Unity Horn Basics

Arri

Member
2016-05-31 2:38 am
Good day everyone

Could someone perhaps advise me as to what rules to follow in determining the unity horn port sizes.
i am interested in designing a three way unity/synergy type horn and after an exhaustive search on the net, i simply cannot find any guidelines regarding the port openings for the mid range and mid-bass range.
I understand the location of these ports relative to each other and with the high frequency driver within the conical horn, but determining the size of the ports is a mystery to me.
i would greatly appreciate any assistance
 

nc535

Member
2011-04-08 5:12 pm
NC
the hole size determines the air velocity through the port. You should keep the holes as small as possible consistent with keeping the air velocity within bounds at maximum SPL, just like the ports in a bass reflex. One way to do this is by simulating in HornResp. This is easy if you already know HR but, if not, you've got a learning curve to climb.
 

Arri

Member
2016-05-31 2:38 am
A learning curve to climb, for sure!!
i am not familiar with the use of HR. (a link for guidance on the use of HR will be helpfull)

In the following patent "http://www.google.com/patents/US6411718" on page 5 of 9 i quote "The loudspeaker drivers communicate to the horn through holes or passages, the sum of which are equal to the horn area so as to match the horn's impedance at the introduction point".
Does that in fact mean that the horn area at the port location, dictates the size of the apertures combined, or am i off course here?
 
That's an approximation, and even Danley doesn't always stick to it.

Really, don't go cutting port holes into a horn until you've modeled what you are going to do in Horn Response. It isn't exact, either, but tends to be surprisingly close and can be used to tell you which way to go if things don't come out as expected. HR isn't *that * hard, though its interface takes some getting used to. There are some tips on using HR for Unities in the pdf file for the SynergyCalc spreadsheet http://libinst.com/SynergyCalc/Synergy%20Calc%20V5.pdf