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  • Electro Harmonix Attack Decay

    By Phil O'Keefe |


    More than just a Tape Reverse Simulator…this is one swell pedal!





    Amplitude (volume) envelope-modifying pedals are deeply fascinating to me, but it seems I've been somewhat in the minority in holding that opinion, and that's always puzzled me. Maybe it's just because many guitarists aren't that familiar with them and don't realize just how much they have to offer. While keyboardists and synthesists have long embraced envelope controls for modifying volume, filters and even pitch over time, their use - and availability - to guitarists has been much more limited.

    Basically a sound's envelope is how it changes - how it starts, develops and ends - over time; how quick its initial transient (the start of the sound) is and how it begins or ramps up, any drop or rise in level after the initial impact, the steady-state volume or sustain, and how quickly it cuts off or fades away to inaudibility. On a synthesizer, this is normally controlled in four stages, using a set of ADSR envelope controls; ADSR is short for Attack, Decay, Sustain and Release, and the EHX has used the first two of those as the name of the pedal under review here, which should give you some idea as to what it's all about… but it may not immediately bring to mind all of the creative possibilities, and it only begins to describe the pedal's many features.




    What You Need To Know

    • Based on the classic EHX Attack Decay pedal that was only made from 1980 until 1981 (and that frequently sells for over $1,000 on the vintage market today), the Attack Decay is a volume envelope modification pedal with a fully-featured built-in fuzz.


    • Housed in a smaller-sized metal enclosure than the original, the new Attack Decay measures 4" W x 4.75" L x 2.25" H, so it's a lot more pedalboard-friendly than its predecessor.


    • The main part of the pedal's housing is unfinished metal, with a multicolor (orange / white / black) graphics silkscreened on the top, it's a straightforward looking pedal with easy to read labeling and a clear, user-friendly control layout.


    • Input and output jacks are side-mounted. Input impedance is 1M Ohm, and the output impedance is 500 Ohm. 




    • There is also a effects loop included, and the jacks for it are also mounted on the sides of the pedal. Anything coming into the Return jack of the loop will be processed by the pedal. The Send jack sends out anything that appears at the pedal's input jack, along with the output from the Harmonix fuzz, if it's engaged.




    • An EXP (expression) pedal jack is also included. The expression pedal can be assigned to control any knob on the pedal. Additionally, this jack can be used as a CV (control voltage) input and for trigger clock input, allowing the envelope on the Attack Decay to be controlled by external devices.


    • In the upper-left corner you'll find some controls that the original Attack Decay lacks, including three Preset buttons, and a Poly mode switch. When Poly mode is selected, each new note or chord you play triggers the Attack Decay and is given its own separate envelope cycle that doesn't interrupt the previous cycle(s), while disabling Poly mode and using Mono mode lets the pedal act like the original vintage pedal, where each note or chord that you play that exceeds the threshold stops the preceding envelope cycle and restarts it from the beginning. There's even a continuous trigger mode where the pedal can be set to re-trigger the Attack and Decay envelopes automatically as soon as the preceding Attack and Decay envelopes complete their cycles; this is useful for tremolo and staccato-type effects. 





    • The Preset buttons allow the user to save three overall setting configurations and recall them at will using the Harmonix / Preset footswitch on the lower-left side of the pedal. Two LEDs next to the switch indicate whether you're in Preset mode or whether the footswitch will instead activate / deactivate the onboard Harmonix fuzz. A quick step on the switch will turn the fuzz on or off, while holding the switch down for two seconds or so puts you in Preset mode.


    • Instead of having a large Sens. (sensitivity) knob like the original pedal, the new Attack Decay uses a smaller knob that's located up near the Poly mode and Preset buttons. Setting this knob correctly is the first thing you should do when using the pedal, since it determines how hard you need to play before your notes and chords will trigger the envelope cycle. As you turn the Sens. knob up, the threshold gets lower and the more easily your playing will trigger the envelope.


    • The four main knobs are similar to what you'll find on a vintage Attack Decay, and have similar functionality. Attack sets the speed of the note beginning (how long it takes to swell up to full volume), and has a range of 4ms to 8 seconds in mono mode. Turning the knob higher increases the attack time.


    • The Decay knob has a similar function, but it controls how quickly the note fades out. It can be set to cause notes to fade away very quickly, chopping off the ends of them and resulting in a very cool staccato effect. The Decay control also has a range of 4ms to 8 seconds.


    • The Blend knob allows you to adjust the balance of the dry and effected signals. As an alternative, it can also be set to adjust the blend of dry and Harmonix fuzz signal that is sent to the volume envelope controls, which is how the Blend knob on the vintage pedal operates.


    • The Volume knob is new, and gives you the ability to control the pedal's overall output volume level - which is another capability the original pedal lacked.


    • While the original Attack Decay had a basic "Edge" slider switch to turn the dirt on or off, and a Harmonics knob to control the onboard distortion circuit, the new Attack Decay takes that several steps further and gives you much more control over the onboard fuzz with three new small-sized knobs.


    • H. Vol is an output volume control for the fuzz, while the Harmonix knob controls the amount of gain and grit the fuzz delivers. A third knob adjusts the Tone of the fuzz circuit.


    • The Attack Decay features a high quality buffered bypass footswitch. This can also be set to trigger the volume envelope manually. 


    • The Electro Harmonix Attack Decay is powered by an included 9V DC 200mA external power adapter. The industry-standard 2.1mm center-negative power jack is located at the top of the pedal.




    • There are no user-adjustable switches or pots inside the pedal, and since it can't be powered with a battery, there's no need to ever remove the bottom plate. The plate itself comes with four round rubber feet pre-installed; these can be easily removed if you would rather put velcro on the bottom to facilitate pedalboard mounting.




    • This is a deceptively deep pedal, with many user-definable secondary modes and options that give it a broad range of possible configurations. Don't expect to buy it in the morning and use it at a gig that night. Even though the well-written manual is chock-full of suggestions and tips, you should plan on giving yourself a bit of time with this pedal in order to really learn everything it is capable of.


    • The new Attack Decay isn't an identical clone of the original, so vintage fans may be a bit disappointed. Everyone else will probably love the enhanced features and functions of the new version.


    • The Attack Decay should be either the very first, or at least one of the first pedals in your pedal chain. While it certainly isn't required, some users may find a compressor placed before it to be a useful aid since it can help level out your playing dynamics and make them more consistent, which may help in the unlikely event that you're having a hard time getting the Attack Decay to trigger consistently.




    All sounds have a basic envelope - how they develop and change over time - including your basic electric guitar sounds. Manipulating the volume envelope of an instrument can lead to many new sounds that it otherwise would be hard-pressed to create. Many types of pedals will have some impact on a guitar's natural envelope. For example, if you add a compressor, you can change the sustain of a guitar, making the sound ring out for longer than it would naturally. Ditto that for using a lot of distortion... while a gated type fuzz will cut off rather abruptly, instead of fading away, changing the end of the sound. The Attack Decay can do all of this too, and a whole lot more besides.

    More than just a rehash of an obscure pedal from yesteryear, the modern Attack Decay is improved in just about every way. The onboard Harmonix distortion / fuzz is far more controllable and flexible than the previous version - which only had the Edge switch and Harmonics knob for controls. The EHX Attack Decay's Harmonix fuzz can be used as a stand-alone effect, and when used with the envelope controls, it gives you more control over the sound's length and sustain, and it really helps in creating realistic bowed string-type sounds too. The new Poly mode opens up possibilities that the earlier pedal never dreamed of and gives you the ability to play sustaining sounds while newly-played notes have their envelopes processed separately.

    This is a very powerful pedal. You can do things like making notes fade in very gradually (similar to a volume pedal or knob "swell" - a technique used by players like Rory Buchanan, Jeff Beck and Phil Keaggy), as well as to simulate pedal steel licks, create realistic sounding reverse tape effects, distinctive tremolo effects and un-naturally short staccato notes, and even emulate other instruments such as bowed cello or violin sounds. It isn't an instant gratification pedal and a little time and effort will be required to learn how to use everything that this pedal has to offer, but those who do will be amply rewarded with a wealth of new sounds and effects. Best of all, it's priced far more affordably than what the vintage Attack Decay pedals typically sell for, and it's even more powerful and flexible. I said it before and I'll say it again - this is one swell pedal!   -HC-



    Want to discuss the Electro Harmonix Attack Decay or have questions or comments about this review? Then head over to this thread in the Effects forum right here on Harmony Central and join the discussion!




    Electro Harmonix Attack Decay ($166.70 MSRP, $125.00 "street")

    EHX's product web page    


    You can purchase the Electro Harmonix Attack Decay from:


    Full Compass

    Guitar Center     

    B&H Photo Video    

    Musician's Friend     














    Phil O'Keefe is a multi-instrumentalist, recording engineer / producer and the Senior Editor of Harmony Central. He has engineered, produced and performed on countless recording sessions in a diverse range of styles, with artists such as Alien Ant Farm, Jules Day, Voodoo Glow Skulls, John McGill, Michael Knott and Alexa's Wish. He is a former featured monthly columnist for EQ magazine, and his articles and product reviews have also appeared in Keyboard, Electronic Musician and Guitar Player magazines.  

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