Classic Recording Studio Equipment

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Korg A1 Reverb Impulse Response

Korg A1 Performance Signal Processor

Korg had made a number of effects units by the time the Korg A1 was released, and for this unit they went all out to match the competition. The Korg A1 was designed to surpass the usual limitations of digital multi-effect processors.

Korg A1 Performance Signal Processor Details

It is the first device of its kind to provide users with exceptional processing power and virtually unlimited programming flexibility – without compromising the high quality of its individual effects. The creative power, speed and operational flexibility of the Korg A1 truly come to the fore in a variety of real-world processing situations. It provides users with an endless variety of processing options that sound great and are easy to control.

Creative Effects Flexibility. The Korg A1 includes 59 different effects with a number of variations. These effects can be assigned in different orders within the 50 variable effects chains, for limitless number of creative recordings, live sound and musical instrument processing options.

User-Compatibility. Designed for maximum ease of use, the Korg A1 is based on the same quick, intuitive user interface as Korg’s popular A3 processor. Effects Chains and parameters can be quickly and easily accessed and edited via the convenient front panel control layout and/or optional remote controller.

Sonic Integrity. The Korg A1 incorporates the latest in digital processing technology to achieve truly superior sound quality. It combines the exceptional processing power of two high speed DSP chips with sophisticated A/D convertors, thus minimising signal degradation and preserving the high order sonic integrity of the individual effects.

Applications. A powerful processor for a variety of professional recording applications, the versatile Korg A1 can also be used effectively in live sound applications, high-tech guitar racks and MIDI keyboard setups.

Effects. The Korg A1 has 59 types of effects with 103 variations for a greater number of creative options. Including everything from studio-quality Delays and Reverbs through Compressors, Gates and EQs to Pitch Shifting, Rotary Speaker effects and Tube Distortion Simulation, it provides effects for any application.

It also offers unique effects not found anywhere else such as a Noise Generator integrated with Reverb processing and a Dynamic Delay effect controlled by the input signal. Each effect has been optimised for matchless sound quality, allowing effects to be used alone or as part of an effect Chain in combination with up to six other effects.

Reverb is an essential effect in professional recording studios. Consequently, the Korg A1 offers 28 variations in reverb. The Dynamics Reverb, for example, is ideal for processing drum sounds. In this effect it is possible to select a specific input level threshold where the reverb is triggered. A signal below the assigned threshold does not trigger the reverb effect. The inverse is also possible using the “Dynamic Polarity” parameter.

Unique Korg A1 effects such as Tempo Delay and Dyna Pan cane locked to MIDI clock, allowing delay time and panning to be synchronised with a song’s tempo.

Effects Chains. The Korg A1 frees the user from the limitations 0f working with specific orders 0f effects or fixed Chains created by the manufacturer. Its open-ended Chains allow up t0 seven effects to be assigned in a variety of different orders or connections. Included are Chains that connect effects in series, (one after another) in parallel for simultaneous processing, and in a dual configuration to process two signals independently. There are Chains that combine series and parallel combinations and even Chains that feature a key Input for gating and compression effects.

Moreover, 59 effect types can be assigned to these Chains. The user can select normal effect combinations in series Chains or experiment with all of the various effects and Chains to create totally original, customised effects programs.

Ultimately, the Korg A1 provides over 50 possible effect Chain variations that can be divided into the five major categories: Series, Parallel, Dual, Key-in and Send/Return.

Effects Programs.  Up 10 100 effects programs can be stored in the internal memory. The Internal programs can be saved individually or in bulk to MIDI DATA FILERS or to removable RAM cards. Programs can be read directly from a ROM or RAM card inserted in the front panel card slot, making a total of 200 effect programs immediately accessible!

The Korg A1 also features a pre-loaded selection of 100 factory programs. Additional programs, written by professional musicians and engineers, will be available on the A1 ROM card library.

Comprehensive Control. The Korg A1 is designed with a logical, intuitive user Interface that, while allowing complete control of an extraordinary amount of processing power, does not get in the way 0f the creative process.

All Chains, effects parameters and other functions are displayed in the large, two-line, 40-character LCD. Dual function knobs below the LCD make editing parameters a simple task. Additional dedicated keys for the Korg A1’s major operation modes are clearly labeled and include Edit Compare and Performance Editor functions for more user friendly control.

The optional RE1 Remote Editor provides even greater operational convenience for the user. The RE1 allows the A1’s edit functions to be available from the user’s listening position.

The optional FC6 Foot Controller allows program changes and effect On/Off switching from the user’s on-stage position in live performance applications.

Dynamic Modulation. For added expressive control, the Korg A1 includes a Dynamic Modulation function that allows the user to control effect parameters in real time using pedals, MIDI data or input signal envelopes.

Some examples of Dynamic Modulation in the Korg A1 factory programs are; using a MIDI keyboard’s mod wheel to control Rotary Speaker speed or the Pedal Wah effect, using MIDI keyboard velocity to control the Dynamic Reverb Input Level of using a volume pedal to control pitch bending in the Pitch Shift effect.

The parameters of the Dynamic Modulation function Include:

  • Dynamic Parameter – Selects the effect parameter to be controlled. (e.g. LFO speed, Input level, effect level. etc.)
  • Dynamic Source – Selects the controller (e.g. foot pedal, MIDI data, etc.)
  • Dynamic Amount – Sets the amount and direction of the dynamic control.


MIDI Control.  In addition, with the ability t0 use MIDI Aftertouch, Velocity, Pitch Bend and control numbers 01 -95 as Dynamic Sources to control Korg A1 effect parameters, it is possible t0 record automated effect mixes and changes t0 a MIDI sequencer. In fact, all front panel buttons such as effect on/off  or effect parameter changes can be recorded t0 a MIDI sequencer in real time directly from the Korg A1.

External Interface: The Korg A1 is equipped with a variety of connectors t0 interface with other equipment. 1/4″ audio inputs are found on the front (unbalanced) and rear (balanced) panels. Rear panel Audio outputs ara provided in both XLR balanced and 1/4” unbalanced formats.

It also has a Send/Receive loop for interfacing with external devices such as other effect units of guitar pre-amps. The EXT control output allows external devices such as guitar pre -amp channel switching to be controlled by Korg A1 program changes or manually with a footswitch connected t0 the Korg A1.

For digital audio signals, the Korg A1 is also equipped with a SP/DIF format digital I/O. This allows two Korg A1 ‘s to be cascaded digitally or the connection of an Korg A1 to an R-DAT machine or digital mixer, processing and transferring entirely in the digital domain.


  • Quantisation: 16-bit Linear
  • Sampling Frequency: 48kHz
  • Frequency Response: 20Hz-20kHz (+1.5/-3dB)
  • Dynamic Range: > 85dB
  • Direct Output: Input gain unity / 2.2k ohm
  • Memory: Internal – 100 Programs
  • Digital I/O: CP340 Type II or equivalent (sampling frequency 48kHz only)
  • Power consumption: 25 watts
  • Dimensions: 430mm x 407.8mm x 89mm
  • Weight: 6.3kg


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The details provided above are drawn from historical documents like advertising brochures or user manuals. They’re shared without bias or review. This info is given solely for your consideration, helping you gauge its usefulness to you.

The Korg A1 Reverb Impulse Responses for Altiverb are a complete package of this classic Korg effects units reverb presets. A total of 18 reverb patches are included. The recording of these impulse responses was done with very careful calibration, through a Focusrite digital audio interface, and recorded into Harrison Mixbus 32C.

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by Anonymous

Sound Quality 100%
Build Quality 85%
Usefullness 75%
Mojo/Funk 100%
Reliability 100%

This unit imo is better than any new device out there today except the AXE FX units, period. The WIDE effect is in super stereo almost similar to SURROUND SOUND. The only reason I don’t use it today is the fact that I am trying to downsize (as far as weight is concerned, getting older not younger) Other than that for the young’uns this device is the bomb!! The gold plated inputs/outputs (I0) are a little weak as in the A2 and A3. (Use another unit such as a preamp to plug into, don’t plug directly into this unit all the time, such as in and out and in and out. It’ll soon come loose and then you’ll have to resolder it back on.

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