Csantucci, on 26 September 2021 - 12:38 PM, said:
Yes, that's a change that has been introduced. It has been stated that mechanical compressors run continuously when the engine is on.
They do and they don't. I think there's a fundamental misunderstanding here in both the way mechanical compressors actually work and the purpose of the sound triggers here. It's much more complex than "the compressor always runs" and the sound triggers reflect the more complex reality and are much more appropriate for the simulation.
Prime mover driven mechanical compressors are always "running" in the sense that the parts are always moving, but are in actuality not always "running" because they don't always compress air. There is a major difference in the sound between these two states. In this case, "on" simulates a condition where the compressor is compressing and "off" simulates when it is not (see:
http://www.rr-fallen...l/f40sm-s05.pdf for more details on how this works on EMD locomotives). This allowed us to simulate the very audible difference. As it currently stands, it now sounds like it's always running and the blow-off does not operate as it should (when the system stops charging). This is completely inaccurate. So one of four things needs to be done:
1. We need a new set of triggers to reflect the "pumping or not pumping" state and every SMS file ever made for any locomotive needs to be updated (as you can imagine, this would be a prolonged undertaking)
2. The current triggers need to be adapted to reflect the "pumping/not pumping" state rather than the state of the compressor "running" or not
3. Acknowledge that the way the sim was set up previously more accurately depicts the output of the system rather than whether or not the parts are mechanically moving, which is relevant to real life if you are a maintenance tech who needs to lubricate the compressor and keep it working but not relevant in the simulator where the only purpose of the compressor being "on" or "off" was to determine if the brake pipe should be receiving air (which the sim already knows) or whether the sound of the system actually delivering air should be playing (which is now broken).
4. Sound developers need to delete all compressor streams because the sound should not always be playing. This would be a major step backwards in realism.
Options 2 and 3 are functionally interchangeable. Either would be fine.
TL;DR: whether the compressor parts are moving or not is irrelevant to the sound simulation. All that matters is whether the compressor is pumping air because that's what determines the sound that it makes. We used to be able to simulate that correctly. Now we can't.