Speed change

[Stephen47]

I am trying to make a sound track for a slide show. After I import and edit the first song everything is fine, but when I import and edit more songs and paste them into the first track the speed changes. I have to reduce the speed by about 6% to get the sound right. Why does cutting and pasting change the speed?

[steve]

I suspect the problem is that you are trying to mix audio with a 44100 Hz sample rate and audio with a 48000 Hz sample rate on the same track.
Audacity 1.2.x does not support multiple sample rates on the same track.
If you keep the imported files in their own tracks then you should not get the problem. Alternatively, upgrade to Audacity 1.3.12 (Audacity 1.3.x does support multiple sample rates on the same track).

[kozikowski]

Audacity doesn't convert well and it assumes the audio standards of the first song imported. I wouldn't be surprised if you came out OK if all your songs were imported from music CDs, but you got stuck if one of the selections was a video. Video and CDs have slightly different sampling rates.

Are you saying that importing songs two, three, and four, causes song one to go off?

Where are all the songs coming from and are they different generic groups, like iTunes, CDs, MP3s, etc.

You might install Audacity 1.3.12 and try that.

http://audacityteam.org/download/

Audacity 1.2 is really really old and may have troubles with newer sound formats.

You can safely install both 1.2 and 1.3, just use one at a time. Audacity 1.3 projects will not open in 1.2

Koz

[Stephen47]

Song one stays the same. The others speed up. Some came from CDs others came from iTunes
I will install Audacity 1.3.12 and report back. Thanks for the timely response.

[Stephen47]

I installed version 1.3.12 and that solved the speed problem. Now however when I try to export it as an MP3 file that option doesn't show up on the file menu, but it was there yesterday. Where did it go?
Never mind I didn't have the track selected.

[Stephen47]

I am still having speed issues with one song. All the other ones I have added to the track play at the correct speed. This song is from iTunes like several others but for some reason it plays fast.
I have adjusted the speed so it sounds right. I have set the project rate at 48000 Hz. I really don't know what that means. Are audio Hz the same as video Hz in that it is about refresh rate? Is there an article on line that would explain this?
One last question I need to add about two seconds of space to this track. Is there a way to insert blank spaces?
Thanks.

[kozikowski]

<<<I need to add about two seconds of space to this track. Is there a way to insert blank spaces?>>>

Generate > Silence [select duration] > OK.

Video tends to be 48000 and Music CD standard is 44100. That's the sampling rate. Music is continuous, but it can't be inside a digital system. It has to be broken up into samples so each sample can be assigned a value. Each second is hacked up into forty eight thousand chunks in a video system which is just slightly higher quality than a Music CD.

Many production systems are color-blind to those two numbers since they're both so common, but some older software like the early Audacity care about it and it's important to know which they are and to get them right.

Audacity can still get killed with a sound file in a compressed format that it doesn't understand. Those files will play fast and the only way out is to convert them to WAV or AIFF or other good quality format before Audacity gets there.

Ever used iTunes to do format conversions?

Koz

[Stephen47]

NO I have never tried itunes conversion.
If I change the project rate to 44100 will that help? I notice some of the songs are at that rate when I import them but I was just changing the rate, not really understanding the implications.
thanks for the reply.

[Stephen47]

Another question. When I started this project I set the project rate at 48000. Can I change the whole project back to 44100 or do I need to star over?

[steve]

You're using Audacity 1.3.12 now?
If so, then yes you can change the project rate any time you like. Just click on the Project Rate box in the lower left corner of Audacity and select the sample rate that you want.