T4S/T8S Stereo and Mono with the headphone jack
The T4S is confusing to use and almost as much so as this Bose community is; navigating it is unintuitive at best but still appreciated for being a thing.
I want to state something to those who will end up spending too much time on the subject of “Stereo” or “Stereo Summing to mono output”. Here are a few facts:
1. The T4S headphone output is always in stereo NO MATTER WHAT YOU DO TO ANY KNOBS OR BUTTONS. PERIOD.
2. Using an in-ear monitoring setup in a true stereo scenario with the T4S is a complete impossibility if you are using one speaker as an output. Period.
3. If you want to have the ability to have a stereo monitor mix meaning a different signal in your left in-ear bud than your right in-ear bud, you have to be using two front-of-house speakers. Why? Read on.
The Bose T4S uses the Right main digital output to get power FROM the LII base unit and at the same time sends ALL input channels, and I mean all of them, to this RIGHT output back to the base unit. If ANY channel is panned hard left, you will not hear it in the LII speaker.
To listen in true stereo, you need two speakers and each one needs to receive its own input that is different than the other speakers’ input. The T4S can send a different outputs to its the left and right outputs but if you have only one LII, you have to settle with only hearing the right side in this example. This means you have to make sure all T4S channels’ pan settings are at least 12 o’clock center or panned to the right fully or to some degree.
Here is where it gets really weird though; the headphone output disregards what pan settings you choose and it supposedly broadcasts in stereo but not really because when you listen back on an in-ear monitors that are set up for a stereo output, you hear the T4S’s left output in the right ear bud and vice-versa.
This is totally weird and I’m sure there is a logical reason but I’m going back to a simpler mixer with outboard effects so I can easily send a stereo output to one speaker and still monitor in stereo. No disrespect to Bose T4S. I’ve been using Bose products for a decade and have made a lot of money doing so but now that I have had to incorporate in ear monitoring, I’ve learned using a Bose T4S is not the way to go if you are using only one speaker for FOH.