Notes summarising the tutorial video by Trond Lossius and additional videos from Martin Parker
Encoding MONO sources to then decode to Ambisonics
In this tutorial we always pass all tracks (ambisonic, 4-channel, B-Format) signals to the master bus. Then we do the decoding on the master bus.
- Setting Up the MASTER BUS
- VIew > Master Track (optional: to see it in track list)
- Set Master Track to 4 channels: ROUTE button then TRHC (This can be set to the maximum number of channels I could use in any of my bounces if I want to bounce several mixes — binaural, stereo, 5.1, etc) – In Martin’s tutorial he sets 6 channels
- If I am doing my decoding using stereo/headphones then BLHC can stay output 1/2 but if I’m doing my decoding in more channels, I need to change output channels as well
- Set DECODING EFFECT on master bus: FX button, find ATK FOA DECODE BINAURAL (First Order Ambisonics)
- In the FX window I can choose Head-related transfer function (HRTF) to pick a head. Pick one suitable to me. Tutorial uses KEMAR Large Piannae Dummy
- OJO: In FX window HRTF status might say MUTED, but if I start playback, should change to “Loaded Successfully”
- After this the tutorial hid the master track (step 1)
- Set up two tracks – Visualize (just for display) & B-format Mix (to mix all audio tracks into)
- Both tracks must be 4 channels (ROUTE button)
- Make sure I keep Master Send TICKED on the B-format Mix Track
- The Visualize track is only for visual reference, therefore UNTICK Master Send.
- I must also Add a receive on the Visualize track to receive FROM the B-format mix. Make sure I change to receive all 4 audio channels using the Audio drop-down
- At this point he opens FX on Visualiz track and adds HARPEX-B (expensive ambisonic decoder/visualizer)
- Create tracks for different types of ENCODING
- Create track and make it a sub-track of B-format Mix by going to the B-format Mix track and below the track number (2 in this case) click on the tiny folder icon (turns into a +). This passes audio up to the Mix track first, rather than the Master.
- Ensure it’s a 4-channel track (ROUTE button): even though we will add a MONO file this will encode it to ambisonics (4-channel file)
- “Planewave” encoder
- We then add an econder effect (FX button): in this case PLANEWAVE
- This gives a UI to control the surround location.
- Add a MONO file to the track
- Planewave is probably most common enconder, very clear direction, it’s not coming from everywhere. If I want to be less clearly defined in direction, add effect to transform B-format soundfield. ATK DirectO
- DirectO has a UI that I can pull in, the sound becomes more “in your head” (more omnipresent)
- To show next encoder, mute the Planewave
- “Omni” Encoder
- Repeat steps A & B then come back
- Omni has no settings (no UI) to tweak. It’s the same result as the previous DirectO transformer pulled all the way in (fully omnipresent)
- This is useful if I am decoding to 5.1. The sub (LFE) channel could be a mix that is Omni (non-directional, coming from everywhere)
- I could also apply another Transform Effect and make this more directional. FX: ATK FocusPushPressZoom
- UI has those 4 modes, I could try push or press and gradually make it more directional, eventually, if I push fully, it’s the same as Planewave
- “Spreader” Encoder
- This encodes different frequencies and spreads them in different directions. It makes a sort of spiral curve pattern across the soundfield from low to high freqs.
- In tutorial it was demonstrated with pink noise and visualizer
- UI allows to change number of bands per octave, which changes the curve pattern
- Using these some of these patterns may be recognizable. I can also add a Transform effect: RotateTiltTumble
- This allows to move around the pattern within a 360º sphere
- I can even add the ATK FocusPushPressZoom to give the different frequecy spreads a sense of direction
- “Diffuser” Encoder
- Similar idea to Spreader, but seems much more of a random pattern
- “Planewave” encoder
Giving the Diffuser or Spreder a sense of direction using a transform gives more spatially “alive” results than using the Planewave, which gives more spatially “flat” results
Martin Sets up Reaper to do multiple decodings easily by using Decode tracks and setting the Decoder FX on those instead of the Master. Therefore each track of sound IS NOT sent to master, but rather sent to decoding tracks.
- Create an additional track “binauralDecoder”
- Set to 4 channels
- For every 4-channel audio track from before, ROUTE, untick Master Send, instead add send to binauralDecoder track, make sure the Audio dropdown is all 4 channels
- New track obviosuly does send to Master
- Add Effect FX ATK Decode Binaural
- For STEREO follow same steps but use ATK Decode Stereo
- Create new “5.1Decoder” track
- set to 6 channels
- To this track we add a Receive > from every 4-channel audio track. Again make sure the Audio dropdown is all 4 channels
- New track does send to Master
- Add Effect FX ATK Decode 5.0
- MonoSignal > 4-channel audio track with encoder > Send to track with decoder > Master Track
- Exporting in B-Format as well to be decoded later on to any format, including huge multi-speaker arrays using Max/MSP.
- Create track “bFormat”
- Doesn’t need to go to Master (we don’t need to hear it), must have 4 channels
- Add Receive from audio source, ensure Audio dropdown has 4 channels
- BFormat track doesn’t need any decoding
Martin also added a BFORMAT WORLD track (4 channels) and send the audio source to it. On this track he adds a Transform ATK FX to move the whole world around. The decoders receive from THAT WORLD TRACK instead of directly from the signal. That way, whatever automation of movement I set to the encoded track on the original audio source can be completely transformed before it goes for individual decoding.
To Bounce all decoded signals: