DandyDon wrote:
hello? anybody out there? is this the wrong forum for this? please help?
No not the wrong forum, the questions are easy, but the answers are difficult. First a lesson in vocal removal.
You can reduce the level of a vocal (or other lead instrument) in a stereo recording by taking advantage of how vocals are generally recorded: in mono and placed centered in the mix. Since the vocal track is present in both the left and right channels equally, you can, in theory, remove it or at least reduce its level by subtracting one channel from the other. Instruments panned away from center will not be removed, although the tone of those instruments will probably be affected. The basic procedure is to reverse the polarity of one channel, and then combine that with the other channel. Any content that is common to both channels will thus be canceled, leaving only those parts of the stereo mix that are different in the two channels. Reversing the polarity of an audio signal means that the parts of the waveform having a positive voltage are made negative, and vice versa. (This is often incorrectly called reversing the phase.) One important drawback inherent in vocal removal is that, by definition, it reduces a stereo mix to mono. Since you are combining the two channels to cancel the vocal, you end up with only one channel. However, there are ways to synthesize a stereo effect afterward, and that will be described later.
You cannot remove vocals effectively if your source is an MP3 file. In order to remove vocals, the vocals in the left and right channels must be exactly identical. Then when the polarity is reversed in one channel and the channels are combined, anything common to both channels - what's panned in the center - is cancelled. But MP3 encoding processes the two channels separately, so they are not identical enough to cancel.
It is impossible to completely remove a vocal or reduce its level, without affecting other instruments in the mix. First, even though most vocals are placed equally in the left and right channels, stereo reverb is usually added to vocal tracks. So even if you could completely remove the raw vocal itself, some or all of the reverb is sure to remain, leaving an eerie "ghost" image. If you plan to record yourself singing over the resultant track, the new vocal can have its own reverb added, and you may be able to mix your voice loud enough to mask the ghost reverb from the original vocal track. Another limitation arises because vocals are not the only thing panned to the center of the mix. Usually, the bass and kick drum are also smack in the middle, and those get canceled along with the vocal! However, you can minimize this problem by rolling off the lowest bass frequencies on one channel before combining it with the other. Since one channel now has less low end than the other, the low frequency instruments will not completely cancel. In fact, of the software programs I've seen that offer a vocal removal feature, none alter the low end on one channel before combining, so the bass and kick are eliminated along with the vocal.
DandyDon wrote:
I simply want to be able to take a .kar, or midi or an mp3, remove vocals or use a .kar file, and sing into wave format, then convert to .mp3 to be able to save as a file or send in email.
I am not aware of converting midi or kar into wave/mp3, but you can play them through your soundcard and record them, unless you have a decent sampler with sounds allocated to your midi events. The you will have a midi/kar file playing the sampled sounds. Otherwise your stuck with the electronic sounds of midi/kar.
DandyDon wrote:
I really would like to start using Karawin, but for the life of me i can't figure out how to use it.
Sorry, I learned it by reading the manual. Karawin is a playback device, not used for recording.
Here are the steps to remove the vocals (keep in mind that results cannot be guaranteed, it depends on the recording)
Steps for Removing Vocals
The most basic procedure is to load a stereo Wave file of the original song into an audio editor program, flip the polarity of one channel and lower the bass level somewhat, and then combine the left and right channels into a new, mono track. I use Sound Forge 4.5 from Sonic Foundry, which includes all the tools needed to manipulate audio files this way. Most other 2-track audio editors have similar capabilities, and this technique will apply to those programs as well. Sound Forge lets you load a single stereo file, manipulate the left and right channels separately, and then combine them to mono all within one edit window. But for these instructions, I split the channels into separate files to make each step easier to follow.
1. Load the original stereo file.
2. Copy just the left channel to a new edit window.
3. Copy just the right channel to another new edit window.
4. Reverse the polarity of the new left channel.
5. Apply a low end shelf cut starting at 200 Hz. (at least 12 dB./octave) to the new left channel.
6. Paste the processed left channel into the new right channel in Mix mode (not Overwrite).
7. Audition the result and, if it's acceptable, save it to a new Wave file.
It is possible that combining the two channels will exceed 0 dB., and you will need to reduce the level of both channels a few dB. If you lower only one channel, the two channels will not combine equally, and the vocal level won't be reduced as much as possible. To roll off the bass frequencies, I used Sound Forge's Parametric EQ in the high-pass mode set for 20 dB. of cut starting at 200 Hz. (This filter setting affects the lows, so why does Sonic Foundry call it high-pass rather than low-cut?!) If you use Sound Forge, be sure to select the highest accuracy filter mode, since how quickly the EQ is written to the file is less important than having the filter perform exactly as you ask it to. Besides cutting the extreme low end on one channel, you can optionally reduce some of the highs too. This lets you retain strings and cymbals and other instruments that have treble content and are centered in the mix. In general, you can cut those frequencies that are outside the vocal range--for male singers you need to start the roll-off at a lower frequency than for females. Remember, the frequencies you cut from one channel are the ones that will not be canceled when you reverse the polarity and merge it with the other channel.
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