Aleksander Mlazev AU effects review – Harmonizer, Warm Distortion and Resonator for iOS in AU format

Download from iTunes App Store Aleksandar Mlazev has a number of iOS music apps available on the App Store but, as yet, I don’t think I’ve actually reviewed any of them here on the Music App Blog. Given that is has launched three new AU-based effects apps within the last few weeks, however, I thought I’d better do something about it. So, if you are, like me, doing your best to embrace the world of AU plugins under iOS, how do you fancy three new, budget-priced, AU audio effects processors to expand your collection?

AU for you?

As is obvious from the app icons and the various screenshots shown here, the three effects – Harmonizer, Warm Distortion and Resonator – are all very much in the ‘guitar stomp box’ style of effects. Rather like the Flora Series apps, there are, therefore, pretty simple control sets with just a few rotary knobs or sliders to experiment with each effect….  much as you might find on a physical stomp box. However, with the AU plugin format, you can, of course, apply these effects to any sound source providing you have a suitable AU host.

Building an AU app collection? Here are three more for your consideration…..

That said, all the apps also work in standalone mode for live processing of your audio input to your iOS device and all are also universal. All will run under iOS10 and each is a tiny download; less than 20MB for each app. Warm Distortion is priced at UK£1.99/US$1.99, Harmonizer is also UK£1.99/US$1.99 and Resonator is priced at UK£2.99/US$2.99. Yep, pocket-money prices even by the App Store’s standards.

Warm Distortion

The app titles are pretty self-explanatory. Warm Distortion is perhaps the most obvious. What you get here is a rather nice distortion/overdrive effect with four controls. Gain and Level are as you might expect but, even wound up full, the distortion never gets really out of hand or super-fizzy; it’s a rather nice distortion and, if you apply the rather wonderfully named ‘Smoothie’ control, you can warm things up even further by taming the high-end a little more drastically.

The underlying algorithm is apparently based upon a tube-style sound but, whatever it is modelled upon, I found it pretty pleasing on the ear. I did my own experimenting within Cubasis and AUM (for all three apps) and I have to say warm Distortion was perhaps the one within the set that I’d have the most use for. It sounded great on all sorts of sound sources for adding a bit of gentle grunginess and, if you dialled the Gain back, it just added a subtle warmth to a sound. I could see this one getting a lot of use.

Warm Distortion working smoothly with Cubasis.

Oh, and all three apps include a global Reverb control. This is primarily intended for when used as a stand-alone app but it works well enough adding a nice touch of ambience if required. Used within am AU host as part of a recording project, I suspect most users would have more powerful/flexible reverb options, but it’s nice to have the option if needed.


Harmonizer provides real-time pitch shifting. You can blend your original sound with up to two ‘harmonies’ (EFX1 and EFX2) pitch-shifted by a fixed amount from the pitch of the original. You get both coarse and fine pitch shift controls for each of these two channels, a level control for each (so you can blend their respective levels) plus a Dry control to blend in the original. And that global reverb also….

Obviously, Harmonizer doesn’t provide key/scale-based pitch shifting so you don’t get a sort of AI-take on the generated harmony voices but there are plenty of creative options for fixed intervals such as a 5 steps, 7 steps or 12 steps (an octave; this is the maximum pitch shift in either direction). Again, used with a range of sources – a lead synth, bass synth or vocals – it works pretty well. With a synth sound, you can obviously push things a bit harder but even used with a clean vocal, the results are good. Set to add just a few cents up/down on the two harmonies, it can fatten up a vocal quite effectively.

Harmonizer…. perhaps still some AU tweaks required but the effect did seem to be working well enough….

Of the three, this is, however, perhaps the one that I felt still needs a tweak or two. For example, used with vocals, there seems to be some audio artefacts in the processed sound that, on sustained notes, isn’t always pleasing on the ear. It’s not such an issue with synthetic sounds though…. In addition, the app through me a warning message when loaded in Cubasis and, while all the processing seemed to be working as advertised, it does suggest that some fine-tuning of the AU support is still required. Oh, and an option to pan the pitch-shifted sounds left/right would also be great :-) That all said, it’s a lot of fun to use and, as the other two apps seem to be working smoothly in this regard, I’m sure it is something Aleksandar will address with an update.


Of the three apps, Resonator is the one that might most obviously appeal to the more experimental sound designer. The idea behind the app is to create natural sounding resonances that can add to the ‘fullness’ of the processed sound. You get controls for the amount of resonance, it’s ‘thickness’ and it’s size. The latter, I assume is related to the ‘size’ of the acoustic body (think small body guitar vs large body guitar; a bigger acoustic chamber produces a fuller sound) but I’m less confident I know what Thickness is modelling….  other than tweaking the control produces quite a marked change to the results, with brighter sounds at lover levels.

Resonator in action within AUM…..

In testing, I found some quite interesting things could be done. For example, if you kept things subtle (lowish Resonance setting), you could add a rather pleasing distortion to a vocal part that did add a little ‘fuller’ element to the sound. However, just as with the resonance control on a synth filter, if you pushed things a little harder, you could get into more ‘experimental’ territory…. perhaps not ideal for a ‘natural’ vocal sound….  but quite good fun on a synth or drum loop if you wanted something a touch more left-field.

As ever, the AU format allows for multiple instances of an app if required…..

Plugin promise

All three of these plugin are fun to use, easy to tweak and priced at a casual purchase point. While none of these are perhaps what you might call ‘essential’ purchases, they do all have something to offer and, with their stompbox philosophy, ought to find a home in many an iOS music app collection. There is no sonic revolution here….   just some nice extra options for those that like choices in the toolbox.

Where they most certainly will score is with those iOS musicians who are keen to embrace the AU plugin format. I’m most certainly in that camp and, while I’ve still got several types of iOS music app that are ‘missing’ from my AU-based app collection (including a virtual guitar rig app), it’s great to see an ‘indie’ developer running with AU. And, like the Flora series apps and the Blamsoft audio effects apps, these compact, KISS-style, audio effects are both fun and creative to have around.

Fingers crossed Aleksander gets the support he needs to take his iOS AU app collection forwards. All three of these are well worth a look and priced at a point that, even for occasional use, they will earn their keep.


Download from iTunes App Store

Warm Distortion

Download from iTunes App Store


Download from iTunes App Store

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