Sound has come a long way in model railroading and there is some room for improvement. But will it be possible to some day imitate the Doppler Effect with horns and whistles on model trains?
Ever notice that when you hear a fast moving train on the prototype, that even if you can not see the train, you can tell how fast it is moving by the sound of the horn or whistle? At high speeds the horn or whistle can sound rather frantic. For some of us, especially in the days of fast passenger trains (over the normal 79 mph on Amtrak) this was an important part of the sights and sounds of railroading. However, on models, at least to me, the horns and whistles sound like the train is always moving at 20 mph.
I suppose it has to do with the Doppler Effect in that sound waves are higher in frequency as they get closer to you and recede as they get away. And with a lot of speed the disparity can be noticed more.
With model trains, even though our horns and whistles come from sound decoders on board the locomotives, I suppose the scale and distance don't provide enough doppler to make it noticeable. I wonder if the sound decoder increasing the frequency of the sound at higher speeds would help?
Doppler is a function of speed. It is not scalable. To get around this, many sound decoders have a mappable function key to provide doppler on the horn when passing. You simply press the associated key and the decoder does the work.
Springfield PA
Thanks. Are there any video links on the Net where I can hear that function?
QSI sound decoders have had a "doppler effect" since the first BLI Hudson came out about 10 years ago. It's essentially a simulation but it's really pretty good. When blowing the horn / whistle, you can either hit another function button (forget which one now) or quickly release and hit the F2 button again and it drops the sound of the horn / whistle in pitch. After you stop pressing down F2 it resets so the whistle or horn is "normal" again. If you time the change just right at say a grade crossing it's pretty realistic.
A friend of mine has QSI locomotive E-units that he let me run on a club layout. I enjoyed using the Doppler feature. As I blow the horn, I would trigger the doppler (I think it was the F6 key on the NCE controller) just before the train would pass by in front of me. That's a very nice effect!
One other feature that I do appreciate and hope that all sound decoders will have is "Reverb". I grew up in NY and Florida and always lived near a major mainline. The sounds of horns reverbrating off of buildings was something I always enjoyed.
Check out this vid clip of prototypes horns. A nice symphony of horn doppler and reverb!
http://www.youtube.com/watch?v=rDLrWOml5fo&feature=BFa&list=PLA038F08B8C110F55&index=28
"I like my Pullman Standards & Budds in Stainless Steel flavors, thank you!"
The revrb or "echo" effect is great and it is present on my BLI Paragon II diesel models of the GE AC6000. Makes everything else sound flat and boring including MTH. Good grief...are we ever satisfied?
If your railroad only has one whistle post, and you always stand at the exact spot where the pitch shifts, Doppler sound would be wonderful.
If you have two grade crossings, where do you stand to hear the same Doppler sound from the same whistle twice? At the first? The second? Somewhere in between?
Sorry, folks. This is just another instance where the realities of physics catch up with our dream world. I don't think I'd have much fun with a model railroad that consists of only a single grade crossing.
Chuck (Modeling Central Japan in September, 1964 - with silent locomotives)
That doesn;t make much sense at all. The doppler sound is not canned, nor is it fixed in duration, nor is it even automatic. So you triggeror it don't trigger it depending on where the viewer is standing at a given grade crossing, and you can run it longer when there is a longer clear open space vs a crossing where the train quickly disappears behind obstacles that owuld mute the sound. ANd on many decoders now, if you are using NCE or Digitrax to control them, have playable whistles where you cnan alter the sound dynamically. No it's not perfect but it's better than a fixed pre-recorded sound that you can;t change.
Real locomotives shake the ground when the pass, so you can feel them even if you plug your ears and can't hear them. Heck I'm 4 blocks from the tracks and I sometimes feel them passing by. My models don;t have the mass to do that - so because I can;t perfectly replicate a real train due to limitations in the laws of physics, I guess I shouldn;t even run anything and just model static scenes.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
When I show people the layout it's the Doppler effect that really makes them shake their heads, and comment that they had no idea how far model trains have come.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
wabash2800 Thanks. Are there any video links on the Net where I can hear that function?
In video number 2 in this link they use the dopplere feature.
HOATLASDash8 40CWNSandDopplerefect
Easier to share it like this:
watch?v=iLn0mHEnpNs&feature=playerembedded
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That video sound was awesome! Now tell me that was the doppler effect in model form and not a recorded prototype train. The sound did cut off fast at the end of the clip. That's what makes me a little suspicious.
Could have been. But if you listen to the click clack of the wheels they definitely sound like model and not the clunk sound that prototypes make.
The NCE ProCab throttles have supported doppler effect in decoders with that capability for a few years already.
That's the playable whistle, not the doppler. Digitrax had the pressure sensor in the DT400 throttles from the start, even though at the time no decoder supproted itWonder what little birdies were whispering in AJ's ear at the time. They just never told anyone else. Once decoders shipped that could use it, then they told you that it's been there int he throttle all along. ANd NCE came out with a firmware update that allowed it to work on a ProCab throttle.
If it's the playable whistle the poster of the video plays it very well.
The NCE procab also does the playable whistle with the throttle wheel.
here you go
qsi doppler
timed for passing me instead of camera, D'oh!
http://www.youtube.com/watch?v=nDuicy5Rgss
Yep, that's a sweet sounding doppler effect! Definitely QSI with what sounds like the Leslie S3 horn. I'm looking forward to QSI's new "Titan" which is supposed to have even clearer, more dynamic sound quality.
river_eagle here you go qsi doppler timed for passing me instead of camera, D'oh! http://www.youtube.com/watch?v=nDuicy5Rgss