ils-labs-dev

ils-labs-dev

How-tos

Recording with a Zoom H4

Last updated on 29 June 2015 by Jan de Mooij

If you have suggestions on how to improve this document, or find mistakes, please send them to labman.gw@uu.nl

Introduction

For research outside the building, we have some solid state recorders available. You can borrow them from the lab technicians in room 0.09. Be aware that you have to reserve a recorder in the reservation system in advance. We have one Zoom H4 compactflash audio recorder available, which is available in the reservation system CF Recorder 4. Other options are the Marantz PMD671 audio recorders (CF recorder 1 and 2), or the Zoom H6 recorders (CF recorder 5 and 6).

The recorder is a small, handheld device, with two high-quality build-in microphones on the top and two external microphone inputs on the bottom, which can both be used as either XLR or 6mm Jack.

This how-to only describes the most common procedures for recording. If you want to do more advances stuff, e.g.record with four microphones at the same time, using the device as a Digital Interface (recording directly to the computer) or playing back audio from the device itself, you are free to figure it out yourself, but we advise reading the manual. You are entirely responsible for the recording yourself, so do make sure you know what you are doing when you try other settings and always make sure to test the setup you are using extensively. When making changes to the setup of the device, always revert them to how you got the device

When you borrow a Zoom H4 recorder, you get a softcase containing:

  • Zoom H4 portable handheld audio recorder
  • SD-card
  • USB cable
  • One pair of AA-batteries
  • Manual
You’ll probably be asked what kind of audio source you have. For recording a group of people, sitting around a table, you need a omni-directional microphone that picks up sound from all directions. But when you want to make a clear recording of the pronunciation of a certain language, it’s better to use a microphone that only picks up the sound from one direction.
The batterylife for the Zoom H4 recorder is decent, but it would not be ill-advised to keep at least two spare batteries around, in case you run out. The same goes for storage space. The Zoom H4 recorder uses a standard SD-card, but the one included is only 2GB. If you need to record lots of audio and do not have access to a computer to back up your recordings regularely, it is a good idea to take a few spare SD-cards with you.

The top

On the top of the recorder are the two microphones. You do not need to touch these and, in fact, should try to make sure nothing else touches it either, because those are very delicate.

Behind the microphones are located the SD-card slot and battery slots, under a small flap. To open this flap up, pull the locking mechanism on the flap to the back and then pull upwards on the flap itself. Once you do this, the batteries will no longer make contact so the recorder will shut down, so don’t do this while using the recorder

The left side of the recorder

From top to bottom:

  • line: A line-in input. This is used to record a pre-amplified source (so not a microphone). This input takes a 3.5mm (mini-)jack plug.
  • phones: Use this to connect your headphones to.
  • <triangle>: Volume control for the headphones (note, this does not affect your recording! Only the headphones).
  • On/off: On/off-switch. The recorder is switched on when this switch is in the top position
  • usb: A mini-usb connector to connect the recorder to the computer (either to copy the recordings to your computer, or to record directly to your computer)

The right side of the recorder

From top to bottom:

  • Jog Dial: Used to navigate through the menu. Can be pressed (to click on a menu item) or pushed up or down (to navigate through the menu)
  • Input1/2/mic: Used to control the gain (sensitivity of the microphones). Input1 and 2 are to control the external microphones which can be connected through XLR/Jack at the bottom, MIC is used to control the gain of the two microphones on the top. Each of the sliders has three positions, for low gain when put all the way to the bottom to high gain when put all the way to the top.

The front of the recorder

The front of the recorder is divided in three column. Each of the buttons on the front light up if that button is enabled:

  1. Left column
    • 96kHz: enable recording in really high quality (uses a lot more space)
    • 48kHz: enable recording in a very decent quality that takes less space. This sample rate is what ZEP uses by default, so if you want to save yourself some trouble while recording for ZEP, use this sample rate
    • 44.1kHz: enable recording in a slightly lesser quality which uses slightly less space
    • mp3: enable recording in mp3 quality. This automatically encodes the recording to use less space, by disregarding all frequencies that cannot be perceived by humans
  2. Middle column
    • Display: The display shows the audio meters of the incoming audio when you are recording, plus some meta information. It also shows the menu when you open it, which allows you to change settings like which folder it will record in or whether or not to use phantom power
    • Joystick: The joystick allows you to open the menu or play back audio. It does not allow you to navigate the menu. Use the jog dial on the right side of the recorder for that
  3. Right column
    • Rec: This button starts the preview when you click it once and the recording when you click it again. Preview means the audio meters start to work (uses more battery) but you are not yet recording. You can use this mode to listen over the headphones if the audio quality is good and check the meters to see if the gain is not set too low or too high. When the rec button flashes red, it is in preview mode. When it is continuously lit up, the device is recording
    • Lights: Access shows the card is in use (either it is being read, or it is being written to) and mode is burning continuously or not on at all if it is recording in stereo mode or using all four microphones simultaneously respectively.

  1. Decide if you want to use the build-in microphones on the top, or if you want to use one or two external microphones. If you want to use external microphones, connect them to the XLR/Jack inputs at the bottom.
  2. If you have any headphones, connect them to the phones plug.
  3. If you have a power supply and a power outlet you can use, best plug in the power supply. Otherwise, use the batteries.
    If you need to make recordings on locations where no electricity is available, the Zoom H4 can operate on two AA size Alkaline batteries or on two rechargeable Ni-Cd or Ni-MH batteries. Make sure you always use the same type of batteries and then check the manual to set the battery type. When not set up properly, the battery indicator will not show the appropriate battery status. In case of rechargeable batteries, you need an external battery charger.
  4. Switch on the power supply by moving the power switch to the up position.
  5. Open the input menu by pushing the bottom of the menu joystick, and select the source you want to use.
    1. Enable or disable phantom power, based on whether you need it. If you have an external microphone that requires phantom power, make sure phantom power is enabled. In all other cases, disable phantom power. The internal microphones don’t require phantom power. Phantom power does drain your batteries more quickly.
      When enabling phantom power on a microphone that does not require phantom power, the best-case scenario is that you won’t be able to get the gain right. The worst case scenario is that you will break the microphone
    2. Decide which quality you want to record in (see the ‘buttons and input’ tab).
  6. Place the microphones in the position you want to use them (remember, closer to the source of the audio results in better quality).
  7. Ask the person that will provide the sound to make the same sounds they will make during recording (this can be speech, singing, making noises or anything else, but make sure it’s the same type of sound they will make during the recording). Press rec once (so the red light in the button will start to flash) and the meters should start to move. Set the gain switch for the microphone you are using to the position where the meters do not touch the right side of the meter bar when the audio source is making the sounds at the loudest level they will use during recording.
    For the best recording quality, the microphone is as close to the audio source as possible and the meters go as far right as they can without ever touching the right side of the bar. When the microphone is further removed from the audio source, you will need a higher gain. After using the gain switches on the right, you can get more control over the gain through the input menu (push the bottom of the menu joy stick). Whenever your gain is too high, meaning the meter will touch the right side of its bar, clipping will occur, meaning you will lose data. This is why you always want to test with the loudest the source is like to be during recording. When the gain is too low, you will hardly hear anything on the recording. This can usually be amplified, but not without severe quality loss. This is why you don’t want the audio source to be louder during testing than it will ever be during recording. Whenever possible, it is good to try to keep the audio source as much at the same audio level as you can as well, but this can often be hard.
    Once you have set up, always make sure to listen through the recording and check the device regularly. Just testing the setup in advance is not enough as people might start to speak louder or less loud once their mood changes, external settings can vary or the device can stop recording on its own accord. By constantly checking how the recording is going, you can avoid nasty surprises afterwards
    If you haven’t done a lot of audio recording before, it is a good idea to experiment with the device for a time, before asking participants to come in. This will help you in knowing what to do and make the participant less wary of having to wait for you to set up the equipment.
  8. Once you are satisfied with how the preview sounds, you can start the recording by pressing rec again. As soon as the light is on continuously, the device is recording. Make sure you, or someone else, keeps checking the device to see if everything keeps working correctly!
  9. To stop recording, just press rec again. This should stop the recording simultaneously to the light in the recording button going off.
  10. You can then play back recordings by pressing the top of the menu joy stick on the front. By pressing right or left you can skip to the next recording, or the previous and by pressing and holding right or left, you can search through the recording.

You can connect the recorder to every computer that has a USB interface. The recorder will behave as a kind of memorystick. You can copy the .wav and .mp3 files to your computer. (Don’t forget to make a backup copy, for example on a dvd or cd-rom!)

To connect the computer to the recorder, follow these steps:

  • Take the USB cable and connect it to the recorder and the computer, while the recorder is switched off.
  • Switch on the recorder.
  • Wait for the recorder to display the “USB MODE SELECT” menu. Use the jog dial to select “CONNECT TO PC”
  • Within a few seconds, the recorder should be visible in your file explorer.

Please remove your audio files after you copied them and before you return the recorder to room 0.09.
You can either delete the files manually from the computer or from the recorder, or format the card entirely. Check the manual for instructions on how to format the SD card.