The first project where I attempted to record external audio was for the Rayo del Alma project. I borrowed a Zoom H4n, which I set on an additional tripod off camera. The H4n is a great product and I highly recommend it. I was amazed by the quality of the audio that it recorded, especially through the expensive Sennheiser headphones that I was using at the time.
Since I would be recording primarily with a DSLR, I realized that I was going to have to eventually purchase one of these digital recorders. I did some research and I decided that the most reasonably priced competitor for the zoom H4n was the Tascam DR-40. Both have similar features and recording patterns, especially since the firmware update for the DR-40, but the Tascam is anywhere from $50-$100 less, depending on where you purchase your gear. I purchased the DR-40 and it didn't disappoint.
I'll start with the aspects of the DR-40 that I like better than the H4n. First, the X and Y patterns of the DR-40 have a more distinguishable sound pattern. When in the X pattern the Tascam picks up noticeably less noise from the sides than in the Y pattern. The Zoom's mics stay in an X position and rotate from a focused 90 degree coverage pattern to a wider 120 degree coverage pattern; however, I still picked up a lot of side noise with the zoom in the 90 degree coverage position. Second, I felt the Zoom picked up a lot of unnecessary high frequency which I had to remove in post. I'm sure this is a good recording feature in some situations, and that it's also purely preferential, but I prefer the range of the DR-40.
Both devices are geared towards musicians and I've been told that the Zoom has more internal mixing and recording features, but since I always adjust the audio in programs like Adobe Audition, this point made little difference to me. As I said before, the Zoom H4n is a great product, and I'm sure that many people prefer it, but I love my Tascam. The only way to truly know which is right for you, is to try them out for yourself. Good Luck!
Picture by dslrfilmnoob.com
UPDATE 05-07-2016!!!
Warning!!! There is a flaw with the Tascam DR-40 that I had the misfortune of experiencing. After a while, the power button just stops working. Mine faltered right after my year warranty expired. After checking online, quite a few people have also experienced this. I still stand by what I said about the DR-40 and it's performance, but buyer beware.
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