The nice and accurate guide to Sound Studio filters.
December 15, 1999
author: Lucius Kwok <lucius@felttip.com>
web page: <http://www.felttip.com/products/soundstudio>
This is a little documentation on the Sound Studio filters. All the filters work on the entire sound file if you haven't selected anything, but if you do select a portion of the file, only the selected part is changed. With that in mind, let's plunge alphabetically into the filters.
Amplify
This is the volume control knob for the sound. 100% equals the current volume. Turn it up, get a louder sound. Turn it down, it's quieter. You want to be sure not to turn it up too much or it will clip the sound. Clipping is when the waveform tries to be bigger than the height of the channel it is in, and since there's no more room (headroom), the parts that don't fit simply get chopped off. Unless you like that kind of sound, you should try not to amplify it too much.
If you're trying to get the sound volume to a certain loudness, try the Normalize filter.
Power user note: you can go past 200% by typing in the desired amplification, for example for 4x amplification, just type in 400% in the input field, and it'll amplify at 400%.
Backwards
I don't know if anybody really uses this filter for anything but having fun. It turns your sound around so that it plays backwards. The effect is the same as playing a tape backwards. Don't blame me if you find Satanic messages when you use it.
Delay
This filter mixes a single copy of your selection with itself, but at a lower volume and offset by the amount of time you specify. It's kind of like having a tape loop which records what you say and plays it back a certain amount of time later, or shouting across a valley and hearing your reflected echo once -- but it reflects the sound only once, unlike a true echo.
You can control how long of a delay you want (you can use decimal numbers like 1.345 here), and the strength, or the volume, of the delayed sound.
Echo
This filter is just like Delay except it keeps repeating itself over and over at lower and lower volumes until it dies out. It's like a real echo, one you'd get if you were to shout inside a canyon. The controls are pretty much the same as for Delay. Note that the echo will end abruptly at the end of the selection unless you first insert silence at the end of the sound file and select the audio plus the silence when applying the echo filter.
Emphasize
This is an equalization filter which emphasizes the high tones (treble) in a sound. It tends to make sounds more crisp.
Fade In
Fade Out
This pair of filters do what they say: they fade in from silence and fade out to silence. The fade is a linear fade, so if you have a constant volume sine wave and you fade it out, you'll see it taper off at the same rate throughout the entire fade to silence. You'll want to select just the part that you want to fade. For example, if you wanted to start fading out at five seconds before the song ends, you would select the last five seconds and appy the Fade Out filter.
Invert
This filter simply turns your waveform upside down. You won't hear a difference after you've applied the filter. If you consider waves which go above the centerline of the display to be positive and waves which go below to be negative, the Invert filter just makes the positive parts negative and vice-versa. This filter is useful when you have a stereo file and one of its channels is inverted relative to the other. The audio will sound like it's coming from the sides when you listen to it in stereo, with no audio coming from the center. This filter will be useful in the future when you can select each channel individually.
Noise Gate
This is a more complex filter. It silences passages of audio which fall below a certain 'threshold' volume for a certain length of time (the 'attack). If the noise level is high, increase the threshold. If you're silencing too much stuff that's not noise, decrease the threshold. If short lengths of noise are not being silenced, decrease the attack. If there's too much noise hanging around the edges of the good stuff, increase the attack.
Normalize
This filter brings the volume of your audio as high as it can without clipping. This way, you can make sure you're using all the bandwidth (height of the channel) that you can get. Adjusting the 'Normalize to' value changes the maximum amount of bandwidth you want to use. At 50%, the sound volume will be brought up (or down) so that only half of the available bandwidth will be used.
The 'Adjust tracks individually' option controls whether you want to treat the two left and right tracks as independent audio tracks or as one stereo track. If the audio you're editing already has its balance between the left and right sides perfectly set, then you want to leave this option off. However, if one side is much louder than the other and you want to wo balanced, you want to select this option.
Smooth
This is the complementary filter to Emphasize. This one reduces the high tones (treble) in the sound file, making it less bright. It can also help reduce perceived noise in the audio by smoothing out the waveform.
Swap Channels
This filter simply swaps the left channel with the right channel, in case you had the left and right cables mixed up when you recorded the audio.
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Lucius Kwok Felt Tip Software
email: <lucius@felttip.com>
web: <http://www.felttip.com/>
snail mail: 807 Keely Place / Philadelphia PA 19128 / USA
