TREO Engineering
TREO KNOB Digital Bass Restoration Processor

Technical Specifications:

  • Maximum input level: 10V RMS
  • Maximum output level: 12V peak
  • Frequency response: 0Hz - 22KHz
  • Total harmonic distortion: 0.001%
  • Signal-to-noise ratio: 130 dB
  • Balanced input signal rejection: >60dB
  • Input impedance: 10K Ohm
  • Output impedance: 150 Ohm
  • Fuse rating: 1A

Download Owner's Manual for the KNOB

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The TREO KNOB is a new digital signal processor designed to give you the power to re-inject lost bass into all of your favorite recordings.

When music is mastered low frequency signals are often downmixed or filtered out. Audio mastering technicians do this for a variety of reasons, most commonly because they believe a large portion of their listening audience may not have the right equipment to play low frequencies correctly. This is especially true for recordings mastered before the widespread adoption of large low frequency subwoofers in the late 1970s.

When music is compressed into an MP3 file low frequency signals are frequently squeezed out. This loss of bass is compounded by the sound processing features on many MP3 players that are designed to play music into tiny headphone speakers. The TREO KNOB can restore the bass lost to both the compression process and the bass roll-off from MP3 player playback.

If you have TREO subwoofers and amplifiers in your car you definitely have what it takes to faithfully reproduce deep bass frequencies and we at TREO Engineering are proud to bring you the TREO KNOB to recreate the low bass you've been missing.

The TREO KNOB contains special circuitry that analyzes higher-frequency signals called harmonics and uses these high notes to re-create the low frequency audio information your TREO amplifiers and subwoofers were designed to bring to your ears.

We have also outfitted the TREO KNOB with a floating subsonic filter to keep your amplifiers and subwoofers working at maximum efficiency.

The TREO KNOB also has a dash-mountable level control that puts you in control of exactly how much bass you want to add. The powerful output signal and low output impedance from the TREO KNOB makes it the perfect accessory to control the subwoofer level of a subwoofer system featuring multiple amplifiers. Up to twenty amplifiers can be controlled by one TREO KNOB.

The TREO KNOB excels at bringing out the deep chest-shaking bass your TREO Engineering subwoofers were built to play in all your favorite recordings and MP3s.


  • Digital bass restoration circuit that analyzes harmonics to restore missing bass
  • Subsonic filter for increased amplifier efficiency and subwoofer durability
  • Works with balanced or unbalanced input signal
  • Accepts up to 10V RMS input
  • Output voltage up to 12V peak
  • Black powder-coated chassis with subsonic filter frequency control, parametric sweep and width controls, and bass restoration LEDs
  • Dash-mountable remote with bass restoration level indicator light
  • Three-year dealer installed warranty

Download Owner's Manual for the KNOB

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