Can a maj7sus4 chord be used like a dominant 7 chord?

Question

I've read that dominant 7 chord drives toward some kind of resolution because the tritone between the 3rd and b7th that creates some form of tension that craves to be resolved one of these two ways :

This concept can be used to create the classic V7 -> I, or sometimes V7 -> vi (or others resolutions I guess)

Question : Extending this concept to other tritone chords, can a maj7sus4 chord be used the same way ? Is there some notable usage of this chord this way (i.e. as a way of creating strong resolutions) ? In other words, Can a maj7sus4 can be used as some kind of "secondary dominant" of another chord ?

Of course, the resolution rules would be different, as the tritone is not in the same place in the chord (for instance, bVmaj7sus4 -> I would work I think).

Answer 1

I think the issue here is that if the tritone resolution is given the standard treatment - A4 resolves by half steps outward, d5 resolves by half steps inward - a maj7sus4 chord's tritone will resolve to a chord with the same root, ie bVmaj7sus4 will resolve to plain bV.

Standard tritone resolution...

...FA descends to MI and TI ascends to DO.

If we give those resolutions a tritone substitution treatment, we get...

...where I use an augmented sixth spelling to keep clear the tritone resolution is the same as a normal dominant seventh chord.

Next, build a bV chord, add a sus4 and maj7 above the root...

Isolating the sus4 and maj7 as the tritone, an A4 that would resolve outwardly, we can see it resolves to Bb and Gb where Gb is the root.

Fill in all the tones...

...resolving the tritone in bvmaj7sus4 moves to bV. The root doesn't change.

That is more of an embellishment of or suspension on the bV chord than a dominant function.

If the upward resolution of the maj7 simply results in no change or chord root, then it seems like I should mention there is another common resolution for a major seventh. A common harmonic sequence places thirds and sevenths above all the root in a descending fifths progression where the sevenths resolve by descending step. At the beginning of the sequence the seventh is major and it too resolved down by step...

You might follow that pattern with something like maj7 resolves down the third and the sus4 moves to a maj7...

...or something like that for a modern sound.

That isn't what you asked about, but it came to mind.

Answer 2

As Imaj7sus4 is identical with V7 over a pedal tone of the tonic it is obvious to me that it has function of dominant 7 resolving to the tonic. The tension of the 4->3 and 7-8 is the same as in V7-I in the end of a piece, especially in the Baroque and Classic era.

Answer 3

Some sonorities give a clear sense of having a certain root and function, while others don't. The one you're describing has a relatively weak and ambiguous root and function, which makes it possible to analyze it in terms of a different root. In the example you give, your analysis is bVmaj7sus4 -> I. Spelling out the notes, we have F# B C# E# -> C E G. But these same notes can also be analyzed as bII7 -> I. The bII has an added 11th and no 5th. So what you're describing can be analyzed as a tritone substitution.

I'm not sure that this type of chord-symbol analysis is even very helpful in this type of situation. However, if you're going to use a chord symbol, it's always good if the symbol is one that musicians can interpret easily, because it looks familiar. A musician who is familiar with tritone subs will understand the bII7 analysis more easily, because it fits a pattern they know. The bVmaj7sus4 is also awkward because seeing "maj7" makes a musician think it's not dominant harmony, but if you resolve the tritone with the kind of voice leading you describe in the question, it's going to tend to function like dominant harmony.