One of the best ways to learn an instrument is to figure out the solos of the musicians you love by listening to them. I would be a better guitarist if I followed my own advice. Before I was born there were musicians who wore out 78 rpm records playing the same passage over and over to learn a piece of music. When I was a teen, the tech solution was to use a variable speed cassette player made for learning music. Half speed not only slowed down the music but kept the pitch in the same key but an octave lower.
Years ago, after music moved from CDs to digital downloads, but before we entered the age of streaming, I used Amazing Slowdowner on Windows to loop and slow tracks of songs I wanted to learn or practice. But there was a period after streaming took hold where you could only slow down and loop a song if you owned a non-copy-protected mp3 on your computer. That’s still the case on Windows and Mac. But, on phones, you can now connect to iTunes or, for me, Spotify and slow down the music.
Spotify’s large library gives you almost any music you can think of to study. The app has controls to select the beginning and end of a phrase to make it easy to loop or concentrate on just a small section of the tune. There are thoughtful controls such as the ability to go back or forward a set number of seconds (you can control how much in settings). You can add a delay to how soon the tune starts after you hit play and between each loop. This can give you time to get setup after hitting play.
The one problem created by Apple when they removed 3.5 jacks from their iPhones is how do you get the ASD playback into your amp if you want to practice with headphones (so as to not drive your family crazy repeating the same phrase over and over and over …).
I can use my Airpod wireless Apple ear buds to listen to ASD loops. It’s nice and private. But that doesn’t help if I want to hear my electric guitar through effects and amplifier. The first, inelegant solution is to use the iPhone 3.5 mm to Lightning adapter. Of course, the stupid adapter is missing or lost so I had to buy a new one to do this. But it works fine. Plug the adapter to a cable with 3.5 mm plugs on both ends, one end into your phone and the other into the auxiliary input on your amp.
The nicer solution is to use a bluetooth adapter. I have several to allow older speakers to be connected to phones and computers. I used a Logitech bluetooth receiver plugged into the amps auxiliary input. Then I could stream the iPhone output from ASD into the amp. Finally, I plugged headphones into the amp and I’m set.
I wish there was a solution where I could stream both my amp and iPhone to my wireless earbuds. The reason there isn’t yet such a thing is because of latency. There’s enough latency in bluetooth so guitar and phone would sound out of sync. Until then, the Amazing Slowdowner app on iPhone (also on Android) is a great learning tool.