Wild Burro Onken

[Pit Hinder]

Hmmm...Klang&Ton once had an Onken style sub with an 18" that allegedly could launch the tiles off the roof. Somehow makes more sense to me than using an Onken cab widerange - sissy I am, I´d be afraid of getting too much midrange smut from the BR channels.

[nesha]

Sorry, my net-connection was down for 3 days, but I'm glad you guys had a little party without me. I know, ZM, I hoped GM would chime in...
Thanks for all answers... GM, I've got 32cm for L'vent (corrected length ) But never mind, I will adopt your calculations... and my wife is sending some kisses for smaller box.
I don't have some specific design goals, (to ignorant for this),but to build nice and balanced sounding speakers , at LOW listening levels. A speaker that 'opens up' at realistic levels is definitely Not my goal...

[GM]

Originally Posted by Pit Hinder

I´d be afraid of getting too much midrange smut from the BR channels.

Oh yeah, the only 'true' pair of Onkens I built were loaded with Altec 416-8Cs and they 'sang' like a flock of Wild Geese in a feather plucking factory, so had to scrounge up a lot of old socks! Sure were sexy looking though and their ultimate owner was quite happy with them sans socks XO'd at ~500 Hz to much tweaked 511/802 horns until the wife sold the whole HIFI system in a divorce battle. Sure wish she'd a done me the courtesy of first refusal.

Oh well, many folks like their foods, colors 'fat'/'rich', so why not their music also? I make no judgment, but it's not for me (except the food ), so don't make it a habit to suggest such alignments.

Anyway, a ~typical measurement, notice the peaking at Fb and broadband peaks/nulls beginning around 190 Hz and extending out beyond 1 kHz if considerable vent damping isn't done:

GM

[freddi]

re:reflex, I ran 4 ~RJ type 18" = ok on the little 6.4 cu.f.t box w. 103g mms - the 130g 18 sounded better midrange-wise in a Karlson-coupler than in the 8.2 cubic foot RJ - they're not quite RJ if aperture area isn't choked down. Since the vents are in close proximity to the cone, nearfield measurements to the cone are pretty much what happens

[GM]

Originally Posted by nesha

Thanks for all answers...

GM, I've got 32cm for L'vent (corrected length )

... and my wife is sending some kisses for smaller box.

You're welcome!

Thanks, I'd kiss back, but too old n' slow to dodge the slap.

As I eventually noted, your extra length is due to making the vent area larger than desirable. Vd = Sd is the max and frankly, in most cases is way larger than they need to be, so if you want to make the cab smaller than what I simmed, just reduce Vd to ~0.7x Sd which will shorten the vents some more, though you'll lose some of the Onken's 'fat' tone.

GM

[nesha]

Well , I have a few old socs spared , so no problem...Sock jokes aside , I hope you don't consider this onken box especially bad solution for BetsyK...

[GM]

Yeah, to my way of thinking, either bone-fide BP load it such as the K or for Vd = Sd alignments use Thuras's bass reflex speaker patent layout (fig. 1, 2):

GM

[nesha]

"BP load it such as the K" - Pardon my bad English, I don't get this one?
I'll check out new 'Swiss cheese look' with my wife...

[GM]

Originally Posted by nesha

Well , I have a few old socs spared , so no problem...Sock jokes aside , I hope you don't consider this onken box especially bad solution for BetsyK...

I've no personal experience with the driver, only the box loading, so all I can say is that if you prefer an 'accurate' sound and/or have significant room boundary gain, then I imagine you'll need quite a bit of vent damping, otherwise you'll probably like it a lot if it doesn't 'color' the voices too much.

FWIW, women typically have much keener hearing everywhere but down low than men, so within certain loose limits I always let them decide what sounds 'best', especially through the critical mids/lower HF where their maternal instincts rule their hearing. This usually has the side benefit of 'smoothing the path' for loud playback and for future upgrades without having to budget for expensive jewelery, etc..

As the ancient truism goes, 'when mama's happy, everybody's happy and when she's not, nobody else is either'.

GM

[GM]

Originally Posted by nesha

"BP load it such as the K" - Pardon my bad English, I don't get this one?
I'll check out new 'Swiss cheese look' with my wife...

Band-pass loading such as the Karlson does, i.e. the driver is loaded with at least a single front and rear chamber to increase its efficiency over a narrower band-width (BW) than sealed or vented does. The trade-off is that it rolls off the driver's mids/HF response above its pass-band, so at least in the case of typical 4th, 6th, etc. BPs, they are unsuitable for 'FR' use.

The Karlson is essentially an 8th order BP, but with a large exponentially tapered slot in front of the driver to try and 'let through' as much of the driver's beaming mids/HF response as practical while still adequately front loading the driver, but me and many others prefer XOing it at around 250-500 Hz depending on the person and using a large wide angle horn for the rest of the BW.

GM