Hey guys. Due to all the kind folks here recommending a high quality tape deck, I was able to get a very important (to me) demo tape from a music group I am friends with onto my computer. One song I was particularly fond of never made it to an album in its full form; it got snipped after 1 minute. On the demo tape I found the full-length version.

Unfortunately, the cassette tapes are over 10 years old and not the best sound quality. However, I am somewhat in luck because on one of the band's albums, the beat to the song is untouched by lyrics for the first few seconds of the song. This means if I can emphasize the vocals of the demo tape and drown out the music/beat (especially the drums) as much as possible, I can then loop the CD's beat and make it sound damn-near as good as they originally intended.

Here's the album version, only a minute and a half long (but perfect sound quality):

http://members.aol.com/filesftp/takethat1.mp3

Here's the demo version, a full 2 minutes + longer (but pretty lousy sound quality):

http://members.aol.com/filesftp/takethat.mp3

I of course am not asking someone to do this for me, I am totally capable of re-looping the music and putting it to the vocals. The only part I am going to have trouble with is drowning the beat out of the vocals from the demo tape as much as possible.

I hope what I am trying to do makes sense. If someone can explain to me my best bet for doing this, you don't know how much I'd appreciate it.

See if you can subtract the beat from the vocal section. If they used a real loop you should be able to line up an inverted section of the beat, mix the two, and end up with an vocal only result. Hopefully any offsets resulting from the tape or beat variance can be hidden by the better quality beat when you add it later.

When it comes to looping perfectly I am totally fine. The inverting is where the trouble begins as I'm not sure how to do that, not to mention even though I tried for a few hours, I cannot get the CD beat the same speed as the tape.

When I've done something similar I've used Audacity which includes an action to invert the selected audio. Also, I wouldn't try to subtract the CD beat from the tape audio. If there's a clean section of tape beat, use that. Then once you have the vocals isolated you can move to matching the speed of the CD and tape. If you can't isolate the vocals by inverting the beat I think your only option is to try playing with filters to just filter out the music. Audacity might have a "karaoke" filter for something like this, but I doubt you'll get the quality results you're looking for.

It's gonna be hard to exactly match the speed of both recordings. Both don't run at exactly 44100 Hz. At the very least you'll have to compare the length of data between two beats far away from each other in clip A with the same beats in clip B, and then resample one of the clips to make the difference zero.

If it is analogue tape you may try as a first step to do noise reduction of the tape noise/hiss.

AFAIK Sony (formerly known as SonicFoundry) has a NoiseReduction Plugin that allows to take a noise fingerprint from a silent part of the tape and subtract that from the rest. But I think there are even more software solutions that include noise fingerprinting than only that plugin.

There is an "old trick" of removing vocals by subtracting the left from the right, which eliminates everything that's identical (and in-phase) in both channels. There are instructions on the Audacity website, but apparently, you want to do the opposite and there is no similar simple trick.

If you attempt to subtract (invert and add/mix) the CD-file from the tape-file (or vice-versa), your results will be useless, due to timing phase differences. The above trick only works when the left & right channels are exactly in-phase... For example, if they are 180 degress out-of-phase, you will double the signal when you subtract!

There are some programs/tools that attempt to extract vocals. Two that I'm aware of (but have never tried) are a plug-in for Winamp called DSP_Centercut and Adobe Audition's Vocal/Instrument Extraction feature.



Right! Most audio editors include a noise reduction filter. Here is the information about Audacity's noise reduction filter.

The Noise Reduction tool does no magic. If you cut everything below a certain threshold, this truly means everything – you cannot recover the low level signal. Basically you trade hiss against the file sounding like an MP3 – artificial, bubbling. NR works if you don't expect a singal to be below the noise floor, for example, if you have only bass notes submerged in HF hiss.

There is a lot of frequency overlap between the music and vocals, which rules out using filters.

Neither the music nor vocals are constant in time (obviously!), which rules out noise reduction.

There is a lot of spatial overlap between the music and vocals, which rules out Audition's Center Channel Extractor.

I am afraid you're out of options. The only way which might lead you to some success is using frequency space editing in Audition. This means working in Spectral Frequency View, painstakingly identifing, selecting, and deleting (better: reducing in amplitude) individual components which constitute music/beat. Chances are that it will take a month or so of work, and the result will be crappy anyway.

This is a pretty depressing end to my attempts but I appreciate all the incredible help here.

If I ever manage to get it sounding good, I'll post it here.

I don't know how to extract only the vocals from this track, however I got it sounding a little better to my ears just by running it through BBE Sonic Maximizer and Audition's Adaptive Noise Reduction.

http://rapidshare.com/files/128617411/takethat.flac.html

Not much of an improvement really, it's too bright and there is some annoying high-frequency swooshing weirdness (I only used default settings - you might be able to do much better with these tools if you have time).

Is this Onyx btw?

Actually that sounds pretty damn good considering it's all cassette audio. My idea was to remove as much of the beat as possible (most importantly the drums) and loop the CD beat to it.

Yeah it's Onyx, it's an unreleased long version of a song from their Shut Em Down album. If you happen to be a fan of theirs I'll send you some stuff for being cool enough to help out.