I was looking into gear like Church Audio mics and a battery box to use with my DR-40 to tape rock concerts,
Good place to come. Welcome!
but I found a recording straight off the DR-40's onboard mics and it sounds better than most recordings I'm hearing by tapers with external mic setups.
We will approach this later.
The shows are going to be outdoors in big venues like the Hollywood Bowl. Taping isn't allowed at some of them, so a simple setup is ideal.
Whether indoors or outdoors, it sounds like you are looking for a stealth setup. Your first sentence is spot on: small mics > bat box > recorder --- ALL CONCEALED.
If I plan to just use the onboard mics, could anyone recommend the settings I should use on the DR-40? I have never done this before so any help is appreciated.
The DR40 was my first deck 5 years ago. I don't remember the settings, but as with my soon-to-be-departed DR680mkii I would imagine line-in and turn the gain on each channel all the way to the max. Bump it down a couple clicks and you should be at a decent starting point. Quieter music... besides not having a great deck for quieter sounds, perhaps mic-in would be your best starting point, but the levels would have to be tamed as well. You will have to pay close attention, but line-in will be the way to go in a loud rock concert situation and you will need more gain than the mic-in setting.
I plan to wear the DR-40 on a lanyard.
Wait? What? I thought you said the venue did not allow taping... We will bundle this with the second part of your first sentence.
I do own a Rode Lavalier mic (professional MiCon lav), is that useful? I have an XLR adapter and used it for interviews with the DR40.
Its usefull. However, to properly record at the quality you want you will need two microphones as a stereo pair. Just like the on-board DR40 mics - one left channel, one right channel.
The DR40 will do what you want... with caveats. If you plan on having the deck on a lanyard, you are open taping. You are now openly recording in a venue or with a band that forbids it. You may get caught. You will miss the show and might lose venue access. This is why another member (and myself and 20 silent readers) are telling you to drop this idea. Unless this is how you want to OPEN tape, this is not a solution for one of the scenarios you mentioned in your post. It may have worked in the past, but its ill-advised going forward.
From the exact same position in a venue, using the on-board microphones on any of the decks you read about on this board will produce a lower quality recording as that of a mic > power > deck set-up. You may feel differently and that is the joy of taping and that is the love of subjectivity. However, going with your first thought of CA mics > batt box > deck is a better, more proven successful way of making a high quality recording that you are uploading for the universe to hear.
As a new member of this board, there is a WEALTH of information for you here. Our search function rocks. Find more on what you would like to accomplish by spending time reading this board. Pages of it.
Also, more technical detail on what you are asking is sometimes dealt with private messages when talk gets deep.