HELIX Premium DSP Amplifier

HELIX P SIX DSP Ultimate – 12 channel DSP with 6 channel amplifier

With the P SIX, Helix may not have opened a new amplifier genre, but it has shown that Class-D amplifiers can be more than efficient and practical. Now comes the P SIX DSP Ultimate, a brand-new upgrade that has been improved in every way.


  • 10 Setups with fast switchover
  • User-defined routing of in- and output ports
  • Control connector for programmable remote controls and accessories
  • Start-stop capability up to 6V
  • Signal-dependent switching to digital or Aux inputs
  • Automatic putting through of all vehicle tones
  • Power-Save-Mode
  • ADEP.3 error protection circuit for factory radios with speaker recognition
  • RTA real-time frequency curve measurement (with optional microphone), automatically adjustment including filter slopes
  • FX menu with dynamic bass, centre and front processing
  • ISA for measuring, summing and correcting inputs
  • Time Machine for taking back and restoring adjustments
  • Device Monitor (temperature and voltage control)
  • ATM automatic time alignment with custom signal
  • Import of setups and data from other devices
  • VCP (optionally activated), virtual channels, routable, with EQ, time alignment and FX processing

Optional Accessories

  • Wired remote control (programmable)
  • Display remote control director with memory, USB, etc.
  • WIFI Control for wireless programming
  • Measurement microphone MTK1
  • HEC Extension Cards

The new P SIX DSP Ultimate is only recognisable as a new model at a second glance. It comes in the same, noble black aluminium housing as the MK2, only that above the “Made in Germany” logo instead of “MK2” now reads “Ultimate”. In Schmallenberg, Sauerland, they are very proud that many products are manufactured in house, and they are even particularly proud of the P SIX DSP Ultimate, because it represents the flagship of the in-house DSP amplifiers. Back in 2015, Helix placed the P SIX DSP at the very top of the market.

Clearly, “digital” Class-D amplifiers were the future, only that most approaches went in the direction of all-in-one, small and practical. The P SIX, however, was intended to play on the level of the best analogue amplifiers, only with modern, efficient technology – a DSP amp for high-enders.

A lot has happened since then and it was time to update the P SIX. For some time now, Audiotec Fischer, the parent company of the Brax, Helix and Match brands, has been a development partner of Texas Instruments. This involves the amplifier ICs, which are jointly being advanced further and further. The latest generation of these marvels manages to deliver enormous power, but without the usual 10% distortion that chip manufacturers like to write into the data sheet.

The usual applications for amplifier chips are smartphones, Bluetooth speakers or sound bars, nothing to do with building a noble car hi-fi amplifier. So a lot of development work has gone into the P SIX DSP Ultimate, e.g. also in the mounting and fixing of the chips, which is extremely important for optimal heat dissipation and thus performance. However, the most important innovation of the P SIX DSP Ultimate might be the upgrade to the current coprocessor platform ACO. Not only is a powerful 32-bit processor used; it is also integrated into the audio work by Helix. This is because Helix programs quite a few features itself, which go far beyond the standard functions of the signal processor. Sound effects like the FX functions or even the (in)measuring functions are not possible without the help of a powerful coprocessor.

Input Stage Analyser

The ISA (Input Stage Analyser) features single or combined measurement of the input channels. Time alignment and equalising can be applied immediately.

Virtual Channel Processing

As an alternative to the normal routing, virtual channel processing can be used to combine groups together and equalise them across the crossover frequencies.

RTA Measurement

RTA measurement of a mid-range woofer: Original curve (red) and result with 24-dB crossing (white). You can see the correction via TuneEQ in green and, at the bottom, the EQ bands 4 – 24 are accordingly adjusted. We measured with an accuracy of 1/6 octave and standard smoothing; finer is possible if desired.

Measurements and sound

During the measurement, we clearly state that the P SIX DSP Ultimate is one of the best amplifiers ever created.
Whether analogue or digital, the P SIX DSP Ultimate is at the very highest level. With a channel power of 129 watts at 4 ohms and 219 watts at 2 ohms, it is one of the most powerful full-range amps ever with more than four channels. This is almost twice as much as a multi-channel all-in-one solution – the TI chips say hello! But that is not enough; it also delivers an extremely clean performance.

Only 0.003% THD+N at 5 watts and 0.005% at half-load are extremely good values. The signal to noise ratio is also top notch for such a sophisticated amplifier, and even the damping is impressive. And in terms of sound? Beyond any doubt. There is no music genre and that the P SIX DSP Ultimate cannot master. It pleases with brute power as well as with breathtaking dynamics. Then it serves acoustic sounds with the fi nest details, which are perfectly reproduced in the room.
Troubleshooting is pointless. Rather, the P SIX DSP Ultimate belongs to those amplifiers that also convey the mood and atmosphere of the music, so that one easily forgets to listen to a canned sound. Maybe even too good or too spectacular? In any case, not common at this level.


With its outstanding features, the P SIX DSP Ultimate basically has no competition. It is a top-notch 6-channel DSP amplifier in its own right or the perfect control centre for a full-blown audio system with high-end aspirations.

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