"EPP" in the Mixer refers to 'Equal Power Panning'.
for Soundscape REd, HDR1+, Mixtreme mixers.
- Many Stereo Digital Mixers & the standard Soundscape Mono Input Channel & Send Output (Mono->Stereo) panners work by maintaining the signal level to the pan side, whilst reducing the signal to the other side, and since there is now only 1 speaker playing where previously 2 speakers, the panned signal decreases in apparent level as it moves from centre to side in stereo speakers (where 'centre' is the result of acoustic addition between the speakers) - ...... A strongly panned signal also drops in level by -6dB when subsequently the stereo signal is made mono electrically.
For years professional mixing console makers have been introducing a gradual gain lift of approx. +3 to +4dB max as the pan is moved to one side of the stereo, whilst reducing the other side. Although this does not completely solve the drop in level of extreme panned signals when stereo is made mono electrically (now -3dB), the panning effect is an acceptable compromise and considered more realistic for stereo speakers in typical listening environments due to the way speakers couple to the room and each other .....
- In Soundscape mixer, making the selection for Channel & Send Output (EPP) (Mono->Stereo), the side signal gain is slowly increased as panned from centre to side, to a max of 3dB, whilst reducing the other side, giving a more realistic panorama. The EPP mode uses very slightly more DSP%.
Possibility of overload: Be aware in the EPP mode that when the Fader is at 0dB, at full pan to either side there is +3dB extra signal leaving the channel (but not registering on local meter, which is always showing pre-fader/pan signal), and so normally the fader must be reduced to at least -3dB if high level or normalized takes are being played. EPP Sends faders must be treated the same, except when selected 'post', where the maximum level is goverened by the main fader setting.
The above is true for Stereo Input Channel & Send Output (EPP) (Stereo->Stereo) channels.
Hint - Always mix to sub-group masters so you can monitor output levels - pull down the track faders or trim part volumes to avoid overloads. When using ANY mixer, always pull down the input channels if there is overload on the subgroup or master output because of A/. EPP panning B/. cumulative level increase due to addition of signals. i.e. Leave the Output Master at "0", and only use it for fade-outs...... that way you are guaranteed there are no overloads on the mixbus, and there is no compromise to the signal to noise ratio and distortion performance.
The Soundscape Mono->LRCS and Mono->LRCLsRs Channel panners are equal power by design, so in this case, when the Fader is at 0dB, at full pan there is unity gain, so there is no possibility of overload. However any inserted Output (EPP) (Mono->Stereo) Sends within these types of channels will still behave as outlined above.