Some guitarists like to tune their instruments lower than normal to achieve a slightly deeper sound. Drop-D tuning is one version of this, and other players tune the whole instrument down a half-step to Eb or even a whole step to D. The effect is quite noticeable and makes the music being played sound darker.
Another very cool option available to the guitarist is to play in a much lower register with a baritone guitar. The baritone guitar is a six-string instrument that falls halfway between the sound of a normal guitar and a bass guitar. It’s generally tuned either a fifth lower (A D G C E A) or a fourth lower (B E A D F# B) than normal. I opt for the fifth below.
The baritone guitar is played just like a normal guitar, except the strings are thicker (especially on the bottom end) and the fret spacing is wider.
If you’ve ever seen an early Clint Eastwood “spaghetti western” movie you’ve heard the powerful and mysterious sound of a single chord being strummed one time on a baritone guitar at key moments.
The sound of the baritone guitar is captivating. It’s an amazing sensation to play the guitar as you normally would and to hear a huge, deep, throaty half-octave-lower sound emanate from your instrument. It can inspire an exciting new direction in your playing and composing.
Danelectro introduced the first solid-body electric baritone guitar in 1957. It looked just like their standard electric guitar but with a neck that was five inches longer! They referred to it as the “UB-2 six-string bass”.
Guitarists as diverse as Jerry Cantrell, Allan Holdsworth, Ani DiFranco, Pat Metheney, Andy McKee, Joe Bonamassa and Dave Matthews have explored the baritone guitar in their recording and performing careers.
Baritone guitars are available from Danelectro, Fender, Gibson, Gretch, Schecter and Ibanez, among others. Try one next time you’re at your favorite music store.
A unique aspect of guitars is that manufacturers are always innovating and making a great-sounding instrument sound and play even better. I remember when the first Ovation guitars appeared in 1966: they were met with a lot of skepticism. Unlike past guitars, only the face of the guitar was made of wood. The sides and back were an unusual semi-parabolic-shaped solid piece of composite material. However, when they started popping up on stage in the hands of artists like John McLaughlin and Al DiMeola who made these instruments sound incredible, people gave Ovations a second look. Turns out, the optimized shape and the composite material Lyrachord combined to produce excellent resonance and sustain. As a result, the guitars soon became very popular.
I recently wrote a post listing the 
Okay, I’m the first to admit it—many of the greatest rock guitarists used long straps that positioned their instruments somewhere just above their knees and played with their arms extended straight downwards in ape-like fashion. Think Slash, Keith Richards, Chuck Berry. And that’s why many of the current generation of rockers follow that example. It’s iconic and it looks cool. But, it creates a lot of technical problems. 
I learned this lesson early in life through the experience of a friend. He left his beautiful Martin acoustic guitar in its hard-shell case on his bed with the case unlatched. Then his mother decided to move the guitar. When she picked up the case by its handle, the top flew open and the guitar fell out and smashed into the case top, destroying the exquisite spruce face of the instrument.
There’s an easy trick: Turn down the volume. The slightly muddy, distorted sound of electric guitar chords that you get with your amp turned up and your guitar volume at 9 are great for playing chunky rock progressions and creating a powerful wall of sound. But what if you’re playing a song that has an intricate fingerpicking part or one that calls for rapid, strong strumming on a solid body electric? In those situations the strings blending together will be working against you.