Excessive background noise - A10 intercom system.

[IRowell]

Background:
Have recently had the MGL Suite of products installed in my Pitts Model12. (IEFIS,2xV16’s, A16, Vega radio heads Michigan avionics wiring harnesses).
I have had numerous noise issues, initially electronic noise- I have installed various filters ahead of:
-the v16 radios (2 installed).
- the A16 intercom. (2 filters as supplied with the A16).
The electronic noise now seems to have subsided.

Problem definition:
- Since adding the filters (don’t believe this noise issue I am now experiencing is related to the filters) I have been unable to hear myself in my earphones when transmitting. I have increased the I/C volume (side tone). I can now hear myself clearly when the aircraft is not running. However since doing this it appears to have amplified the cockpit noise to unacceptable levels when running the aircraft. If I turn this volume down I can’t hear myself or radio transmissions even with the Vega radio volume set to max.
Also still can’t decouple pilot and copilot microphones-even after software upgrade/fix.

Requirements:
- how do I resolve this issue? I can’t fly due to this issue and need it resolved ASAP.

[rainier]

OK, you added the filters - those don't have any effect on the signal FROM the radio - they only affect what goes to the radio and are only of value during transmit as they block any chance of RF from getting into the V16 via the microphone input.

The background noise you hear - we need to establish if that is acoustic noise your microphones are picking up or electrically induced noise.

Cup the microphone tightly with your hand with engine running - does it reduce/go away - if yes it would seem your VOX is not adjusted.

Once your have an external intercom the V16's own intercom must be set to "bypass". In that case there is no VOX to be set in the V16 itself. This all moves to the A16 intercom.

First thing - make sure your microphone gain is set correctly - there is a setting for each of the six microphones. Note you have a bargraph in the MIC setup that shows your current MIC audio level - adjust the gain (without engine running) until the loudest parts of your voice just hit the marker. Make sure your MIC is located close to your mouth when you do this. Now you can run the engine and adjust the VOX until the background noise goes away.

Note that each of the six MIC inputs has its own settings - keep that in mind if you have other headsets plugged in - if any of these is not setup it will happily add whatever noise its microphone is receiving to the mix.

For electrical noise - please ensure that any unused input you may have is switched off or has its input level gain set to minimum - unconnected inputs are typically high impedance in this system and they will pickup electrical noise.

[IRowell]

Thanks Rainier.
I have placed my hand over the microphone and the noise reduces significantly but is still way to loud for functionality. I believe it is my helmet mic that is picking up acoustic noise and amplifying it.

I have set my system up in accordance with recommendations from Adam O’Conner. (He is extremely helpful and a pleasure to work with).

I will go back and check my settings as per what you indicate. I don’t recall adjusting any of the additional channel setting you reference- this may well be the source of the background noise. I live in Florida but am in Chicago through Saturday this week so won’t be home to make the setting changes you recommend until Monday of next week. I will let you and Adam know the outcome sometime next week.
Goed gaan, geniet jou week.

[rainier]

If your microphone is not switching off (like in completely off) you have not adjusted your VOX level.
Please adjust your VOX level so the microphone switches off when you are not talking into it.

If you find you cannot achieve that even with maximum VOX level setting it simply means your microphone gain is way too high - in that case please adjust the input level DOWN until the signal gets back into range where the VOX can work with it.

Then you can adjust the volume up so it has the desired level.

It sounds like you have too much gain and then are reducing the volume - that then moves the working point of the VOX out of range.

You must get the VOX to work so it switches the microphone off completely. The way the VOX in the A16 works is a bit different to a normal VOX that is a hard on/off switch. With the A16 the VOX blends the signal from your microphone gradually between off and on but within a relatively narrow range of signal level. In a way this is a combination of the traditional VOX and the VOGAD we developed for the V6 and V10 radios combining the best effects of both systems into an easier to use way (just a single adjustment). You also do not get the effect of a normal VOX system that likes to "swallow" the first syllable of your speech (there tends to be a bit of a delay before a normal VOX opens as your voice starts below VOX level before it gets loud enough to open it - our VOX system does not have that issue). The VOX built into the V16 works the same way (but in this case you will not be using it).

[IRowell]

Reiner
As an FYI.
As you know I have not been able to resolve the background noise issues with my MGL, V16’s and the a16 I/c system. I have followed your directions above and still can’t make this system acceptable. I’m hoping to work with Adam this week to see if I have misse something and through Adam attempt to resolve my issues. (It’s now over a year that I’ve not had a fully functional aircraft since beginning with the installation of your system, and I’m getting very frustrated).
If I can’t resolve these issues I will be looking to remove the V16’s and the A16 and reinstall my Garmin radio and I/C set. I will look to keep the IEFIS in place but not patch the radios into the system as I had originally planned on doing when I elected to use 100% of your integrated components. If you have a chance it might be helpful if you reach out to Adam to discuss any other solutions you may have.
Thx in advance.

[adamoconnor]

For anyone who finds this post, Ian and I have worked to find the solution to this issue.

In Ian's case, the intercom volume for the pilot and copilot were set too low, and so he was compensating for this by cranking up mic gain, and overloading the mic channel. Once we cranked the intercom volume up for pilot and pax circuits and then turned down mic gain, Ian is now enjoying vastly clearer communications. We still have some fine tuning to do, but it's been a tremendous help. On the iEFIS, the intercom volume can be easy to miss, but if you just hit the "adjust" button at the top without tapping on a radio source or mic source, you'll find intercom volume in there. I believe the Razor interface makes the intercom volume a little more prominent versus the iEFIS.

Regards,
Adam

[JoshuaEmove]

them low frequencies, the wavelengths will be too long to detect any real direction. unless, ur gonna press the mic down onto the various surfaces to see if u get any transmissions... hmm, if so, interested to know if it detects any thing.