Yes im crazy.*horns involved*

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#22
Doing these types of designs in the mid to late 80's was interesting
because then, we didn't have monster woofers and high powered
amplifiers were expensive :smash:

But you have to be careful as horn critics will say that
it aint a horn at low frequencies because they is no
acoustical gain - a qualifier for being called a horn. It looks
more like a midbass 'horn' but not LF 'horn' even though
you do have LF response.

Anyways, these types of projects are fun 😎 😎 😎
 
#26
the tweeking method

To Mattcatt

You will need to find read and make sure you fully understand every horn related resource you can or............cheat your way to horn success like me!

Firstly you need to find a published horn design with its associated specs, for me this involved a trip to mikee12345's website where he has helpfully posted a screenshot of his 40HZ HORNS specs. I entered these into Hornresponse and started making big changes to each of the horn parameters in turn whilst looking at the spl curve after each change to see what affected what. I then swapped the T/S's of the drivers I wished to model for his and the began tweeking the horn parameters until I got a smooth(ish) spl curve. Be warned this takes a lot of trial and error and I went through several drivers that I couldn't get to "work".
for an example enter these specs into Hornresponse
sd-225.6
cms1.10E-03
mmd-20.20
re-5.6
bl-8.94
rms-1.16
le-1.4
es-2.83
vrc-18
lrc-40
fr & tal-0
vtc-1000
atc-500
s1-150
s2-300
s3-420
s4-720
s5-1500
then the 4 CON boxes from the top-
41.8
33.6
57.6
59.4
This is what you can get after a bit of fiddling with an Audax ap210g6. It still needs a bit of work to get the response lower but as this is a test piece to se if horns are for me I might build it as is.


There are proberly a million better ways of starting out with Hornresponse but this method seems to work for me and a least it gives you somewhere to start from.

Apologies to mikee12345 for "borrowing" his horn specs and a big thumbs up for his excellent website.
 
#27
You can save yourself a bunch of time if you get Marshal Leach's horn papers and generate a spreadsheet to calculate a good starting point.

For instance, using these specs I found on the net for the Audax and calculating BL/Cms/Mms:

Fs = 33.7Hz

Qms = 3.68

Qes = 0.3

Qts = 0.2774

Vas = 79.73L

Re = 5.6ohms

Sd = 225.6cm^2

BL = 8.98N/A

Cms = 1.0914E-03

Mms = 0.0204361Kg

I don't currently have Hornresp loaded so it's not transparent to me what your horn's BW is, so I'll just use Fl = 40Hz and Fh = 224.63Hz (calculated mass corner):

rear chamber = 704.034in^3

front chamber = 50.154in^3

throat = 18.057in^2

'M' = 0.636

compression ratio = 1.937

Make the horn long enough for the mouth area to = 2254.2in^2 in 4pi space (sitting on the floor up against a wall) and I'm confident that it will sim pretty good. Obviously, for best performance the driver(s) used will need to be measured and whether it will perform as predicted (excluding HF extension since HR doesn't calculate it) will depend on whether it can handle the compression.

GM
 
#28
Hi GM,

Just wondering - did you study under Dr. Leach at Georgia Tech? I used the three-way box design on his web site when I was in need of a two cu. ft. cabinet design for a pair of 12" sub drivers that I got for Christmas. The boxes are sealed and stuffed with polyester filling. I used 3/4" MDF and two by two bracing.

One of the boxes is performing beautifully in the HT system here, and I sent the other one out for Texturelac coating. Picking it up tomorrow, and planning on trying it as the low end on a studio / rehearsal bass guitar system.

I visited your home state last September, and plan to return in August of this year. Jekyll Island is a lovely place to be!

dooper
 
#29
Evening!

>Just wondering - did you study under Dr. Leach at Georgia Tech?

====

No, I wish I had the math smarts to have done so though. I did meet him when he first arrived though, and had several audio 'bench racing' sessions with him, mostly about horn design. At the time we both had Altec horn systems, only his had custom wound VCs and home brew XOs/amps.

====

>I visited your home state last September, and plan to return in August of this year. Jekyll Island is a lovely place to be!

====

Indeed it is, though not nearly as much as it was in my youth IMO. 🙁

GM
 
#30
in HORNRESP after inputting parameters use the HYPEX TOOL!

chose BW,and away you go! chop that horn! reduce that mouth! work it work it! watch that response go wobbly and that excess volume drip off before your very eyes!

🙄 🙄 :dead: :devilr:
 

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