Multicell horns

[noviygera]

GM,
What if the room has a rear wall with a recession (a nook or a deeper portion) so that about half of the back wall is deeper. How do you calculate the peaks then?
(my room btw)

What if the room has one wall angled(not my room)?
What if the room has 5 walls?

 

[GM]

Honestly don't know, just imagine the minor fundamentals, harmonic structures will blend with whatever dominates and the cavity will create a notch somewhere in the room response.

Angled walls turns the room into a horn of sorts and if > 12 deg included will allow 'slap'/flutter echo to decay quickly enough to not be an issue, so a good thing and one reason why cinemas, symphony halls expand to the rear.

Obviously, > 4 walls is going to increasingly randomize its eigenmodes, 'slap'/flutter echo, etc., so can be the makings of an above average audio/video room. You want a neat room for audio/video; expand walls, ceiling from the sound wall >12 deg. and make the rear wall a deep 'V' [> 12 deg angles] facing into the room to breakup/randomize the <sub>bass. AKA live end/dead end [LEDE]. One adaptation of the principle with 'V' to the rear: 20,000 Watt Home Hi-Fi System

GM</sub>

 

[Patrick Bateman]

Altec 814A, circa 1976

Dutch & Dutch, circa 2019

 

[NiToNi]

This eBay seller is making his own multi-cell horns by the looks of it:

MK1005A Multicell Horn for 1,4" driver Altec288 | eBay

 

[djn]

Here is my first foray into horns. A7 cans with Altec 515s, 1505 horns with two 288 CDs each, and Beyma CT25 tweeters.

 

[Pano]

Wow! Where did you get all that?

 

[DorinD]

Another one entering Nirvana

 

[midrange]

Has anyone ever tried making their own multi-cell Horns?

 

[Pano]

There is a whole thread on that subject in this very forum!

 

[noviygera]

Has anyone tried nesting a dedicated tweeter horn in the center cell (closing off or removing the cell for this tweeter)? This would make a coaxial muticell horn.

 

[POOH]

They have been obsolete for a long time.

 

[Pano]

Tweeters? Or something else?

 

[noviygera]

What is the obsolete part about them? Aside from difficult manufacturing.
The modern tweeter horn would play from 3Khz up.
So we are looking at the multi cell to cover approximately 600 Hz to 3 kHz. The question then becomes what are the issues with the multi cell in that specific range?

 

[Ro808]

How many Cells does one want/need?

 

[noviygera]

POOH commented that the multicell is obsolete but my question is what makes it obsolete? Bandwidth limitations -- is it in the upper frequencies? Or manufacturing expense?

 

[Ro808]

Multicellular horns may be obsolete, but that doesn't mean they are no longer used. On the contrary I would say.

Traditional exponential multicellular horns are reportedly subject to beaming and multicell comb filtering, aka fingering.

 

[Ro808]

Follow up:

 

[Ro808]

Pat Brown published EASE and CLF ballon data of an Altec 1005 on SynAudCon.
Unfortunately, the files are no longer retrievable, not even through archive.org.


Who wouldn't want this?:

 

[phase_accurate]

Shearer ?!?

 

[schiirrn]

I feel I have seen these before. Are they in Europe (France?) in some guys multi million mansion who inherited his parents' (fabric or paper?) factory and managed it against the wall but still came out pretty well for him self? With very good room acoustics?