|How to Record and Edit Digital Music
(by Vic Ceder)
|Digital Music Interest Session
This paper is for square dance callers interested in
using Cool Edit to record and edit music.
It describes how to use Cool Edit to record music from vinyl into MP3 files on your computer.
This paper addresses the following:
- Connecting Your Computer to Your Turntable/Amplifier
- Setting Recording Volume
- Recording Music
- Eliminating Spikes
- Normalizing Volume
- Noise Reduction
- Removing Leader and Trailer
- Other Functions
- Saving Music
|Connecting Your Computer to Your Turntable/Amplifier|| |
To record music in digital format, your computer must first be connected to the music source.
- Plug a cable from your amplifier's output (Tape/Line Out) to your computer's input (Microphone/Line In). Most likely, this cable is a dual RCA male connector at the amplifier end, and a stereo 1/8" phono plug male connector at the computer end. The connections on the amplifier and the computer should both be 'low' level connections. Don't use the speaker output ('high' level) from the amplifier! Using a 'high' level connection may overload your computer's sound card.
- If possible, use a shielded cable. This minimizes interference such as that caused by inadvertently draping the recording cable over an AC power cable.
|Setting Recording Volume|| |
The recording volume should be set so that the level is neither too soft nor too loud. Either condition may result in distorted recordings.
- In Windows, open up your sound card's mixer panel (double-click on the speaker icon in your system tray; or, from Start/Settings/Control Panel, select Sounds and Multimedia followed by Audio/Volume). Make sure that wave is not muted, and that the volume sliders are at least halfway up.
- Within the mixer panel, set the sound card's recording devices by going to Options/Properties/Select Recording and click OK. Make sure that Line In is not muted and its volume slider is at least halfway up.
- Launch Cool Edit. Go to Options/Settings and click on the Devices tab. Make sure that your sound card is selected for both Waveform Playback and Waveform Record.
|Recording Music|| |
Recording is the process of getting the music into digital format (WAV) into the computer.
- In Cool Edit, create a new file by selecting File/New. Choose 44,100 samples per second, 16-bit, mono, and click OK. Mono is fine for square dance music, since most of our sound systems are mono. You can select stereo if you prefer, but be aware that the resulting WAV and MP3 files will be twice as large.
- Click the record button and then play the music you want to record. Watch the decibel meter (the pulsating bar near the bottom of the Cool Edit screen). The level should typically vary between -18 and -3 dB. If the level goes past 0, then the input signal level is too high (overloaded), and the recording will be distorted. Adjust the input volume level as necessary so that a desired dB range is achieved throughout the recording. If you modify the input volume level, be sure to start over and record from the beginning of the music. When the music is finished, click the record button again to stop recording.
- The amplitude wave form for the music is now displayed.
|Eliminating Spikes|| |
Occasionally, a piece of recorded music may contain one or more high amplitude abnormalities (spikes). This is somewhat rare, and might occur only in about one out of fifty records. These spikes should be eliminated so that the volume can be normalized (balanced within a normal range). If the spikes are not removed, 'normalizing' has little effect.
- Examine the amplitude wave form and determine if there are any spikes. A spike is a single large vertical line within the wave form. It may be caused by a 'pop' in the record, or some other music abnormality. For each spike, highlight the area and zoom in on it. Repeat until you have zoomed in a few times, and you've only highlighted the spike itself. This will usually be about five to ten data points. Data points are indicated by dots on the wave form.
- From the Cool Edit menu, select Transform/Amplitude/Amplify. Click on the 'Constant Amplification' tab and drag the 'Amplification scroll bar' to the left to decrease the amplification percentage to about 40%. Click the OK button. The amplitude of the spike should now be reduced to an acceptable level.
|Normalizing Volume|| |
Normalizing increases the volume of the 'loudest' point (sound) to the maximum volume level, and proportionately increases the volume of all other points. You should 'normalize' all your music before you save it, so that the volume level is the same on all your files. Normalizing ensures that when you change music selections, you don't have to change the volume controls on the computer or the amplifier.
- Highlight the entire the wave form (click anywhere on the wave form). Then select Transform/Amplitude/Normalize. Normalize to 100% and click OK.
|Noise Reduction|| |
Noise Reduction removes or reduces hissing, scratches, and other non-desireable noise. The resulting music often sounds significantly better, especially when recordng from older vinyl.
- When music is recorded from a vinyl record, there is a section of noise at the beginning (after the needle is placed on the record and before the music starts), and a section of noise at the end of the record (after the music stops and before the needle is lifted). Noise sounds like the light hissing you get when you play an old or slightly worn vinyl record.
- Select a sample region of noise by highlighting it (highlight as much as possible -- at least 2 seconds). You may need to zoom in to the area before highlighting it.
- Choose Transform/Noise Reduction/Noise Reduction. In the resulting dialog box, click on Get Profile From Selection. This generates a noise curve from the selected region. This noise curve will be used by Cool Edit as a template to find and remove similar noise from the entire recording.
- Close the noise reduction dialog box and zoom back out to the entire wave form. Make sure the entire wave form is highlighted (click anywhere on the wave form).
- Choose Transform/Noise Reduction/Noise Reduction. In the resulting dialog box, click OK. Cool Edit will now use the previously generated noise curve, and remove noise from the entire recording.
- After the noise has been removed, the region you initially selected for the sample noise should now look more or less like a flat line.
- Listen to part of the recording to make sure that it sounds okay. Sometimes too much noise reduction makes the music sound tinny. If this is the case, undo the change, then get back into the noise reduction dialog box and try lowering the 'Noise Reduction Level' from 100% to perhaps 80%.
|Removing Leader and Trailer|| |
Within a recorded piece of music, there are usually a few seconds at both the beginning and ending of the recording consisting of blank space. That is, the recording contains the few seconds before the needle was placed on the record, and a few more seconds as the needle reaches the start of the music. The leader and trailer 'blank' space should be eliminated so that the recording contains only music.
- Highlight the region of the wave form before the music begins and delete it.
- Highlight the region of the wave form after the music ends and delete it.
|Other Functions|| |
Recorded music can be modified in many other ways.
- Change tempo and pitch independently (via Transform/Time & Pitch/Stretch).
- Increase volume for certain section (select a section and then Transform/Amplitude/Amplify).
- Use an equalizer to reduce drums or vocals.
- Cut out a section (such as a long intro), or cut and paste to increase the duration of patter music.
- Apply filters to the music (boost or reduce treble or bass, old time radio, etc.)
|Saving Music|| |
The recorded music should now be saved on your computer. I usually save each music selection as both a WAV file and an MP3 file. I copy WAV files to CD-ROM for backup purposes and then delete them from my computer. I copy the MP3 files to my laptop so I can play them at a dance.
For Mono recordings, the size of a WAV file for an average square dance record is about 20 MB. The size of the corresponding MP3 file is about 1.7 MB. For stereo recordings, the respective sizes are about 40 MB for WAV and 3.4 MB for MP3.
- To save the recording as a WAV file, click on File/Save As and select Windows PCM (WAV).
- To save as a MP3 file, click on File/Save As and choose MP3. If there is an option to save as Variable Bit Rate, do not select it. Some players have trouble playing variable bit rate encoded MP3 files.
|Cool Edit Software and Help|| |