Joined: 06 Jun 2007
This topic applies to Element versions 220.127.116.11 or later
Our current Element manual is found here: http://www.axiaaudio.com/manuals/files/Element_v2.0UsersManual_rev1.0_web.pdf This topic provides a bit more background on this very important (and confusing) subject.
Talkback and back-feeds are a bit complicated and are commonly misunderstood even in the analog world. This document assumes you know what talk-back is and what it is used for in the world of broadcast. Make sure you fully understand this topic before attempting to setup systems as described in this document. This document describes the "default" or normal case where the phone of codec source profile is configured with "Feed to source mode" is set to Auto(PGM1/PHONE)
The audio node output (destination) that feeds audio to the caller (phone back-feed) must be configured as “to source” and must use the same Axia channel designation as the caller source. Here is how it works if "Feed to source mode" is set to the default of AUTO. When the phone channel is “OFF”, the caller will receive a pre-fade, pre on/off mix-minus of anything assigned to PGM 4. When the phone channel is “ON”, the caller will receive a mix-minus of PGM 1.
Talkback to the caller is not really relevant since the operator can talk to the caller hands-free by simply assigning his mic to PGM 4 and leaving his mic OFF. It is, however, possible to use the talkback feature while the caller is on-air. Note that whenever the operator is performing a TB function, his mic is removed from PGM 1 regardless of the ON/OFF status of the operator’s mic or his PGM 1 assignment.
The codec now behaves almost exactly like a phone in terms of its back-feed. A codec will (in AUTO feed to source mode) receive a mix-minus of PGM 4 when the channel is “OFF” and a automatic mix-minus of PGM 1 when the codec channel is “ON”. You can optionally specify something other than PGM 1 as the back-feed in the Element codec source profile.
Tallback to a codec source will always be on the LEFT audio channel only. The right channel of the codec will always have the desired back-feed and will be uninterrupted by talkback. Be careful to use the left channel if you are connecting this back-feed to a mono TB input.
Studio Mic Sources
There are a couple of ways to set this up. The studio guest (talent is the Axia term) can be configured for a dedicated back-feed (using “to source”) or configured in a more generic manner by using the Talent HP feed.
1. Generic back-feed
This is a simple case where all studio headphones are driven from a single amplifier. Configure the destination feeding the HP amp as “Talent HP” and “from source”. This will use the mix engine source that is a generic HP feed. TB to these guests will be via the “talk to monitor 2” button only.
2. Dedicated back-feed
In this case, each studio guest will have a dedicated HP amplifier. Configure the destination feeding the HP amp as a “to source” using the same channel number as the studio mic. When you configure it this way, the studio talent will hear TB to Monitor 2 as above plus you can TB to him/her independently of other generic guests by using the TB button on his mic channel.
Note that there is now a HP level setting on the Element Show Profile/Channel Options that needs to be set to 0 dB for unity gain on dedicated back-feeds.
Note also that all Livewire codec backefeds are currently dual mono, not stereo. This may have implications when integrating with other Livewire-enabled devices. (Element 2.0.x and Engine 2.4.8w3 or earlier)