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Mission Statement 

The purpose of FLAPS-2-APPROACH is two-fold:  To document the construction of a Boeing 737 flight simulator, and to act as a platform to share aviation-related articles pertaining to the Boeing 737; thereby, providing a source of inspiration and reference to like-minded individuals.

I am not a professional journalist.  Writing for a cross section of readers from differing cultures and languages with varying degrees of technical ability, can at times be challenging. I hope there are not too many spelling and grammatical mistakes.


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I use the words 'modules & panels' and 'CDU & FMC' interchangeably.  The definition of the acronym 'OEM' is Original Equipment Manufacturer (aka real aicraft part).


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Journal Archive (Newest First)

Entries in Sound (4)


Sounds Reworked - Flight Sim Set Volume (FSSV) - Review

Immersion is a perception of being physically present in a non-physical world.  The perception is created by surrounding the user of the simulator in images, sound or other stimuli that provide an engrossing total environment.  When something does not replicate its real world counterpart, the illusion and immersion effect is degraded.

LEFT:  Engine sounds will be at their highest at takeoff.

Engine Sound Output

The sound output generated by a jet aircraft as heard from the flight deck is markedly different when the aircraft is at altitude.  This is because of differences in air density, temperature, the speed of the aircraft, drag, and thrust settings.  The noise emitted from the engines will always be highest at takeoff when full thrust is applied.  At this time, the noise generated from wind blowing over the airframe will be at its lowest.  At some stage, these variables will change and wind noise will dominate over engine noise.

As an aircraft gathers speed and increases altitude, engine sound levels lower and wind levels, caused by drag, increase.  Furthermore, certain sounds are barely audible from the flight deck on the ground let alone in the air; sounds such the movement of flaps and the extension of flight spoilers (speedbrake).

Being a virtual flyer, the sound levels heard and the ratio between wind and engine sound at altitude is subjective, however, a visit to a flight deck on a real jet liner will enlighten you to the fact that that Flight Simulator’s constant-level sound output is far from realistic.

Add On Programs

Two programs which strive to counter this shortcoming (using different variables) are Accu-Feel by A2A Simulations and FS Set Volume (FSSV).  This article will discuss the attributes of FSSV (Sounds Reworked).

Flight Sim Set Volume (FSSV)

FSSV is a very basic program that reads customized variables to alter the volume of sound generated from Flight Simulator.  The program is standalone and can be copied into any folder on your computer, however, does require FSUIPC to connect with Flight Simulator.  Wide FS enables FSSV to be installed on a client computer and run across a network.  

The following variables can be customised:

(i)     Maximum volume
(ii)    Minimum volume
(iii)   Upper mach threshold
(iv)   Lower mach threshold
(v)    Engine volume ratio

Each of the variables will alter to varying degrees the Mach, engine %N1, rounded engine speed and volume percentage.  

For the program to have effect it must be opened either prior to or after the flight simulator session is opened. 

LEFT:  FSSV pop-up screen showing customised variables (default) that can be set and current reads-outs for the simulator session (click to enlarge).

It’s an easy fix to automate the opening of the program to coincide with Flight Simulator opening by including the program .exe in a batch file

A pop-up window, which opens automatically when the program is started, will display the variables selected and the outputs of each variables.  If the window is kept open, the variables can be observed ‘on the fly’ as the simulation session progresses.  Once you are pleased with the effects of the various settings, a save menu allows the settings to be saved to an .ini file.  The pop-up window can then be set to be minimized when you start a flight simulator session.  

How FSSV Works

The program reads the sound output from the computers primary sound device and alters the various sound outputs based upon customized variables.  The program then lowers the master volume at the appropriate time to match the variables selected.  FSSV will only alter the sound output on the computer that the program is installed.  Therefore, if FSSV is installed to the same computer as Flight Simulator (server computer) then the sound for that computer will only be affected.

Possible Issue (depends on set-up)

An issue may develop if FSSV is installed on a client computer and run across a network via Wide FS, then the program will not only affect the sound output from the server computer, but it also will affect the sound output from the client computer.  

A workaround to rectify this is to split the sound that comes from the sever computer with a y-adapter and connect it to the line-in of another computer, or use a third computer (if one is spare).

In my opinion, it’s simpler to install and run the program via a batch file on the server computer that flight simulator is installed.  The program is small and any drop in performance or frame rates is insignificant.


The program, although basic, is very easy to configure and use - a little trial and error should enable the aircraft sounds to play with a higher degree of realism.  However, the level that you alter the variables to is subjective; it depends on your perception to the level of sound heard on a flight deck – each virtual flyer will his or her own perception to what is correct. 

The program functions with FSX and P3D flawlessly. 

Finally, If you are unhappy with the result, it’s only a matter of removing/deleting the folder you installed the program to, or close the program during your simulator session to return the sound levels to what they previously were.  FS Set Volume can be downloaded at no charge at http://forum.simflight.com/topic/81553-fs-set-volume/.  


The below video is courtesy of the FSSV website.


Using PMDG 737-800 NGX Sound In The Default 737-800

I have received a few e-mails from individuals asking how to replace the default sound with the sound from the PMDG 737-800 NGX.  This is a relatively easy task and the improvement in audio quality and experience over the default B737 sound is second to none. 

Before continuing, I should state that PMDG have designed their NGX audio package to only be used with the PMDG flight model.  As such sounds that PMDG have mapped to specific actions within their flight model will not work outside the PMDG flight model.  I'm sure there is a way to strip the actual "specialist" sounds, but the time required outstrips the enjoyment.  This said, the basic engine sounds and environmental sounds are easily separated for use in other flight models, such as the default 737 and ProSim JetStream738 flight model.

In the examples below, my main FSX folder is located in a directory on C:/ drive and is named FS10.  You may have a different directory location and name for FSX.

Let's Begin....

When you install the PMDG 737NGX, the program copies audio to the following folders:

  1. FS10/simobjects/airplanes/PMDG 800 NGX/sound    (main engine sounds & some envirionmental sounds)
  2. FS10/sound/PMDG 737-800NGX/sound......   (specialist sounds such as gear lever movements, switches, call outs, etc)

The default B737-800 model’s audio is located in the default 737/800 folder (FS10/simobjects/aircraft/737-800/sound)

Make a copy of the sound folder and store to desktop in case of an issue.  Then, delete the sound files in the folder so you can start afresh

Two Methods - Back-up, Copy & Paste or Alias

There are two methods to access or link to the actual PMDG sound files.  You can either copy all the sounds (from the PMDG 737-800NGX/sound folder) and paste them into the default 737-800 sound folder – OR – alias the sounds.  

If you decide to alias the sound, you do NOT need to copy the files.

Either way you MUST have a sound.cfg file in your audio folder.  If you alias the sound.cfg, the content of the sound.cfg file located in the sound folder should look like this:


If you have issues opening the sound.cfg file, use notepad as your editor.

If you decide to actually copy the files, then ensure the sound.cfg is also copied to your default sound folder.

Personally, I prefer the alias method......

The above process will allow you to play and hear the NGX engine package when flying the default B737 flight model (basic FSX B737-800).  You can also use the same methodology to replace the default sounds with the with the ProSim JetStream 738 fight model and with the FS9 version of the PMDG 737-800.

Following On - Replacing Audio

Following on the theme of the last two journal posts, you may wish to add additional sounds to the NGX audio package, for example, the TSS sounds Gear Up and Gear Down sounds.  This is easy to do.

Copy the TSS sound to the SAME folder as the PMDG sounds (if you did the alias method this will be the PMDG folder).  Now, open the sound.cfg file.  Search until you find the Gear Up and Gear Down entries.    Now, you have to modify the file name in the sound.cfg file so it matches the TSS.wav file you just copied into the audio folder.  In this example, the pertinent lines that need altering are in bold and include the actual name of the action (gear up) and the file name for the action that you wish the program to play (TSS gearup).  

[gear up]
Filename = TSS-gearup (or whatever the .wav file name is)

Make sure you do NOT have two files that do the same thing, such as gear up TSS and gear up PMDG – your computer will explode!!! (not really, but the sound will not be heard correctly).

Important Point To Know (Gauge Commands)

PMDG, i-Fly and several other sound designers configure their custom sounds to play only when specific actions or commands are triggered - these are called gauge commands.  A sound initiated by a gauge command only works when that gauge is moved by whatever action.  Often it's not possible to use these sounds without some major editing work to the sound.cfg file.  For example, I've been attempting to use the speedbrake sound in ProSim, but as yet have not been able to do so.  This is because the speedbrake is configured to a specific "in house" command or action - in this case the speedbrake. 

You cannot just grab any sound, copy it to the audio folder, and then expect it to play.  There has to be some logic to when the sound is played.  This can be most challenging and frustrating part of manipulating custom sounds.

I hope this journal post, as an addition to the last two sound related posts, helps more than confuses.  Sound can be a nightmare and can be challenging to explain in a short jouranl entry.  It is also very much a trail and error activity (the Americans say "suck and see") - Good Luck.


Separating Audio To Different Speakers - Sim Avionics & ProSim 737

When I did my PPL some years ago, I had purchased a David Clark headset for use during my flight training.  The headset was a wonderful aid to hear ATC and my instructor whilst filtering out the engine noise and other ambient sounds found in a small cockpit of a Cessna 182.

Although it’s not common place to use a pair of David Clark headsets in a B737 (unless a military version), I decided to use the headset to filter out engine noise, ambient noise, and to hear ATC and ATIS announcements a little more clearly.

Using a real headset

Using a real headset with FSX isn’t that complicated if you’re satisfied with the way flight simulator separates audio.  It only becomes complicated when you want to attempt to replicate exactly what occurs in real flight deck. 

In a real flight deck, all communication and navigation sounds (ADF, DME, markers, etc) can be heard through the headset and /or flight deck speaker.  Unfortunately, in FSX the opposite occurs, with navigational sounds being heard through the main speakers only.   FSX only separates ATC and ATIS (voice).

So how do we separate audio to hear various sounds through different speakers and the headset.

Separating Audio – Choose Your Poison

There are several methods to achieve audio separation; some methods are easier than others.

You can either utilize what is already available on your computer through FSX.  This is the easier and simplest method and works well with my policy of KISS (keep it simple stupid). 

If you’re feeling more energetic, and wish to separate sounds to several strategically placed speakers, then a second sound card is probably your only option. With two sound cards on your computer, you can now select which sounds play through which sound card. 

If you’re loath to install a second card to the innards of your computer box; then, explore one of the several add on sound cards that can connect to your computer via USB – some cards offer 5:1 surround sound while others offer just a basic sound card interface.

Another method (which I have chosen to follow) is to duplicate sound programs and run them on separate networked computers.  High-end flight avionics software such as produced by Project Magenta, Sim Avionics and ProSim 737 support this.

The Easy Way with FSX

FSX supports the separation of basic audio.  It’s as easy as opening the sound menu in FSX and selecting which sound is played on which device - speakers or headset.  Engine sounds will be diverted to the surround speakers and ATC and ATIS will be diverted to the headset.  This works very well, however, only ATC and ATIS voice is diverted to the headset.  Navigation sounds, call outs, etc are not heard through the headset.  To divert these sounds requires a little thinking “outside the box”.

I’ve attempted to explain basic audio segregation using two popular flight avionics suites: Sim Avionics and ProSim 737.

Using Sim Avionics – Basic Operation

One of the upsides of using Sim Avionics or ProSim 737 is that it allows you to simultaneously operate different facets of the flight deck from multiple computers.  In my set-up I am running two computers – one with FSX installed (called the server PC) and one with Sim Avionics installed (called the client PC).  Both computers have speakers attached. 

To install audio on both computers you will need to copy the sound.exe file and audio folder found in your Sim Avionics main directory to the server PC (computer that has FSX is installed).  You will also need to copy the Client_TCP.exe file as this file allows Sim Avionics to communicate between networked computers.  Once copied to the server PC, click the executable sound.exe file after you have opened FSX.   Sounds will now be heard through speakers on both the client and server PC.

Using Sim Avionics – Separating & Customizing Sound

This is comparatively easy and involves selecting the sounds you do not want to hear and either removing them from the audio folder or renaming them.  In the audio folder on the server PC, I have removed most of the sounds  and have left in the folder the sounds that I wish to hear only through the headset (navigation aids, TCAS warnings, GWPS warnings & call outs – V1, V2, VR, etc).  Therefore, the sound program on the server computer only has those sounds I want to hear through the headset.

On the client PC, to avoid duplication , I have removed the above mentioned sounds from the audio folder.  It’s important to edit/remove the sounds from the audio folder that you do not want to hear.  Failure to do this will result in duplication of sound.  In other words you will hear V1, V2, Vr, etc through your headset and through the main speakers being run from the client computer.

Therefore, what you now have running is:

Server PC – engine sounds being heard through the surround speakers, ATC and ATIS being heard through the headset (via FSX sound separation), and customized sound (navigation, call outs, etc) being heard through the headset (via separately installed Sim Avionics sound program).

Client PC – all other “specialist” sounds being heard through the attached speakers (via separately installed Sim Avionics sound program).

Adding Customized Sound

Adding customized sound can often is challenging.  Add the sound file (.wav format) to the audio folder.  Then search and find the sound .cfg file.  Edit the .cfg file to reflect the added sound and when/how you want the sound to be played. 

The easiest method is to duplicate the section relating to sound from an already operating sound.  Then edit to reflect the new sound.  This way you do not run the chance of making a syntax or topographically error.

I explained how to edit a sound file in my earlier Journal post “Are the Engines Running – B738 Sound"

Using ProSim 737 – Basic Operation

The methodology of manipulating sound in ProSim 737 is similar to Sim Avionics. 

You copy the ProSim sound program from the server PC to the client PC so each program can send customized sound to separate speakers on each computer.  To select which sound you want to hear, open each sound program and select/deselect the appropriate sound from the list.

Adding Customized Sound

If you are wishing to add additional customized sounds to the sound program, you can do this in the configuration section of the ProSim 737 main program. 

First, you need to add the actual sound to the audio folder.  All sounds should be in .wav file format.  The sounds are usually kept on the ProSim737 main folder/Audio folder (but can be linked from any folder if you wish).  After adding the customized sound, to ensure correct operation, you may need to edit the actual sound file.  This file is found in the ProSim 737 main folder/audio.  The file you are looking for is named config.xml.  Unlike other software, which uses config (.cfg) files, ProSim 737 uses the .xml file format.  To edit this .xml file right click the file with your mouse and choose edit.  Whenever editing anything, always make a back-up first.

Once the new sound file has been added, you need to link the file within the sound program.  To do this, open the file tab in the main Pro Sim 737 program menu and select “add audio”.  Follow the prompts to name and link the .wav file.  Then, you should be able to see and select the sound file from the Pro Sim sound program.  Click the sounds you want to be heard and press “test” to hear your sound.

In ProSim 737, as opposed to Sim Avionics, you only enter the sounds once through the main Pro Sim 737 program interface (installed on the server PC).  Any installation of the sound program on client computers has access to this main audio folder. 

Alternate Methods in ProSim 737

ProSim 737 also provides alternate ways for customizing sound.  This is done through the main ProSim 737 main program.

One method involves selecting an internal audio for the added sound in the file/config/audio tab.  This triggers the main program to read the sound automatically.  Another way to join a sound to a specific task is to use what Pro Sim call a gate.  A gate can be used to link the sound to a pre-defined and named action.  This method is very easy if your defined sound output is actually named in the pull down menu list. 

If the added sound is linked to a button press or specific action, then you can link the sound using FSUPIC or via another device such as an I/O card.

ProSim’s alternate methods of adding and linking sound appear to be quite convoluted and confusing (at least to me).  I direct you to the PS737 manual for further information and instructions on how to do this.

PM Sounds – an easy way to add additional sounds

I have used PM Sounds (PMS) for many years and have enjoyed its simple interface and ability to just work “out of the box”.  PM Sounds is a small, stand-alone add on released by Project Magenta used to supply customized sound to their fleet of products.  The program is is compatible with many other avionics suites.

The program is stand alone and does not load into FSX.  To hear sounds from each computer on your networked set-up requires that PMS be installed on each computer.  PMS comes with a large selection of sounds and you can easily select which sound you require by checking or un-checking the box and “pushing Q” on the keyboard to save the selection.  Activation of the sounds is achieved by running PMS before you start FSX.  The rest just works…

Adding Customized Sound to PMS

To add customized sound to PMS, it’s a matter of finding the audio folder (located under PM Sounds/) and adding the sound (in .wav format).  To hear the sound within PMS, you then must edit the sound.cfg to reflect the sound name, file name and location.

To use PMS on any computer other than the computer running FSX requires you have a copy of WIDE FS as PMS uses this program to communicate between the server computer and the clients.

PMS can be used in addition to whatever sound program you are using.  The program can be found on the Project Magenta website.

Important Point To Know (Gauge Commands)

Several sound designers configure their custom sounds to play only when specific actions or commands are triggered - these are called gauge commands.  A sound initiated by a gauge command only works when that gauge is moved by whatever action.  Often it's not possible to use these sounds without some major editing work to the sound.cfg file.  For example, I've been attempting to use the speedbrake sound in ProSim, but as yet have not been able to do so.  This is because the speedbrake is configured to a specific "in house" command or action - in this case the speedbrake. 

You cannot just grab any sound, copy it to the audio folder, and then expect it to play.  There has to be some logic to when the sound is played.  This can be most challenging and frustrating part of manipulating custom sounds.

There You Have It…

Sound can be as easy or as complicated as you want it to me. 

I've attempted to provide, within the last two journal posts, an incite into audio separation using Sim Avionics and ProSim 737.  Certainly, the process described above has worked relatively well in my simulation set-up.  Your configuration may differ to what I have, but what will not alter is the basic method of audio segregation.


Are The Engines Running - B738 Sound 

One of the main purposes of building a flight deck is to increase the realism and immersion levels when simulating flight.  You want to move real yokes, flick real switches and spin real rotaries whilst maintaining focus on real instruments within a modern glass flight deck. 

Simmers go to exuberant lengths to create the illusion of flight.  Purpose built flight decks, aircraft shells, real aviation equipment and stunning external visuals all add to the immersion effect.  But, what about sound – in particular realistic aircraft engine sounds.

But what about sound……

All of us have had that dejavoo feeling when we have smelt a certain smell or heard a certain noise and are projected back to that event and time.  Vietnam veterans often have vivid flash-backs when they hear news helicopters flitting overhead.  We all can recall a song within out romantic past which conjures up images of a past partner or event.  The power of sound and smell cannot be underestimated. 

If the engine sound of your chosen aircraft is perfect or near perfect you will barely notice it – the sound will blend with everything else.  However, if the sound is not correct or is video arcade game-like, you will always be thinking how it can be improved.  This is especially so if you’re using the standard stock FS9 (FS2004) or FSX aircraft engine sound.

I feel confident saying that: “with decent sound, your one notch higher concerning realism and immersion”. 

Sound makes a huge difference to the simulation experience.  When on final approach, concentrating on flight adjustments and jigging with the throttle to obtain the correct thrust, the sound you hear, if realistic, will make you forget you’re sitting in your spare room!  It’s like that smell or sound I mentioned earlier – you’re mentally transported back to the source.  I recently trialled the PMDG 737-800NGX in the simulator, and the first thing my girlfriend in an adjoining room exclaimed was “that sounds like a real plane”.  

The recently released PMDG 737NGX has an exceptional sound package; however, not everyone flies this aircraft model.  What is available to augment or replace the default flight simulator sound files?

Turbine Sounds Studio (TSS)

Turbine Sounds Studio (TSS) produces a variety of different sound packages that are direct recordings of the real aircraft engine sounds.  The sounds have been professionally recorded from specific aircraft types and in my opinion are exceptionally good and eons ahead of anything supplied by Microsoft. 

The package to purchase for the B737NG is the: Boeing 737NG CFM56-7B HD Sound Pack for FSX.  If you fly the older classic series B737, TSS also produces a sound package specific to the 300,400 and 500 series aircraft.  To actually hear a sample of the sounds, I recommend your navigate to their website at http://www.turbinesoundstudios.com/

TTS – Software Installation

The software provides you with an executable file, which when selected, will download to your desktop a “sound” folder containing a number of engine, instrument and ambient sounds specific to the aircraft type.  It’s just a matter of backing up your original sound folder in the aircraft of choice and copying the TSS sound folder in its place. 

How To Add Custom Sounds

If you’re not happy with every sound in the package, it’s quite easy to remove or replace a particular sound with another favourite.  Search for the sound folder, usually located within the aircraft folder (FS10/sim objects/aircraft).  Within this folder you will discover various sounds and a sound.cfg file.  If there are no sound files within the folder, they maybe aliased to another folder in another aircraft. Open the sound.cfg file and note the folder/file location.  Follow the trail until you actually discover where the .wav files are stored.

It's important that when you replace sounds, that the replacement sound is in the same format and has the same file name as the file you are replacing.  If the file name is different, you will  need to alter the specific parameter in the sound.cfg file to reflect the file name change.  The same is for the location of the sound (if this if different).  The sound.cfg file must have the correct name, format and location of the actual .wav sound. 

Always back-Up Before Editing

Always back-up the folder and files you wish to edit BEFORE editing anything.  If you make a mistake or something is not quite right, it's then easy and straightforward to put your system back to where it was beforehand.

In my set-up I am using the base NGX sound pack installed into the FS9 737-800; but I have customized a few of the sounds to those that I prefer.

If you want a more or less accurate sound set for the B737, but don't want to go to spend the time hand-picking, renaming and customizing your sound files, then either give TSS a fly or use the PMDG NGX sound set, which is a tad more realistic than the set provided with the PMDG FS9 B737.  Whichever set you choose (or combination thereof), it will be far better than the default sound that comes packaged with flight simulator. 

In a future post I’ll tackle the issue of separating sounds to different speakers on different networked computers.  This allows you to have ATC through the headset, engine sounds left and right of the flight deck and other sounds played through another pair of strategically placed speakers..

Well, I’m more or less pleased with my sounds.  Should I throw some avgas on the carpet to get that aviation smell….