B)

i am currently converting my 6.5 inch's thiele small parameters into results to help me work out the enclosure size in litres.i am after a system q of 0.707 but the problem is when i put my drivers qts value in the compliance/alpha equation (which is higher than the qtc value ) i get a negative result
see below

@ = (qtc/qts)² -1

@ = (0.707/0.765)² -1

@ = -0.145 ?????

does this mean that my speaker is probably more suited to a ported enclosure.i have done this equation before on several subwoofers but i have never gotten a negative result like this??

why do you want to make a box for your 6.5??
just curious

i am currently designing an extreme door install and i am trying to find a way to seal the door of completely when the window is closed i think it may just be possible !!
once i find what size my enclosure needs to be for a q of .707 i can work out how much of the inner door space is required for my 6 inch midbass B)

qtc cannot be greater than qts, something is wrong with your values there.

i think you may be right here!! i did some searching on the net and it seems speakers with a high qts have extremely stiff suspension so they will work really well in an infinite baffle (car door!!)/ported enclosure.if the qtc you choose is lower than than the qts value the sealed enclosure that is chosen will be useless in damping the speaker since it is already designed that way.
the speakers i was looking at were focals both have qts values above .707 B)