voice recording over mp3

[steve]

So you can record a vocal track into an empty project and it works fine, but if you import another file into the project, then try to record, it sounds bad.

Could you tell us a bit about your computer - what's the hardware, sound card, operating system, how much free disk space, other programs running (including anti-virus, desktop widgets, firewall and everything)

What settings do you have in:
Edit menu > Preferences > Audio I/O tab
and
Edit menu > Preferences > Quality tab

[LMPeach01]

sound card is SigmaTel Audio (recently updated to newest version), OS is Windows XP, i have Macafee anti-virus (no firewalls that i am aware of) and 68GB of free-space on my hard drive.

I/O settings are set to use SigmaTel Audio for both playback and recording, with boxes checked for "playing other tracks while recording a new one" and "software playthrough."

Quality settings are:
default sample rate - 44100Hz
default sample format - 32-bit float
real-time sample rate converter - fast sinc interpolation
high-quality sample rate converter - high-quality since interpolation
real-time dither - none
high-quality dither - triangle

does that info help?

[steve]

Try dropping the bit depth from 32 bit down to 16 bit.
Also see if you can set MacAfee to ignore ".au" files (if MacAffe is checking audacities data files as they are being written it will seriously interfere with recording).

Can you upload a SHORT example of the distorted vocal track to http://www.sendspace.com/ or somewhere similar, then post a link so that we can hear what kind of distortion you have. (post it as a WAV or FLAC).

[LMPeach01]

i have tried changing the bit from 32 to 16. as far as mcafee is concerned, i'm not sure how to set it up so that it doesn't interfere with .au files.....

i've uploaded an example of the noise i get to sendspace: http://www.sendspace.com/file/3acy7z

hopefully that gives you a better idea of what's going on!

[steve]

i've uploaded an example of the noise i get to sendspace:

Oh, that's not actually a sound file, it's the "Audacity Project File".
When you save an Audacity Project, there are two parts to the project; there is the ".aup" file and a folder containing lots of little data files. The .aup (Audacity Project file) just contains instructions for Audacity to tell it how to organise all of the little data files. The .aup file does not actually contain any of the audio.

To get an audio file from an Audacity Project, you must "Export" the audio (File menu).
In this case, to export the vocal track, you need to select the track, or part of the track that you wish to export, then select "Export Selection" from the File menu.

Although I can not play the file that you sent (it won't play in Audacity on my computer because I do not have the data that belongs in the project) I am able to tell that the volume level of your music track ("07 - Ceremony - How Beautiful (Twila Paris)") is very high (with peaks over 0.99 on the vertical scale). If you play another track at the same time, even though both tracks may be below 0dB (+1.0 to -1.0 on the vertical scale) and not distorted, if you play them back together without reducing the volume the result will be distortion.

When you "mix" tracks together (play them at the same time) it is effectively "adding" the two signals together.
If you look at the playback meters while you play back the two tracks, you will see that at times the level goes right up to the top of the scale (0dB) and is actually trying to go further, but because 0dB is the maximum level it is distorting. To prevent this from happening, you need to reduce the volume level of the individual tracks. You can do that using the volume level sliders on the tracks.

[LMPeach01]

ok, here's the new link uploaded as an exported file: http://www.sendspace.com/file/d5b15h.

also, if i understanding your feedback regarding the volume of the track correctly, it seems like all i should have to do is adjust the volume of the track using the sliders.....but i've done this and it doesn't seem to make much of a difference.

[steve]

if i understanding your feedback regarding the volume of the track correctly, it seems like all i should have to do is adjust the volume of the track using the sliders.....but i've done this and it doesn't seem to make much of a difference.

I've got that audio file now - it helps a great deal to see what is happening. That is certainly a lot more than just a little bit of distortion on the vocal, the vocal signal is completely breaking up into digital noise.

The point made above about adjusting the volume sliders is still valid (and yes I think you do understand correctly), and that will help with the quality of recordings once we get the microphone working correctly, but this horrible noise is caused by something different, so we need to sort that out first.

Unfortunately this is not an uncommon problem with some USB devices.
As a matter of interest, what make and model is your microphone? - also, what is your computer, (laptop, desktop, model number)?

What is happening is that for some reason the USB connection is being momentarily lost, and then the data coming through it is all out of sync and is received by Audacity as that horrible digital noise instead of your beautiful singing. The USB connection is almost working correctly as we can hear that it sounds fine for the first 20 seconds or so, but it is just on the edge of not working, and as soon as anything increases the strain a tiny bit, the sync is lost and signal turns to noise.

We need to find a way of making the USB connection more reliable (and preferably without having to buy new hardware).

Try this as an experiment:
Shut down your computer and physically disconnect your internet.
Reboot, then shut down all non-essential things that are running (anti-virus, wireless, any "widgets" or other auto run applications...)
Open Audacity.
Now try recording a vocal track - does it work?
If that works, try recording another vocal track (a new track will automatically be created). - does that work?
Keep adding more vocal tracks until the problem occurs - how many tracks can you get?
(If you zoom out to view the entire show, then Audacity will not need to scroll the display while recording, and this may allow you an extra track or two).

[LMPeach01]

well, i'm using the mic (SigmaTel Audio) that came with my webcam....so it's not the greatest. but seeing as it works fine when just recording a new sound file, i feel like there's got to be more going on. my computer is a Dell Inspiron E1405 laptop. the weirdest part about this USB connection is that if i attempt to record over the track, but do no speak or sing into the mic (i.e. just let it record nothing) then the weird sound distortion doesn't occur. so it's almost as if it's my use of the mic that causes the problems rather than just some weird USB connection....

i will try disconnecting everything and rebooting and recording again and let you know what happens. did you want me to record a new, clean vocal track or try it over the mp3 file again?

[steve]

i will try disconnecting everything and rebooting and recording again and let you know what happens. did you want me to record a new, clean vocal track or try it over the mp3 file again?

Reboot your computer.
Shut down all non-essential auto-start programs.
Start a new Audacity project.
Record your voice (creates track 1)
Record a second voice part (creates track 2)
Repeat the above adding voice tracks.

"On my ancient Pentium III 500MHz desktop computer I can achieve 8 tracks before the recorded sound starts to break up - this is with a conventional microphone, not USB - also, I'm using Linux and not Windows).

[LMPeach01]

i finally had a chance to test recordings. following your instructions, i've been able to record 16 tracks on top of each other without any feedback, echo, or distortion....is this sufficient to tell you what you need to know or should i keep going for however long it takes to before the sound starts to break up????