Modeling throat - vented horns - When is that arrangement useful to the hobbyist? How should it be simulated?

[karlson3]

Here's a very short throat thoat ported horn with K33 and EQ to reach 31Hz level in a corner.

The baffle would be 18.5" x 22.5" and mouth area like PWK's La Scala (or Belle)

 

Its pretty big but not horribly big (by mancave standards) - can you make  a sketch of how it

might be built?  There's 4 cubic feet of back chamber..  Two shelf ports, one above the woofer and other below could make the 10 inch deep ports.

 

At 77cm horn length - it may need more cowbell.

 

[grindstone]

Just catching-up (lost today running-around).  Looks/sounds squatty to hide 4 ft3 behind at first read (probably get pretty deep).  Will look tomorrow if someone hasn't already done it by then. 

[karlson3]

forget that sim   - here's one I actually like - is this result real and is it even "buildable" ?  IT's K33 spec and no EQ at all.

 

[grindstone]

That one is really pushing-it.  Implem/realization would have to be (?) compression driver phase plug geom with novak-ey inlet (low diyer-friendliness).  It has become a different thing, not amenable to treatment such as David's first pass (itself skimpily representative owing to HR segment limitations). 

[karlson3]

OOPS - had L34 in inches rather than cm and re-did it with L34 = 30 cm as assume

that path has to be a bit more than half the baffle's width.

 

I'll fix this mess later - the result of a usable L34 appears to drop the high end

to around 200.  K33 is a great spec for the low end.

 

I'm sorry to clutter up this forum - hopefully I'll learn something

which might be useful

 

I might ask the moderator to remove the thread until I'm more confident with things.

 

its baby steps - like one forwards then one back

 

 

am getting closer to a buildable horn.   The back chamber at 100 liters sans port and driver displacement would be less than 15 inches deep with a throat-baffle width of 18.5 inches and baffle height of 22.5".   I don;'t know if the horn could fit a rectangular box 2ft by 2ft by 3ft.    The final horn segment could be shortened from 70cm to 55 cm with a small hit in response but max efficiency (0.5 pi) would be 60% at ~53Hz -  -nice for kickdrum.

 

Maybe a wizard like ClaudeJ could fold this mess.

 

I "did" very much like the size and predicted performance numbers -  but that could not be built lol

 

 

HERE is input with a minimum width for L34 -  L34 has to be at the minimum one half the width of the

"thraot-baffle" (that baffle is 18.5 inches wide in this case.

 

It would not hurt to sim with a taller baffle and compare.  This baffle width is about as narrow as can be made so the composite throat would be somewhat larger with a taller baffle.

 

The low end stays strong but the top at best power-wise is

F6 around 250Hz - so it might use a 150Hz tractrix midhorn drven by a hot pro 6 - 8 "inch speaker.

 

 

 

 

 

 

 

 

[geezin']

Please don't delete. This is enlightening to me. I know squat in this arena so I'll take anything I can get.

[ClaudeJ1]

29 minutes ago, geezin' said:

Please don't delete. This is enlightening to me. I know squat in this arena so I'll take anything I can get.

Interesting academic exercise based on reasonable guesses.

 

As for actually BUILDING something (like I'm doing now) out of Baltic Birch, I believe in getting only to 50 Hz. on the top end.  Rest is crossing from there down to big Tapped Horn Subs that get to 20 Hz. easily with a monster driver and 250 watt amplifier.

 

Great sounding solution for any program material, including simulated plane crashes in HT, and absolutely realistic Drum Solos with 124 dB peaks.

 

I'd rather listen to music on what I bought and built than THEORIZE all day on a product that does not yet exist!  Just sayin'.....................

[grindstone]

An aside of advocacy of the original horned one -

Edgar worked on khorn/belle/LS here:

 

 

Suggest application of HPF, EQ to the existing (and throat-ported variants as you choose).  A lot of links are broken from the board change, but there's still some geometry and sim stuff there.  (Surely there's other threads, that's just what came-up first/best for me).  

 

Alternatively (or in-concert), maybe try protecting & pumping-up your khorns to see what you think (with your own ears in your own digs)?  Just ideas.  

 

[Edgar]

Wow, has it really been twelve years since I did that? 😲

[karlson3]

Hi ClaudeJ

 

FWIW with aid of YouTube and ESS headphones (lock most sound "in" so no one is ever disturbed) I listen to opera, bluegrass, orchestral., percussion, old jazz,

 

I'm not worried about cloning a speaker where one cabinet costs more than what my house and probably all its belongings are worth less than its cost. 

 

I just want the ability to understand differences in approach and how to choose.  I'm 71 with heart failure, my house ruined while I was in the hospital in 2019 for an allergic reaction which put me on a ventilator for 9 days.

 

My main interest are John Karlson's approaches (don't laugh as can be pretty good) and those aren't easy to sim.  Even XRK971's Akabak2 sims are off in the basics of response and impedance. Akabak3 might come close if the model is sophisticated enough and requires AutoCad, Fusion 360 plus Akabak3 - all way beyond what my feeble brain can do. 

 

You can ask the moderator to remove the thread (I don't kn ow how)

 

Best!

Freddy

 

PS - the sim from above and repeated below was for a K33 design - about 12 cujbic foot cabinet - if the horn would fit - lol

 

It's pretty good on the low end but loses some on the top vs a K33 in a vented Ka Scala

 

[grindstone]

That behavior is basically what I got from stuffing a port in Edgars' Belle model, too.  Adding bass always costs what it costs.  These throat-reflex-stubby-pipehorns are a slightly different rodeo to try to damp, though.  I didn't compare the throat-ported stuff to Dennis' atmospheric vented stuff, so can't guess what wins at what net size.  (Another interesting inquiry for someone else )  

 

Your normal reflex sort of "djk'd belle" was pretty smooth, comparatively.  Didn't look/sim it, myself, but it's another useful boundary in this region of the sandbox.  Tradeoffs/prefs arise again.  For me, this stuff is too ringy but I realize the painting is broad-brush yet and that lousy damping is the frequent companion of undersizing.  Those questions stay pretty open while the broad-brush (wider survey/investigative-mode) is still out.

 

And I hear you about the K-deviations (why couldn't you pick an obsession that's easier to model?)  Might be able to help some (another board/PM/etc for that).  

 

It's nice to have to think about somebody else's speaker problem for a bit, though, so sincere thanks for the gift of something interesting.  Glad you're still out there instigating and wish you well!

 

Sooooo...question would seem to be if you got what you need out of this or not.  If you still care about the 3x2x2 something or other, suppose we could thrash that to death for fun, or something else.  Anything coalescing or...thoughts?  With the 19x23 or whatever it was, this is wide/lowboy, right?

 

 

[karlson3]

FWIW a comparison posted a day or so ago at the high efficiency speaker asylum

 

one cabinet  (throat ported) is somewhat larger but both cabinets have the same rear chamber size and

tuning )~31Hz) - there's no HPF or EQ in this sim