Our take on the Helix P-DSP
Everything is under control
If you're an ultimate tweaker who's crazy about sound quality, then Helix's P-DSP processor will be a welcome addition to your system. After downloading the application and software from Helix, you plug your PC or laptop into the P-DSP'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 P-DSP, as it appears on your computer's screen
Switcher, EQ, time alignment, and more
The P-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 has 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.
An insane filter section
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 bullets), 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 don't have to drive around with your computer plugged in. You simply download your settings to the P-DSP processor, after saving them on your laptop. The P-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 processor settings.
Also works with Helix vehicle-specific Plug and Play wiring
The P-DSP can also serve as a digital processor in a Helix Plug and Play factory upgrade system. You use an EPC5 Easy Plug Cable and a Helix vehicle-specific adapter harness to plug your P-DSP directly into your vehicle's stereo to get its input signal, with no wire-cutting or splicing necessary.
Highlights:
- digital signal processor
- DSP settings and adjustmenets made via laptop or PC through USB port
- download DSP PC-Tool Software from helixhifi.com
- 6 assignable inputs
- inputs: 6 RCA preamp, 4 speaker-level, 1 optical SPDIF
- 8 preamp outputs (4 volts)
- 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 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
- includes 57" USB cable
- optional microSD memory card for saving and applying settings (sold separately)
- plug and play input from select factory radios with EPC5 Easy Plug Cable and a Helix vehicle-specific harness (sold separately)
- dimensions: 5-15/16"W x 1-11/16"H x 6-15/16"D
- warranty: 2 years
- Our 60-day money-back guarantee