Product overview
ISM 400.2DSP – 2-channel subwoofer amplifier module with integrated DSP
The ISM 400.2DSP is a powerful 2-channel subwoofer amplifier module with an integrated 1-channel DSP – making it a compact high-performance innovation for modern subwoofer upgrades. It combines strong amplification, precise digital signal processing, and a space-saving modular design to create an active subwoofer solution that integrates cleanly into the vehicle and delivers controlled, punchy bass. Thanks to its EV-Ready architecture, it is also suitable for today’s hybrid and electric vehicles.
The smart module for targeted subwoofer upgrades
The ISM 400.2DSP is focused on targeted subwoofer retrofits in vehicles with factory sound systems – whenever an additional subwoofer needs to be integrated cleanly and reliably without rebuilding the entire system. It is especially attractive where installation space and effort are limited, but a high-quality, precise bass upgrade is still required. The ISM solves this by bundling amplification, DSP, and intelligent integration specifically for this use case: it delivers up to 460 W RMS maximum power at 2 × 2 Ω for strong power reserves, and the heavy-duty stereo highlevel input (up to 32 V RMS) enables safe signal pickup in systems with OEM amplifiers, while ADEP.3 supports error-free integration with modern factory head units. The integrated signal-sensing turn-on function also ensures reliable power on/off, regardless of the technology used in the factory amplifier. With the integrated DSP, you get the foundation for controlled subwoofer integration – tuned to installation position, vehicle acoustics, and the desired bass character. In addition, the DirectDSP function offers a practical option: when needed, the input signal can be routed directly to the power stage without DSP processing. This is ideal when an external DSP is already in the system and the ISM is used purely as a powerful subwoofer amplifier. Thanks to its compact concept, the ISM is also an excellent basis for custom-built active subwoofer solutions.
Power, efficiency and precise sound tuning
For demanding subwoofer applications, the ISM 400.2DSP delivers plenty of power in a compact format: 2 × 130 W RMS at 4 Ω, 2 × 200 W RMS at 2 Ω, and up to 460 W RMS maximum power at 2 × 2 Ω – an ideal foundation for ambitious bass upgrades. To achieve high efficiency and extremely compact dimensions, the ISM 400.2DSP uses Audiotec Fischer’s Class HD concept. It combines the benefits of Class-H technology with the principle of a Class-D amplifier. The internal supply voltage of the output stages is continuously adjusted depending on signal amplitude, which drastically reduces average power losses, especially at low to medium output levels. The result is outstanding efficiency, low heat generation, and a particularly compact subwoofer module format. For signal processing, an extremely powerful 64-bit fixed-point audio DSP is used in combination with high-quality AD/DA converters – the basis for clean signal handling and precise bass integration. With DSP PC-Tool 6, you have access to the full range of modern DSP tools and tuning options to tailor the subwoofer to the vehicle, installation position, and personal sound preferences.
DeepImpact – Dynamic bass restoration
With the ISM 400.2DSP, we introduce our DeepImpact DSP algorithm for dynamic bass restoration. Regarding signals from factory sound systems, DeepImpact compensates bass loss caused by applied high-pass filtering and reconstructs missing low-frequency content. With full-range signals, DeepImpact reacts dynamically to the source material: if a track lacks impact in the lower frequency range, the algorithm boosts the bass in a targeted way to deliver a fuller, more powerful sound.
Efficient integration thanks to IMPACT enclosure subwoofer compatibility
The ISM 400.2DSP allows “ISM-ready” passive 2 x 2 Ω enclosure subwoofers to be converted into an active solution by simply replacing the connection terminal. For an efficient start into sound tuning, suitable presets for IMPACT enclosure subwoofers are also available in DSP PC-Tool 6.
EV Ready for modern vehicle platforms
For maximum compatibility and everyday usability, the ISM is “EV Ready” and can be used in hybrid and electric vehicles without issues. The start-stop capable power supply with an extended input voltage range up to 18 V ensures stable operation in modern vehicle architectures with different powertrain concepts – especially in vehicles where maximum current draw is often limited. Thanks to very high efficiency, heat generation and space requirements remain low, further supporting flexible installation concepts.
ACO – Advanced 32 Bit CoProcessor platform
Rapid processing power beyond the signal path – the high-performance 32 Bit ACO platform handles all control tasks and ensures ultra-fast data communication with the DSP PC-Tool software, including lightning-fast switching between up to ten sound setups. But ACO offers even more: integrated features like Augmented Bass Processing, RealCenter, Dynamic Loudness Control (DLC), and Remote Tone Control (RTC), along with the new Advanced Input Signal Analyzer (AISA), provide unmatched tuning versatility and allow analysis and compensation of input signals from factory sound systems that already contain sound settings.
Key features
- 2-channel amplified subwoofer module with 1-channel DSP for high-quality subwoofer upgrades in modern vehicles, delivering powerful yet controlled bass:
- Ideal for targeted subwoofer upgrades in factory-installed sound systems thanks to integrated DSP and high power stereo highlevel input with up to 32 V RMS input sensitivity
- Direct upgrade of passive 2 x 2 Ω IMPACT enclosure subwoofers by simply replacing the subwoofer connection terminal
- Perfect starting point for custom-made active subwoofer solutions
- Up to 460 W RMS output power at 2 x 2 Ω for driving powerful subwoofers
- Start-Stop capable power supply with an extended input voltage range up to 18 V – ideal for modern electric vehicles
- Very compact design with low heat dissipation thanks to extraordinary efficiency
- Extremely powerful 64 Bit “fixed-point” Audio DSP and high-quality AD / DA converters for clean signal processing and maximum bass performance
- Smart highlevel input with ADEP.3 for trouble-free integration into OEM sound systems
- Additional auto turn-on via music signal for maximum compatibility with factory sound systems
- ACO – Advanced 32 Bit CoProcessor platform for system an
- AISA (Advanced Input Signal Analyzer) and InputEQ AISA (Advanced Input Signal Analyzer) and InputEQ for easy analysis and correction of input signals
- DLC (Dynamic Loudness Control) and RTC (Remote Tone Control) for volume-dependent dynamic adjustment of highs and lows
- Proprietary TuneEQ function for automated adjustment of the input, virtual and output equalizers
Technical specifications
| Technical data | |
|---|---|
| – @ 4 Ohms | 2 x 130 Watts |
| – @ 2 Ohms | 2 x 200 Watts |
| – @ 1 Ohm | – |
| – bridged @ 4 Ohms | – |
| – bridged @ 2 Ohms | – |
| Max. output power (≤ 10% THD+N) | Up to 460 Watts RMS @ 2 x 2 Ohms |
| Amplifier technology | Class HD |
| Inputs | 2 x RCA / Cinch | 2 x Highlevel speaker input |
| Input sensitivity | RCA/Cinch: 0.4 – 4 Volts resp. 0.8 – 8 Volts | Highlevel: 1.6 – 16 Volts resp. 3.2 – 32 Volts |
| Input impedance | RCA / Cinch: 47 kOhms | Highlevel: 9 – 33 Ohms |
| Outputs | 2 x Speaker output | 1 x AISA signal output |
| Output voltage RCA / Cinch | – |
| Frequency response | 10 Hz – 20,000 Hz |
| DSP resolution | 64 Bit |
| DSP power | 1 x 295 MHz (1.2 billion MAC operations/second) |
| Sampling rate | 48 kHz |
| DSP type | 1 x Audio signal processor |
| Signal converters | A/D: BurrBrown 32 Bit | D/A: AKM 32 Bit |
| Signal-to-noise ratio (A-weighted) | 102 dB @ full power |
| Distortion (THD @ 50 Hz, 1 W into 4 Ohms) | < 0.005 % |
| Distortion (THD+N @ 50 Hz, 1 W into 4 Ohms) | < 0.015 % |
| Damping factor | 85 |
| Operating voltage | 10.5 – 18 Volts (max. 5 sec. down to 6 Volts) |
| Power rating | DC 12 V ⎓ 45 A max. |
| Idle current | 260 mA |
| Max. remote output current | – |
| Operating temperature range | -40 °C to +70 °C |
| Fuse | 1 x 40 A LP-Mini-fuse (APS) |
| Additional features | Start-Stop capability, Clipping LED, DirectDSP switch, Smart Control Port, 32 Bit CoProcessor, ground lift switch, highlevel input with automatic turn on function |
| Dimensions (H x W x D) | 54 x 231 x 105 mm / | 2.13 x 9.09 x 4.13" |
| Product properties | |
| Dimensions – width | < 250 mm, < 300 mm, < 350 mm, < 400 mm, < 450 mm |
| Dimensions – depth | < 150 mm, < 200 mm, < 250 mm, < 300 mm, < 350 mm, < 400 mm, < 450 mm |
| Dimensions – height | < 60 mm |
| Output power @ 4 Ohms | > 30 Watt, > 50 Watt, > 70 Watt, > 100 Watt |
| Output power @ 2 Ohms | > 30 Watt, > 50 Watt, > 70 Watt, > 100 Watt, > 200 Watt |
| Load stability | 2 Ohm, 4 Ohm |
| Signal-to-noise ratio | > 80 dB, > 85 dB, > 90 dB, > 95 dB, > 100 dB |
| THD | < 0,05 %, < 0,1 %, < 0,2% |
| Advanced features | ACO platform, ADEP highlevel input, Auto remote switch, Integrated DSP, Regulated power supply, Smart Control Port, Start-Stop capability |
What you are ordering
The exact HELIX model shown above, APEX catalogue SKU H424523. Review the listed inputs, outputs, impedance and system requirements before ordering.
Technical information verified against the official Audiotec Fischer product page.
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