There are a lot of Musical Miracles. I’m going to feed them to you one at a time.
For practicing the bass, I use the H4n “Handy Recorder”. I got a 1/4″ Mono to 1/8″ Stereo adapter at Radio Shack. I set the H4n to Mono mode, plug any one of my playback units (computer, tablet, CD player) into Mic 1, the bass into Mic 2, and put on a headset. Set the level to accommodate the bass, and adjust the level of the playback unit to suit.
I can practice as loud as I want (always avoiding ear damage!) with excellent tone quality, and nobody more than a few steps away can hear anything. I can play along with any rhythm or chord track from just about any source. And perhaps most amazing, between YouTube and all of the legitimate music available on the internet, I can pull up any artist – Ella Fitzgerald, Frank Sinatra, Tony Bennett, Jimi Hendrix, to name a few – and play along in a perfectly balanced mix.
I figure playing jazz bass for the Chairman of the Board whenever I want is a pretty good miracle!