reduce the back volume of a mid horn

Angelow wrote: I have two of these boxes, one with a burnt driver, and one still working. let's talk about stuff produced in 1985! The recone kit can only be found for new versions. At the practical test the neodymium rcf cone is less efficient than the original, but has a power handling more than 3 times higher (700w instead of 200w)

In the 1980’s, “Bigger Is Better” was the concept. Large horns with high efficient speakers were common.

Today, smaller and easier to transport is the concept. Efficiency is traded off for more power handling in which, you can make up the loss in efficiency by high wattage amplifiers to, achieve greater SPL.  

Those are very good horns you have there. You should get far better coverage horizontally with those boxes than the majority who build their own horn-loaded mid cabs.

Best Regards,

Personally, I would not cut it. All you are going to do is destroy the box's performance. What little chamber that is left to extend the low frequency response of the 12 inch driver is needed. 

Best Regards, 

You would have to scale the internal chamber of the horn in WinISD to determine what the 12 inch is seeing in terms of frequency response. It may be best to just create a new smaller box for the horn instead since you pulled the horn out of the old box. This will allow you to compare the old design to the new design (Hear the difference) which, will tell you how much low frequency loss will come into play by using a smaller box. 

The above would be the safe method instead of butchering an old box based on opinions of others who have no on hands experience owning such a design. 

When it comes to such modifications you are really on your own to determine if downsizing a cabinet will meet up to your requirements from a sound quality standpoint.

Best Regards, 

fatfreddiescat wrote: Elliot Thompson wrote: You would have to scale the internal chamber of the horn in WinISD to determine what the 12 inch is seeing in terms of frequency response. It may be best to just create a new smaller box for the horn instead since you pulled the horn out of the old box. This will allow you to compare the old design to the new design (Hear the difference) which, will tell you how much low frequency loss will come into play by using a smaller box.  The above would be the safe method instead of butchering an old box based on opinions of others who have no on hands experience owning such a design.  When it comes to such modifications you are really on your own to determine if downsizing a cabinet will meet up to your requirements from a sound quality standpoint. Best Regards,  WINISD won't model the low end cutoff of a horn as your dealing with reactance annulling, hornresponse and akabak will, hornresponse being much more user friendly for this purpose.

Possibly, you are mistaking internal chamber of the horn to canal of the horn. I am talking about the internal chamber of the horn. 

Under those circumstances the method I suggested does work in WinISd for I did it nearly 20 years ago with some large 180 Hertz Straight Horns. Straight horns with vents are a hybrid in which, follows the same principal as a reflex cabinet in terms of the rear chamber and port interaction. 

Best Regards,