I rarely have to search for apps in a hurry, because during a pandemic, a computer with a full set of software is always at my fingertips. Today was a sunny day and I could not resist going out of town. Of course, one of the clients needed to add background music to the podcast, and it is not really convenient to do this on the phone. A Google search for guides on how to mix two music tracks left me confused.
The first thing that surprised me was that almost all the articles on highly respected sites are slightly modified variations of the same source. The problem is that the original article was not written by an expert, and the rest of them thoughtlessly spread these harmful tips among their readers. Take, for example, the recommendation to merge MP3 files by simply copying the files through the command line. What will happen to the ID3 tags? Some decoders will ignore them, others will give an unpleasant click, and others will stop playback altogether. The main thing - it is not clear why to give such advice if competent merging is not much more complicated and does not require buying additional software.
The second thing that surprised me is that to combine audio files, they recommend non-profile software, which was originally designed for other tasks. Yes, you can hammer nails with a microscope, but why? With a huge variety of sound editors and online tools, buying video editors or screen recorders looks silly, to put it mildly.
And lastly, all the advice on merging files comes down to sequential merging, the mixing operation is nowhere mentioned. My experience with sound shows that even with consecutive merging you should at least equalize the volume and apply smooth transitions. And it would also be nice to take into account the matching of tempo and key, but that's a topic for a separate article.
Given this situation, I decided to outline my recommendations for mixing audio files using different tools. Of course, no article about audio editing is complete without mentioning Audacity, so let's start with it.
1 Open source way
We open two files, but for some reason, it starts with two separate copies of Audacity. Okay, highlight the sound section and see what operations are available from the context menu. Right-click on the highlighted sound and nothing happens. Maybe there are operations you need in the main menu? Alas, they are not. C'mon guys, are you serious? Do you want to zoom in with the mouse wheel? Forget it! That said, I do notice the ability to add a new track to a project and import an audio file into it. Yes, after that both files play in parallel and you can apply effects to them, I couldn't move the beginning of one track relative to the other without digging in the documentation.
What conclusions can be drawn? The developers have their own, original, idea of convenience. They have not heard of multi-window interfaces and contextual menus, and even I could not figure out the individual effects without looking at the help. It's hard for me to understand the popularity of this editor because its only merit is that it is free. It was impossible to quickly mix two files in the usual way, and the creation of a multi-track project with subsequent mixing puts us in a completely different weight category, where the full-fledged DAW rules.
2 Online audio mixers
Maybe we should try online solutions? The first one that came up was Clideo, but it got stuck on preprocessing for a long time and was shut down for a while. Later I gave it a second chance and waited for the files to be downloaded and processed. It did not surprise me with anything good, so let's take a look at its competitor Audio-joiner.com. It loaded quickly, but all options are limited to changing the order of audio tracks and setting the fade-in between tracks. There is also an obscure option to trim each track by selecting a certain range. Who and why it was needed, history is silent.
So is there something simpler and more convenient with mixing capabilities? Yes, about that in the third part of the article.
3 Balanced approach
WaveCut Audio Editor was originally designed to handle multiple files in multi-window mode. Microsoft has been diligent in getting rid of MDI applications imposing the concept of tabs, but they are much more convenient for visual work. Right after loading two files, we can visually estimate the volume. This is not an exact method, you can read more about volume levels and normalization in a separate article. Here we just use the usual normalization for easy reference. Under no circumstances should you set the level to 100%, as you will encounter overload when mixing. The next step is to set smooth transitions at the ends of the files. It all depends on your preferences. At this point, the preliminary preparation is complete. you can move on to the hard part. Although... it's not that hard, we just select and copy a file in one window, and then we choose the paste position in another window, and then press Paste Mix. This is a fairly natural order of action, familiar from Notepad. Moreover, the channel selection panel on the left part of the window allows manipulating the individual channels - you can copy and shuffle them in any order.
4 Conclusion
As always, you have three options to choose from. If you have plenty of free time, you can dive into learning Audacity and get pretty good results. If you don't have time to study and download software, then online tools are not much help. At least the ones that are free. The last option, using WaveCut involves buying a lifetime license for $15. Then comes the simple arithmetic - if your time is worth more than $15, then the commercial program will cost you less than the free one. So that's the surprise.