Recently in Audacity Category

"I have recorded some tracks in Audacity using the project sample rate of 44100Hz. I also imported a track from a portable device at 16000Hz. All tracks sound fine when played simultaneously. However, when I want to insert an audio into the 16000Hz file, it is
distored. I have 2 questions:

1. Is there a way to integrate the two files into 1 track; and
2. Will I have a problem exporting mixed sample rates to CD?"

Mixing sample rates in an audio project can cause all sorts of problems with your final output. There is an easy fix to your problem, which is to simply resample one of the audio files so that it matches the other files.

"Is there a way to add two audio clips to a Windows Movie Maker video which overlap each other?"

Windows Movie Maker only supports two audio tracks: the audio track recorded with the video is one of the tracks; the other movie maker audio track is the Audio/Music track. In your case you need an additional audio track, so that you can layer your two audio files on top of each other. If you plan to do this regularly , the easiest thing to do is graduate to a more complete video editing suite, like Pinnacle Studio, Roxio Creator, or Sony Vegas. If you're on a tight budget or you'll only do this one time, you can combine the two tracks in another application, save out a single audio file, and import the combined audio file into Windows Movie Maker.

Tony writes, "Part of [my] podcast will involve material I record on an Olympus Digital Voice Recorder WS-100. It transfers the files to the PC via USB connection. However, when I tried to open the file with Audacity, it says the file is a Window Media file and need to convert it."

The Olympus WS-100 is definitely a convenient tool for voice recording applications. Before I get into how to convert Windows Media WMA files to WAV files you can edit with Audacity, let me offer an important tip: if you plan to edit the audio recorded with the WS-100, make sure you record in the HQ mode. The lower quality modes apply extra compression which is great for saving space, but your audio won't sound good if you recompress to something like MP3 later.

To convert files from WMA to WAV, the easy (although somewhat ugly) solution is WinFF. The app uses file conversion support from FFmpeg to convert between many different audio and video formats. Below are step-by-step instructions for converting from WMA to WAV with WinFF.

Converting WMA to WAV with WinFF

1) After downloading and installing WinFF, launch the application and select the WMA file or files you want to convert to WAV.

2) Choose the Wav for CD option from the Choose Format to Convert to... menu.

3) Pick a Destination folder to save your file(s) and click Start Converting.

When the conversion finishes, you're ready to edit the WAV files in Audacity or any other audio editor.

This tutorial should work for both Linux and Windows.

Mike asks, "I have a 7 second heartbeat audio track. I want to make it a 5 minute track. What is it called and how do I do it?"

What you're describing here is what's commonly referred to a looping an audio track. This is frequently done with a section of audio that's either repeated for a few times throughout a musical composition or a loop might be used to create a bed for an entire segment of music. The actual implementation varies slightly depending on which audio application is used, but the basic premise is the same - you figure out how long the piece of audio you want to loop is (7 seconds in this case) and then you establish how many times you need to play a 7 second file to achieve 5 minutes of continuous playback. I'll walk through the process of creating a 5 minute loop from a 7 second track using Audacity, which works for Windows, Mac and Linux.

If you don't already have it, download Audacity and install it before starting this project.

First open your audio file in Audacity by launching the application and choosing Project > Import Audio from the menu. With the audio file open, select the entire audio file either from the menu by choosing Edit > Select > All or the key command Ctrl+A.

Choose Effect > Repeat from the menu

Audacity bases repeats on the number of times required to repeat the file to achieve the desired length. 5 minutes is 300 seconds, so assuming your file is exactly 7 seconds long, it needs to play almost 43 times.

In order for the file to play 43 times, you need it to repeat 42 times because the first time it plays already exists on the audio timeline.

You can see after clicking okay the timeline shows 5 minutes of audio instead of the 7 seconds we started with. Save your new file by choosing Export as WAV from the timeline and you now have a 5 minute audio file with the original 7 second file left untouched.

How do I combine two audio files with different sample rates in Audacity? I get voice mail files that come in at 8000 Hz, some recordings with my portable recorder at 16,000 Hz and my music files tend to be 44,100 Hz. When I play the tracks in Audacity, the lower sample rate files play to fast and sound weird. How do I fix this?

Sample Rate is important to audio files for two reasons. Sample Rate is the number of times per second you capture a snapshot of audio information during recording. Higher sample rates result in great audio detail, the same way you get smoother motion in video by capturing more frames per second. On playback, it's necessary to know the sample rate for compatibility with output specifications.

Audacity assumes everything in your project is the sample rate of the first file in your project. So if the first audio file in your project is an 8000 Hz file, the rest of the files are played as if they were 8000 Hz files also. Even though the Audacity track details show the original sample rate of a file, the software automatically matches the sample rate to the project sample rate during the import process. What you describe sounds like you changed the rate of an 8000 Hz file in a 44100 Hz project using the track Set Rate feature. This is easily fixed and you can get matching sample rates across files in a few simple steps.

What you describe is the result of using the Set Rate feature on any given audio track. Changing this setting from its default actually alters the waveform to conform to that sample rate. Because 8000 Hz audio takes up less digital space than 44100 Hz audio, changing its rate from 8000 Hz to 44100 Hz using Set Rate results in the same kind of playback speed increase you get from playing a 33 RPM record at 78 RPM. Avoid Set Rate for matching sample rates on files.

Instead, save the audio file at the current Audacity Project Rate. The project rate is located in the lower left corner of the Audacity interface. It defaults to the first audio file added to a project. So if your first Audio file is a 44100 Hz file, the Project rate is 44100. All tracks exported from the project will default to 44100 Hz. If the first track imported into a project is 8000 Hz, the entire project will be 8000 Hz and exported files will be saved with a sample rate of 8000 Hz.

To make sure all files have a matching sample rate, open the files you want to use for your project. Verify the Project Rate for the files is the sample rate you want for your entire project and choose Export Multiple from the file menu. At that point, you select the output format (WAV is best for incomplete projects), an output location and the naming convention for output files.

Close the project after exporting all tracks. Reopen Audacity and import all the tracks you just created. All files will have matching sample rates.