SeaBass80 Posted April 11, 2022 Share Posted April 11, 2022 Hi, I always thought that speed of sound was modeled more or less correctly in DCS. When watching videos of F-16 strafing as filmed from the ground, it is noticeable that the bullets fly past the observer before the gun sound can be heard. Not too surprising. I just tested this out in DCS and to my surprise found that the sound arrives way too early. My setup: F-16 flying 432kn (222 m/s) and firing SAPHEI (PGU-28A?) at 6000ft (1830m) slant range. The bullets have a flight time of 2.4s, a little faster than public data available from the manufacturer webpage. (graphics modified from here to include speed of sound as well as measured and expected time of flight for bullets) The faster flight time might be entirely correct as the gun is moving at 222m/s in addition to firing ~1000m/s bullets. Very cool to see the good match. What is suprising though is that if you stand on the ground near the target, you can hear the gun sound even before the bullets impact the ground. It should actually arrive about three seconds later. Track and Tacview attached for reference. F16-guns-bullet speed.trk Tacview-20220411-223120-DCS-F16-guns-bullet speed.trk.zip.acmi Link to comment Share on other sites More sharing options...
Solution toutenglisse Posted April 13, 2022 Solution Share Posted April 13, 2022 I hear no gun sound playing your track. What you call gun sound, is in fact ground impacts sound (another bug imo, described just below). When I reproduce the same scene I can hear the gun sound just after the impacts. But there is another issue in both your track and my own test : there are 2 impacts sounds : ground impacts (just before visual impacts) and target impacts (same time than visuals). On 4/11/2022 at 10:51 PM, SeaBass80 said: ...What is suprising though is that if you stand on the ground near the target, you can hear the gun sound even before the bullets impact the ground... Link to comment Share on other sites More sharing options...
SeaBass80 Posted April 13, 2022 Author Share Posted April 13, 2022 (edited) On closer inspection, I might have been misled. The sound i took for the gun sound is actually the supersonic bullet noise. The actual gun sound is much more delayed (so very likely entirely correct). The reason I apparently got miseld is that at least the F-16 gun sound fades away with distance from the aircraft nicely up to some distance, and then more or less suddenly vanishes once a certain not too large distance is reached. From the distance in front of the aircraft that I tried, it just cannot be heard at all, not even faintly. I guess this is a little disappointing but only a minor issue - likely the cutoff is there to keep performance up. Consider this issue "solved". And applause to the ED team for the rather cool implementation. The doppler shift is taken into account correctly. If you listen to the gun from a stationary observer, the gun sound gets doppler shifted correctly. If you fly in front of the aircraft, you hear the gun sound at normal pitch. The bullets sound more or less the same every time, as they travel at well over supersonic speeds even for moving observers. Really great stuff. toutenglisse: only saw your posting after writing this - thanks for taking a look! I guess though the remaining issues are only minor and there are more important real "bugs" for the team to go through. Will mark this as solved. Edited April 13, 2022 by SeaBass80 1 1 Link to comment Share on other sites More sharing options...
toutenglisse Posted April 13, 2022 Share Posted April 13, 2022 (edited) 27 minutes ago, SeaBass80 said: ...The sound i took for the gun sound is actually the supersonic bullet noise... Yes I looked closer too and I think you are right. The sound I called "ground impacts" is in fact supersonic bullets shockwave. Placing the view point at right places makes it obvious. Edit : And I agree with you the sounds in DCS are of a very high quality and are one of many points that dramatically improved with years. Edited April 13, 2022 by toutenglisse Link to comment Share on other sites More sharing options...
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