Does the zoom h4n record all external mics at 44.1
When we play back our videos on mac's the internal speakers drop the miked sound recorded on zoom h4n. Headphones or ear plugs fixes this problem?
So this is a little confusing, but I'll take a stab at it...
What program are you playing the files in? If your audio files were recorded with more than 2 channels, there is a chance that the audio you recorded is not on tracks 1 and/or 2, in which case some programs won't play it back (I have experienced this issue with Quicktime). Load it into an editor like Audition, Audacity, or FCP to check if there are "hidden" tracks.
Seeing that the h4n can record 4 channels, this could be your issue. However, the headphone thing confuses me because as far as I know there shouldn't be a difference. I guess a simple debugging question I have for you is: do the internal speakers play any other sounds, like iTunes?
The Zoom H4n is able to record its external mics on other formats. On the Stereo mode, you can record at all the available recording formats. On the 4-channel mode, you only have 4 options which are 44.1/16, 44.1/24, 48/16 and 48/24. If you need to record higher than 44.1, do note that you need to be off the Stamina mode as this mode only allows record and playback at the lowest sample rate of 44.1/16 in mp3 format.
It would be good if you can elaborate on what you mean when you say 'When we play back our videos on mac's the internal speakers drop the miked sound recorded on zoom h4n.'
Do you mean the volume decreases? or the frame rate? or something else?