With all these designes, the long pipe inside the tank is not needed, this is the minimal that is required, the overlfow will not faill provided that air doesn't get into section D, the output A will set the water level of your tank, input B must be lower than the output A, the curve at C must also be below the water line.
it doesn't matter if the input is curved up it will still work however this will cause the vortex to form that makes the noise, the air going in could cause the syphon to fail, and so you will need to extend the pipe inside the tank.
I see no reason why you need to have the intake facing up, other than to take scum off the surface, if this is a must then use the idea Locutus shows, but same goes with the length, It doesn'thave to go all the way to the bottom of your tank.
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