High Efficiency Speaker Asylum

RE: GPA/Altec 902 all the way down to 500Hz?

82.93.53.235

Jacobusje

In Reply to: RE: GPA/Altec 902 all the way down to 500Hz? posted by GM on August 04, 2007 at 09:42:25

Well, The diameter of the horn is 52cm, which whould translate into a Flare cutoff freq. of ~220 if I'm correct. The horn length is 33cm and the throat entry is made for a 2'' driver.

Follow Ups:

My calc's give a length of 48 cm - jnorv 06:30:27 08/05/07 (5)
for a 2" dia throat and Fc = 220. The mouth dia seems right.

Jim N
- RE: My calc's give a length of 48 cm - GM 09:51:33 08/05/07 (4)
  Hmm, I get a ~52.56 cm axial length with a 26 cm mouth radius down to a 2.54 cm throat radius and ~70.54 cm for a 1.27 cm throat radius, making it ~ the horn equivalent of a 'pencil neck geek' ;^).
  Loud is Beautiful if it's Clean!
  - This is the horn - Jacobusje 13:36:55 08/05/07 (1)
    mmmm, I think that it is not a Tractrix then?
    - RE: This is the horn - GM 14:47:24 08/05/07 (0)
      The horn appears to be a tractix except with possibly a short transition throat section, but can't tell for sure, and it looks like the adapter preserves the driver's wall angle and accept a glitch in the expansion higher up at the adapter/horn junction.
      
      The bottom line is the horn needs to be carefully matched to each driver size/type for best performance since the first few inches represents the entire HF BW, which they appear to have done, so probably is fine, though it will beam excessively by my standards due to the slow overall expansion.
      
      As always though, YMMV. ;^)
      Loud is Beautiful if it's Clean!
  - Like this? - jnorv 13:07:11 08/05/07 (1)
    What are you using for sonic velocity?
    
    Jim
    - http://cgi.ebay.ca/Tractrix-Horn-2-140-Hz-Lowcost-Version-without-BMS_W0QQitemZ9718926978QQihZ009QQcategoryZ14980QQcmdZViewItem (Open in New Window)
    - RE: Like this? - GM 14:17:23 08/05/07 (0)
      Something like that. Just imagine the taper continuing down to 1", the driver will be basically firing into a pipe, choking it somewhat.......
      
      I use 1130 ft/sec.
      Loud is Beautiful if it's Clean!

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