file modelling an horn for a 8"

10 years 5 months ago #6105 by bitzo
modelling an horn for a 8" was created by bitzo
Hi all,
I'm trying to model an horn for a 8" driver to cover 800 hz 2000 hz. I want to use rcf mr8n301, regarding Tony ASS advise about coil. I've already simmed on HR
Here's the input data
s1=36
s2=959
tra=31.2 f12=256.40 at=9.12
vtc=90
atc=400
vrc=0.56
lrc=8

My intention is to build this horn using wood or mdf. The phase plug would be conical (because is simpliest to build). So the main issue is modelling the throat to fit (as possible) the effective driver diameter. A square shape is too large, a round one best fit but not easy to build...so I'd go for a exagonal shape.

here's the sim at 2xpi, 0 degrees off axis

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10 years 5 months ago #6118 by bitzo
Replied by bitzo on topic modelling an horn for a 8"
This horn will have 2 flare on the side, 2 straight panel on upper and downside. So the height expansion is conical, start from 16.8 cm (effective piston are of 8" driver) and end at 22 cm. So if I divide the exported area of Hr by these heights I obtain the width of the horn from the throat to the mouth, but I think this would be so little and it's no good for resonance issue. In order to resolve this I would add the conical phase plug to start the widths' flare at 16.8 cm but, a square mouth is too large so I modeled an exagonal one. The exagon become a square.

I have some doubt about the phase plug's lenght.... is it better a plug long like the horn or shorter?
The flares get vey close to the plug, could be cause a resonance problem?
what shape must have the plug's bottom part? spherical conical or other?

soon to come some sketch

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10 years 5 months ago #6124 by bitzo
Replied by bitzo on topic modelling an horn for a 8"
the throat is too small for a an hexagonal shape.....a round ones would fit but.....impossible to built for my layout so I need a remodel. Surely I loose many db.

edit: remodelling the exagonal shape was a good a idea now I can figure the build... and I've modeled another horn with larger and square throat rcf 8mr301 have a nice response in this one but the second choice drier b&c pl21 sucks, this one would be better in the first horn.

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10 years 5 months ago #6136 by bitzo
Replied by bitzo on topic modelling an horn for a 8"
here's the new horn input data and sim (halfspace)
s1=221
s2=959
tra=15 f12=227.21 at=20.37
vrc=0.1
lrc=8
fr=40
tal=4
vtc=182
atc=282



and the sketch


this is the layout but...I would change soon to be more buildable and to get more db. It pretty easy to obtain the measure with my spreadsheet.

opinion? advice? In Particular about plug shape and bottom part of plug...

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9 years 10 months ago #7608 by mykey
Replied by mykey on topic modelling an horn for a 8"
stick a phase ball in the throat smiley20
this looks good

Anyone got any ply?

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9 years 10 months ago #7610 by bitzo
Replied by bitzo on topic modelling an horn for a 8"
thanks mykey but mine was a stupid concept... this was an horn to fill the hole in my modded voice of theatre (upper roll off at 800hz), but I finded an altec 811, loaded with bms 4550, this combo do the job with more higher extension, less money less woodwork ;) . But this was an useful exercise of modelling.

cheers

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