direct listening comparisons, tractrix, JMMLC, oblate spheroid

[angeloitacare]

hi all

i am just wondering : has anyone ever made direct listening comparisons of tractrix, JMMLC, and oblate spheroid flare horns ?

Since i have the tools, i am thinking eventually to built a horn of each flare, of same size, and try it out.

Angelo

[JoshK]

If they are all the same size, they wouldn't be able to be used over the same range. OS has much less loading that say the LC or tractrix. This is because it isn't a horn.

[angeloitacare]

Originally posted by JoshK
If they are all the same size, they wouldn't be able to be used over the same range. OS has much less loading that say the LC or tractrix. This is because it isn't a horn.

hi Josh

true. This would have to be considered. What would be the size of OS to cover above 800hz ?

[JoshK]

I need to calculate it but it is going to be bigger than 16" at the mouth. I know this because the 16" mouth radius is what Dr. Geddes's Summas were that were used down to 900hz. The Horn Theory part 2 article in AudioXpress gave a formula for the effective loading Fc.

[angeloitacare]

Originally posted by JoshK
I need to calculate it but it is going to be bigger than 16" at the mouth. I know this because the 16" mouth radius is what Dr. Geddes's Summas were that were used down to 900hz. The Horn Theory part 2 article in AudioXpress gave a formula for the effective loading Fc.

to cross a tractrix or JMMLC at 800hz, a 400hz Horn is needed. Since i have already a tractrix horn ready here, with 20", i will only need to turn a JMMLC and OS. i will do it after finish a big midbass horn. Then i will post my impressions here.