Most of this has been posted here and there before, but I thought a summary might now be handy.
Should I be reading this?
Much of the following advice assumes you will download your H2 recordings to a PC for post-processing. If you are using it simply to record and play back via its headphone/line output, you may find some of the built in functions more worthwhile. ISome advice on settings is also perhaps more applicable to wave format recordings than mp3 recordings, where the processing that goes on to compress and decompress the audio can introduce other considerations in some circumstances.
The Zoom H2 is the audio equivalent of a point and shoot digital camera. Such cameras normally have provision for digital zoom and colour effects like black-and-white or sepia, but nobody in their right mind uses that stuff if they have access to Photoshop software or the like. It's much better to process copies of the images in the PC than irrevocably in the camera. Likewise, the H2 has digital level control (functional equivalent of digital zoom) and limiters etc (comparable with sepia effects) which are best avoided if you will have the opportunity later to apply such changes to the recording in your PC at your leisure and non-destructively.
The key feature of the H2 is its twin stereo mics. Consider what you would have to take out with you as an alternative - two stereo mics, mixer with four mic preamps, multichannel recorder or a laptop with firewire audio interface, and associated cables. Make the most of the built in mics and you'll get the most from the H2.
Analog recording level control
This is the switch on the side marked H M L (High, Medium, Low).
Tests using wave format recordings have shown that there is no audible difference between the H and M settings, if you raise the level of a low-level recording you made using the M setting by 10dB in the PC later on. Noise levels are identical. The H setting risks overloading and distortion in the analog preamp if there is an unexpected loud event. Therefore, you may find that you only ever need to use the M and L settings to record from the built in mics - forget about H. However, the L setting introduces about 6dB more noise than the M setting and should only be used if you are convinced that overload will occur with the M setting. M seems to cover most situations apart from loud amplified music. With that advice in mind, do some tests of your own and see what works best for you.
Digital recording level control
The record level control (0 - 127) should always be set to 100. This control simply changes the level in the digital domain and you can do that in the PC afterwards just as effectively - and at that point you'll know what the recorded levels were. Raising the recording level in the H2 above 100 risks digital overloads unnecessarily. Lowering the level in the H2 below 100 will not prevent analog overloads - all you will do will be to reduce the level of the already-distorted audio. (If recording very loud amplified music, L100 might result in both analog and digital overload - you might find that using a setting below 100 in that kind of situation could give a better result by at least removing the digital distortion component, though you'd still hear quieter analog distortion - I'd suggest doing your own tests).
Rec Mode settings
Tests have been unable to show any useful outcome from using 24 bit wave recording mode settings in the H2. The analog stage noise levels, while perfectly acceptable for making recordings from the built in mics and from line-in sources, are above the 16 bit noise floor. Using 24 bits to record significantly increases file sizes for no proven benefit, with this recorder.
Using higher than 44.1kHz settings can provide extended frequency response but whether the resulting larger file sizes are worth the benefits should be considered. (However, there is evidence that the chipset in the H2 is optimised for 48kHz recording - you might want to try that yourself and judge the benefits).
High frequency cutoff at about 16kHz in mp3 recordings even at 320kbps can be seen in tests but this may not be a significant problem with most sound sources. If space on the memory card is not a problem, don't use mp3 settings - you can easily convert from wave format to mp3 in your PC later.
Making long recordings (over 2Gb)
The file size limit on the H2 is about 2Gb - how long a recording that provides depends on the recording format you are using. There's some guidance at http://www.zoom.co.jp/english/products/h2/sd.html
which might help you work out what's you'd get into 2Gb. When the H2 reaches that limit, it will think for a while - maybe around 20 seconds - then it will create a new file (or files, in 4tr surround mode) and carry on. You'll lose that 20 seconds of audio. If you really need very long recording times without stopping, and you don't need 4tr surround, consider using mp3 format at the higher bitrate settings, which should avoid the whole problem.
AGC, limiters and compressors in the H2 all appear to work in the digital domain. They will not help in avoiding analog clipping in the preamp. It is recommended not to use them in the H2 as the mangling of the sound that results cannot be undone afterwards. If you want a compressed or limited sound, use one of the many built in or freeware effects in your PC audio editing software after recording, and save the result as a copy, thus preserving the integrity of the original recording in case you change your mind later. To even out the level of spoken word recordings in your PC, try "Levelator" freeware software.
Using the built in mics
Be aware that you can't use the 4 channel surround mode for mp3 recording, but the H2 will automatically switch in and out of wave format for 4 channel if you normally have mp3 selected for recording in other modes.
If you have space on the memory card, you might consider using the 4 channel surround recording mode in preference to the 2 channel surround mode, as it permits you complete freedom afterwards to remix the front and rear mic files. That gives you remarkable flexibility in creating the sound image.
Using external mics
Noise levels when using external mics have been found by most users to be higher than expected. If you have a minidisc recorder, you'll probably get better results from that. If you are thinking of buying an external mic to go with the H2, take the H2 to the store to test compatibility. And expect to pay more than you paid for the H2!
Using line level sources
The sensitivity of the line input socket seems slightly higher than it should be. You cannot control it from the H2 in the analogue domain. If the device you have connected to the H2 has no means of controlling the level it outputs from its line-out socket, see if the level from any headphone socket it may have can be controlled, and connect that to the H2 line in - you will probably get perfectly good results that way. As a line-in recorder the H2 seems at least as good as a minidisc recorder, and of course subsequent file transfer is much simpler and quicker.
Be aware that this is a one-shot process - once the H2 has started recording and then stopped, it will not start again. It's basically intended to allow a musician wanting to record their own performance to set up the H2, get in position at their instrument, and then have the H2 record from the start of the performance.
Monitoring of the built-in mics or external inputs can be switched on permanently in the menu, enabling you to judge the effect of changing menu options before recording - normally you cannot enter the menus when in record-pause mode. You could use the H2 as a mic outputting to another recording device in this mode. But monitoring will continue during playback. This could be a nuisance sometimes, or handy if you want to hear what's happening around you while listening on headphones. Note that if you connect to an amp and speakers while monitoring is on, you could get feedback.
If you don't have that option you need to download and install the latest firmware from http://www.zoom.co.jp/english/download/software/h2.php
- basically it allows you to set the left/right soundscape correctly when you record with the rear mics facing the performers.
Almost everything in the file menu would be more quickly accomplished in the PC later but if you are on location and you want to delete unwanted files, you'll be glad to be able to do this in the H2 itself. Normalising and converting to mp3 in the H2 seems to take a long time - if you can, do that in the PC.
Playback operations are pretty straightforward - the only unexpected thing is that to play back a four-channel file, you need to have the four channel surround mic pattern selected on the front of the recorder - then it will access the dedicated four-channel folder for playback as well as recording. The way the fast-forward and rewind keys operate depends on the file type in use and whether you are paused or actually playing - investigate what happens if you hold down the buttons.
Transferring files to the PC
The USB port on the H2 is USB2 but "full speed" - slow! - rather than "high speed", which is true USB2. You will probably get a quicker transfer by removing the memory card from the H2 and putting it into a USB2 high-speed card reader instead.
USB Audio interface
I've found that the H2 doesn't work well as an audio interface if connected via a USB hub. If you have problems, try connecting it direct to your PC.
The manual says that cards up to 4Gb can be used but cards of 8Gb are now listed as working with the H2 on their site at http://www.zoom.co.jp/english/products/h2/index.php
- keep an eye on that site for updates. But bear in mind that the maximum filesize the H2 can record without a break is 2Gb. You may also need an SDHC compatible card reader for your PC if you use cards of 4Gb or more.
Be aware that the H2 settings are stored on the memory card and will be lost if you format the card, or use a new card with the H2. You will then need to skim through the menus setting things back the way you like them, although if you accept most of the advice above you will find the default values are about right. You can copy the settings from the sys folder on the card if you want a backup.
Enjoy your H2!
If your expectations are realistic, you'll find the H2 is a great little device for the things that it's good at - chiefly as a surround mic for the price of a stereo mic, with a built-in recorder thrown in free. Please do add your own hints and tips to this thread - and correct me if you think I'm wrong on any point!