Altec 604 D Enclosures

[charly1944]

Sorry GM,
My message to David where i said i was looking for your guidance went through just before i could read yours. Let me make sure that i understand your comments(Dont forget that i am French and although my English is decent i tend to miss some subtleties of your language and certainly miss a lot when it comes to technical terms).I understand that there is nothing fondamentally wrong with my friend's enclosures and that improvements can be achieved.Do you mean that optimally i should get those reconed drivers measured in terms of impedance and TS parameters in order to adjust the dimensions of the enclosures and the vent.If yes this is a bad news because i will need a lot of help to measure those drivers.But i am ready to go for it. Few questions:
If we are making the assumption that indeed those reconed 604 D dont have the 604 E characteristics,i guess we have to use the trial and error approach rather than any approach based on modelling.What elements could we easily and reversably change to lower the tuning ;Ex:If i have to reduce the vent,should i make drastic changes and is there a formula to help me in doing that.Same thing with the feet :to day,2 inches.Should i change that and by how much .The dimensions of the enclosure without changing the volume:Higher,deeper? Sorry if my questions dont make sense but i badly need specific(and if necessary ,iterative) recommendations to make progress.
Thanks in advance.
Charles.