By "ribbon" do you mean simply "flat" cables or cables with flat/wide ribbon conductors as opposed to round wire conductors laid out in a flat plain?
I found speaker cables using flat/wide ribbon conductors to be flat (scooped?) in the upper mid's compared to round wire cables from the same manufacturer.
This is regarding the 4708 47 labs cable I've used for 20 years now VS their "ribbon" cable (forget the model, but it wasn't expensive @ around $600/pair).
The ribbon version was less forward offering increased subtle detail while not being bright/brighter (maybe a bit less harmonically rich).
I prefer fat, forward, rich and in-my-face (though with exception to the latter I did not marry that way).
I heard the same difference with mystery cables @ a DIY speaker get together 20 years ago.
Mystery round wire speaker cables swapped out with mystery DIY wide flat ribbon cables driving DIY speakers sporting Ted Jorden's (sp?) tiny wide band drivers.
In this case the ribbon cables sounded better (to me) and the ribbons were much wider than the half inch, or so, 47 Labs cable I tried (they tamed sibilance).
This said, I experienced the same upper midrange change when switching Kimber 4VS with Kimber 4TC in my old Audion 300B/Reynaud Twins setup.
I preferred the less expensive 4VS for its fuller midrange and both were braided cables made from round stranded wire.
I sold all the Kimber @ that point and went with the 47 Labs cable that I still use today.
Not much experience here, but that's my take and I'm sticking to it.
DeKay