Look at pink noise & note the curve, that’s how the human ear works, the top end tails off.
Look at white noise & that’s all freq present at the same amplitude. You don’t want to replicate this as it’ll sound really harsh & b’cos of what I said about pink.
So when you’re playing a track thru the top should tail gently off. Play some commercial tracks thru, you’ll see.
Playing individual tracks thru will often show lots of sub activity, 25-60Hz or so but your studio monitors won’t go that low so you won’t hear it!
Unless you want the track in question to provide lots of sub it’s best to hi pass filter it out so when you go live it isn’t shaking the room to pieces!
Also, if you just send L & R from the OT to the PA & the in house engineer hears it, he’ll just high pass everything & your intended sub will be lost!