It is moral if it is also legal.
The moral issue here is stealing (or not).
If the owner of the music (copyright) makes it available for free and offers it for download, then there’s nothing wrong with downloading it.
If it is not offered for free download by the actual owner (either directly, or by legitimate proxy), then it’s stealing.
The easiest way to know is to ask the simple question: is it legal?
The next question is: how does one know whether a particular download is “legal”?
The short and simple answer is: Do I have a choice of paying for this, or getting it for free? If you have a choice, then you have to pay. No one puts a song on iTunes for $1.99 to give it away elsewhere. Similarly for movies and apps. The “free” option is provided by a third-party who has stolen their work, so that they themselves can make money assisting other people to steal it.
One can apply a bit of commonsense, by first asking:
- Is it likely that this artist or their publisher intended this to be free?
- Does this app, or site, appear to circumvent the legitimate means of distribution?
The answer to the first question is that, in most cases, professional artists and their publishers expect you to pay for their work. They do not go to the effort and expense of producing quality work, just to give it away. If you are downloading a free copy of anything by a professional artist then look for affirmation from the artist or producer that this particular work is intended to be free. For professional artists, paid work is the rule, and free the exception.
Upcoming and indie artists sometimes provide work for free, as self-promotion. If such is the case, then it should be clear. Download it only from their personal page, where they make it available.
Artists know and care about copyright, and if they intend something to be free then they will say so. You don’t have the excuse “No one told me that this wasn’t free”.
The answer to question two is also quite simple, in most cases. Any site, or app, which provides a large number of free downloads of professional work is illegal. How to tell? If you can search for any current hit or movie and download it, then it is illegal (and stealing if you use it). 100%.
There is an important distinction between downloading and viewing. Downloading is when you make your own copy of the item, and viewing is when you watch it on the site, or play it on your phone, without keeping a copy. This is where many violations of copyright happen. If the publisher of a video or song intends you to download it, then they provide a Download option on the site, or app. If you have to use a third-party app to download it, then you are stealing. The most prominent example is YouTube. YouTube material can be watched legally on the site, but to download anything is “stealing”, because you are circumventing YouTube’s copy protection.
In short, if you have a choice of paying or getting it for free, then pay, except when you are watching the clip without downloading. Anything else is almost certainly stealing, unless you can prove that this particular case has published for free by the artist or producer.