Bose Engine Noise

I have recently installed 4 Bose X headsets in my SR-22.
I am now hearing a RPM noise while I taxi and during run-up.
The avionics vendor suspects the grounding in the charging system.
Does anyone have any similar experience or advice?

Are the headsets running off ships power? If so, a ground loop is likely to be the cause. It might be worth trying isolating the ground side of the power connection, relying on the audio ground to complete the power circuit, though that has potential to cause other problems.

Is the noise an rpm-related whine (alternator noise) or a clicking (ignition) noise? Try turning off the alternators and see if the noise stops.

I hear a faint sort of clicking sound in the Bose during taxi. I do not recall hearing it on the run up and do not hear it in flight. I am using a 9 volt battery. I agree with Clyde that if it was from the alternator you would hear a whine that corresponds to engine speed. I do not hear any whine. The sound I hear is so faint that it is not even a problem that needs dealing with.

I plan to get the battery eliminator that Mike Radomsky is putting together. I saw an email from him that he is getting close to building them.

The Bose are fantastic. I really get the impression of the degree of the noise reduction whenever I take them off to put on oxygen or the JeppShades. I plan to get one more soon. I only have one at present. My CFII still likes his D.C.'s so I just need one more at present for my friend.

I gather from your post that you are using the panel mount version of the Bose. I don’t know what I will hear once I get the Radomsky battery eliminator installed. That will be the equivalent of the panel mount that I suspect you have.

Mike Radomsky, if you see this post, maybe some additional filtering of the D.C. would be in order to eliminate the kind of noise that seems to be coming through from the aircraft. I believe the fix for automotive alternator whine is a choke in the D.C. line to the audio component.

Another idea: have you contacted Bose about the noise? I am sure they are anxious to know of any condition that affects their products and they may have a suggestion on a fix.

In reply to:


Mike Radomsky, if you see this post, maybe some additional filtering of the D.C. would be in order to eliminate the kind of noise that seems to be coming through from the aircraft. I believe the fix for automotive alternator whine is a choke in the D.C. line to the audio component.


Steve,

I’ll be sure to let you know if I see this post! [;)]

Seriously, I do plan to include a choke and some capacitors to decouple the DC supply.

Mike.