dbx 520 - 500 Series De-Esser with HF Only Mode and 800 Hz–8 kHz Frequency Control

dbx 520 - 500 Series De-Esser with HF Only Mode and 800 Hz–8 kHz Frequency Control

The dbx 520 is a 500 Series de-esser based on the classic dbx 902 circuitry to reduce high-frequency sibilance and harshness in a natural and consistent manner. Unlike traditional de-essers, the 520 uses no threshold ; it intelligently compares high-frequency energy against the entire band and maintains stable attenuation even when the source level varies by up to ±60 dB . With Frequency control ( 800 Hz–8 kHz range), Range control ( 0–20 dB de-essing amount), LED reduction metering , and hardwire bypass , it's a fast and effective tool for vocals , overheads/cymbals , strings , guitars , or for cleaning up effects sends . The Mode selector allows operation in Broadband (covering the entire spectrum) or HF Only (high frequencies only), expanding its versatility.

Main features

• Classic dbx algorithm based on the renowned dbx 902 , with RMS detection between high band and full band.
• Sweepable Frequency Control from 800 Hz to 8 kHz (12 dB/octave filter, phase coherent) to focus the sibilant region.
• Control Range from 0 to 20 dB to set the exact amount of de-essing.
• Processing mode : Broadband or HF Only with dedicated indicator.
• LED reduction meter up to 20 dB for immediate visual adjustment.
• Hardwire bypass (true bypass) to compare processed/original signal without coloration.
• Professional-grade response and performance : 20 Hz–20 kHz +0/−0.5 dB , THD+N < 0.006 % (uncompressed), DR > 114 dB , noise < −92 dBu .
• Levels and I/O : electronically balanced inputs/outputs, +22 dBu max., impedances of 20 kΩ (balanced input) and 30 Ω (balanced output).
• 500 Series Form Factor : 1 slot; ±16 V ( 76 mA/rail , 2.4 W ) power supply; 13.34 × 3.81 × 15.24 cm , 0.59 kg .

Product benefits

• Consistent results without chasing the threshold : The threshold- free design maintains the correct attenuation even when the singer whispers or raises their voice.
• Quick integration : Two controls (Frequency and Range), HF Only mode and LED meter speed up setup in the studio and on-stage.
• Transparent sound : selective treatment of sibilance with minimal impact on overall timbre (especially in Broadband).
• True versatility : from modern voicing to taming cymbals, fret buzz, or cleaning up reverb/delay sends.

Use cases

• Lead and backing vocals : set Frequency to 4–7 kHz and Range to NORM range to soften “s”, “sh”, “ch”.
• Overheads/hi-hat : HF Only mode with Frequency in 6–10 kHz (upper range barrier) to control harshness without turning off the kit.
• Guitar/Bass : Reduce fret/string noise by setting Frequency to 2–5 kHz and adjusting Range to taste.
• Effects sends : Place the 520 before reverb/delay to prevent sibilance from exciting the effect.

Frequently Asked Questions

• What is the difference between Broadband and HF Only? In Broadband, de-essing attenuates the entire signal when it detects sibilance; in HF Only, it affects only the high-frequency content, useful for more surgical instruments or treatments.
• Where do I start adjusting the Frequency? For vocals, a good starting point is around 2.5 kHz ; from there, sweep until the meter indicates reduction when sibilance appears.
• How fast does it act? It depends on the program : attacks as fast as 0.6 ms during intense events and releases as fast as approximately 925 dB/s , preserving transients and a natural sound.
• Can I overprocess? Yes; turning Range beyond the NORM zone can create creative effects, but vocals often sound more natural within NORM.

Description for projects

dbx 520 De-Esser (500 Series, 1 slot) ; based on dbx 902; Sweepable frequency 800 Hz–8 kHz (12 dB/oct filter, phase coherent); Range 0–20 dB ; Broadband / HF Only modes ; LED metering up to 20 dB; hardwire bypass ; Electronically balanced I/O, +22 dBu max.; Performance: 20 Hz–20 kHz +0/−0.5 dB , THD+N < 0.006% (uncompressed), noise < −92 dBu , DR > 114 dB ; Chassis power ±16 V ( 76 mA/rail , 2.4 W ); Dimensions 13.34 × 3.81 × 15.24 cm ; Weight 0.59 kg .