hello, limo1!
welcome to the forum. thanks for your kind words!
i'll try and answer your questions for you...
scale - a series of notes differing in pitch according to a specific scheme (usually within an octave)
you've undoubtedly heard the most common example of this, the 'major scale' played many times before.
modes are examples of scales, more specifically applied to the individual scales that start on each successive degree of the major scale, but still retain the same key center. they represent one of the most fundamental examples of 'diatonics'. modes can be used primarily in 2 ways:
1. they allow you to move all up and down the neck while still staying in the same key center (you can accomplish this because each successive mode of the scale starts on each respective scale degree and occupies a new position on the fingerboard.)
2. they allow you to stay in a single position and change keys, or 'modulate'. (for example, if you used the same starting note for each of the modal fingerings, you would be changing keys as each pattern changes.)
arpeggios are simply nothing more than broken chords. in other words, they are chords that are played one note at a time, individually spelling out the color of the chord. harmonically and functionally, they are basically identical to chords; however, they are usually used in the context of melody or improvisation.
when you extract chord tones out of each of the successive modal patterns, you essentially 'harmonize' the scale.
finally, if you are getting fret buzz constantly, regardless of how you try and set up your bass, chances are you might need to have an expert guitar repairman or luthier do some work on your bass. a lot of times, instruments will have fret heights that are a little bit out of spec in certain ranges of the instrument that cause the types of symptoms you are describing. without seeing the bass in person, it's hard for me to diagnose accurately, but i would get someone you trust to look at it to evaluate it.
hope that helps,
adam
