dominant 7th alt chord in "GLOSSARY - iReal Pro" thread

[shin1ro]

Hi, Moderator and Gabor,

I'd like to thank you all so much of the useful information
on All chords of iReal 2018 a/b chart.

But I've found questionable info here in
All chords of iReal 2018 b_gk (part 2).

QUOTE =======================>
05-24-2018, 01:39 AM #6 Gabz
iReal Pro chords and the scale notes they include
......
Part 2
All chords of iReal 2018 b_gk - G.KRISTOF
......
<======================= QUOTE

The C7alt chord here has "1 3 b5 7" notes.
But IMHO C7alt could have "1 b2 #2 3 b5 #5 7".

I know not all of these are played at the same instant as a harmony,
but chosen notes (b9 or #2, and b5 or #5) are (should be) played in fact.
(there's a further discussion about altered chord in Wikipedia, if you want)

cheers,

shin1ro

[pdxdjazz]

So a C7alt is: whack-all-the-black-keys/C ? Ah, jazz.

I think I saw Jerry Lee Lewis play that
@ about 2:30 here https://m.youtube.com/watch?v=Fw7SBF-35Es
)BOB

[Keith88]

It's a bit more sopisticated than "whack all the black keys." A pianist (at least I would do it this way) would often voice a C7alt chord with the 3rd-7th tritone in the left hand (E and Bb) and the #9 and b13 in the right (D# and Ab), often with the root in the middle; it would look like E and Bb in the left hand and an Ab triad with the Eb on top in the right hand. The "formula" is: the dominant 7th tritone with the b13 triad on top.

[pdxdjazz]

Thank you Keith!
)BOB

[shin1ro]

Keith,
Thanks, you explain very well how C7alt is performed by human player in reality.

Gabz recipe says C7alt = 1 3 b5 7
(that is C E Gb Bb)

While in my observations of C7alt by 8-bar tests,
- piano, strings in Jazz Long Notes style
- guitar in Latin Brazil Bossa Acoustic style

iRP player's C7alt output notes vary frequently (not every time)
#1 C E Gb Bb Db (1 3 b5 b7 b9)
#2 C E G# Bb Db (1 3 #5 b7 b9)
#3 C E Gb Bb D# (1 3 b5 b7 #9)
#4 C E G# Bb D# (1 3 #5 b7 #9)
In Bossa guitar, root C is always omitted.
(actually #2 is not found on the piano)

I think it would be better the recipe to be updated,
reflecting the fact of what iRP player plays at C7alt.