NOTATIO

What do members of the forum think might be the neatest way to notate that the ‘m’ of ‘doom’ should perhaps be held as a voiced consonant for the whole of the last bar in the screenshot?

I can think of several different ways which should all be understood, but am looking for the neatest.

I had a similar issue, but I am not sure what is the best way to do it.
Maybe superscript doo, or m to be bold.
Another way is to separate m from doom, or to add another m:
doo/m_________
doo-m_________
doom/m________
doom (m__________)

Or just simply as a footer:
doom*_________
(*hold "m")

Another is to define it rhythmically, as "doo" to be a grace note with tie and "m" to be the main note. In any case, doo+m creates rhythm, therefore defining it would be good to have. Singers can come with a legal question: how quick will "m" come after "doo"?

It would be good to hear what you or other people think, I am also somehow uncertain.

Are either of these any good?

Sorry, I read to quickly (as usual). Now I see you wanted to have m in the last measure, not immediately.
I think the first example is perfectly clear even without hyphen and a dot.

David, I would just add "(mm)" as a syllable under the last note, possibly in italics. I've seen that used in some contemporary music I sang recently.

Agree with benwiggy. That's how I've seen it done in choral works I've performed and it was very clear. Put "(mm)" or even just "(m)" on the syllable where you want it to begin and the choir will know what to do.

(m) under the note when you want humming to begin. So doo - (m)

Schonbergian wrote: ↑09 Apr 2019, 04:05 (m) under the note when you want humming to begin. So doo - (m)

I would include the m in 'doom' as well as having it later. Underlay needs to 'show the word' so the singers can identify it, and only then 'show the place' for special effects such as this.
I have seen stuff like 'pea - - - - - - - - - - ce' just on a normal lengthy note, which is totally unnecessary and actually makes things less clear. (Who would place the sibilance anywhere else?)

Apropos of humming, I have also seen humming indicated with the 'dynamic' symbol in the underlay. I suppose this stops jokers from singing the word 'hum' as an actual word....