I remember some people talking about putting audio units into the 340, and the output from these units not being loud enough. Perhaps it was not the unit; this is a post from another source:
After installing A Garmin 340 Audio Panel, I noticed that the side tones all but vanished when the Â“push-to-talkÂ” button was depressed. (I have a pair of Narco MK-12Â’s) In addition, the outer marker light is so bright that it illuminates all three marker lights, so itÂ’s impossible to tell which light is really lit. I complained to my installer who immediately informed Garmin (both by phone, and in writing) of the problems. Unfortunately Garmin could not have been more uncooperative. They told the install that you just have to live with the maker situation, and that they have no idea why the units isnÂ’t compatible with the Narco radios and that he should try and figure it out. My installer then called Narco, (who bent over backwards to help, unlike Garmin). The Narco people confirmed that several other Garmin 340 installations were having the same problem, and suggested several ways in which the problem could be rectified. They also confirmed that Garmin is aware of the problem, but doesnÂ’t want it publicized. As if this wasnÂ’t enough, the 340Â’s music input is so low it canÂ’t be heard with the engine running no matter how high you turn up the volume on the CD unit. The Garmin manual says your installer can make an adjustment and increase the volume. However, when Garmin was contacted about this problem, my installer was informed that there is no such adjustment, and that the problem as been acknowledged and will be corrected in the future. Another fact the Garmin has elected not to publicize. Pretty sad. All I can suggest is that anyone thinking about an audio panel upgrade should consider spending the extra money, (itÂ’s worth it), and seriously look into a unit from PS Engineering. IÂ’m sorry I didnÂ’t.
PSÂ…. I was going to purchase a Garmin 530, but have decided never to deal with Garmin again.
N237CD; delivery 7/23