Alairex HALO (H.A.L.O.) Overdrive Review

Alairex HALOI’ve been plenty surprised to find an overdrive/distortion pedals that didn’t sound remotely to my liking on demo videos but yet in-person, I immediately get hooked on them. For the case of Alairex HALO (H.A.L.O. = Hamonic Amp-Like Overdrive) it was the designer/founder Alex Auilar’s demo videos that made me go “I gotta get my hands on that.” And actually, this review comes after a year of owning the prototype of this pedal, which is slightly different from the production model.  I’ve always wanted to check out the production model, and so I jumped at a chance to do so.  What I discovered was that the prototype and production models are voiced slightly differently, but they are both amazing overdrive pedals.  What follows mostly focuses on the production model, but I’ll describe the difference between it and the prototype toward the end.


Two-channel overdrive with two sets of Gain and Level (which is similar to how Barber sets up his dual-channelers), 4-band EQ and 3-way clipping switch, and one more switch thrown in for adding one additional gain stage in the signal chain. That may sound overwhelming, but actually once you get used to what each does, it’s fairly intuitive to dial it in.

The 4-band EQ has the Tone (treble) knob sitting in the middle among the Gains and Levels, and the rest are on the upper-right corner.  Just get past the confusing nomenclature: Contour is the low-mids, Presence on this pedal is the high-mids, the area where the pick attacks live, according to the manual.  I wish he’d just designed it four knobs in a low and called it bass, low-mids, high-mids and treble and called it a day.  But once you understand them you’d appreciate them for being pretty effective, with a nice range on each band to dial it in.  The range is perhaps a bit more than necessary but they’re not hyper-sensitive either.  It’s really nice to have two bands for the mids, as it’s perfectly possible to dial in fat tones or bright tones without becoming thin or muddy.

The 3-way clipping is symmetrical, asymmetrical and diode-lift.  The middle position, diode-lift, is predictably the lowest-gain and loudest, but even on this mode if you turn up the gain you’ll find plenty.  I appreciate that unlike some other pedals this switch makes noticeable difference.  Asymmetrical is the darkest and most compressed but also natural sounding.  Symmetrical is brighter and more gritty sounding.

The additional gain stage can be bypassed, assigned to only channel 2 or both.  This switch makes a significant difference as well, as it adds compression and saturation (at the cost of reduced volume).  The saturation it adds is similar to the asymmetrical mode — even in the diode lift position, if you add this additional gain switch you get a sound similar to asymmetrical position.

The pedal has an easy-access battery enclosure and can take anywhere between 9-18v DC power supply.  The footswitch are not a regular true-bypass, as it switches softly and does not have the typical “click.”  It’s a joy to step on them but one mystery remains — is this pedal a true-bypass or is it buffered?  I don’t have it addressed anywhere in the manual or the website.  I don’t find any coloration on the bypass signal myself.


The intent of this pedal is to be a true do-it-all for your overdrive/distortion needs (intended to be plugged into a clean amp), with the exception of modern metal and fuzz sounds.  And amazingly, it mostly succeeds.

The channel 1 (yellow) is the low-gain channel and at Gain set low it is super transparent.  There’s no coloration at all, no frequency range dipping or peaking, it sounds just like your guitar’s bypass signal. As you goose the gain, brilliant, full-range overdrive starts creeping in.  A lot of overdrives get their color by limiting its frequency range — if the highs remained completely intact it can sound harsh or fizzy, if the lows remained intact it can sound muddy or squishy/saggy.  This pedal does neither.  To be fair, when it’s not in diode-lift mode, the extreme highs and lows get a bit held back as the rest of the frequency range gets overdriven.  You don’t detect it as it getting mid-heavy, that subtle roll-off of extreme frequencies simply results in a big, full overdrive without fizziness or muddiness.

How it gets overdriven depends on the clipping mode.  With symmetrical mode, the overdrive is crunchy and brilliant — I would associate the sound to that of the Hiwatt camp, very uncompressed with bright “kerrang” but otherwise without any frequencies getting emphasized.  With diode-lift, the low-end doesn’t get held back so you do get more of “boink” on the bottom on the 6th string.  The top-end is even brighter here so you may want to roll back Tone and Bass to compensate.  The asymmetrical mode is the darkest but its saturation is more complex and colored, the most “amp-like” of the three.  With all three modes, even on the yellow channel there’s plenty of gain on tap — dime the Gain clockwise and you get enough gain to play palm-muted hard rock riffs or old-school metal even.

Now, the red channel 2 is no copy of channel 1.  Its gain kicks in at lower dial position and it has far more gain available, and the low-end gets tighter.  The top-end is held back a tad, too, to prevent being too hairy but the note definition remains extremely tight and defined.  The difference between the three clipping modes are the same here, but within the context of more saturated, focused and tight voice of channel 2.  It’s very impressive how even at the highest gain setting. You can hear every note inside a dense chord, all the difference in overtones produced depending on where you pick on the string, and the tonal difference between various pickup settings.  Some pedals sound good with one pickup but not so with another — this pedal lets the difference comes through yet it all sounds good.

A few more details are worth noting.  This pedal is very dynamic, but its dynamic response is not so much of the dirt getting varied depending on the input strength — the response is reflected on the volume.  So while rolling off the volume knob has some effect on the amount of dirt, it actually just gets quieter with little difference in the amount of dirt.  And the additional gain stage sounds very much like asymmetrical clipping, so if engaged, even when the main clipping is set to one of the two other settings, adding the additional stage makes it sound close to the asymmetrical setting.  As you pile up more gain, the sound gets more saturated and compressed, but it all feels very natural.  And even at highest gain setting — asymmetrical mode with additional gain stage, Gain dimed — you still feel the impact of the pick attack very clearly.  The pedal remains very quiet throughout most of its range, except the last quarter or so of the gain range for channel 2, where some background hiss creeps in.  And also don’t forget to explore the opposite ends of each channel’s intended usage.  With Gain turned up channel 1 has some fearsome low-end punch still without being muddy, while channel 2 low-gain also sounds excellent for rhythm playing thanks to its tight, highly articulate sound.

I did try this pedal with both 9v and 18v voltage power supplies.  The difference is subtle.  18v obviously has more dynamic range, but again this pedal responds more in terms of volume difference than amount of dirt — so the fundamental tone stayed pretty much the same, with 18v having more dynamic range available (meaning, the difference between soft and loud was bigger.  But it’s a subtle difference).


I’ve played many pedals but this one takes the cake for sounding authoritative from the lowest to the highest gain range.  It definitely has its own voice, but in terms of dynamic response, natural feel, and the nuances of your playing/pickup/guitar coming through — this pedal is utterly impressive.  Some pedals are good at letting those nuances through but sometimes in the process it forgets to sound good because it’s just too transparent and forgets the fact that if you simply distort the full range of frequencies coming in from the clean signal, it just doesn’t sound good.  Distorted tones need judicious rolling back of extreme ranges, which this one does without really making it noticeable.  On the other hand no frequency range gets accentuated noticeably either (unless you EQ it to be so) so it is a very flexible pedal as well, thanks to its powerful 4-band EQ.  You can tweak it to concoct everything from scooped hard rock tone to thin and bright or fat and dark.  The EQ has good range so it’s possible to make it sound bad but with this pedal you’d really have to try hard to make it sound awful.

That being said, here are key features to note about this pedal:

  • Its dynamic response results in volume difference, not int he amount of distortion.  So if you’re looking for a pedal that gives you more dirt the stronger you pick, this pedal won’t do it.  It just gets louder.  Similarly, volume-knob riding isn’t the greatest here either.
  • The pick attacks are quite accentuated (without sounding unnatural) so if you want sag or “bloom” look elsewhere.
  • While it’s tamable, this pedal is good at sounding brilliant with righteous top-end “kerrang.”  Hiwatts are known for its brilliance and unforgiving steeliness, and that’s how I’d describe this pedal, too.

So with those things considered, this pedal will be great if you’re looking for Hiwatt-like bright and defined low-gain and tight and defined hard rock/classic metal sound.  The two channels share EQ but I found it really easy to sound great on both channels, unless you’re looking for a completely different EQ curve on each channel.

The only bummer part about this pedal is really the price tag.  $400 is a lot to pay for an overdrive, and while some pedals in this range are known for its point-to-point or tube-driven design — this pedal is neither.  I would say that it does live up to its high price tag, but I can’t wholeheartedly say it scores very high in terms of its bang-for-buck value.  I hope Alairex figures out how to manufacture it for perhaps $300, which is still a lot, but at that price point I’d be jumping up and down excited about what a tremendous value this pedal offers.

Production vs. Prototype

Alairex HALO Prototype

Now, as I said in the beginning I have two versions of this pedal, and the one I have had longer is the prototype, which is branded “Audiolex” and the product named “Active Aggressive.”  The basic features remain the same, but there are a few differences, both in terms of features and sound.  The proto has only two clipping modes — symmetrical and asymmetrical, and the additional gain stage is either on or off.  It doesn’t have the easy-access battery compartment either.  Tonally, pick attacks are less accentuated on the proto and the additional gain stage is so subtle the difference is virtually non-existent.  The proto is voiced darker as well, so it feels like Tone at all the way up is the unity and then you can cut from there.

It’s completely subjective in terms of which is better.  Obviously the production model has more flexible feature set, and thanks to its diode-lift mode it excels in the low-gain range.  On the other hand, the pedal sounds most complex when set to darker voicing so the proto sounds smoother, more organic and forgiving, especially at 9v where it is more compressed.  They are voiced very similarly, though, so you can’t go wrong with either one.  For me personally, I A/Bed it side by side and decided that I would stick with the sound of the prototype I grew so fond of over the last year that I had this pedal.  I think very highly of the production version’s brilliance and dynamic response, but I am personally not drawn to the Hiwatt school and for my low-gain sounds I prefer pedals that I can adjust the amount of distortion based on the picking strength.  That said, I do think the tightness and definition of the high-gain red channel sound must be heard to be believed and I’m sure the production model would have won me over if I had heard that one first.  I have been using my prototype at 18v to get the most dynamic response and with channel 2 set low-gain for tight rhythm and channel 1 set high for fat lead sound.

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