I Hey everyone,
I’m a sound designer and had the opportunity to create a site-specific radio play in 3D audio using Echoes.
Since it was an exciting process, I wanted to share some of my findings when working with Ambisonics in Echoes.
The result is situated in Munich and exists in two versions:
- A binaural version that does not require head tracking, which works quite stably and reliably.
- An Ambisonics version, which has some bugs but is still worth checking out.
For detailed information about the project, see the director’s (Regine Elbers) homepage (unfortunately only available in German).
Technical Production Background
The entire play was produced in 3rd-order Ambisonics (O3A). Dialogues were recorded with the Eigenmike® em64 in the recording studio, and background ambiences were captured on-site with the Schoeps ORTF-3D microphone. (It was a co-production with the German Broadcast Union, hence the high-end equipment.)
Editing and arranging were done in Reaper with plugins from DearVR, IEM, and Blue Ripple. The head tracker used during production was custom-made by Martin Rumori (sound artist and developer based in Graz), with whom I had collaborated on a similar project before.
I ended up with three export buses in Reaper:
- Stereo Bus: Containing both binaural and regular stereo content.
- O3A Bus: Primarily containing dialogues and accompanying Foley parts.
- Ambience Bus: Featuring the ambient layer, rendered to binaural stereo.
Structure in Echoes Creator
These output files were included in Echoes. I essentially created two layers on the map:
- Ambience Background Layer: Containing one-minute ambience loops that seamlessly crossfaded while walking.
- Scenic Layer: Including stereo files (in-head narrator, binaural recordings, and sound elements not requiring head tracking) and 16-channel O3A files for the scenic dialogues.
Notable Findings
- Sound Rendering Issues:
- The O3A renderer in Echoes causes significant frequency coloration. I tried compensating with an EQ on the O3A bus (see attached screenshot). A more precise filter curve would have required additional technical testing, but the result was acceptable. However, this made the mixing workflow inconvenient since I couldn’t hear the final result in my DAW.
- I only routed tracks that were essential to localize to the O3A bus, mainly dialogues, rendering the background ambience binaurally in Reaper.
- Reverb Artifacts:
- The renderer adds reverb to sound files, even regular stereo ones, which was particularly noticeable on clean in-head recordings like the narrator’s voice.
- Head Tracking and North Calibration:
- Stable north calibration is crucial when working site-specifically with an Ambisonics sphere. The system calibrates north when starting 3D playback, so it’s essential to face north with headphones on and the phone pointing north. However, drift still occurred during walks, which didn’t break immersion but is important to note.
- Publishing Considerations:
- Be aware of Echoes’ licensing system. The 3D versions of walks are only accessible to users with an “Extended Professional” membership in the app. Creators can unlock all qualities for their audience with an “Extra” membership.
- Ensure that Echoes has access to iPhone fitness data; otherwise, head tracking won’t work. Echoes should prompt for this, but in our case, it didn’t always do so.
- Playback Reliability:
- In both versions (binaural and Ambisonics), disabling the lock screen was necessary, as Echoes didn’t reliably trigger sounds when the screen was locked. This drained the battery but was the only solution.
- We enabled Guided Access on iPhones and used pouches to prevent the audience from accidentally using other phone functions.
- We provided iPhone SE 23 with iOS 18.1 and EarPods Max to the audience.
- File Management:
- Occasionally, some files were missing, a known issue already discussed in another thread.
Additional Insight
After some initial tests, I decided not to use the 3D sound elements provided by Echoes, as the spatial localization of virtual sound sources seemed too blurry and inaccurate for our needs—likely due to GPS and Ambisonics rendering limitations. I encountered similar issues with other audio-walk tools. I look forward to future technological advancements that could enhance precision and unlock even more exciting creative possibilities.
Discovered Bugs
- The hide functions of an echoe did not seem to work.
- In the Ambisonics Version some scenes (Echoes containing O3A Files) were repeatedly not triggered.
- One O3A File is always played back very quiet and without spatialization when triggered on site. Although it worked fine when testing in the app at home.
Wishes and Suggestions
- File Name Visibility:
- It would be helpful if the original file name appeared in the “File Size” menu. Since I often iterate on files and extend their names with render dates, seeing the original file name would improve project management.
- Max Volume
- At the moment the Volume adjustment in each sound object is greyed out. In fact it would be very convenient for detailed mixing, when working with several layers.
- Project Duplication:
- It would be great to duplicate walks in the creator’s backend to create backups before making significant changes.
Conclusion
Working with Echoes has been a super exciting experience. I was genuinely impressed by how intuitive and generally reliable the tool is. I’m excited to see the platform grow and evolve, unlocking even more creative possibilities in the future!
I hope these insights are helpful for anyone working with Echoes and Ambisonics!