[roeter]

OR has the ability to switch diesel engines off and back on again.
However, very few engines have proper sound setup for this feature because these soundfiles were created for MSTS which did not have this ability.
The sound of diesel engines is regulated by 'Variable2'. This variable has a value between 0 and 1, based on the relative value of the RPM in relation to RPMmin :

               RPM - RPMmin
Variable2 = ----------------
             RPMmax - RPMmin

The settings based on Variable2 are therefor also related to RPMmin, and the sound which is played when Variable2=0 is therefor the sound related to the engine running on RPMmin. Switching off the engine will not switch off the engine sound.

Proposal is to introduce an additional variable, 'Variable4', which has similar behaviour as 'Variable2' but is related to zero :

             RPM
Variable4 = ------
            RPMmax

This would allow proper rundown of the engine sound when the engine is switched off.

The existing sound pattern can be maintained by converting 'Variable2' to 'Variable4' :

             (RPMmax - RPMmin) * Variable2 + RPMmin
Variable4 = ---------------------------------------
                         RPMmax

Using Variable4, switching off the engine will also switch off the sound.

Examples of frequency and volume curves as set up for Variable2 and Variable4:

				FrequencyCurve(
					Variable2Controlled
					CurvePoints ( 5
						0.000		0000
						0.005       9000
						0.010       11225
						0.020		15500
					      1.000       18000
						)
					Granularity ( 100 )
				)
				VolumeCurve(
					Variable2Controlled
					CurvePoints ( 5
						 0.000		1.0
						 0.005		0.1
						 0.010            0.1
						 0.020            1.0
						 1.000		1.0
					)
					Granularity ( 0.10 )
				)				

--------------------------------------------------------------------------------

				FrequencyCurve(
					Variable4Controlled
					CurvePoints ( 5
						0.000		0001
						0.320       9000
						0.626       11225
						0.900		15500
					      1.000       18000
						)
					Granularity ( 100 )
				)
				VolumeCurve(
					Variable4Controlled
					CurvePoints ( 5
						 0.000		1.0
						 0.320		0.1
						 0.626            0.1
						 0.900            1.0
						 1.000		1.0
					)
					Granularity ( 0.10 )
				)				

I would have liked to play an example of the sound using the above parameters but, alas, the system will not let me upload either mp3 or wav files. Sorry.

Regards,
Rob Roeterdink

[Hamza97]

Great Idea...... :sign_rockon: I fully support this Idea.., Even I am facing same problems with sounds for my diesel locos. I have to use a complex setup to manage startup & shutdown sounds and even then sounds don't turn off properly sometimes.

However, a slightly different way to above can be implemented such whenever the engine ON/OFF sound trigger is activated.., OpenRails automatically stops playing any sound that uses Variable2 feature. That way no modifications would have to be made for existing rolling stocks...

[ErickC]

I just put the startup and shutdown in my idle clip with a startlooprelease/releaselooprelease command, but this could be useful, too.

"Ammeter load" would be another useful variable. It would make traction motor and exhaust sounds a lot easier.

[Hamza97]

Quote

I just put the startup and shutdown in my idle clip with a startlooprelease/releaselooprelease

Whole startup, idling & shutdown in one single .wav file with idling sound loooping... Like that...?? Does this work when for example you shutdown the locomotive, save the game & resume later..??

[ErickC]

I have no idea. I never really save. The 16-567 is public domain at train-sim.com, though, so have at it. It's subject to the view change bug, though, just like horns. That's one limitation. In practice, it really hasn't been much of an issue, and I actually doubt most users even know there that I included startup and shutdown sounds (although you hear the engine start when the sim loads).

[Coolhand101]

Hamza97, on 09 February 2019 - 09:15 PM, said:

Whole startup, idling & shutdown in one single .wav file with idling sound loooping... Like that...?? Does this work when for example you shutdown the locomotive, save the game & resume later..??

If you shutdown the engine then pan out far enough and pan back or quit and resume after a save, the engine sound is playing even if the engine is switched off. If the engine has internal and external sounds, there is a severe delay or looping between the two. I believe I did write a bug report about external and internal sounds out of sync when using the variable streams.

On another note, does this mean that the diesel engine could be off by default and on if the engine is in motion?

Thanks