Really Not Understanding Studying 4 Part-Writing

I'm reading in a lot of part writing rules about how doubling the 3rd is bad and if one voice moves to the 3rd then another voice that's on the 3rd should move away to another note in the harmony so the 3rd isn't doubled, but that would suggest that this really simply melody over a basic chord is wrong according to the "rules":

Surely there's nothing wrong with the 3rd in the melody doubling the 3rd that's playing in the background chord? if you were a student and had to follow the rules for an exam or something would it really be considered a breaking of a rule because the 3rd is doubled in this situation? I mean it seems to be implying that if you have a full traid sustained over a bar as accompaniment then you can't use a 3rd in the melody because it will be doubling the 3rd...I'm obviously missing something here.

I think they are talking more about situations where all parts are moving in time together, producing chord, chord, chord, as opposed to a melody over a static chord, (polyphony as opposed to homophony), but I'd be curious what other folks have to say about it.  

I think they are talking more about situations where all parts are moving in time together, producing chord, chord, chord, as opposed to a melody over a static chord, (polyphony as opposed to homophony), but I'd be curious what other folks have to say about it.  

I second this, as far as I know most (if not all) of "the rules" are concerning parts moving together rhythmically, minus non-chord tones. This has a closer resemblance to a right hand playing the melody while the left hand is playing a I chord. This is at the very basic theory level though.

Regarding the doubling of 3rds, you have a lot of flexibility in melody lines or chords if there is a solid root in the bass, in your case C. But if there is a 3rd in the bass, and this generally denotes a moving bass, you must be careful not to double the 3rd elsewhere in the music. In fact, when this is the case, it is helpful to double the fifth of the chord or the root in order to offset the 3rd, which is not considered a strong root. In the example, which progression sounds bad to your ears?

From what I've learned, it's recommended to double the 3rd if it happens to be an important scale degree (i.e. scale degree I, IV or V as part of a VI, II or III chord, respectively) otherwise it's not that bad, but also not ideal. Doubling the 3rd is FORBIDDEN if it is a leading tone (i.e. in the V chord).

Although, as said above, it's not so important for melodies above chord progressions.

"The modal degrees, by their insistence are hear by the ear as tonal degrees of another scale."-Piston.  The explanation I've heard is that doubling the third can give it more importance to your ear than it is due, and lead to confusing the key to the listener.  Since the key is established in our minds by hearing a lot of the tonic and fifth.  If you hear too much third, your ear starts to assume the third is the tonic or the fifth instead of the third.  Which can be an interesting effect to play with, but should be used intentionally and sparingly, or you just end up with mush.  Nothing wrong with having a key, changing to a different one, changing back, peeking at a key and then not actually going there.  That's all fine and lends interest to your piece.  But there needs to be enough of an established key to create expectation in the listener's mind.  Half of our pleasure in music is the anticipation of the continuation of a pattern.  (And the surprise when the music doesn't go where you expect.)  Got to establish it first.  

One of the biggest mistakes on harmony theory was to assume that the rules that were originally conceived to vocal parts, to avoid problems related to a choir, people singing, had to be applied to every single thing can produce a sound. The SATB behavior was simply copied into strings section, keyboards and other instruments, and soon it became mandatory to any 4 part writing.

I don't think many teachers will approve this I'm telling you, neither you will find it in books, but trying to care of every single interval as you were singing in a violin part, or piano or oboe or others is ridiculous.

The doubling of the 3rd is to be avoided because this note, the 3rd, influences a lot the color of your chord, and doubling it will make a notorious overpowered 3rd, which is consider "wrong", other intervals like 5th doesn't seem to modify so much your overall balance, which you suppose to maintain equal in voices.

In your example, you static chord in left hand already suggest you are not following the SATB rules, is only a piano part, since your rhythm is clearly not trying to follow the melody, (remember that if you were in choir, you also would have to care of lyrics). In a Piano part there's nothing wrong in that example, in a Choir part, the last two beats you are not only doubling 3rd but is also 8ved 3rd above your bassline, which indeed makes an ugly effect in choir, (maybe strings too). I'd say the only case where double+8ved 3rd can work (still against rules) is maybe in a 1st inversion of your chord as 8ved bassline, maybe.

If you really want to write 4 voices and keep the rules, then keep reading, and continue to counterpoint, there is where you find how to move voices without breaking the rules.

I think the rules differ according to the authority.

CPE Bach says:

"According to circumstances, the octave of the bass may be omitted and either the third of fifth doubled. However, when the third becomes major by chromatic alteration it is not played."

I think this is a fairly liberal rule, as I understand it. It essentially only applies in minor keys or passages, and the rule follows from rules about treating leading tones. There is an additional "soft" rule that it is better to double roots or fifths, because otherwise it unbalances the chord from sounding like its function, but that rule is violated all the time in real music.

Kirnberger has a similar rule to Bach. I'd have to do more research to see how the rule differs for others.

What is the source for the rule as you understand it? Give a verbatim quote or screenshot.

Since the third lends the quality to the chord (i.e. makes it major or minor) doubling the third can make it stand out more than you may want. Of course doubling the third is better than having parallel perfects, but you should avoid it if possible.

They are only rules if you are a student or are doing a strict exercise. Otherwise all of it is just guidelines set forth for specific reasons. If it works in the musical context, you need not worry whether it is correct or not.

Thanks for the advice everyone.

So it is happened that accidentally I shortly worked out the possible explanation for this question. This explanation may be derived  from the J. Rameau’s text in his book "Traité de l'harmonie" and  works of H.Helmholtz. The text is presented in the article "J. Rameau of the properties of harmonies  ( http://theoryofmusic.wordpress.com/2007/11/27/jp-rameau-of-the-properties-of-harmonies-1722/).
Rameau claims that main dissonances are placed in the soprano, that is, in melody,
that they mustn't be put arbitrary and  it is better to avoid dissonances than to set unnecessary ones without corresponding musical idea. In the Your example the note E in melody has strong dissonance with 3 harmonic of  the tonic note C in bass register, that is, the strong dissonance is introduced with unknown aim.
To regret music theory was busy ,in general, with invention of vague notions as consonance, perfect  or imperfect consonance (all chords in some degree dissonant) , tonality etc. but not with analysis of music phenomena through doubtless elements of perception as dissonances.

Good Day
Yuri Vilenkin