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sorenb

Reason for 3rd party aircrafts phasing sound, FSX

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Hi there,Just want to help with my recent discovery regarding the strange phasing sound effect many people (including me) gets with 3rd party aircrafts in FSX.There has been a number of posts from frustrated simmers having this problem and now I think I found the reason:In my case I had this annoying problem with my Wilco Airbus Evolution 1 series. It showed out that in the 'sound' folder a number of wave files had identical twins with different names (two different .wav files contained exactly the same sound/waveform). From my knowledge from sound engineering and sound design in music production I know that having two sounds with identical waveforms played simultaneously but just a little offset / out of sync will indeed introduce a phasing/ flanging effect. And this is exactly what happens in FSX with these identical sounds.So what I did was, I loaded all the twin sounds into my wave editor and simply reversed them (made them backwards) so they no longer were identical with the other ones (can't hear the difference with a looped engine sounds anyway). Then I replaced the original sound files with the reversed ones. Now the phasing effect has completely disappeared.Hope this is useful for all the simmers having this problem./Soren

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Hi Soren:Excellent information ! :( As an example, if we look at the \Sound folder for the FSX default twin Baron at:[FSX install path]\SimObjects\Airplanes\beech_baron_58\sound\...we can see that a "different" version of the same *RPM*.WAV file is provided for the right and left engines.There are 2 copies of each such file designated with a "f" and "r" suffix in the file name, IIUC, to identify "Forward" and "Reverse" waveforms.Ex: "xbaron_rpm4_left-f.wav", "xbaron_rpm4_left-r.wav" and "xbaron_rpm4_right-f.wav", "xbaron_rpm4_right-r.wav"IMHO, we must also note that when a "full" range of engine RPM sounds are rendered in FS as aircraft throttle and/or airspeed velocity changes, multiple WAV files are played and processed with manipulation of 'perceived' pitch to achieve a smoother transition between the actual recorded RPMs of the source WAV files when played... for each engine. :Nerd:IIUC, this involves transitioning between multiple WAV files to render "steps" in the velocity range for engine sounds.Thus, one might assume that rendering neighboring "steps" in that velocity spectrum would also properly require WAV files to have alternating "Forward" and "Reverse" attributes in their waveforms, since 2 such neighboring sound files may be played simultaneously by FS for each engine RPM range "transition" (2 for the left side, 2 for the right side ... all at one time per 'RPM range transition'). Perhaps more sophisticated ways of creating aircraft sound sets might involve consideration of alternating "Forward" and "Reverse" attributes between neighboring steps in the (usually) 4 WAV files used for each engine RPM sound set "viewpoint": inside the cockpit, and outside the cockpit ? :( And of course, these may be further alternated at the same 'RPM steps' for each engine based on whether it is for the left side or right side of the aircraft, so the RPM step 4 WAV file used for the left engine has a "Forward" waveform, and the RPM step 4 WAV file used for the right engine has a "Reverse" waveform... as you described above. B) Thanks for pointing out this important aspect of how one might produce better sound sets for FS multi-engine aircraft... both with "newly recorded" 3rd party packages, and by "converting or correcting" copies of legacy FS sound sets which have not yet been configured with "Forward" and "Reverse" waveform attributes ! :( GaryGB

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Interesting thread. I have this problem with the Flight1 Mustang and it's pretty annoying. But I'm looking in the sound folder and I don't see duplicate engine sounds, unless I'm missing something.

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Interesting thread. I have this problem with the Flight1 Mustang and it's pretty annoying. But I'm looking in the sound folder and I don't see duplicate engine sounds, unless I'm missing something.
You should try to listen to each of the .wav files to find out if some of them are actually the same sounds. In my case a whole range of airbus sounds where called different names but contained identical sounds.The wilco airbus has a range of sounds: ban11, ban12, ban13 etc up til ban24. Each of these are identical to the sounds in bbn11, bbn12, bbn13 up til bbn24.So what I did was to load bbn11 to bbn24 into a wave editor and reverse them then replace the original bbn11 to bbn24 with the reversed versions. That stopped the phasing completely in the airbus.Now I can taxi, turn and bank without this happening anymore.Hope this made it clearer.Maybe this is not the reason for problem with all 3rd party aircrafts (I just kind of hoped so).I have the same problem with my FSX version of the Level D 767.Will look into that one as well to see if the cause is the same as in Wilcos airbus.

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Hi Soren:Excellent information ! :( As an example, if we look at the \Sound folder for the FSX default twin Baron at:[FSX install path]\SimObjects\Airplanes\beech_baron_58\sound\...we can see that a "different" version of the same *RPM*.WAV file is provided for the right and left engines.There are 2 copies of each such file designated with a "f" and "r" suffix in the file name, IIUC, to identify "Forward" and "Reverse" waveforms.Ex: "xbaron_rpm4_left-f.wav", "xbaron_rpm4_left-r.wav" and "xbaron_rpm4_right-f.wav", "xbaron_rpm4_right-r.wav"IMHO, we must also note that when a "full" range of engine RPM sounds are rendered in FS as aircraft throttle and/or airspeed velocity changes, multiple WAV files are played and processed with manipulation of 'perceived' pitch to achieve a smoother transition between the actual recorded RPMs of the source WAV files when played... for each engine. :Nerd:IIUC, this involves transitioning between multiple WAV files to render "steps" in the velocity range for engine sounds.Thus, one might assume that rendering neighboring "steps" in that velocity spectrum would also properly require WAV files to have alternating "Forward" and "Reverse" attributes in their waveforms, since 2 such neighboring sound files may be played simultaneously by FS for each engine RPM range "transition" (2 for the left side, 2 for the right side ... all at one time per 'RPM range transition'). Perhaps more sophisticated ways of creating aircraft sound sets might involve consideration of alternating "Forward" and "Reverse" attributes between neighboring steps in the (usually) 4 WAV files used for each engine RPM sound set "viewpoint": inside the cockpit, and outside the cockpit ? :( And of course, these may be further alternated at the same 'RPM steps' for each engine based on whether it is for the left side or right side of the aircraft, so the RPM step 4 WAV file used for the left engine has a "Forward" waveform, and the RPM step 4 WAV file used for the right engine has a "Reverse" waveform... as you described above. B) Thanks for pointing out this important aspect of how one might produce better sound sets for FS multi-engine aircraft... both with "newly recorded" 3rd party packages, and by "converting or correcting" copies of legacy FS sound sets which have not yet been configured with "Forward" and "Reverse" waveform attributes ! :( GaryGB
Hi Gary,Thanks for the details, I have never developed aircrafts in FS only scenery, had no idea so much is involved.Do you know why this was not a problem in FS9 ?Soren

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Thanks for the info. I have heard similar conclusions but your solution made a little more sense to me.I don't have problems with all 3rd party aircraft in FSX - only ones that were originally designed to FS9. Sounds created for FS9 don't work well in FSX.A lot of people claim that they have no problem older sound packs so it may be due to variances in OS, something else or it is possible that some people just don't notice it.The Xtreme Prototypes Lear, Airbus X and all of the FSX packs from TSS sound great on my system.Developers have to learn that they can't just port over those sound packs. They have to create all new sound packs for FSX.

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I have the same problem with my FSX version of the Level D 767.Will look into that one as well to see if the cause is the same as in Wilcos airbus.
That would be great if you could find a solution for that :(

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That would be great if you could find a solution for that :(
Yep and the cause is the same but in Level D 767 they do not have multiple .wav files with the same sound, instead they just point to the same .wav file in the pairs of engine soundsexample from their sound.cfg:===========================================// //// ENGINE MAIN SOUNDS //// //===========================================-------------------------------------------//LOW N1 HUM-------------------------------------------[JET_WHINE.1.00]filename=767_1flags=0viewpoint=1rparams=0.07,1.0,0.7,1.6vparams=0.1,0.0,0.20,8.0,0.35,20.0,0.50,0.0link=JET_WHINE.1.01[JET_WHINE.2.00]filename=767_1flags=0viewpoint=1rparams=0.07,1.0,0.7,1.6vparams=0.1,0.0,0.20,8.0,0.35,20.0,0.50,0.0link=JET_WHINE.2.01-------------------------------------------//INTERMEDIATE N1 WHINE-------------------------------------------[JET_WHINE.1.01]filename=767_2flags=0viewpoint=1rparams=0.40,0.60,1.00,1.1vparams=0.0,0.0,0.50,0.0,0.82,14.1,0.88,0.0link=JET_WHINE.1.02[JET_WHINE.2.01]filename=767_2flags=0viewpoint=1rparams=0.40,0.60,1.00,1.1vparams=0.0,0.0,0.50,0.0,0.82,14.1,0.88,0.0link=JET_WHINE.2.02...etc.I assume one is left engine and the other right engine.So what I did was to load each of the sounds into a wave editor and reverse the wave then save the new file as <filename>r.wavThen I changed my sound.cfg to this:===========================================// //// ENGINE MAIN SOUNDS //// //===========================================-------------------------------------------//LOW N1 HUM-------------------------------------------[JET_WHINE.1.00]filename=767_1flags=0viewpoint=1rparams=0.07,1.0,0.7,1.6vparams=0.1,0.0,0.20,8.0,0.35,20.0,0.50,0.0link=JET_WHINE.1.01[JET_WHINE.2.00]filename=767_1rflags=0viewpoint=1rparams=0.07,1.0,0.7,1.6vparams=0.1,0.0,0.20,8.0,0.35,20.0,0.50,0.0link=JET_WHINE.2.01-------------------------------------------//INTERMEDIATE N1 WHINE-------------------------------------------[JET_WHINE.1.01]filename=767_2flags=0viewpoint=1rparams=0.40,0.60,1.00,1.1vparams=0.0,0.0,0.50,0.0,0.82,14.1,0.88,0.0link=JET_WHINE.1.02[JET_WHINE.2.01]filename=767_2rflags=0viewpoint=1rparams=0.40,0.60,1.00,1.1vparams=0.0,0.0,0.50,0.0,0.82,14.1,0.88,0.0link=JET_WHINE.2.02...etcNow the left engine and the right engine sounds are no longer identical, therefore no phasing/flanger.Remember to do this for all internal sound pairs and external sound pairs if you also want to get rid of the effect in external view.Soren

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What do you need as a sound editor, and how do you do this?Interesting thread. Thanks, Br cue.

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What do you need as a sound editor, and how do you do this?Interesting thread. Thanks, Br cue.
Yes, fascinating topic I too would like know how to do this.

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I have not tried fixing things yet and I know very little about sound editing but I downloaded Audacity a while back when researching this annoying issue. I think you can make the changes with it. It is freeware.

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I'm not sure if this thread covers the same issue but the problem I have with FSX sounds is the Doppler like phase shift you get when in cockpit view and the aircraft changes heading. While the effect would be realistic if I was an external observer and the aircraft was changing direction relative to my position it is most unrealistic and very annoying when I am in the cockpit and of course the aircraft is not changing relative to my position. I first noticed this problem a couple of years ago with the LD 767 and raised the matter in the LD forum but got nowhere, no one seemed to understand what I was on about. I have since found that the problem afflicts many FSX aircraft and not just those ported from FS9. In fact using an FS9 sound file seemed to fix the problem in some cases.Bruceb

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As mentioned above, the unpleasant phasing or strange sound is present only when two or more waves are being played, and where there are either two engines on opposing sides with very similar wav files, or on a single engined aircraft when there are two waves overlapping at the rpm change point and the two wavs are not sufficiently different in character to avoid phasing.The reason for phasing is essentially two almost identical or exactly identical wav forms literally cancelling each other out due to the wav forms coinciding or crossing the boundary point between wav forms rising and falling in phase with each other.I've never understood why some sound "designers" don't understand this basic phenomenon and continue to apply the same wav shape for multiple engines which, if running at the same rpm, are bound to phase each other out. This would be like recording a synthesised instrument and panning it hard left, then overdubbing EXACTLY the same synthesiser playing exactly in time and pitch with the first recording and panning it right. The two stereo images would cancel each other out and result in a reduced or cancelled signal, or at best a badly phased and mono sound appearing in the centre of the stereo image.The solution is to make sure two separate engines are recorded, and their natural ambience and character would be sufficiently different to avoid phasing, even if they are at the same pitch, or better still in some cases, as described above, to copy the first wave then literally reverse it so the "end" of the first wav equals the beginning of the second, or vice versa. You can even do this with gear up and down sounds, flap sounds or almost any FSX sound which would benefit from a stereo image. This is very easy to do with even basic sound editing software.

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Just a question, couldn't this happen in real life anyway with multiple engine aircraft, after all the engines would all have the same sound but they may well be slightly out of phase causing the same effect.Just a thought.CheersMartin

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Hi again:As this thread might stimulate some increased interest among the FS Community for tinkering with aircraft sound sets, I thought a few other threads with some related info on the subject might be worth mentioning here. :( At the time I posted to the following threads, I did not address the issue of "Forward" versus "Reverse" attributes in *.WAV files, but I did mention the potentially significant consideration of methods to resample *.WAV files with less loss of audio quality.Additionally, I questioned whether FS "Stereo" versus "Mono" FS aircraft *.WAV file formats might be best to use with what, AFAIK, is now DirectX DirectSound 3D audio processing in FSX.Regarding FSX "positional" sound, I also shared some ideas for implementing FSX "sound cones"Some links to those threads follow... I'd be curious as to what insights others have on these ideas related to aircraft sound set creation / conversion, so please post back here ! :( http://forum.aerosoft.com/index.php?/topic/26346-ascdll-and-surround-51/page__p__164151#entry164151http://www.fsdeveloper.com/forum/showthread.php?t=15956Additionally, I suggested that one might be able to improve AI aircraft sounds with some experimentation: :( http://forum.simflight.com/topic/44824-fsx-sounds/BTW: Subsequent to the latter discussion, Alan Constable implemented some nicely enhanced FS AI sounds with his add-on here:http://secure.simmarket.com/a-constable-traffic-sounds-fsx-extreme-edition-2009.phtmlFYI: < I have no connection to that project, but was glad to see the results of his inquiries were successful >I hope these links might promote further exploration and discovery with both legacy and FSX aircraft sound sets. Angel.gifPS: Anyone able to make a sound utility even better than Aerosoft's "asc.dll"...for both freeware and payware aircraft ? Consider using Doug Dawson's 'gauge kits' for FS9 and FSX:http://library.avsim.net/esearch.php?CatID=fs2004gau&DLID=95460http://library.avsim.net/esearch.php?CatID=fsxgau&DLID=158634http://library.avsim.net/esearch.php?CatID=fsxgau&DLID=158611Happy Tinkering ! :smile:GaryGB

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Just a question, couldn't this happen in real life anyway with multiple engine aircraft, after all the engines would all have the same sound but they may well be slightly out of phase causing the same effect.Just a thought.CheersMartin
Hi Martin,It's true that real engines do slightly phase together, but because of slight differences in sound due to position, vibration, ambience and other factors, they do not phase quite so artificially as when similar or same wave files are repeated in FSX. As you will know, twin or multiple engines are "synced" either manually or automatically to eliminate annoying surges or oscillations due to them being nearly the same rpm. As with a piano note that is made up of two or more strings, or tuning one note relative to another, "beats" can be heard which represent the slight difference in frequency ratio.Even where real world engines are syncronised, there is an ever so slight difference in pitch and this sets up a very slow oscillation (the type you can hear at night when a twin engine flies overhead and you hear a slow frequency "drone" sound which is the small difference in rpm between the two engines).In an artifical simulated scenario the phasing effect is much more annoying because the wave sounds are so similar and are not affected by other influences like ambience, distance between the engines, or different sound qualities caused by variations in the stroke of the engine parts, exhaust sound and other factors.By the way, when using FSX's sound cone system to place wave files like engines and wind effects in a stereo field, all the wave files using the outside cone have to be in mono. If they are already stereo sounds FSX fails to place them in the desired position.Rob - RealAir

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Just a question, couldn't this happen in real life anyway with multiple engine aircraft, after all the engines would all have the same sound but they may well be slightly out of phase causing the same effect.Just a thought.CheersMartin
Indeed and sometimes you can actually hear the two engines phasing as they are not 100 pct in sync if you are close to them in the passenger cabin.However, from the inside it sounds quite different from the phasing sound you get in FSX (which sounds more like exterior fly by kind of thing).And in the cockpit it would probably hardly be noticable.So in my case I would rather be without it.Soren
Hi Martin,It's true that real engines do slightly phase together, but because of slight differences in sound due to position, vibration, ambience and other factors, they do not phase quite so artificially as when similar or same wave files are repeated in FSX. As you will know, twin or multiple engines are "synced" either manually or automatically to eliminate annoying surges or oscillations due to them being nearly the same rpm. As with a piano note that is made up of two or more strings, or tuning one note relative to another, "beats" can be heard which represent the slight difference in frequency ratio.Even where real world engines are syncronised, there is an ever so slight difference in pitch and this sets up a very slow oscillation (the type you can hear at night when a twin engine flies overhead and you hear a slow frequency "drone" sound which is the small difference in rpm between the two engines).In an artifical simulated scenario the phasing effect is much more annoying because the wave sounds are so similar and are not affected by other influences like ambience, distance between the engines, or different sound qualities caused by variations in the stroke of the engine parts, exhaust sound and other factors.By the way, when using FSX's sound cone system to place wave files like engines and wind effects in a stereo field, all the wave files using the outside cone have to be in mono. If they are already stereo sounds FSX fails to place them in the desired position.Rob - RealAir
Sorry Rob, I answered Martin before I saw your post ;-)Yes I agree.Soren

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Hi All:Just an update to add info about the MSDN ESP SDK docs for those adventurous enough to "tinker under the hood" with aircraft sound sets:http://msdn.microsoft.com/en-us/library/cc526952.aspxBTW: ESP SDK docs are nearly identical in content, but more clearly laid out and IMHO, better explained than... FSX SDK docs. :( < Ahem >... Nice to see a better "free alternative" for docs we PAID extra to get with FSX "Deluxe" and Acceleration or FSX "Gold" SDK packs ! :( PS: ANY legacy FS sound set can theoretically be updated for use with FSX by use of a sound (WAV) file editor.Ex: One can add the FSX "Sound Cone" info, make Stereo into right or left channel only, make Stereo into Mono etc.I look forward to seeing posting of more new and/or converted FS aircraft sound sets in the future... :wink:Hope this helps ! :( GaryGB

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Has anyone noticed that if you change just one throttle in a two engined aircraft (so as to put the engine sounds out of phase) that the sound will stay out of phase no matter what throttle setting you apply, even moving the throttle back to the exact same place so that engine speeds are identical (at idle for example) results in there being no phasing at all ever. It seems almost impossible to make them phase again, that is until you change the view from internal to external or vice versa, as soon as you change view the phasing is back instantly, if the engine speeds match of course. Give one of the throttles a tweak for a second or so the move it back again and the phasing is gone again until you switch view again.I've tried fixing the horrid phasing in the F1 Mustang that aircraft has got to have the most prominent phasing of any sound sets I've ever come across in FSX. I tried creating reversed files for the combustion and whine sounds and adding the new filenames into the sound.cfg but it didn't work, I just ended up with sounds working for the left hand engine only and all cone effects were completely gone too, moving the right throttle didn't illicit any change in any sound at all, all I did was create reversed files and name them differently i.e. added _r to the filenames and then adjusted the filenames in the sound.cfg accordingly.Does anyone know if the Wavs have to be mono when you have separate files for each engine in a two or more engined aircraft, or does it not matter and all Wavs can be in stereo?

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