13. July 2018 by Peter
On my old setup I had a setup for flying online on VATSIM. There was a lot of electronic noise on the speakers. So I decided to redo parts of the sound-setup in my cockpit rebuild.
The solution turned out to be rather simple. Before I used amplifiers from eBay. But I realised that using a soundbar like the one you have underneath your monitor was better at noise reduction.
Online flight is a great thing and I encourage everyone to at least try it out. If you are building a cockpit I am sure that you fell home in aircraft/navigational procedures and know what to say and when.
So back to the sound setup. I had a few challenges:
- The sound from the ACT (Output from the computer) had to go to a set of speakers and two headsets.
Each with an individual volume control.
In order to get sound out of the speakers I needed some sort om amplifier
- The sound from the microphone (Input to the computer) was a challenge as well. There are a total of 4 microphones. 2 headsets and two hand held microphones.
Not all microphones can transmit at the same time. That would create too much (background) noice
- Earlier I used a button on my joystick as PTT (Push To Talk) button. The PTT-button is the one that make you transmit your voice on VATSIM. Now I have a PTT-button on each handheld microphone (2 total) and two in the pedestal. So I must interface those buttons with vPilot (The VATSIM software).
Output / Speakers
This is the easiest part. 🙂
I used some $10 amplifiers from eBay before. But due to my ATX power supply they had a lot of electronic noise. So either I had to find a $100 linear power supply or find another solution. It turned out Soundbars are great sound for lille money. So I use two, one for the speakers and one for the headsets. They are connected to the computer using a simle Y-splitter.
Soundbar 1 is for the headsets. Each headset is just connected to the two jack stick on the side of the soundbar. That also cancels the sound from the speakers in the sound bar. I run wires across the cockpit to each eyebrow window where there is a (home made) panel for connecting the headset. On this panel (in each side) there is a potentiometer for controlling the volume in the headset.
Soundbar 2 is for the speakers. This soundbar I had to take apart and cut the wires for the speakers so I could extend the wires to my own speakers. Further more I had to cut & extend the wires for the volume control. I simple took the volume control out of the soundbar and installed it with the headset-volume-comtrol on the captains side. So the captain can adjust the volume of the speakers.
Input / Microphones
This is not all that difficult. But once interfacing it gets a lot worse. But the problem is that I have four microphones and when transmitting to the ATC only the microphone in use should be transmitted. Else there will be too much background noice from the other microphones.
This is solved using an “audio relay” it contains 4 phono connectors. Depending on which channel is activated only the input from that microphone will be send through the relay.
The downside to this solution is using these relays is they are mechanical. Mecanical relays “spark” when the relay throw. That creates a hard click. I have tried with SSD realys to avoid that moving part. But SSD relays require more power than used in my setup.
Push to talk
Last issue is the Push to talk (PTT) button. This issue is two sided.
On each of the two hand held microphones there is a button that is pushed when sound from the handheld microphone is used. For the headsets there is a button on each ACP (Audio Control Panel) on the pedestal. So that is a total of 4 push to talk buttons. And depending on which is pushed the specific sound relay (Mentioned above) must be activated. Furthermore the push to talk button must also trigger the PTT-function in VATSIM software.
These two functions are achieved with a 8-set relay board. Each PTT-switch is connected to two relays. One of the relays sendt a signal to the audio relay. The other sends a signal to a interface card.
The “Relay to sound relay” set up is pretty strait forward. The reason I use this relay board instead of connecting directly to the audio relay is because I need the same signal from the PTT switch to also activate the signal to the interface card.
The other relay is – as mentioned – used to transmit the PTT signal to an interface board – in my case an OpenCockpits MasterCard. All 4 relays is connected to the same wire. So there is only one input on the interface board. Via SIOC (The OpenCockpits code language) I trigger a FSUIPC Offset. The Offset you need is FSUIPC offset 3340. By using this you can trigger a virtual joystick within FSIUPC via SIOC. This is my SIOC script:
Var 9210 name FO_JoyStick64 Link FSUIPC_OUT Offset $3340 Length 4
Var 9211 Link IOCARD_SW, Device 2, Input 71, Type I
&FO_JoyStick64 = CHANGEBIT 0 v9211 // toggle bit 0 of joystick 64
It triggers “bit 0” on Joystick “64” when one of the PTT switches are activated.
Inside FSUIPC you must go in to the tab “Buttons” and then press a Push to Talk button. This activates joystick 64 bit 0. Then select “Keypress” and set the keyboard key you use as Push To Talk in the VATSIM Client. I use Scroll Lock.
When following these steps it ought to work. I look forward to see you up in the virtual skies of VATSIM.