How to align two tracks

I had an Audio FIle. I didnt used audacity at time.
I actually had to deleted a small section of that audio and add the required fade out and fade in. Now, I did that on a Android based editor. I was not so happy with the quality and now I want to recreate the EXACT changes in AUDACITY. For that I thought to subtract the original and the file edited on my android smartphone. But it seems that the android based editor not only reduced quality a bit, but also offsetted the audio signal, and not to mention, also added a really small, narrow, loud pulse near the start. How to I align the two signals so that I can subtract the two signals so I can see the difference ( where exactly the fade ins and fade outs started and ended) and recreate them in Audacity. Please help and suggest any FREEWARE to do this or maybe any inbuilt way in Audacity to do this. I spent a lot of time in this project, cant just start-over

That’s very likely with an Android based editor. It is probably using a “lossy encoded” compressed format (such as MP3). Production should always be done in the highest quality available - Audacity works in “32-bit float PCM” which virtually “perfect” quality.

You probably won’t be able to “subtract the two signal” because it is very likely that the waveform of the Android edited version is too different from the original.

What you can do, is to import the edited version into Audacity, and import the original version, then line them up by eye. Use the Time Shift Tool to slide the tracks left / right.

You can also use the track “Solo” buttons to flip between one and the other on playback. Aligning by eye and ear is probably the best you will get - note that you can use Audacity’s “Zoom” features to zoom in / out both horizontally and vertically:

When you have them approximately lined up, Solo the edited track and try to identify where your edits occurred. You may find it helpful to label those parts (

Then apply your edits to the original.
When you are happy with the result, delete the Android version (click the [X] in the top left corner of the track) and Export your completed work.

Note: Ensure to keep backup copies of the original work - just in case.

I did try that, it didnt work very. There was a small signal all the time in the subtraction after aligning that didnt allow me to actually trace the point where the fade out actually started.

I actually oversimplified my situation to get a quick answer.

my original edits are a such:
I took file. Let us imagine it to be divided into three parts. I had to remove the middle part and add the fades. I actually was not sure with length of the fades so I created multiple files. Now it happened such that I liked the first part of a particular file and last part of some other file. So thats what I did, silented the last part in file 1 first part in file 2. And merge them together. Now unfortunately it happened such that the offset generated by my android based editor is different in both files. Although I like this different offset and I want to recreate exact this. This increased a lot of my work.
Still I tried manually aligning it for both parts one by one. As I said there is this small signal everywhere that does not allow the exact tracking. Secondly, its not happening for both left and right. Its not happening on Left. I tried not inverting one of the track and merging but it doesnt work either. Also for the second part, no matter how nicely I align the signals, couldnt get satisfactory results.

Its probably happening bcoz of two signals of each file not being in sync.
Is there a way that I can SEE only one side of all the signals but when I edit anything it occurs on both Stereo signals. I dont want to convert stereo to mono. Thanks

Please someone tell me a way so that i can view only left or right channel of all tracks in audacity but whatever editing i do, reflects on both channel exactly same way. That will really help. Or is there a quick way to invert left and right channel?

You can invert the left channel by selecting the (stereo) track, then applying this code in the Nyquist Prompt effect:

;version 4
(vector (mult -1 (aref *track* 0))
        (aref *track* 1))

or to invert the right channel:

;version 4
(vector (aref *track* 0)
        (mult -1 (aref *track* 1)))

Alternatively you could download, install and use the “Channel Mixer” plug-in: