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Old 19th April 2012, 12:42 AM   #1
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Default MJK simulations - double mouth back loaded horn help.

hi,

i hate to ask this but could someone please check if i'm using these spreadsheets correctly please? i really don't think i'm doing it right at all.

i've attached the sketchup doodle in the link below, and my 'calculations' for it using the MJK sheet.

relevant driver information, i am also aware that the driver isn't really suited for horn use.

Fs - 50hz
Re - 7.2
Lvc - 1.56
Bl - 12.81
Sd - 530.9cm^2
Vas - 78.06
Qed - 0.72
Qmd - 7.6
Qtd - 0.658

any help is extremely appreciated as always. thanks

double back loaded horn.skp

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Old 21st April 2012, 10:45 PM   #2
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different question,

if this is how this design simulates, is it worth giving it a go with a build? i know its not going to be that great, but i need to get my feet wet at some point instead of all this playing with simulations.

thanks

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Old 21st April 2012, 10:47 PM   #3
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best place for these questions

quarter-wave : Quarter Wavelength Loudspeaker Design
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Old 21st April 2012, 10:56 PM   #4
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Both of the designs you have shown are BVRs (Big Vent Reflex), not horns.

The 2nd one is very elegant -- but perhaps a bit tricky to build.

dave
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Old 21st April 2012, 11:00 PM   #5
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Quote:
Originally Posted by planet10 View Post
Both of the designs you have shown are BVRs (Big Vent Reflex), not horns.

dave
oh right, thanks for the correction!

does this mean the entire sim, as its using the double mouth horn sheet, is fairly worthless?
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Old 21st April 2012, 11:02 PM   #6
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MJK doesn't care what we call the box... it is fairly accurate if the geometry is correct.

I do know that when Scott does designs like the 1st he has some home-made tools he also uses.

dave
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Old 21st April 2012, 11:04 PM   #7
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Originally Posted by planet10 View Post
MJK doesn't care what we call the box... it is fairly accurate if the geometry is correct.

I do know that when Scott does designs like the 1st he has some home-made tools he also uses.

dave
thanks again for the watchful eye.

would this be worth building as a practise type exercise? i have utterly no idea what a speaker of this creed actually sounds like (good or bad), everything i'm used to has been generic bass reflex ported things.
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Old 21st April 2012, 11:18 PM   #8
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This kind of design is intended to eliminate some of the problem with generic BR while retaining the positive parts. The price paid is complexity.

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Old 21st April 2012, 11:24 PM   #9
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This kind of design is intended to eliminate some of the problem with generic BR while retaining the positive parts. The price paid is complexity.

dave
would you be referring to smoothing out the peaky bass response that a bass reflex normally gives? or at least the peaking my current speakers have at 70hz.
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Old 21st April 2012, 11:34 PM   #10
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A BR is usually tightly tuned to a set of T/S parameters. But T/S are not scalars and they change as a function of how much drive (and weather, and, and...). The BVR & my miniOnken (and some others) essentially add an R to the vent, giving them a greater tolerance to changes in T/S under dynamic conditions (ie music)

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