AKG® BX 20 Spring Reverb

AKG® BX 20 Spring Reverb


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The only AKG-licensed emulation of this one-of-a-kind spring reverb.

Introduced in the late 1960s, the AKG BX 20 reverb was a high-water mark for AKG’s esteemed engineers. An ingenious assembly of mechanical and electronic componentry, the BX 20 offered the glorious depth and color of spring reverb without any of the limitations.

The AKG BX 20 Spring Reverb plug-in for UAD-2 hardware and Apollo interfaces is exclusively endorsed by AKG Acoustics, Austria and envelops your sources in gorgeously dark, dense ambience that only spring reverb can provide.

Now You Can:

Mix with the only licensed and endorsed AKG Acoustics BX 20 reverb plug-in

Envelop instruments in dark, dense, clear ambience with original dual spring tank configuration

Harness new "plug-in only" features like stereoized A/B Tank Select, Direct signal defeat, and BX 10 Tone controls

Mix with artist presets from Patrick Carney (The Black Keys), Vance Powell (Jack White), and Jacquire King (Kings of Leon)

Take a Listen

Take a Listen
5-Minute UAD Tips
5-Minute UAD Tips

5-Minute UAD Tips

Featuring the AKG BX 20 Spring Reverb.

Unparalleled Density

Unparalleled Density

The AKG BX 20's utterly unique character makes it a versatile tool for ambience as well as tone shaping. Its sonic personality features the quick onset of a classic plate reverb, and also the natural-sounding density and diffusion of a chamber — with little of the flutter or “boing” artifacts common with other spring reverbs. Unlike other spring reverb emulations, Universal Audio's hybrid delay network/convolution design provides the only plug-in representation of this mechanically controllable, acoustic ambience system. To that end, UA obsessively emulated a “golden unit” BX 20 from legendary producer, Jon Brion.

Spring Time

Spring Time

The BX 20 plug-in expertly captures the hardware’s unique two-stage decay. This yields warm, organic sounds whether it’s applied on percussion, vocals, or guitars, adding a unique timbre that can make individual tracks stand out — or melt away — in your mix. Short textures are chock full of colorful depth and dimension, while longer decays are rife with lush three-dimensionality, while never washing out.

New Features, More Control

New Features, More Control

The BX 20 plug-in provides the complete sound and features of the original, plus new "Mk II" features for an expanded sound palette. Tank Select provides the exact sound of the original A/B dual tank system, but includes a “stereoized” tank A or tank B, for more balanced stereo imaging. The Direct function allows you to mute the tank's direct signal for more control and minimizing conflict with the source audio — perfect for buses. The Baxandall-type tone controls — borrowed from the smaller AKG BX 10 — offers the last bit of seasoning to tailor your reverbs.

Watch The Reviews


      Input Select, Mono/Stereo: Changes input between summed mono or stereo
      Tank Select, A / B / A+B: Under stereo use, changes tank options among stereoized "A" and "B" and original "A+B" configurations
      Direct, Off / On: Disables/enables the spring tank's naturally occurring direct sound component
      Low Cut, Off / 80 Hz: 12 dB per octave, 80 Hz filter
      Bass, ±10: Continuous tone control borrowed from the AKG BX 10, ±8 dB at 150 Hz
      Treble, ±10: Continuous tone control borrowed from the AKG BX 10 ±4 dB at 5 kHz
      Dry/Wet, 0 to 100%: Continuously adjusts Dry and Wet signals under insert use case
      Wet Solo, Off/On: Disables/enables Wet Solo function
      Predelay, 0 to 250 milliseconds: Continuously adjusts Predelay amount
      Channel 1 Decay, 2 to 4.5 seconds: Continuously adjusts Channel 1 Decay time
      Channel 2 Decay, 2 to 4.5 seconds: Continuously adjusts Channel 2 Decay time
      Channel 1 Volume, ∞ to +24 dB: Continuously adjusts Channel 1 Volume
      Channel 2 Volume, ∞ to +24 dB: Continuously adjusts Channel 2 Volume
      Channel 1 Pan, ±100: Continuously adjusts Channel 1 Pan
      Channel 2 Pan, ±100: Continuously adjusts Channel 2 Pan
      Link, Unlinks/Link: Unlinks/Links Decay, Volume and Pan parameters
      Mix: Continuously blends processed and unprocessed signal
      Power, Off/On: Disables/Enables plug-in (all DSP processing is bypassed)

      Customer Reviews

      AKG BX 20 Spring Reverb

      Overall Rating

      A. Thomas

      June 17, 2020

      Amazing! Ignore the word 'spring' and listen to it, cause it's just great.

      Great reverb for a bunch of different sources and uses. Beautiful ambience and 'room' sound. Don't be fooled by the word 'spring' and assume it's only for guitar. This is definitely one of the greatest in-the-box reverb units. Well done, UA.

      D. Ollivierre

      May 29, 2020


      You can't not make this thing sound beautiful

      E. Soza

      May 23, 2020

      Great reverb

      True vibe

      R. Pressman

      May 15, 2020

      Great reverb

      One of the only springs reverbs I actually like and have used on vocals.

      R. Faulkner

      May 12, 2020

      Worth it

      I love the response and the ease you can edit. It does use a lot of processing power. Still worth it

      J. Aguirrezabalaga

      May 11, 2020

      True vibe

      I`ve been using different real spring reverbs for years, they all have in common some nice density and “real vibe”. Uad BX 20 keeps that feeling to me, plus lots of flexibility. Couldn`t be happier with it!

      S. Rose

      May 1, 2020

      Beautiful dual-spring without the "sproing"

      Brilliant, lush, massiveness. Is that a word? It's a sound. Use it on everything.

      A. Chudzinski

      April 17, 2020

      Dive In the Room

      Nice warm reverb. Organic room designing especially ducked by the kickdrum ;)
      But not usable for al purposes...

      G. Berry

      March 19, 2020

      Dark and lush

      This is a must if you want dark reverb that fills all the wholes in a mix!

      Q. Dykes

      March 18, 2020

      Authentic reverb

      I’m totally impressed with just how great this plug-in sounds. One thing about UA plug-ins...once you get one, you want to collect them all!

      K. Thura

      March 3, 2020

      Best reverb for my mix

      Amazing quality and great presets.

      B. DU

      February 13, 2020

      UAD makes the best Reverb

      I am impressed by the rich and smooth sound of this reverb

      C. Chrysogelos

      January 31, 2020

      As always...

      UA delivers amazing quality and superb sound! One of the best spring reverbs!

      G. Baker

      January 23, 2020


      Insanely lush and rich spring reverb. Amazing on guitar and vocals. It’s a dsp gig for sure though. Worth it.

      M. Keilhauer

      December 17, 2019

      Top Reverb

      Great Presets ! No need for much tweaking to dial in a perfect sound.
      But keep in mind that tweaking this box is lots of fun !

      L. Roccatagliati

      December 16, 2019

      A little different from the others

      I really love this kind of reverb, proper analog feeling

      M. Fletcher

      December 5, 2019


      Another great reverb from UA. I have never owned the hardware to this or any of the UA plugins that I’ve purchased from UA but what a thrill it is to have such quality at my fingertips in my home. Thanks UA

      P. Choudhury

      November 26, 2019

      Happy to Have this Reverb

      Thanks to me that I purchased this reverb. Endless things can be done and the sound!! Ah!!!! just toooo good!!!

      P. Etherington

      November 22, 2019

      Great replication

      Sounds just like my BX 20. Incredible

      A. de David-Beauregard

      November 4, 2019

      Excellent reverb but hold up

      Now listen, this thing sounds great no doubt, but only in VERY specific scenarios.