MJK simulations - double mouth back loaded horn help.

[gafhenderson]

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

[gafhenderson]

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

[Zen Mod]

best place for these questions

quarter-wave : Quarter Wavelength Loudspeaker Design

[planet10]

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

[gafhenderson]

Originally Posted by planet10

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?

[planet10]

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

[gafhenderson]

Originally Posted by planet10

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.

[planet10]

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

[gafhenderson]

Originally Posted by planet10

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.

[planet10]

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)

dave