English: Magnus 890 electric chord organ. Chord Pad Detail. This instrument creates sound by blowing air past reeds. Circa mid 60's

The lower white keys play bass notes, as you can tell from the notation just to the right of the keys. Like the other buttons on the panel these are arranged in the "circle of fifths." That's common in accordions and useful in that it tends to group needed buttons together for any given key signature. Any song in a major key will mostly use the I, IV and V chords and those buttons are grouped together when arranged in the "circle of fifths." For example songs in C major mostly call for C (I), F (IV), and G (V) and as you can see from the photo, those three buttons are grouped together. A song in A major would mostly call for A (I), D (IV), and E (V), and you can again see that those buttons are grouped together.

The "circle of fifths" order is particularly useful when applied to bass notes. The root and fifth tones of any chord are the most important tones when playing bass and for any chord on this key panel the root and fifth tones will be adjacent, making playing bass easy. (Examples: G chord uses G & D in the bass, F major uses F & C in the bass. As you can see from the photo, the buttons mentioned are adjacent).

Very few chord organs include bass notes and this normally limits the chord organ to being a toy. With the bass notes the chord organ is a totally different instrument and you can really wail! The left hand can play a full sounding accompaniment in various rhythms like polka, beguine, ranchero, and waltz. Bass on an organ is normally played with the feet, but this clever panel arrangement allows the thumb of the left hand to play bass. That's a lot easier than playing with the feet and also eliminates the expensive and bulky pedal board. It puts a lot of musical power under the left hand. Piano players often use a similar technique by playing what are called "bridges" with the left hand. Using the left hand, they jump back and forth between playing a bass line (with the pinky mostly) and chords. It's often used in ragtime music. That's quite difficult but sounds great. These bass keys make playing rhythms like that easy.

Chord organs have largely been replaced with inexpensive electronic keyboards that feature amazing automated accompaniments. Like the chord organ, these keyboards allow the novice player to play chords with a single finger. As fun as those are, those accompaniments have a few disadvantages: they're "canned," i.e. they always sound exactly the same, the tempo is fixed, sacrificing expression by way of accelerando, decelerando, rubato, and fermate, and they come from musicians in Japan, not from the musician playing the keyboard. These bass keys allow the chord organist to make some real music.

TheLarryBrown (talk) 04:10, 24 January 2010 (UTC)