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6-channel car amplifier with digital signal processing — 120 watts RMS x 6

7 Reviews | 2 questions - 5 answers

Item # 975PSIXDSP

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Our take on the HELIX P SIX DSP MK2

HELIX's P SIX DSP MK2 combines a 6-channel amplifier with a powerful 8-channel digital signal processor to create a new world of sound in your vehicle. The amp section sends out 120 watts RMS per channel to six different speakers, adding power and definition to all your music, no matter what style you listen to. And the processor allows you to fine tune the sound to get maximum performance from your system. In a large system a P SIX DSP MK2 can power front tweeters and midrange drivers, rear-fill speakers, and send a pair of processed signals to a subwoofer amplifier.

An all-in-one solution for gourmet sound

HELIX's P SIX DSP MK2 combines a 6-channel amplifier with a powerful 8-channel digital signal processor to create a new world of sound in your vehicle. The amp section sends out 120 watts RMS per channel to six different speakers, adding power and definition to all your music, no matter what style you listen to. And the processor allows you to fine tune the sound to get maximum performance from your system. In a large system a P SIX DSP MK2 can power front tweeters and midrange drivers, rear-fill speakers, and send a pair of processed signals to a subwoofer amplifier.

High-tech innards

HELIX uses "Class Ultra D" amplifier technology to improve the frequency response and damping factor of the traditional Class D amp, as well as to lower distortion. The P SIX DSP processes its digital signals at 64-bit resolution and 48 KHz sampling rate so you'll get very high fidelity along with virtually no noise or distortion.

Computer-controlled processing

Once you've downloaded the application and software from Audiotec Fischer (HELIX's parent company), you plug your personal computer or laptop into the processor's USB port. A detailed control panel will appear on your computer screen that lets you set virtually every tunable audio parameter to achieve the best musical fidelity possible in your car. The visual display shows the resulting sound curve of each setting, so you'll know for sure how your adjustments are affecting audio output.


DSP PC-Tool main screen

Switcher, EQ, time alignment, and more

The HELIX P SIX DSP MK2 processor accepts up to six inputs, which you can assign to up to eight outputs (six powered, two line-level), ideal if you're running separate tweeters, mids, woofers, and subs. Each channel features its own output volume and a 30-band paragraphic equalizer with precise 0.25 dB adjustment steps that give you incredible control over the sound. The paragraphic EQ works like a graphic equalizer, but with adjustable center frequency and bandwidth for each slider, so you can get in between the preset bands to smooth out any rough spots.

An onboard real-time analyzer (RTA) helps you set the EQ curve exactly the way you want for the best sound. A time alignment feature lets you correct for each speaker's placement in your car, so the sound from all the speakers will hit your ears at the same time, centering the stereo image for your sitting position.

Detailed filter section for fine tuning

You can configure almost any type of high-pass and low-pass filter on each channel in order to dial in the sound of each speaker. Not only can you adjust a crossover's frequency, but you can also choose the slope, its "filter characteristics" (see below), and its "Q-factor," which adds a bump at the crossover point for certain settings. Filters and EQ can be set separately for each channel, or channels can be linked together for common settings.

Save your settings

Don't worry, you won't have to drive around with your computer plugged in. You simply download your settings to the HELIX P SIX DSP, after saving them on your laptop. The P SIX DSP MK2 can store two settings at once, so you can toggle between them to see which sounds better.

Digital and analog inputs

The HELIX P SIX DSP MK2 can use up to 6 preamp or speaker-level inputs to get its signal, so you can hook one up to almost any factory or aftermarket system. It also features an optical digital input so you can play music directly from your compatible device and maintain the highest sound quality possible. When you connect both analog and digital inputs, the HELIX P SIX DSP MK2 normally prioritizes the digital input if active, then switches to the analog source if not.

If you get an optional URC 2A or DIRECTOR remote control, you can manually switch between the analog and digital inputs. You'll need to get a remote in order to manually control your digital source's volume.

Power Save Mode

Many newer vehicles feature accessory circuits that remain on for several minutes after the engine shuts off, so an aftermarket amplifier could possibly drain your vehicle's battery. The P SIX DSP MK2 solves this problem by turning off the amps connected to its remote output after not sensing music for 60 seconds. It'll turn the amps back on within a second after sensing the signal.

Product Highlights:

  • 6-channel car amplifier with digital signal processing
  • 120 watts RMS x 6 at 4 ohms (230 watts RMS x 4 at 2 ohms)
    • channel A and B stable to 4 ohms only
  • DSP adjustments and settings made via computer (Windows only) or optional remote control
  • download DSP PC-Tool Software from Audiotec Fischer
  • Burr/Brown A/D and D/A converters
  • 6 assignable inputs
  • inputs: 6 RCA preamp, 6 speaker-level, 1 optical SPDIF
  • 6 powered outputs, 2 processed line-level outputs
  • channel settings can be separate or linked together
Adjustment Details
  • time alignment in 3.5 mm increments
  • 30-band paragraphic EQ with 0.25 dB steps and fine tuning
  • adjustable high- and low-pass filters (20-20,480 Hz)
  • selectable filter slopes (6, 12, 18, 24, 30 dB/octave)
  • selectable filter characteristics
    • Butterworth: sharp transition, suitable for most applications
    • Bessel: gradual transition, suitable for smooth speakers, but not subs
    • Linkwitz: recommended for high-end speakers only, not subs
    • Chebyshev: very sharp transition, useful as high-pass for tweeters or low-pass for subs
    • Self-Define: selectable Q-Factor, 12 dB/octave slope only
  • adjustable Q-Factor in Self-Define mode (0.2-2.0) increases signal at crossover point
  • phase adjustment:
    • switchable 0/180 degrees on channels designated full-range
    • adjustable 0 to 348.75 degrees in 11.25-degree increments on channels designated subwoofer or mid/high
  • AutoSet real-time analyzer simplifies equalization (requires optional HELIX MTK1 measurement tool kit for this function)
Other Features:

What's in the Box:

  • 6-Channel amplifier
  • Three 20A ATM fuses (installed internally)
  • 58" USB cable (Type-A on one end mini-B on other end)
  • Four 3/4" Screws
  • 4mm Allen wrench
  • 2mm Allen wrench


Average Customer Review(s):

(7 Reviews)
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Hands-on research

Product Research


Overview: The Helix P SIX DSP Mk2 is a 6-channel amplifier that delivers clean power and outstanding sound processing using its "Ultra HD Class D" amp technology and cutting-edge 8-channel DSP. Features like a 96 kHz sampling rate, an extended audio bandwidth of more than 40 kHz, and user-friendly 64-bit internal DSP allow for superior sound quality. The P SIX offers a lot of configuration flexibility with 6 RCA inputs, 6 high-level inputs, an optical digital input, along with 6 speaker outputs and 2 processed RCA outputs. Internal jumper plugs are provided for changing sensitivity level ranges on all of the speaker and pre-amp inputs. The Helix Extension Card slot (HEC) allows for additional features, such as Bluetooth audio streaming and high-resolution audio playback, to be added with one of the optional Helix Extension Cards (sold separately).

Internal DSP: The P SIX needs to be connected to your PC, via the supplied USB cable, for configuration using the DSP PC-Tool software. This can be downloaded to your PC from the Audiotec-Fischer website and is compatible with Windows XP, Vista, 7, 8, and 10. The "fixed point" Audio DSP features 64-bit resolution and 1.2 billion MAC operations per second and also includes a Real-time Analyzer (RTA), digital time alignment, phase adjustment, high-pass and low-pass filters, a 30-band parametric EQ, and output level adjustment. The internal DSP is applied to all outputs of the P SIX including the RCA line outputs.

Ultra HD Class D Amp: Helix's new "Ultra HD Class D" technology combines the high-end sound quality of Class AB amps with the benefits of Class D amplifiers. By running at a 96 kHz sampling rate, the audio bandwidth isn't limited to 22 kHz and can achieve an extended frequency response of more than 40 kHz.

Power Save Mode: The Power Save Mode will turn off the internal amplifier stages and the remote outputs when the input signal has dropped off for more than 60 seconds. When a signal is re-applied, the amplifier and remote outputs will reactivate within a second. This feature was developed since many newer vehicles use a CAN or BUS system which may "invisibly" keep the factory radio on for up to 45 minutes after the vehicle has been turned off, thus, keeping the sound system active. The turn-off time can be changed or deactivated completely using the DSP PC-Tool software.

Advanced Diagnostics Error Protection (ADEP): The P SIX utilizes Helix's new ADEP circuitry that allows it to be integrated with OEM (factory) car stereos. Many newer OEM stereos can detect the presence of connected speakers and when amplifiers are installed, the radio may display a failure message causing some features, such as fader control, to be lost. The ADEP circuit avoids these problems without loading the speaker outputs of the factory stereo during high volumes.

Ready for 24 V: The P SIX can operate with either 12 or 24 volt (e.g. large trucks) systems without changing any settings. In both operating modes the amp will have equal performance characteristics.

Helix Extension Card slot: Helix has included an Extension Card slot inside the amplifier to accommodate one of their optional Extension Cards. Each of the cards comes with a replacement side panel for the amp, which provides the necessary cut-outs for the additional ports. To access the Extension Card slot (along with the configuration jumpers), the bottom panel is removed by taking out ten hex-head screws with the provided 2 mm Allen wrench. The four available cards are:

  • Optical In - Provides an additional optical input that accepts all digital sources with S/PDIF format (stereo PCM only).
  • Aux In - The AUX card has a stereo 3.5 mm jack to input an auxiliary audio source. Also includes an optical digital output.
  • BT - This card allows for a Bluetooth (v. 3.0) connection to the amp for audio streaming from a Bluetooth device. Also includes an optical digital output.
  • HD-USB - Adds a mini-USB (Type B) input that accepts PCM digital inputs with 32 kHz to 192 kHz sampling rate and 16-, 24-, or 32-bit resolution. Supports Windows, macOS, iOS, and Android devices.

Helix Director: The P SIX is designed to be used with the optional Helix Director, a wired remote control that adds flexibility and control over the DSP functions without having to access the amplifier. Its 2.8-inch color touchscreen, with 180-degree display rotation and auto-dimming, can control amp input source selection, volume for all sources, subwoofer volume, sound setup selection, and can switch between 22 stored DSP setups. The Director also allows connection and control of the optional Bluetooth expansion card.

Connection Panels: All of the P SIX inputs are on one side of the amp with all of the outputs on the other side. The two panels are as follows:

  • Input Panel:
    • Control push button: This button is used to switch between the setups and to reset the amp.
    • Status LED: This LED indicates the operating mode of the DSP and which setup has been chosen.
    • USB (mini type-B 2.0): Connects the P SIX to your PC for configuration.
    • Control Input: This round 8-pin socket is used to connect an optional wired remote control such as the Helix Director.
    • Optical Input: For connecting sources with a digital audio output (2 channel PCM only) with a sampling rate between 12 and 96 kHz.
    • Input Sensitivity: Three dials are provided for adjusting the input sensitivity of the six high- and low-level inputs. The dials are labeled: A/B, C/D, and E/F.
    • Line Inputs: This section has six RCA inputs for line level signals. Inputs are labeled A - F.
    • High-Level Inputs: A twelve-section terminal block, with set screws, allows for speaker level input connections. Each pair of connections is labeled: A - F.
  • Output Panel:
    • Speaker Output Channels A - D: This eight section terminal block, with 2mm hex-head set-screws, contains the speaker outputs for channels A - D.
    • Clip LED: This red LED will light if one of the analog inputs is overdriven.
    • Fuse LED: This red LED will light if one of the internal fuses is faulty.
    • Power/Ground/Remote: This three-section terminal block has +12 volt and Ground connections, that can accept up to 4ga.wire, and a remote terminal that can accept wire up to 16ga. Power and ground use 4mm set-screws while the remote terminal uses a 2mm set-screw.
    • Line Outputs: Two RCA connections for channels G and H provide a pre-amp output for connecting outboard amplifiers. These outputs can be assigned to any of the inputs using the DSP PC-Tool software.
    • Remote Output: The P SIX has a set-screw terminal block with two remote outputs for triggering outboard amplifiers.
    • Speaker Output Channels E/F: Two additional speaker outputs, using 2mm set-screws, are provided for channels E and F.


  • RMS Power:
    • Channel A - F @ 4 Ohms: 120 watts per channel
    • Channel C - F @ 2 Ohms: 230 watts per channel
  • Signal Inputs:
    • 6 x RCA
    • 6 x Speaker level
    • 1 x Optical
  • Signal Outputs:
    • 6 x Speaker
    • 2 x RCA
  • Input Sensitivity:
    • RCA: 2 - 4 volts or 4 - 8 volts
    • Speaker Level: 5 - 10 volts or 10 - 20 volts
  • Line Output Voltage: 3 volts RMS
  • Frequency Response: 20Hz - 44kHz
  • DSP Resolution: 64 bit
  • Sampling Rate: 96kHz
  • A/D, D/A Converters: Burr Brown
  • Signal to Noise Ratio:
    • Digital Inputs: 105 dB
    • Analog Inputs: 100 dB
  • THD: < 0.008%
  • Damping Factor: > 100
  • Dimensions: Width - 10.232", Height - 1.953", Depth - 7.467"

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Q & A

Customer Q&A

2 questions already asked

For specific information on installation and/or compatibility with your system, you would be better served contacting an Advisor directly by phone (1-800-324-9695) or online chat. They will be able to go over all the details to help you determine whether this is the right component for you. [ Larry  Feb 24, 2017 ]  Staff
Not sure if the original poster received the answer, but you only really need 2 channels to run this unit on all 6 channels. I'm using it as a 3 way active with only my front preout as the input to the Helix. That 2 channel front preout is also allowing me to control my sub and rear door speakers mono. [ Chad  Sep 11, 2016 ]
You can use from 1 to 6 of the RCAs (or high level inputs) and up to 2 digital inputs. The DSP tool will have you configure which inputs will go to the various channels, and they can be EQed differently. You can also mix up to 4 inputs (at any percentage) per output channel. Their DSP PC-Tool will let you try out configurations in demo mode which is really handy for seeing if a configuration will work, and getting a feel for things before the amp is installed. [ Jeremy  Aug 20, 2016 ]
Kim, I would contant Helix because the answer above does not make sense. You should be able to use all 8 outputs with only a stereo input. If indeed it requires 4 inputs, you could just use splitters on your rca cables. [ Jason  Jul 06, 2016 ]
I checked with our tech support department and they confirmed that you'll need at least 4 RCA pre-amp inputs to utilize all 6 channels of the Helix. I hope that helps! My Bio: [ Ryan  Mar 24, 2016 ]  Staff