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I am new user for Audacity. I have a music file in mp3 format which is of long length. I need to cut it short to create jingle for playing them in background of a standup comedy show. When I cut the big file in small parts, the audio comes in mono format. I want the output to be in stereo mode. Can anyone tell me how to get mp3 format in stereo mode using Audacity when I don’t have its original uncompressed format with me?
Audacity imports mp3 files in stereo mode by default. But if you see the wave editor for that file, you will see that all the sound signals that are represented by blue color lie in the top channel of the track. Right click on the wave to get the track menu. I the menu, choose ‘Split Stereo Track’. Now you will have one empty track which you need to delete. Now you will have the audio file in mono format which plays through both the speakers. Now even out the volume using ‘Compressor’ effect. As you said that it will be used for standup comedy show, chances of it having laughter noises is possible. Set the noise of laughter at the ratio to 10:1 along with the music. Remove the unwanted noises or maybe noises that aren’t needed.
Another way to maintain the stereo mode of mp3 file while working in Audacity is by splitting the main track into subtracks. After converting them into subtracks, they will be in stereo mode. But then chances of it converting automatically in mono mode increases as you will start applying effects or start editing the track. To avoid this, problem, work on the subtracks in ‘Solo’ mode. Using Solo mode will create new instance of workspace for every workspace under same project. The ‘Solo’ button can be found on the left side of the track.
When an audio is encoded in mp3 format, some of the data is eliminated to optimize the file in small size. This loss is unnoticeable, but when trying to extract data from mp3 file, one realizes that it was necessary for processing. This data cannot be recreated or recovered again. To avoid this, next time you record audio or get recorded audio, see to it that it is in lossless format like .wav, .flac, .aiff. Mp3 format should be used to deliver music and not for presentation of production quality of music.
If you are working on wav format then to convert mono track into stereo mode, then I know the best method that will help you. For now you can simply convert the existing mp3 file in wav forma and try this out. Follow the steps,
1) Import the long wav file as stereo in audacity.
2) Split the track according to you need. Remove he unwanted parts.
3) Now remove DC offset using Normalize effect.
4) Apply dynamic compress with optimal settings. The values I used were like Ratio: 0.8, Hardness: 0.8, Floor: -18.0 to -32.0, Noise gate falloff: 4.0, Maximum amplitude: 0.99. You can use them according to your need and condition. This will clear the unwanted noises during silent parts in audio.
5) Apply High pass filter to control bass. To remove pitch, use Low pass filter.
6) Now normalize the audio and then render it in stereo format.
I too work on audio on Audacity and I have worked on many such files which are mix of music, speech and laughter. Many which I worked on were mono and converting them in stereo is one uphill task. If you are having any problem converting Mono to stereo, I know a method using which you can acquire good quality of audio in mono mode.
a] Split the mono track and delete the remaining empty channel.
b] Create an instance of the remaining track in the empty channel.
c] Remove the DC offset.
c] Apply Low Pass filter of 48 dB per octave @ 7000 Hz to tackle the crackling sound.
d] Apply High pass filter of 48 dB per octave @ 80 Hz to remove any thick unwanted voices.
e] Apply Level reduction of -12 dB, Threshold -37 dB, Attack/Decay 250 ms to keep the silent parts clear.
f] Apply Equalization, 800 Hz slider at +6 dB and Amplify up to +1 db.
It will give a good quality of audio in mono mode. Converting it into stereo mode will enhance the effect.
I have used the above method many times and it works great. But to improve the effect generated by it. You can normalize the audio before removing the DC offset. You can also try Applying Normalize before applying amplify effect. It may not be needed every time but is worth a try. Try vale of Amplify effect between -1 db and 1 db. You can play along to see which value suits the best for you audio.
If you are working using computer speakers or speakers that have quality like Television speaker then they eliminate certain small effects in sounds. Some effects work better if you are using Headphones. So I suggest you to try out the output you get on various speakers. IF you find difference in them, then you can render different versions for headphone and audio speakers. You can use amplify to achieve this.
If you are working on audio samples with difference in intensity of volume, then I suggest you to remove the DC offset with different values. When you remove the DC offset, the headroom is decreased. To compensate for this loss, normalize effect is used. It optimizes the audio peaks to make available some headroom for further editing.