Thor app review – Propellerhead’s brilliant synth comes to iOS

Download from iTunes App Storethor logoThere are some days when you just know you are going to spend most of the day with a big daft grin on your face. For me, yesterday was one of them. And the reason for this abundance of happiness? Propellerhead’s Thor music app.

If you are familiar with Reason under Windows or OSX, then you will also be familiar with Thor, one of the flagship synths within Reason and, as software synths go, a bit of a classic. Propellerhead have now ported Thor to the iPad and, a couple of understandable features aside, this is a comprehensive implementation. Indeed, comprehensive enough that patches can be imported/exported between the iOS and desktop versions.

Thor within Reason has always been a bit of a synthesist’s wet dream. So, time for a Thor app review to see if, within the confines of the iPad, Thor still an impressive beast…. and if you want to see the app in action, then check out the video at the end of this review.

Thor Basics

Thor's Keyboard screen. Click on any of the images to see a full-size version.

Thor’s Keyboard screen. Click on any of the images to see a full-size version.

Propellerhead describe Thor as a semi-modular synth in that, rather than having fixed oscillators and filters, you have a range of different oscillator and filter types that you can choose from and combine in a variety of ways. Thor has six different oscillator types available; analog, wavetable, FM pair, phasemod, multi osc and noise. These can be placed into three oscilator slots and, given the very flexible routing options, combined in an almost limitless number of ways. Sonically, there are a huge range of possibilities here.

The synth also has three different filter slots into which you can place the four different filter types; low pass ladder, state variable, comb and formant. In addition, you get three envelopes, dual LFOs and delay and chorus effects. Add to this the modulation options, a very well specified 16 step step sequencer, MIDI, Audiobus and background audio support, some excellent performance options via the touchscreen and a huge collection of fabulous presets ported from the desktop version, and Thor represents a whole lot of synth for a pretty modest price (£10.49 or the equivalent $/€ price at the time of writing).

Thor Tour

Access to all these features is provided via three main screens, each opened from one of the three buttons – Keyboard, Knobs and Routing – located top-right of the display within the ever-present Menu Bar; more on these below. Other features accessed here are the Settings (mostly set and forget), the Play button (used, for example, when a patch is configured to work with the Step Sequencer) and the patch load/save options.

The Keyboard Page

The keyboard section includes a range of additional performance options.

The keyboard section includes a range of additional performance options.

The Keyboard page is divided into two parts; the upper Controller Pane and the lower section that actually contains the keyboard. The Controller Pane allows you to set the polyphony and portmento values, adjust the trigger mode, tweak four virtual controls (these can be assigned to your preferred parameters within a patch via the Routing page) and adjust the master volume.

By default, the keyboard layout looks a little uninspiring and, given the rather unconventional positioning of the black keys, takes a little adjusting to, but it hides a host of very clever performance options that (like Propellerhead’s Figure) make the app both easy to play and very flexible. For example, the keys themselves are velocity responsive based upon where you tap them with higher velocities at the bottom. This explains the rather unconventional layout of the black keys.

Immediately above the keyboard itself are options to access other performance options. The Modulation button toggles on/off the virtual pitch bend and mod wheels. The Assist button allows you to specify a key and a ‘color’ (number of tones per octave) and this then colour-codes the key so that only those ‘in key’ are highlighted. While all the keys are active, this colour-coding does make it easier to avoid ‘duff’ notes. The Collapse button takes this one step further and toggles off all the out of key notes making performance via the touchscreen much easier.

You can select which portion of the overall keyboard span is visible by swiping the mini keyboard. The Latch Keys button does exactly what you would expect. More novel is the Strum button that provides you with a strumable strip for whatever notes are currently being held on the keyboard (or locked on via the Latch Keys options). The strumming bar is velocity sensitive (high velocities if you strum towards the right edge) and there is an additional ‘hit’ strip that plays all the held notes together (also velocity sensitive as with higher velocities at the bottom like the main keyboard). This is all very neat, the only catch being that it took me a little while to constrain my strumming so that I didn’t also swipe across the Latch Keys button and mess up the ‘latched’ chord I was trying to strum.

Lots of Knobs

Thor's Knobs screen is divided into four sub-sections, any two of which can be displayed at a time.

Thor’s Knobs screen is divided into four sub-sections, any two of which can be displayed at a time.

The Knobs page – and there are lots of knobs – is where you can start to get your programming fix. In fact, there are more knobs than can comfortably fit on a single screen so you can select which two of the four different sub-sections of the display are showing in full at any one time. Tapping on the ‘Expand’ button of a closed section opens that and automatically closes another. Moving from left to right, the four sub-sections of the Knobs page allow you to configure the oscillators, filters 1 and 2, LFO 1/envelopes and, finally, the effects, filter 3, LFO 2 and the global envelope.

There are way too many options and flexibility in Thor’s Knobs page than I could possibly do justice to here. Perhaps it’s just best to say that, given the choice of the six different oscillator types and the three different filters, even without the excellent modulation options, you just know Thor is going to be capable of a wide range of timbres; it doesn’t disappoint. The options for combining the oscillators in different ways and routing them through the filters and onwards provide plenty of choices.

And here are the other two sections expanded.

And here are the other two sections expanded.

What is perhaps more surprising, however, is that given all these options, exploring programming in Thor is a remarkably intuitive process. Experienced synthesists should soon feel at home but, if you are still finding your programming feet, then Propellerhead have a range of resources available on their website to help get you started. This includes an excellent series of tutorials by Gordon Reid that uses Thor to explain the basics of synthesis (the Reason version but it all applies to the iOS version).

Follow The Route

The Routings page provides access to the modulation matrix and the step sequencer.

The Routings page provides access to the modulation matrix and the step sequencer.

The Routing page is split into two sections. The upper portion provides the modulation options while the lower section contains the rather splendid step sequencer. The modulation options are split into three sections and these each provide slightly different options. The main set of seven (on the left) provide simple source-destination-scale choices. As you might expect, assigning parameters to these positions simply requires tapping on a slot and then selecting the required parameter from the pop-up menu that appears. The two modulation sections on the right provide a smaller number of slightly more complex routing possibilities with options for dual destinations and dual scaling both available.

The Step Sequencer provides up to 16 steps and, in each step, you can program note pitch, velocity, step duration, gate length and two seperate curves that can be used within the modulation routing section to control parameter changes. The sequencer can be set to run free or in sync with the tempo. There are also various options such as one-shot mode, repeat mode and different direction settings. You can program the steps either one step at a time or while the sequencer is running; again, plenty of choices without being so complex that newbies would just run screaming.

The Sound Of Thor

If you have experienced Thor via Reason then you will not need me to tell you just how good this virtual synth can sound. If this iOS version is going to be your first encounter with Propellerhead’s God of Synths, then you are in for some fun.

Thor comes supplied with a huge range of excellent presets derived from the desktop version.

Thor comes supplied with a huge range of excellent presets derived from the desktop version.

And, thankfully, given that the app is supplied with a massive collection of excellent presets, it doesn’t take much effort to explore what is possible. If you just want some ‘real’ instrument sounds – strings, brass, acoustic pianos, acoustic drums, etc. – then perhaps Thor isn’t the most obvious choice; it can do synth-based versions of all these (and there are some excellent electric pianos, synth strings and organs amongst the included presets) but find yourself a sample-based virtual instrument if you need ultra-real.

However, if you want analog basses, sweeping filters, techno stabs, evolving pads, weird textures, searing leads, rhythmic bleeps and dubstep wobble basses galore, then Thor ought to really rock your sonic boat. The presets are extremely well organised with groups for basses, FX, leads, textures, etc. as well as a Signature Patches section with contributions from a number of different programmers (including Gordon Reid). When programming your own patches, Thor provides a small set of template patches that can get you started. Equally, it is very easy to move patches between the desktop and iOS versions vis iTunes and the Patch dialog’s Inbox option.

In reviewing Waldorf’s Nave recently, I commented on just how many really great iOS synths were now available. In terms of pure synthesis, Thor is right up there at the top of the current crop. In terms of the sounds and programmability, I can easily see Thor becoming my synth of choice… and given the quality of the competition, that’s quite a recommendation.

In Use

I had no problems hooking up an external MIDI keyboard and getting Thor to respond quite happily. Indeed, given a suitable way of getting sound out of your iPad, I could imagine Thor being a brilliant instrument in a live context. It sounds absolutely fabulous.

Thor worked well in a recording context via Audiobus and linked to DAW apps such as Cubasis.

Thor worked well in a recording context via Audiobus and linked to DAW apps such as Cubasis.

In a recording context, Thor played very nicely with the likes of Cubasis via Audiobus. I was able to send MIDI data from Cubasis to Thor while recording Thor’s output to an audio track in Cubasis at the same time. This all worked very smoothly.

The only other comment worth noting is that Thor – not surprisingly perhaps – and like many of the other top-end iOS synths, does require a fair amount of CPU grunt to pull off its impressive sonic results. The Cubasis CPU meter jumped from about 15% to around 65% with a single instance of Thor playing back a Cubasis MIDI track on my 3rd generation iPad. The sounds are definitely worth it but it does mean that you have to work around the horsepower of your iOS hardware if you want to fully capitalise on what Thor can offer when recording on the same device.

The same restriction obviously doesn’t apply if you are passing Thor’s audio to a different device (iOS or desktop) for recording. If you don’t own Reason, Thor under iOS is a heck of a lot of synth to add to your recording system for the price of a pizza and a beer.

In Summary

There are some truly excellent virtual synths now available for iOS, the best of which are the equal of their desktop equivalents. Propellerhead obviously know exactly what it takes to create a killer synth in software; Reason is testament to that. They have also created what – for me – is one of the most innovative music creation apps for iOS in Figure; an app that, for all its simplicity, demonstrates just how creative touchscreen technology can be for music making.

Their port of Thor to iOS brings the best of their virtual synth expertise – with some suitable interface tweaks to exploit the touchscreen capabilities – to the mobile musician. It is awesome.

It’s hard to pick a single ‘best virtual synth’ from the current top of the crop that iOS has to offer but, if my initial experience with Thor is confirmed by extended use, then it is very hard to fault. Thor is a truly professional software synth and available for a ridiculously modest price. Buy it now before Propellerhead come to their senses and put a great big smile on your face to match mine.


To see Thor working and hear some audio demos, then just watch the video.


Be Sociable; share this post....


    1. Nilesh Deshpande says:

      I liked your review on Thor app
      I have iPad air2 and I want to buy this app
      I have EWI5000 electronic wind instrument as a midi input. I want to use indian sound samples Swarplug app with programmer capability of Thor.
      Can you please guide me how to use Swarplug via GarageBand through Audiobus to Thor


    Speak Your Mind