Mixing final song in real time

Hi all,
This is my second post. I am very new to Audacity and received great advice on my first post that totally rectified issues I was having with recording. Now I have successfully completed a multi-track song and would like some help with mixing down a final version as a .wav file in real time.

The tracks that I am recording are on top of pre-existing recordings a friend of mine sent me (he wanted me to add keyboard parts over his guitar, drum, bass, and vocal parts, so the songs he sent me are single tracks even though multiple instruments are present). He wants me to email him only the parts I have added and he will mix them onto his final recordings. I have successfully recorded all of the tracks I wish to add and have saved them in Audacity’s .au format. I now wish to mix them into a “final” wav file to send him. What I wish to do is mix them in “real time”, however, so that I can tweak the levels of each track individually as the recording plays. The reason for this is that I want the volume levels of certain tracks to either increase or decrease at various points during the song. When I used to use N-Track back in the day (or my old school Tascam devices), this was very easy to do. You would simply select “Mixdown while playing” when saving your wav file and this would give you the ability to tweak each track’s level individually while listening to the track in real time. Can anybody walk me through how to do this in Audacity? Or will I need to obtain a separate software to perform this sort of function.

Another quick note: the original track that my friend sent me I want to mute entirely so that the track I send him includes only the tracks I am adding to it. I see that I can click “mute” on that track while doing a playback. Will this also remove it entirely from the final mix? Or is there a better way of achieving this? Thanks everybody so much again for your time and help.

I believe muted tracks do not contribute to the final mixdown on Export. You can MUTE as many tracks as you want.

You might consider Mix and Render to a New Track and test that track for volume and overload problems. Then you can either export that one track or delete it and Export normally.

If you have a pile of individual instruments each on their own track, you can select each one by clicking just above MUTE and File > Export Selected. That would be my choice unless the music producer said not to. You can get to a mixdown from the individual instruments, but you can’t start from the mixdown and get back to the individual instruments. If you provide a mixdown and do any one single thing wrong, that’s the show in the bin.

Audacity doesn’t do anything in real time. It’s a feature request.

saved them in Audacity’s .au format.

It’s dangerous to get this wrong. Audacity will not save a sound file. It saves Projects. This is a Project.

If you know about .AU files, then you’re in the wrong place. Double click the AUP file and it will launch Audacity and tell it how to manage your show with all the stuff in the _DATA folder. If you delete, move, rename or damage one of the .AU files by accident, you could trash your show.

Projects only open in Audacity, so no, they’re not generic audio files. There is no AUP or AU sound format (although the AU files will play briefly in Audacity).


Koz, thanks again for your expertise.

You are correct about the au files. I meant that I have saved all of the tracks I am adding in one Au project. What I now wish to do is mix these tracks (there are five individual instrumental tracks I added in this project) into a single final wav file to send my friend. I really need to do this–mix them together–in real time while listening to the audio, though (just like in a regular professional studio, the ability to tweak each track’s levels individually in real time while making the final mix is critical for me, since at certain points in the song I want certain tracks to either grow louder or quieter individually). You say that Audacity cannot do this, so would my best bet be to save each of my 5 tracks as individual wav files then mix them together in real time using a software that enables mixdowns while playing (such as N-Track)?
Thank you so much for your help.
I have saved two different au project files by the way (a back up just in case something goes wrong).

Is there anything else I should be aware of or look out for?

You say that Audacity cannot do this, so would my best bet be to save each of my 5 tracks as individual wav files then mix them together in real time using a software that enables mixdowns while playing (such as N-Track)?

Yes, the software of your choice. It’s a very common error to press Export by accident instead of Export Selected and then wonder why it’s taking way longer than you thought it should. Export is trying to process all the tracks in the whole show instead of the one track you picked.

Your job is messier than you think. Not only do you have to “move the volume sliders” in real time, your software has to remember the moves, right? Audacity can do something like that with the Envelope Tool (two white arrows and bent blue line). But it’s very note-by-note manual and totally not real time.

Select a track > Make a change > Listen to it > Repeat.



For multitrack mixing, a [u]DAW[/u] (digital audio workstation) application is more appropriate than an audio editor. With a DAW, you can usually move the volume sliders in real-time like a hardware mixer, or you can automate the sliders.

In Audacity you can adjust each track’s gain-slider

in real-time, ( i.e. while it is playing ).

However the envelope-tool can’t be adjusted while the track is playing …