Dual IFD audio issues

When dual IFD units (540/440) are installed, should both units have their TAWS audio output wired to an unswitched audio input on the audio panel, or is it sufficient to have only the 540 audio connected?

Thanks

The short answer is "It depends".

The longer answer is that it depends on what you are trying to accomplish.   Many, but not all, of the aurals are shared between dual IFDs so if one box is wired to the audio panel then you are okay.  I do have a few notes in the Pilot Guide about the details of this as well as the Installation Manual.

For example, if you have a traffic sensor wired to one IFD, as long as you don't have two different traffic sources connected to your IFDs (e.g. one ADS-B box and one active  TAS box), then the traffic aurals are shared between the IFDs and all you need is one IFD wired to the audio panel.

But, there are so many configuration variants, perhaps the simplest thing to ask you is "What exactly are you trying to accomplish in your airplane?" or "What do you have in mind?"


Edited by AviJake - 26 Dec 2015 at 10:09am

What you have now is essentially optimum. You could wire the 440 alerts to an unused input, but at minimal operational difference. You definitely do not want two devices both wired into a single input at the audio panel.

In my case, I have the alert audio on a switched input, and glad I do because I sometimes operate low-level flights and the alerts can become an annoyance. On those flights, terrain awareness is already front-of-mind so I don't need the electronic safety net to nag me.

On the other hand, if it was wired into an unstitched input, a similar result could be achieved by turning the volume all the way down to zero, I presume.

David Bunin

The audio on my IFD is stellar, I haven't seen any comments here about audio issues.

And yes the audio panel is factory.

Okay great - I'll check on both of those. Appreciate the feedback...i know I'm all over the place with these issues, but it looks like you have been active on the forum. I did fly for the first time today with the units and had the same issues as some of the others whereby the VLOC stayed yellow on an ILS approach today, but was green on a VOR approach. Sounds like I'm not the only one experiencing that.

oskrypuch wrote: The outputs that I'm talking about are two different physical conditions on the back of the unit. Normally folks use the one that the 430W used.

I will point out that DPCraig is asking about the Comm audio quality.  The two different physical connections on the back the Orest mentions are for the alerts audio.

Apples to oranges.

I agree, the comm audio quality is fantastic.  DP is probably dealing with an installation wiring problem.

DavidBunin wrote: I will point out that DPCraig is asking about the Comm audio quality.  The two different physical connections on the back the Orest mentions are for the alerts audio. ...

Edited by oskrypuch - 04 Jan 2016 at 1:38pm

I have a whistle problem during com tx (IFD540) that I'm troubleshooting. At this stage, I'm don't really know yet  if it is the IFD540, alternator, ACU, or other. It appeared after an avionics upgrade incl the 540 last spring and is proving troublesome to clear. The whistle freq and volume change with rpm.

AviJake wrote: I'll put my 2015 bonus on the line that it's not the IFD540 causing your whistle but hope you can get that resolved pronto.

comancheguy wrote: Flew the comanche four days in the row over the holiday, and noticed with my wife's halo plugged in and my lightspeeds, the volume when I transmitted was LOUD.   Flew the next day by myself and the next with a friend with a different headset and didn't notice it.  I'll pay attention to if it's just those headsets.  What issues were someone else having with the halos?

I have two pair several years apart that seemed to have a very high modulation that was causing the IFDs to clip when talking to certain ATC centers.  The problem from my point of view is the "Halo + IFD540s + ATC Center Receivers".  Its not specific to a frequency and other aircraft can hear it just fine.
Any other headset works perfectly fine. I think we surveyed about 10 different types, but didn't try the Clarity Aloft.

If you do get reports of clipping or poor transmissions please relay it to Avidyne team.

comancheguy wrote: Thanks for the info.  No issues like that.    But, I'll keep my ears on it, and report any oddities.  Ken

FWIW, you won't hear or notice anything. You'll get a "Say Again" or the like from ATC or they won't respond when you check in.
From the conversations I've had with center when this happens and I've swapped headsets, they can usually hear the very first second or so fine, so quick short responses do seem to work.  I was also told to move the MIC about 2+" from my mouth to help with this over modulation issue.

Again the "works 100% of the time solution" is to just use my old ANRs.