From the very first glance the Garmin GMA 340 looks to be an impressive unit. The

buttons are easy to use and the general layout flows and blends well with any instrument

panel. It has some features that I really like such as the ability to isolate the pilot and the

crew separately from the rest of the passengers. This feature is really appreciated when

you have young kids in the back seat since you can let them listen to music or a portable

DVD player without worrying about missing ATC instructions plus you can carry on a

private conversation with the right seat passenger or co-pilot without including the rear

seat passengers. Another feature is the separate volume control on the intercom for the

pilot and passengers. It allows finer adjustments of the intercom volume and squelch

levels. The GMA 340 has a unique feature that allows the pilot and co-pilot to each

transmit on separate radios. That is a valuable asset to have when the cockpit workload

increases and you have a capable co-pilot to help with the communication duties. A

stereo input jack is provided for plugging in an I Pod, XM radio, or any other stereo

device with a standard audio plug. A smart feature mutes the music when intercom or

radio traffic is detected. Of course like most modern Audio Panels the marker beacon is

built-in and functions the same way as most others.

I had a King KMA 24 Audio Panel installed in Aerobelle before I purchased the Garmin

unit. In retrospect the King panel looks a little “cheesy” when comparing it to the GMA

340. Before I was introduced to the Garmin I thought the double row of push buttons on

the King unit looked very businesslike and fit well within an aviation cockpit. The only

drawback to me at that time was that the buttons were a little on the small side and I have

been known to hit the wrong button or two buttons at once when flying in turbulent air.

On the other hand the Garmin unit has nice big buttons that are both easy to read and

push. It also seems to fit the aesthetics of the modern cockpit better that the King unit

which seemed more at home in a steam gauge panel that one loaded with glass. I really

like the fact that the GMA 340 has little LED lights to indicate which button is active.

The King panel had no indicator lights other than the standard marker beacon and the

active function was indicated by the button being depressed. Another obvious difference

between the units was that the intercom was built-in on the Garmin unit whereas the King

system depended upon an external intercom. In my particular case the external unit was

the old aircraft standard Sigtronics SPA-400 TSO unit. A person may gather that based

upon the previous statements that Garmin GMA 340 is a perfect system with none of the

King’s faults and it thus far superior to the old King KMA 24, but I must admit that there

are a couple of features that I liked better about the KMA-24. Number one was the fact

that on the KMA-24 I could individually select where I wanted the audio output from

each device to go. I could have my #1 Com broadcast through the headset and #2 Com

broadcast over the cabin speaker. I could also have the Nav audio broadcast of the

speaker while I reserved the Com audio strictly for ATC. Not so with the Garmin GMA

340. You either get the output through the headset or over the speaker but cannot

individually select between the two. I miss that feature mostly because if you are

listening to two radios and trying to indent a Nav device it gets a little cluttered with

everything coming through the headset or over the speaker without having the ability to

split audio between the two. Another thing I like more about the KMA-24 was that I

could also individually select which radio I wanted to talk over without necessarily

having to listen to the same radio the Mic switch selected. An example would be if you

wanted to transmit on one frequency and listen on a VOR you could select the #1 Com

Mic and select the #1 Nav receiver to come over the speaker or headphones. With the

Garmin unit if you select the #1 Com Mic it automatically selects the output to be the #1

Com. You have to select the Nav and then the audio mixes with the Com radio making it

sometime difficult to make things out where on the King unit you can do isolation and

send one to the speaker and one to the headset. Other than those two items I really do

like the Garmin GMA 340. I can live with the minor drawbacks that it has. I have flown

several hours with the system and am impressed with its reliability and ease of use. I do

recommend that you check out Garmin's website at if you are


considering a new or replacement Audio Panel.

Mike M