3 – Filtering Audio through Thor

In this project I’m going to demonstrate a few ways you can use Thor’s filters, FX (Delay and Chorus), and LFOs creatively by routing any of your audio sources through Thor. This can be a great way to punch up some drums from a Redrum, or to create some new innovative sounds from any of the synths. Furthermore, you’re not limited to using only 1 filter. You can connect your audio through a series of Thor devices to gain access to more than 1 filter at a time. So let’s start our exploration.

Basic Audio Filtering through Thor:

1. Open Reason. In the rack create a Combinator and inside the Combinator create a Thor, initialize the patch, and then create a Redrum underneath. Add a drum kit and create a simple pattern with a kick, high hat and a few other drums. Don’t make it too complex. Use about 4 or 5 drum samples to create the pattern.
2. With all the hard work done, now we’ll do some routing. Flip the rack around and route the Left and Right audio output from the Redrum into the “Audio In 1” and “Audio in 2” on the Thor.



3. Flip the rack back around, show the Programmer for Thor, and uncheck all the little green lights in the “note” section (the section that is dark and not light brown). Also, turn the analog osc.1 off, and bypass the Ladder Filter (Filter 1). Then turn off the routing between Osc.1 and Filter 1 (the little red “1” light). In the top device section, set Polyphony and Release Poliphony to “0” and turn off both trigger lights (Midi and Step Seq). The point is that you don’t need any of that mumbo jumbo.
4. Add a Filter into the third Filter slot of Thor. A Low Pass Ladder or Comb filter works well with Drums, but you can use any filter you like.
5. At this point, most people will press play and think that they should be hearing something. But we’re not finished yet. We need to reroute the default Thor audio signal. Here’s how to do that: In the MBRS (short for “Modulation Bus Routing Section”) of Thor, in the first row on the left, click on the “Source” and select the bottom-most option “Audio Input > 1” then set the “Amount” column to “100.” Click the “Destination” column and select “Filter 3 > Left In.” On a new row, do the same thing, but for Audio Input 2 as a source and “Filter 3 > Right In” as the destination.



6. Now press play. You’ll hear the drum pattern, which is routed through Filter 3 in Thor, then to the Chorus and Delay section, and back out to the mixer.
7. Optionally, you can use the FX (Delay and Chorus), or route the LFO2 to affect any of the parameters in Filter 3 or the FX. One thing I like to do is turn on both the Delay and Chorus. Then in the MBRS section, program the two FX Dry/Wet parameters to the two Rotaries. If you use amounts of +100 for both, then turn the actual Dry/Wet knobs on the FX all the way down, you create a controllable Delay and Chorus effect via the Rotaries. I also use the Mod wheel to control the Filter 3 Frequency or Resonance or both. That way, it’s all controllable. If you want to push it further, you can assign the LFO2 to affect the Frequency or Resonance via one of the Thor buttons. This all gives you a great degree of control over affecting the sound. Download the example file (at the bottom of this post) to see these routings.

First, here’s an example of the original sound:
[ti_audio media=”177″ repeat=”1″]

Second, here’s an example with the audio filtered through Thor (remember, you can adjust the filter to taste):
[ti_audio media=”175″ repeat=”1″]

As an aside, if you’re using Record and have an audio track, you can still route your audio through Thor, by cabling the direct output of the audio track to the Thor inputs 1 + 2 as shown below.

Audio Filtering through a Series of Thor Filters:

By now, you will have noticed that plugging audio through Thor gives you access to the global section (the parts of Thor that are light brown). What if you want the use of more than one filter. Let’s say you want your audio path to move this way: Audio Device > Formant > Comb > Low Pass Ladder? Well, it’s really quite simple. Follow the above directions to set up your first Thor, and then build upon that as follows:

1. Flip the Rack around. Right-click over Thor and select “Duplicate Devices and Tracks.” Do this one more time. You should now have 3 Thor devices.
2. Move the “Audio In” cables from the first Thor to the bottom-most Thor’s “Audio Ins” and then cable the “Audio Outs” from that bottom-most Thor into the Thor above’s “Audio Ins.” Finally, cable the “Audio Outs” from the middle Thor to the “Audio Ins” of the top-most Thor.
3. Flip the rack around again to see the front. Then switch the bottom-most Filter 3 to “Formant” and top-most Filter 3 to “Low Pass Ladder.”
4. Press Play and adjust the three filters to taste. It might help to bypass the filters on the top two Thors. Adjust the bottom filter, then turn the middle filter on, adjust it, and then finally turn the top Thor filter on and adjust it. That’s all there is to it. 3 filters affecting one sound source.

Example of the Filters in Series:
[ti_audio media=”178″ repeat=”1″]

Audio Filtering separate Drums through Thor:

All of the above is fine and dandy, but what if you don’t want all the Drums filtered the same way. Let’s say, for example, you want the Bass Drum to be filtered by a Low Pass Ladder filter and the High Hat to be filtered through a High Pass in a State Variable filter. Well, without getting too complicated, here’s what you do:

1. Follow the steps to create a Basic Thor Filter above.
2. Create a Line Mixer 6:2 and move it to the top of the Devices in the Combinator.
3. Flip the Rack around, and delete the audio output cables from the Redrum.
4. Duplicate the Thor device (so you now have two Thor devices under the Line Mixer.
5. Move the Audio Outputs from the first Thor into the Master Audio Outputs of the Line Mixer.
6. Cable the Bass Drum Audio Outputs from the Redrum to the first Thor’s Audio Inputs 1 + 2
7. Cable the High Hat Drum Audio Outputs from the Redrum to the second Thor’s Audio Inputs 1 + 2
8. Cable the Audio Outputs from the two Thors into Channels 1 & 2 on the Line Mixer.



9. Cable the other Drums into the free channels on the Line Mixer.



10. Flip the Rack around again to the front, and then insert the Filters of your choice into the Filter 3 slots of both Thors. Adjust them to taste in order to affect the Bass and High Hat Drums

Example of separately filtered Drums (with a little delay on the High Hat):
[ti_audio media=”176″ repeat=”1″]

Some Final Thoughts:

Finally, just because you filter one sound through the Global section of Thor, this doesn’t mean you can’t use the Thor to generate a sound of its own. This way, you end up merging two sounds together in a kind of layering. If you want to see how this is done, look at the “Synth+Filter – Droid Chatter” Combinator in the example files. You can do some pretty interesting things this way. Additionally, you can take one sound source, split it into two different Thor filters and then route them to two separate channels in the mixer, or back into one channel if you like. A wealth of options and possibilities, for sure. 

Example of a Synth Arp + Thor with an Analog Oscillator, both generating sound. The Synth Arp is being filtered through Thor while Thor is generating a sound of it’s own. This creates a layered effect:
[ti_audio media=”179″ repeat=”1″]

So as you can see, routing audio through Thor is not difficult, but most people miss the step about the Modulation Bus Routing Section. If you remember to reroute the audio signal, you’re golden. That’s it in a nutshell. nothing fancy.

I mainly use Thor’s comb or Low Pass Ladder filter to affect drums and then put it all in a combinator. But that’s just one way you can use Thor.  Are there any other ways you Route your audio through Thor? Do you have some creative ideas that I haven’t covered here? Please share them. I’m curious to see how people are using Thor to affect external sources.

Download the Example Files