

Power Save Mode

The Power Save Mode is incorporated in the basic setup. It allows to significantly reduce the power consumption of the amplifiers that are connected to the HELIX M FOUR DSP once there’s no input signal present for more than 60 seconds. Please note that in many up-to-date cars with “CAN” or any other internal bus structures it may happen that the radio remains “invisibly” turned on for up to 45 min. even after locking and leaving the car! Once the “Power Save Mode“ is active the remote output and therefore the connected amplifiers will be turned off.
The M FOUR DSP will reactivate the remote output within a second if a music signal is applied. It is possible to either modify the turn-off time of 60 sec. or completely deactivate the “Power Save Mode” via the DSP PC-Tool software.

Start-Stop capability

The switched power supply of the HELIX M FOUR DSP assures a constant internal supply voltage even if the battery’s voltage drops to 6 Volts during engine crank.

DSP features

RealCenter

The “RealCenter” feature is an algorithm, developed by Audiotec Fischer, that emphasizes the music information which is present in both the left and right front channel to create an unique center signal. In contrast to common procedures, in which only the channels are summed up, the intensity of the center signal is also dynamically controlled by the stereophonic informational content of the left and right channel.
Sounds complicated but this effect is astonishing: That means if solely the left or right channel delivers an audio signal, the center channel will not reproduce a signal. In the case of common algorithms, the volume level of the center channel is only reduced by 6 dB (= half volume level). Audiotec Fischer’s “RealCenter” allows a unique, broadened sound staging for both driver and co-driver at the same time! Therefore, the disadvantages of a conventional center channel, such as an intrusive, small sound stage, are things of the past.

Augmented Bass Processing

Audiotec Fischer’s proprietary “Augmented Bass Processing”, consisting of the two revolutionary sound features “Dynamic Bass Enhancement” and “SubXpander”, has been especially developed to dramatically improve the bass reproduction of subwoofers.
The “Dynamic Bass Enhancement” ingeniously combines maximum deep bass and highest sound pressure – regardless of the music style or the tone controls in the head unit. Depending on the input signal, the “Dynamic Bass Enhancement” gains the lower frequency range and varies the cut-off frequency of the subsonic filter. The result is a significantly more powerful and deeper bass response at low and medium volume levels without the risk of overloading the subwoofer neither mechanically nor electrically at high volume levels. It is simply fascinating which bass performance is suddenly possible.
If you want an even lower and “darker” bass reproduction, the “SubXpander” can be additionally activated. Therefore, subharmonic tones are added to the fundamental tones in the frequency range between 50 and 100 Hz.

StageXpander

Depending on the speaker arrangement in the vehicle, a more or less wide stereo sound stage can be created on the front seats. A center speaker may limit the spatial reproduction of the music additionally. This is where Audiotec Fischer’s new “StageXpander” comes into play – a sound feature which seems to break the acoustic limitations and thus allows to create a way broader stereo base without negatively affecting the precision of the localization of voices or instruments!
The effect can be adjusted according to your personal preferences in four steps.

ClarityXpander

You are looking for more transparency and substance in the treble reproduction? With the “ClarityXpander” Audiotec Fischer is now offering the right tool. Properly adjusted (and therefore selectable in three steps) the feature adds additional harmonics in the upper frequency range – this is especially useful if the original speakers lack some brilliance in the treble response. The extra treble-kick is not only available for the two front channels but also separately adjustable for the center channel. Even better – the center channel allows to activate an automatic and dynamic control so that music with “loads” of treble doesn’t fatigue your hearing.

Specifications

Power RMS  ≤ 1% THD+N: 
- @ 4 Ohms: 4 x 100 Watts 
- @ 2 Ohms: 4 x 100 Watts
- @ 1 Ohm: - 
- bridged @ 4 Ohms: 2 x 200 Watts
- bridged @ 2 Ohms: - 

Max. output power per channel*: Up to 135 Watts RMS @ 4 / 2 Ohms

Amplifier technology: Class D

Inputs:
6 x RCA / Cinch
6 x Highlevel speaker input
1 x Optical SPDIF (12 - 96 kHz)
1 x Remote In

Input sensitivity:
RCA / Cinch 1 - 4 Volts
Highlevel 5 - 20 Volts

Input impedance RCA / Cinch: 22 kOhms

Input impedance highlevel: 9 - 33 Ohms or 20 kOhms

Outputs:
4 x Speaker output
6 x RCA / Cinch
2 x Remote Out

Output voltage RCA / Cinch: 6 Volts RMS

Frequency response: 20 Hz - 22,000 Hz

DSP resolution: 64 Bit

DSP power: 295 MHz (1.2 billion MAC operations/second)

Sampling rate: 48 kHz

DSP type: Audio signal processor

Signal-to-noise ratio digital input: 105 dB (A-weighted)

Signal-to-noise ration analog input: 102 dB (A-weighted)

Distortion (THD): < 0.03 % 

Damping factor: 100

Operating voltage: 10.5 - 16 Volts (max. 5 sec.down to 6 Volts)

Idle current: 1500 mA

Max. remote output current: 500 mA

Fuse: 2 x 30 A Maxi-fuse (APX)

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 / 2.00 x 9.06 x 6.06“

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