Hello friends, I want to share with you an old friend I recently pulled off the bookshelves and began diving back into. Harmonic Experience by W.A. Mathieu seems like a standard college music theory textbook, but within a few pages you quickly realize it isn't. He has you learn to sing different scalar tones against a drone and uses simple ratios, overtone series, rhythms, North Indian vocal music training, and what's called a five limit lattice to guide the reader into a new and more connected understanding of Western harmony. When I first read it years ago, and did the exercises, I had already graduated college with a degree in Jazz Studies, Performance, (yippie!) so I had a slightly better than basic background in harmony but it wasn't much more than dry Roman numerals and song forms. This book opened up a whole new world for me. I finally understood what that feeling was when a tune moved to the four chord, or to the flat 6, etc etc,. This new understanding made learning tunes far easier and more enjoyable. I don't know that a musician ever feels "finished" with any aspect of music, but I finally GOT IT and had a whole new arena to learn and grow. I also had a completely different and improved context for intonation. This last point I found most important for double bassists. I'd been practicing with a drone before this, but once he guided me through the ratios and harmonic context of each scale degree, my drone work shot through the roof and my ear sharpened enough to elicit several responses from musicians I worked with often. To that end one might use sine waves or a keyboard patch and I did for a while. But for me the best tools come from an Indian classical musician cum iPhone app developer. Prasad Upasani has written iTanpura and iTablaPro, both of which I bough long ago and use almost daily. They aren't cheap but are so well made and so flexible, and have taught me so much I see no need to justify the price further. iTanpura is an app which generates the sound of the tanpura, the 4 (or 5) string Indian drone instrument you hear in the background of every Ravi Shankar record. Any key, and raga, very customizable. iTablaPro combines that with a very musical and flexible Tabla machine, allowing any taal, tempo, etc. Us bassists likely need only one or the other, I ended up with both because he wrote one first then came out with the other a year later, and I like playing along with a tabla keeping time better than a metronome. So, that's what I brought for show and tell. I hope someone here picks up one or all of the tools I mentioned and profits from them as much as I have. I'm not affiliated with either W.A. Mathieu or Mr. Upasani, just sharing the love.