Our take on the HELIX DSP
The ultimate tune-up
If you're a constant tweaker who's crazy about sound quality, then the HELIX DSP processor will be a welcome addition to your system. This deceptively simple box works with your PC to offer a world of sonic adjustments that can maximize the performance of almost any car audio system.
Simple to use
Once you've downloaded the application and software from Helix, 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 highest 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.
The main control panel for the HELIX DSP, as it appears on your computer screen
Switcher, EQ, time alignment, and more
The HELIX DSP processor accepts up to six inputs, which you can assign to up to eight output channels, perfect if you're running separate tweeters, mids, woofers, and subs. Each channel features its own output volume and a 30-band graphic equalizer that gives you incredible control over the sound. The EQ section features a fine tuning adjustment that lets you get in between the preset bands to smooth out any rough spots. The time alignment feature lets you correct for each speaker's placement in your car, so the sound from each speaker arrives at your listening position 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. Not only can you adjust a crossover's frequency, but you can also choose the slope, its "filter characteristics" (see Highlights below), and adjust 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 DSP, after saving them on your laptop. The HELIX DSP can store two settings at once, so you can toggle between them to see which sounds better. You can also use an optional microSD memory card to store and transfer settings to your HELIX DSP, which comes in handy when you want to switch settings without plugging in your laptop.
Digital and analog inputs
The HELIX DSP can use up to 6 preamp or 4 speaker-level inputs to get its signal from your vehicle's 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 types of inputs, the HELIX DSP normally prioritizes the digital input if active, then switches to the analog source if not. If you get the optional URC-2A remote control, you can manually switch between the analog and digital inputs. You'll need to get the URC-2A 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 HELIX DSP solves this problem by turning off the amps connected to its remote output after not sensing music for 60 seconds. The HELIX DSP will turn the amps back on within a second after sensing the signal.
Installation note: Because of its high gain potential and digital connections, setting up this processor improperly could damage your speakers. Please read the instruction manual carefully before you connect your HELIX DSP.
HELIX DSP output and control panel
- digital signal processor
- DSP adjustments and settings made via computer (Windows only), microSD memory card, or optional remote control
- download DSP PC-Tool Software from helixhifi.com
- Burr-Brown AD/DA converters
- 6 assignable inputs
- inputs: 6 RCA preamp, 4 speaker-level, 1 optical SPDIF
- 8 preamp outputs (4 volts RMS)
- channel settings can be separate or linked together
- time alignment in 7 mm increments
- 30-band graphic EQ with fine tuning
- 1-band parametric EQ
- 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 front and rear channels, adjustable 0 to 360 degrees on sub channels in 22.5-degree increments