Let's focus on the basic I/O configuration of the Hybrids:

In order to record two individual callers simultaneously, independent, dedicated telco lines are required. Each independent telco line connects to the telco line inputs of each hybrid. Also, we will be using the signal XLR inputs switched to 'line', along with the standard XLR outputs.

Our goals are to 'send' the studio mic channel out to each caller so that the host can be heard, provide communication between the participating callers, and feed the caller audio back to the console for monitoring and routing. This will provide the capability to record interviews using a specific recording device and/or DAW. Keep in mind that if the studio channel is not intended to be included in the interview session, the channel fader can be adjusted accordingly.

Aux Send Buses: An Explanation

In most cases, Aux Sends [and Returns in the following example] are used to 'tap' a portion of a channel signal, and send it out through some sort of parallel processor. The processed signal is then returned to the console via Aux Returns. When implementing a mix-minus with a single hybrid, a one directional routing path is all that is necessary in order to present the host audio to the input of the hybrid. Since the channel signal originates on the console, and it is available on the main outputs of the console for subsequent recording, there is no need to 'return' the host channel audio back to the console using the Aux. Returns.

Aux Send buses can also provide a one-directional routing path intended to feed the inputs of two hybrids on an alternate basis. Remember - we need to send the caller 1 audio to caller 2, and the caller 2 audio to caller 1. Lastly, we need to send the studio channel to both callers.

Let's review the Aux Send Connections and Settings:

Aux Send 1 Out on the console is routed to the input of Hybrid 2. Aux Send 2 Out on the console is routed to the input of Hybrid 1. Notice that the Aux Send 1 + 2 level pots for channel 1 [mic] on the console are set to 'tap' a portion of the signal. This allows both callers to hear the host.

Notice that the Aux Send 1 level pot for channel two is set to 'tap' a portion of the channel signal, and send it to the input of Hybrid 2. Notice the Aux Send 2 level pot for channel three is set to 'tap' a portion of the channel signal, and send it to the input of Hybrid 1.

Let's review the Hybrid Outputs

Our goal is to capture and record the callers on independent tracks. The output of Hybrid 1 is connected to the left input on channel two on the console, and the output of Hybrid 2 is connected to the right input of channel three on the console. The pan pots for each channel are panned hard left and hard right accordingly. This ultimately provides a two channel recording of the callers. They will be independent on a left/right basis.

I realize this seems a bit confusing. However, think about what is actually happening, and the specific path of the audio: the caller's can hear the host [if necessary], and they can also hear each other due to the alternate Aux Send bus routing. The entire conversation passes through the console, and is available on the main outs of the console for recording.

One final note - besides the availability of Aux Send level adjustments on specific channels, *most* consoles include master Sends as well. They control the level of an entire bus on a cumulative basis. For example, if you were tapping five channels on a console using Aux Bus 1, and each channel bus level was unique, the Master Aux Bus [Send] would maintain the level settings for each channel, and increase the level of the entire bus on a cumulative basis.

-ptfigg, ny.

08.11.2006

Copyright © 2006 P.Figgiani Msc All Rights Reserved