I am designing an exponential Midbass Horn (50-200Hz) in hornresp. when I input the cutoff that I want, I get a huge mouth as expected. What is the best way to truncate the horn or change just size of the mouth but keep the length in hornresp? Do I just change the value of S2, or will this no longer give me an expo profile? @David McBean
1. For the exponential flare cutoff frequency F12 to remain unchanged, both the axial length L12 and mouth cross-sectional area S2 need to be reduced. The required values can be found using the Horn Segment Wizard.
Assuming that the required F12 is 50 hertz:
Attachment 1 shows the calculation option required to find L12 given S2.
Attachment 2 shows the calculation option required to find S2 given L12.
2. Reducing S2 while keeping L12 unchanged lowers F12.
If L12 is specified as Exp then the profile will be remain exponential regardless of the values chosen for S1, S2 and L12 (except for the zero flare cylindrical case of S1 = S2).
Attachments
Ok, thank you. So if wanted to design a horn that had a regular length for a given cutoff, but an undersized mouth, is there any way to do that? I am guessing that would mean it is no longer exponential, so can I just model it without the wizard?
Not sure what you mean by regular length, but as I attempted to explain in Post #2, if L12 (Exp) is calculated given F12, S1 and S2, then reducing S2 while keeping S1 and L12 (Exp) constant will retain the exponential flare profile but lower the cutoff frequency F12.
As indicated above, if L12 is specified as Exp then the flare profile will remain exponential.