Keith G wrote:




But will it matter at the end of the day? Just putting new drivers into
(presumably) old 3-way speakers is going to alter things even if only
slightly and it will only take 20 minutes to absorb the changes.



Yes it matters.
There is the Thiele Small parameters of the enclosure, the cross over
network and how many drivers in each enclosure and how they are
configured to seamlessly intergrate etc. Then there is the "load" that
the driver represents to the amplifier. And the sensitivity of each
driver and the enclosure as a whole etc. The wrong mid-range driver
will result in either a mid-range suck out if too insensitive, or an
overall drained and stressed sound if too awkward a load. Conversely
an over sensitive new drive could result in dominant mid-range and a
percieved premature roll off in HF and LF.
Fitting a drive just because it fits the baffle cut-out is not a good
idea.