I have recently heard of the concept of a "key cell" as a short modulation (number of bars) that contains a tonal model progression, which can be analyzed in the context of two closely related keys. Can anybody elaborate? Thank you!
Alright, so I did some Googling and could find a grand total of 1 resource that specifically mentioned a "Key Cell" and, sure enough, it was referring to short, temporary, modulations.
However, he never makes any mention of any "models", but does refer to short "modal" modulations within the context of those "key cells".
So, in short, a "key cell" is, as you mentioned, simply a short modulation; And, that it is possible for a short modulation to be one where, instead of modulating to
Am by resolving
Am, we see the piece moving from
Am as the sign that the piece has 'modulated', temporarily, to
Am (and the progression of
Am is considered modal within this "key cell" context).
However, like a previous person had noted, this is not common terminology and would likely only serve to confuse if attempted to be used with someone who was not specifically aware of that "key cell" concept.