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In the Forum: Horn-Loaded Speakers
In the Thread: Deep End DIY - Australian take one Macondo.
Post Subject: More about angling the hornsPosted by Romy the Cat on: 7/2/2017
As some of your know Anthony live in AU and they have for themselves a site where Anthony regularly post the progress of his project. I do not post in there, I was banned from there, I am not sure why but usually it is because I refuse to suck the moderator’s disk and because the moderators have no other place to stick it then into the feeble brains of unfortunate audio people. Anyhow, it id not about the AU site but about the subject that was touched at the forum.  
 
http://www.stereo.net.au/forums/topic/75784-deep-end-diy-my-first-speaker-project/?page=66  
 
Q: Are you able to angle the top horns down at all?
A: There has actually been a big discussion about angling of horns (or making them non-parallel) on Romys site and the quite firm opinion is that it does not work as we think it would.  The opinion was firm enough that I did not consider it in my design.    
 
I never understood the desire the people to angling horns. Horns are not guns, the do not shoot bullets from the middle axis. Yes, the maximum HF you get from the center line horns have VERY predictable and very constant attention of HF off the middle axis. If you need a slightly more HF then probably the main axis is a good place to be but in Macondo topology the upper horn is rolled at 1000Hz and the difference between to be at axis and to be way off is absolutely negligible. In fact the more HF will be removed from that top horn then better it would be, this is why I use third order in there is I am not mistake… 
 
So, there is no benefits for angling horn but let to consider the problems. Time align the speaker of Macondo topology and then angle down the top horn. Not even angle down the top horn but angle any horn’s axis in any direction. Your time align will collapse. So it is normal that with attention we have time delay that throw the whole angling out of balance. Now, anybody who did experiment with time angling and listening benefits know that a time angling in a single point it is good but is very much not sufficient. The objective is to align the playback and to make the playback to go away from the alignment in proper axis of line in the room. In most of the cases the alignment escape line need to be parallel to floor but in some of the cases it might be very slightly angled to the floor. It is not only for the purpose of multiple listeners or have wide sweat spot but also to improve the imaging in the very sweet spot. So, with angled horns you NEVER will be able to get a long and smooth alignment escape line but you will be getting 5” sweet spot and then the alignment will be very abruptly ended. 
 
There are many arguable points to the subject. At what frequency to measure the alignment in reference to the angled horn?  What cut off got reverberation to set when you measure the time alignment? They are all valid point but as we go lower than 1000Hz then there is no good answers. One might hear it during subjective experiment other not. My question is: if the rules of alignment and angling works at 10Kz then why they should not work at 500Hz. Particularly if there is no benefits to angle the horns….
I have been opponent of the horn angling for many years. I remember even 16 year back I gave giving a difficult time to an idiom who angle the horn just to make good picture and to write a review… 
 
https://db.audioasylum.com/mhtml/m.html?forum=hug&n=6349& 
 
Rgs, The Cat

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