How splice audio selections smoothly?

[14452dollars]

First off, I apologize if this sounds like a really dumb question. I'm a true blue newbie and I appreciate any pointers and help.

I opened an MP3 file of music in Audacity 1.3.x Beta in Windows 7 and deleted the sections of the file that I didn't want.
I then copied and pasted that section into a new track in Audacity twice and put them next to each other.
I wanted to hear how the sections sounded when put back to back while having the option of adjusting each section to get rid of residual "ticks," hums, clicks, etc. when one selection ran into the other one due to, say, the resonance of a bass from the now-deleted sections of the initial file.
I just don't know how to minimize/get rid of those annoying sounds without further trimming off bits of my sections and affecting the music I hear.

I've heard of voice removal, equalizers, envelope tool, etc., but I'm not sure that those methods are suitable here.
I plan on continuing this splicing for a video project I'm working on. So I'm open to advice.
Thank you for reading!

[kozikowski]

Step one we warn people never to do production in MP3. MP3 is a compressed sound format and has compression damage built-in. The damage goes up as you use the file in your edit.

So from the idea that it's never going to sound perfect, you need to make sure that there is no DC level on each of the parts of an edit. This is a blowup of a bad edit caused by DC in the show.

http://kozco.com/tech/audacity/pix/DCOffset.jpg

You can't easily fix this in post production.

Each of the pieces of the edit (Before the edit) can be run through Effect > Normalize with only "Remove DC" selected. All the pieces of work that you do that to should cut together with no serious click or pop problem. This is where MP3 kills you. You can't export a corrected clip without additional quality damage.

If you still have very slight 'things' at the edit point, you may need to go into serious wave level editing. The Out point of a clip must match the In point of the next clip. The up and down wave rhythm has to be maintained.

Like this...

Screen shot 2011-08-27 at 9.55.25 PM.png (15.92 KiB) Viewed 3911 times

Not like this...

Screen shot 2011-08-27 at 9.56.26 PM.png (12.95 KiB) Viewed 3911 times

[kozikowski]

You will find yourself living in the magnifier tools so you can see problems like this. Drag-Select and Control-E, for controlled zoom in, Control-F for full, Control-1, Control-2 and Control-3 for fine zoom control.

The corrections need not be crazy. You can select the first quarter of the wave after the edit in illustration 2 and delete it to make the wave rhythm line up again. That's a very, very, tiny fraction of a second of show time.

I doubt you'll need corrections like this, but it does depend on the show.

Koz

[14452dollars]

Oh. So with that in mind, would it be better to convert the mp3 to another format if I can to have a better file to edit or is the damage already done and I can't get any higher quality than that? I'm assuming it's the latter.

BTW, thanks for your help so far. It was very informative.

[bgravato]

Oh. So with that in mind, would it be better to convert the mp3 to another format if I can to have a better file to edit or is the damage already done and I can't get any higher quality than that? I'm assuming it's the latter.

The damage on mp3s is permanent and irreversible.

When you make a recording you should make a backup in an uncompressed format such as wav or flac.

You should do all the editing using uncompressed formats. You can save it as an audacity project, while you're working on it. MP3 exportation should be only the last step (and you should still keep an uncompressed copy of the final work).

[steve]

You will find yourself living in the magnifier tools so you can see problems like this. Drag-Select and Control-E, for controlled zoom in, Control-F for full, Control-1, Control-2 and Control-3 for fine zoom control.

You can also zoom in and out using the mouse wheel while holding down the Ctrl key.
While zoomed in you can scroll left/right along the track with the mouse wheel while holding down the Shift key.

would it be better to convert the mp3 to another format if I can to have a better file to edit or is the damage already done

The damage is already done, so there's no point converting. Koz's comment is really "for future reference" you should (whenever possible) use high quality originals that are in an uncompressed format. If the source material is not available as a WAV or Flack file then just use the best quality source file that you can obtain.

[14452dollars]

Okay, thanks for all the suggestions. If I encounter any mystifying problems, then I will come back and ask appropriately.