Electro Harmonix – Knockout REVIEW

The Knockout pedal from Electro Harmonix is an interesting take on what is essentially a tone-shaping EQ tool. The unusual filter approach in combination with the blend knob opens new tonal ground.

Electro Harmonix claims that the Knockout ‘Attack Equalizer’ will turn a Les Paul into a Stratocaster, and some online videos demonstrate how the pedal is in fact capable of at least ‘swapping ballpark’. Guitar is not my main instrument, but while I think the videos show how Knockout can make a humbucker guitar sound somewhat like a single coil guitar, it just doesn’t really nail it. Kind of like when you try to replicate a Precision bass with a Jazz bass by favoring the neck pickup. It may get you relatively close, but never actually there.

So, before plugging into the Knockout stomp box I had no illusions that it would be able to turn a Precision or Stingray bass into a Jazz bass – or vice versa. And the short answer is: No, it didn’t – not even close. But that doesn’t mean it’s useless for bass. In fact, EHX claims that it can do wonders for bass tones as well. I decided to wipe the board clean and just take a creative approach trying to dial in some nice sounds for various basses…



ehx-knockout-attack-eq-control-knobsThe way Knockout handles your signal is essentially by boosting low and high pass filters. The low pass filter is cutting at 85 Hz and the high pass filter is cutting at 6.5 kHz. In other words, it mostly tweaks the very highs and lows of your bass tone.

That is exactly why the DRY knob is so essential. On their own, the LOW and HIGH filters won’t be able to create useful sounds, but using them gently and adjusting your dry (and full) signal accordingly, you can indeed enter some interesting tonal territories!



white headphone with rhythm symbol

I ran a number of basses through the pedal and chose to focus on two quite different examples of how to use the EHX Knockout.


NOTE! Please use headphones or ‘real’ speakers. You simply can’t judge low-end material on laptop, tablet or phone speakers…!

NOTE! If you are on a mobile device, please turn it to landscape mode to see the knob settings of the pedal for each audio clip.




You can definitely sculpt some very useful tones with the Knockout – and many more that are completely silly or just too extreme to ever be used for anything other than messing around.

That said, I have used loads of pedals just for one specific application, and as long as they did exactly that, they were the best pedals in the world. If you find just the right setting for just the right bass and just the right rig, I see no reason why the Knockout couldn’t be ‘one of those pedals’!



The pedal seems sturdy with its raw, industrial look, but it was actually lighter than expected when I first picked it up. The knobs feel all right, but without the same firm grip of more expensive pedals.

Design-wise, there really isn’t much to say. The three parameters works fine for what they are intended to do, and I can’t think of any obvious controls that were missing.

OK, there may be one thing, but it’s a minor issue. You have remove four screws to access the battery, but if you – like me – always power your pedals from an external power supply this is not an issue after all as the pedal has a standard 9V power input.



You can pick up a new Knockout for just $68 today! (2015) I mean, at this price I almost feel guilty criticizing anything about it. Knockout definitely scores high on the Value for Money parameter.



Overall, I got mixed feelings about this pedal. I like some of the sounds I can tweak out of it for certain applications, yet most settings are too extreme to my taste.

But again at this price, if you can find but one useable sound it’s justified. I guess in the end it depends on whether you find that one great sound in your setup – and if it’s great enough for you to actually reserve precious space for it on your pedal board.



Can really add some character to your tone

Can be extreme – creative purposes for recording

Fairly versatile

Great value for money



Be careful, just a little LOW bump can make some mud

Tends to slow down the attack

Build quality not impressive









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