The last time I wrote about the mix technique, I took you through the very basics of how I approached that movie and how Dolby Atmos works and what happens in it. This time, since all of that is clear, I decided to go with one idea at a time on the blog. I won’t be writing about the movie or story, since as always, that is under wraps until the movie is released.

Ping Pong Delay Technique

This idea is not new and was inspired from the way the stereo ping-pong delay is created. The regular way before we had plugins, was like this:

  1. Send from the channel via a bus to a mono aux Panned to Left. On this, insert a delay plugin with the feedback set to 0 and mix to full wet.
  2. From this Left, send a signal at 0 dB to another aux panned to the right, with the same delay inserted and feedback set to 0 and mix to full wet.
  3. From the Right Aux, send a signal back to the Left, with level at 0.

The way this works is when the signal hits the left channel, it is sent to the left after the delay time set and at the same time sent to the right. The right will induce its delay and send it to the right channel and the left. The left then induces the delay and the cycle will continue indefinitely until the signal is dropped by even .5 dB. This is how it looks in the stereo world.


Stereo Ping Pong. Note all sends are 0 and the plugins have 0% Feedback.

Surround Infinite Delay

What I did next was to adapt this for the surround format. In this case, I sent from the main channel to the Left, Left to Center, Center to Right, Right to Right Surround, Right Surround to Right Rear Surround, Right Rear to Left Rear, Left Rear to Left Surround, Left Surround to Left. This gives me a delay that will circle clockwise in the mix room by a single send, for a very long time or until the signal drops. Now, here is where I advanced this to the next step.

Each send was randomised differently. So, instead of Left to center, it would be Left to right or Right surround. In this way, I had 10 different send combinations (on a, b, c, d, e etc.) What this allowed me to have was a complete control on different pans based on which I unmute in that given time. So, to achieve this, I grouped all the auxes and had the send mutes also part of the group.

Surround PingPong

Surround PingPong with various movements

In the above setup, the group parameters can be seen. The first set of inserts is clock wise, the second is anti-clockwise, the third is an X-Y banding etc. The beauty in this method are:

  1. I can change the rotation by simply changing the send mutes.
  2. I can send to any channel apart from Left and have the movement begin from a different channel. Ex, if I send to Right, the pan movement will begin from the Right Aux.
  3. I can add a low pass filter after each delay and create a progressively filtered delay for this.
  4. I can change the feedback and have any channel feedback for a longer time thereby creating a delay shadow. (You need to be careful with this as it can lead to an increase in volume)
  5. I can have a master set up for the Aux returns and have Spanner on it and rotate it even further!!

As you see, the opportunities are endless with just 7 auxes. You can also increase this to an infinite number of auxes and have Objects set up for this to give you a truly amazing delay combination.

So, until next time, enjoy and as always, share if you find it useful!