The theremin was invented in 1919 and became the first electronic musical instrument that had a career in the XX-century and it is still the only instrument which can be played without any mechanical touching. The theremin-player moves his hands near two antennas. The proximity of the right hand to the vertical antenna changes the electromagnetic field thus changing the pitch of the sound over a six-octave range. Left hand controls the volume. Theremin's sound remembers sometimes the cello or violin, sometime the flute and often the human voice. The instruments circuit uses a beat frequency oscillator, in which an audible musical tone is derived from the beating between two high-frequency oscillators. The frequency of one of the oscillators is fixed. The frequency of the other is altered by the performer's proximity to the pitch antenna.
For over 40 years Time Life has been releasing music collections in many different genres of music. Their latest is a bonanza for hard rock and hair metal fans. Hard And Heavy is 152 songs on 9 CDs.
Hard And Heavy is a massive collection of songs from the '70s and '80s. It includes classic rock artists like Foreigner and Bad Company, pop artists like Pat Benatar and Billy Idol, hair bands such as Winger, Warrant, Skid Row and Poison along with more traditional metal bands such as Judas Priest, Motorhead, Megadeth and Queensryche.