I really enjoyed the festival. It attracted high-quality composers from around the world. I especially enjoyed reconnecting with friends in New York!

Video by Macie Landon.

The work was performed at the Eyedrum Art and Music Gallery in Atlanta, Georgia at an event entitled “Forest in a City.”¹ I was specifically interested in this venue because of the unique sound playback system. There were eight wooden panels used as speaker objects spread throughout the performance space,² and the audience members could move freely through the speaker objects. The wooden panels were made by an Atlanta luthier named DJ Betsill from an 800-year-old “Sinker Cyprus” log found preserved on the Georgia coast.

The video above shows footage from the venue and is accompanied by a binaural, walk-about sound recording of a portion of Induction-Transduction from the event.³

¹ This was the 40^th anniversary of the conference and was a series of events around the country.
² Dayton Audio exciters were attached to the panels to vibrate them mechanically.
³ Special thanks to SEAMUS, Adam Mirza, and the new music ensemble, Bent Frequency, for hosting the event.

Install the Software

Download and install Reaper:

https://www.reaper.fm/download.php

The version I downloaded was:

reaper683_universal.dmg

Reaper is a stand-alone app that you place in your applications folder. They provide a fully-functional, 60-day trial.

Download and install the IEM Suite plugins:

https://plugins.iem.at/download/

The version I downloaded was:

IEMPluginSuite_v1.14.1.pkg

The installer puts all the plugins in the correct places:

Plug-ins here:

/Library/Audio/Plug-Ins/VST
/Library/Audio/Plug-Ins/LV2

Stand-alones here:

/Applications/IEM Plug-in Suite

Launch Reaper. You can see the plugins by going here:

View–>FX Browser–>[Search for IEM]

You should see all the IEM plug-ins (both VST and LV2).

Set up Reaper and the IEM Plug-ins

Create a new project in Reaper (if one hasn’t already been created).

Click on the icon with the “i” with a circle around it. Check the box and match the sample rate to your sound files.

Double-click in the mixer area to create a new track, one for Headphones, and one for Ambisonics.

Rename the tracks by double-clicking above the track number in the mixing area.

The Headphone track will be used for binaural monitoring and rendering. The Ambisonics track will used for all the sound sources and their spatial positioning.

Click on the Route button (above the word “Route” on the tracks in the mixer area).

On both the tracks, change “Track Channels” to match the number necessary for the order of Ambisonics you are using. This is obtained with the following formula: ((Order+1)^2).

For example, 7^th order is: ((7+1)^2)=64.

Note: It looks like Reaper does Track Channels in even numbers only; for an odd number, set it to the next higher number; for example, for 6^th order Ambisonics (i.e., [[6+1]^2]=49), set the Track Channels to 50, don’t use the last channel, and upon rendering, render out 49 channels.

On the Ambisonics track (on the dialog box that appears after pressing the Route button), uncheck “Master send channels from/to”, but leave it checked on the Headphone track.

Click and drag the Route button from the Ambisonics track to the Route button of the Headphones track.

In the dialog box that appears, click Audio–>Multichannel source–>Select “1–64” (or use the number you need for the Ambisonics order you are using).

At the top of each track, click on the bar that says FX.

Add the plugin “VST: Binaural Decoder” to the Headphones track.

Add the plugins “VST: Multi Encoder” and “VST: Energy Visualizer” to the Ambisonics track.

If you have a single audio file for your sound source(s), drag and position the file on the Ambisonics track in the arrange window. The audio file can be mono or multi-channel (a single sound file can be up to 64 channels; above that, it doesn’t return an error, but the waveforms of the track don’t appear in the region).

If you have multiple audio files for your sound source(s), create new tracks by double-clicking in an empty area under the track headers in the arrange window. Set the size of each track according to the Ambisonics order you are using (press the Route button on each track and adjust “Track Channels”). Select the new tracks and drag them onto the Ambisonic track (the tracks will appear indented, showing they are succesfully routed to the Ambisonic track). Drag and position your audio files on the new tracks as desired. The audio files can be mono or multi-channel.

Go back to the “VST: Multi Encoder” plug in, in the upper left corner, select the number that matches the channel count of your highest multi-channel sound file. For example, for a 64-channel audio file, change it to 64. This will add azimuth, elevation, gain, solo, and mute controls for each channel in the sound file(s).

Using the “VST: Multi Encoder” plug-in GUI, position each channel in the audio file(s) in the sound field as desired. Add automation, if needed.

Note: Double-click on the sphere GUI in the “VST: Multi Encoder” for a linear readout.

The 1^st input channel may clip (i.e., the omni channel or W channel), even when the original multi-channel render is rather low (i.e., -6dBFS to -12dBFS per channel). To prevent this, insert the plug-in “VST: OmniCompressor” in the Ambisonics track (before the plug-in “VST: Energy Visualizer”). Set the Threshold to -0.1dB, Ratio to inf:1, Attack to 0.0ms, and turn on Look Ahead. You can leave Knee and Makeup at 0.0dB. Adjust the Release to taste.

Render the Audio Files

The IEM plug-in suite uses the following as default:

Channel ordering: ACN (AmbiX)
Normalization: SN3D (AmbiX)

To render a track, click on the track in the mix area so it is highlighted.

Go to: File–>Render…

Source: Selected tracks (stems)
Channels: Stereo if rendering the Binaural track, or click and type in 64 (or the number for the Ambisonics order you are rendering) if rendering the Ambisonics track.

Note: Rendering large files (i.e., >4GB) requires a format like Wave64 or CAF.

See the following sources:

https://plugins.iem.at/docs/installation/
https://plugins.iem.at/docs/tutorial_basicrouting/
https://plugins.iem.at/docs/plugindescriptions/
https://plugins.iem.at/docs/compatibility/
https://www.youtube.com/watch?v=K5K4Q2Ze92o&t=183s (starting at about 3:03)
https://forums.cockos.com/showthread.php?t=176041
https://www.youtube.com/watch?v=_G-oEZrRtPw

See the following for up to tenth-order Ambisonics:

https://www.youtube.com/watch?v=e7PdqEfHTO0
https://www.ssa-plugins.com
https://leomccormack.github.io/sparta-site/

The Come, Follow Me (Art Companion) is produced by the Center for Latter-day Saint Arts.

From a spatial music perspective, there were exciting elements. We began the concert with a spatially separated men’s choir (placed in front and behind the audience). In the middle of the concert, we had a 20-piece trombone choir spread across the front of the hall. We ended the concert with my wife singing “The Wexford Carol” accompanied by electronic music composed by me (4-channels: left, right, left surround, right surround).

There were a variety of other ensembles that performed music from several genres (see the program below). All of them did a great job. My wife curated the performances. I ran the sound (assisted by Zack V. and Teesha A.).

The concert was well advertised, including radio spots, posters, and hand bills. We had a good audience turn out. We had a full house with additional people standing on the sides and in the back of the hall.

We also had a Christmas message given by Keith K. and there was a collection of nativity scenes on display in a nearby suite of rooms.

Overall, the music was fantastic, everything sounded great, the lighting and decorations were attractive, the transitions between acts were smooth, the refreshments were delicious, the Christmas message was uplifting, and everyone seemed happy and uplifted. All around it was a terrific concert. We were very blessed. Congratulations to the concert committee, the participants, and all those who helped!

The top photo is the view from the mixing desk, about mid-way back in the hall.

John D. Moeller, “Multichannel Works for Nonstationary Audiences,” Computer Music Journal, 42:3 (Fall, 2018), pp. 17-27. © 2018 Massachusetts Institute of Technology, published by the MIT Press. https://www.mitpressjournals.org/doi/abs/10.1162/comj_a_00470

See also: https://goo.gl/63zSo4

Download the “SDK Platform-Tools for Mac” from:

https://developer.android.com/studio/releases/platform-tools

Unzip the downloaded file by double-clicking on it.

Move the unzipped folder (i.e., “platform-tools”) to a useful location (e.g., I put it in a folder called “android-sdk-macosx” in a folder called “SDKs” in my home directory: ~/SDKs/android-sdk-macosx/platform-tools/).

Add “platform-tools” to your PATH variable by invoking the following in the Terminal (make sure to change the file path to reflect where you placed the folder “platform-tools” on your system):

echo 'export PATH=$PATH:~/SDKs/android-sdk-macosx/platform-tools/' >> ~/.bash_profile

Execute the following command to reload your bash profile (this applies the change to the PATH variable):

source ~/.bash_profile

Note: The PATH variable is the search path for commands. It is a list of directories, each separated by a colon, in which the shell looks for commands. To see what values are currently in your PATH variable, use the following:

echo $PATH

To see if everything is working, connect an Android device and enter the following in the Terminal:

adb devices

It should return something like this (if you have one Android device attached):

List of devices attached
200804114c28b9e	device

Please note, to use ADB with an Android device connected over USB, you will need to enable USB debugging. See the section “Enable adb debugging on your device” at the following site:

https://developer.android.com/studio/command-line/adb

See:
https://stackoverflow.com/questions/31374085/installing-adb-on-macos

Use libsndfile

How to install libsndfile.

Run the following command in the Terminal app (tips: make sure the sound file is in your current directory or else provide a path; put quotes around sound files with spaces):

sndfile-info soundfile.wav

Here is an example read-out:

File : soundfile.wav
Length : 34552556
RIFF : 34552548
WAVE
fmt  : 16
  Format        : 0x1 => WAVE_FORMAT_PCM
  Channels      : 1
  Sample Rate   : 48000
  Block Align   : 3
  Bit Width     : 24
  Bytes/sec     : 144000
data : 34552512
End

----------------------------------------
Sample Rate : 48000
Frames      : 11517504
Channels    : 1
Format      : 0x00010003
Sections    : 1
Seekable    : TRUE
Duration    : 00:03:59.948
Signal Max  : 3.6503e+06 (-7.23 dB)

Use SoX

How to install SoX.

Invoke the following in the Terminal (once again, make sure the sound file is in your current directory or else provide a path):

sox soundfile.wav -n stat

Here is an example read-out:

Samples read:          11517504
Length (seconds):    239.948000
Scaled by:         2147483647.0
Maximum amplitude:     0.435150
Minimum amplitude:    -0.415886
Midline amplitude:     0.009632
Mean    norm:          0.037648
Mean    amplitude:    -0.000052
RMS     amplitude:     0.056270
Maximum delta:         0.052995
Minimum delta:         0.000000
Mean    delta:         0.004222
RMS     delta:         0.006267
Rough   frequency:          850
Volume adjustment:        2.298

Or, you can use the following command (note the “s” on the end of the word stats):

sox soundfile.wav -n stats

Here is the example read-out:

DC offset  -0.000052
Min level  -0.415886
Max level   0.435150
Pk lev dB      -7.23
RMS lev dB    -24.99
RMS Pk dB     -15.07
RMS Tr dB   -3202.27
Crest factor    7.73
Flat factor     0.00
Pk count           2
Bit-depth      23/24
Num samples    11.5M
Length s     239.948
Scale max   1.000000
Window s       0.050

You can also use this command (note, you can replace ‐‐info with ‐‐i, if desired):

sox --info soundfile.wav

Here is an example read-out:

Input File     : '/Users/name/soundfile.wav'
Channels       : 1
Sample Rate    : 48000
Precision      : 24-bit
Duration       : 00:03:59.95 = 11517504 samples ~ 17996.1 CDDA sectors
File Size      : 34.6M
Bit Rate       : 1.15M
Sample Encoding: 24-bit Signed Integer PCM

Using QuickTime

Apple’s QuickTime Player also provides useful info.

Open the file with the QuickTime Player, then go to Window–>Show Movie Inspector (or cmd-i).

Here is an example read-out:

Inspector
soundfile.wav
Source: /Users/name/soundfile.wav
Format: Linear PCM, 24 bit little-endian signed integer, 1 channels, 48000 Hz
Data Size: 34.6 MB