I am a newbie, so sorry for the lack of detail, but I have been able to turn off the onboard mics when using an xlr mic.

It took some time clicking through the menu to find the source, but you can pick the input source and there is an option that doesn't include the internal mics.

The internal mics only turn off automatically when you insert something into the mini-plug on the back of the H4n.

You select between MIC and (XLR) INPUT using the front buttons. Page 11, 38, 39. If the MIC button is lit up then the internal mics are still live. In 4CH mode you can select any combination just by pressing the buttons, which will light up when the respective input is active.

Thank you Mike and Adam but you have not answered my question. I already know how to set the H4 for recording in the different modes and have been using it a lot, but only noticed this problem when I blew hard onto the mic in OFF position with XLR 4-channel switched on and external mics attached (normally you wouldn't notice it unless there was a strong wind blowing against the Zoom and your extrnal mics where completely out of the wind - such as when using wireless mics at a distance). I am not asking how to set the H4 out of Mic mode, or how to select the front buttons to obtain 4-channel.
I am asking if anybody realises that even when the Menu option source MIC is switched OFF, and set to 1&2 (onboard stereo mics switch to off), and then a mic attached via the XLR, there is still some slight reception via the onboard mics. The onboard mics are OFF, and will not record voice, but if you blow hard on the heads of the two onboard mics they will still register that blow sound through your headphones.
Could somebody who has a Zoom H4 with them please try this simple test with headphones on and get back to me with results (I haven't got a second H4 with me to try).

Sorry, I was just responding to this incorrect assumption, so no one else would think the H4n is supposed to do this.

Yes, sorry Adam, I should have mentioned that Stereo Mic mode is also switched off and set to 4-channel first before the XLR leads are plugged in.

If you have a Zoom to hand Adam, and could test to see if your unit also picks up high wind when onboard mics are "off" I'd appreciate it. I just want to find out if mine is still functioning correctly before I take it with me on a filming assignment next week.

I've just finally found out one way to avoid the wind noise when the onboard stereo mics are switched off. Thanks to a little snippet from Johnnie on the 7D forum!
First, by turning the onboard mic levels completely down to zero level on the Zoom's display when in MIC mode, then switching back to 4-channel and XLR external mics, it seems to work well and avoids any annoying wind noise being picked up by the onboard mics while using external mics or radio mics.
It is a bit of a bind having to do all that each time I want to switch between onboard and XLR, but at least I now know what best to do when I'm filming in high winds with external mics.
I've also now added permanant foam & home-made double fur layer dead-cat to the Zoom's onboard mics for outdoor recording.
Thank you Johnnie... :)

Tony, sorry I haven't had a chance to check the H4n as you requested, but seems like you've found a solution. But I'm curious, because I'm not really an audio expert, if you're just using the XLRs, why would you be in 4CH mode? Why not just Stereo? Is there some other advantage to 4CH mode even though you are only using two inputs?

Yeah, I just use stereo mode when using external mics. You can switch between the externals and on-board mics without touching the menu as well. No hassles there.

With the Zoom H4 in stereo mode switched to 1&2 and you plug a mic into the left XLR port it will provide mono to left external speaker and a second mic in right XLR port will provide mono to the right external speaker. If you want a single mic plugged into the left XLR to provide a stereo signal to both left & right external speakers the Zoom must be set to 4 channel 1&2.
Also, even when the Zoom is in stereo mode with Mic switched off and set to 1&2, plus external mics plugged into the XLR ports, the onboard mics are still semi-active, so the levels must be dialled to zero to avoid wind noise.

I'm just curious why it would be necessary to record a single mic to both channels, unless it was a stereo mic? If the mic's not stereo, I would just record it to one channel and pan it to center in post. Is there a reason why this would be a bad idea? Andy

Yes, for when using an external stereo mic. For mono mics, like you mention, recording to one channel is OK.

Got it. Thanks! I thought I might have been misunderstanding something. Andy

H4n additional Mikes.
 

Please forgive my ignorance, but I have only just purchased the Zoom H4n recorder to use when recording my choir singing in concert. I have been playing about with the different mode settings ,Stereo and 4 channel. I used the recorder in Stereo mode during a recent concert for the first time to test the internal mic pickup without extra inputs. Whilst I was happy with the sound quality I did experience the occasional sound dropping when either the choir sang too quietly or the piano stopped playing at the end of phrases and I missed the begning of the next bar, etc. I also has difficulty in picking up the soloists as changes in their volume output also led to sound dropping. I did say I was a beginner with this type of recording and no doubt had used the wrong input settings -maybe too high to pick up the drop in volume?

However, I have bought a Kam KWM 1932 wireless mic set and have switched to testing the 4channel mode keeping the internal mics on and linking the wireless mic receiver via an XLR connection to Input mic 1 port on the base of the H4n and also with a 1/4 inch jack lead from the receiver's jack point to input port 2 on the H4n. This enables me to mic up the soloist(s) with a lav mic and allow the choir presenter to use a hand held wireless mic from the set. All 4 channels appear to work happily together as I assumed that enabling the internal mics to operate alonside the additiopnal mics in 4 channel mode was a good thing to have?

I expect that the internal mics will pick up the full choir and, the lav mic the soloist, at the same time when they perform together? It is important that the internal mic and the lav work together. The radio mic can be used on its own. The internal mic will be used to record the piano when accompanying the solo artists without the choir as well. I realise that this has not answered your question directly but I may have misunderstood that using the internal mics and the external mics to record together is either NOT supposed to be possible or that you can switch off the internal mics when recording. The manual is not that helpful. Sorry for the length of the post but I would welcome further advice. Please note that I am a novice. Thankyou

Your basic assumptions about 4-channel recording are correct. You can use the internal mics and the XLR-1/4" inputs simultaneously, when in the 4-ch mode.

It's a little difficult to tell from your description the nature of the problem with your technique. Obviously, you're hearing a problem. Can you say more about what you're perceiving when the audio "drops out"? Is the volume now too low to hear, or, has the recording stopped and restarted?

Potential problems:
Use of the "Auto Rec" function, which could turn off the recording function when the sound volume drops below a preset level. This one is found in the Rec submenu, Auto Rec should be switched "Off"

Use of automatic recording gain controls, which are almost always a poor choice for music, and may be producing volume-related "drop out" problems. This is found in the Input submenu. Level Auto should be switched "Off".

(While you're checking these menu settings, I'd also recommend that you select Input | Comp/Limit and set both the Mic and Input to "Limit2".)

Once you're no longer using automatic recording levels, you'll need to set these levels manually.

a) In 4-ch. mode, press the Rec button once - it is now flashing, it is in record-pause.

b) Have the choir and piano perform at their greatest volume that will be used.

c) Click the Input-Mic button once, then (within 2 seconds), use the Rec Level control on the side of the recorder to set the Mic volume display such as the peaks in the volume hit about 3/4s up the scale.

d) Have the soloists do the same, perform at their greatest volume.

e) Click the 1 or 2 button, then (within 2 seconds), use the Rec Level control on the side of the recorder to set the IN volume display such as the peaks in the volume hit about 3/4s up the scale.

f) You're now ready to start recording, click the Rec button again - it is now lit solidly and you're recording.

These recording volume settings will be retained, and you should not need to touch them again during a performance or rehearsal.

These is the start of a "best practices" approach to recording in 4-ch. mode. I'm hopeful that this will cure your drop-out problem, however, it is quite normal to do further work on the volume of quiet & loud passages by bringing recordings into a computer-based audio editor.

Re: Zoom H4n weakness...
 

Thought I'd ring in on this. Yes this last gig I dropped the H4n and broke the other external mic....I'd dropped it a few weeks ago and broke the first one.....jbwelded it back on and will probably operate on the other mic tonight - definitely needs a guard or some kind on it cause it's going to drop eventually.

Wish I could order a top mic portion from somewhere but don't know where that would be.