I only have a moment, but an Onken is ultimately just a vented box with a large distributed vent CSA. So assuming you don't want some colouration from vent harmonics (some do, and the combing is likely responsible for the characteristic presentation of some Onken designs), then ideally, you want a unit that requires a reasonably large Vb for a given tuning in order to keep the duct length down.
Thanks (as always) Scott!
I’m thinking of using some kind of large coax speaker for this experiment.
More research
I’m thinking of using some kind of large coax speaker for this experiment.
More research
And, as always, thanks Dave!
I’m looking to build something a bit larger…
12” coax kinda thing, so I’m hoping I won’t have too hard a time sourcing a driver that’s appropriate.
P
I’m looking to build something a bit larger…
12” coax kinda thing, so I’m hoping I won’t have too hard a time sourcing a driver that’s appropriate.
P
Do a search for the older Onken threads here, there is a lot of information in those threads. There are several experts on Onken here on the forum - hopefully they will find this thread soon.
I built 11 cu ft Onken cabs back in 2006 which are still in use today.
The Onken Mini is considered to be an Onken as far as I am aware - a number of my friends have them and they're just smaller (12 inch drivers) but otherwise very similar.
The Onken is based on the older Jensen Ultraflex design.
I built 11 cu ft Onken cabs back in 2006 which are still in use today.
The Onken Mini is considered to be an Onken as far as I am aware - a number of my friends have them and they're just smaller (12 inch drivers) but otherwise very similar.
The Onken is based on the older Jensen Ultraflex design.
Translated into Thiele Small parameters, that roughly means Qts = 0.4 - 0.6 .
Slightly higher is acceptable if the frequency response does not have to be perfectly flat.
Onken cabs around here were built with drivers like the 515, 416 and 412 which are all low qts drivers. I believe TBTL's recommendation would result in somewhat flatter overall response than designs traditionally based on lower qts drivers.
Mine are built around Iconic 165-8G which are essentially a 515-8G.
Mine are built around Iconic 165-8G which are essentially a 515-8G.
I've confirmed this Onken Calculator gives fairly similar results to the Onken calculator I used to design mine. I'm not at liberty to share that calculator.
Calculate Onken Bass Relex Loudspeaker
Calculate Onken Bass Relex Loudspeaker
A driver that sounds good.
And works in a vented box.
Its basically a reflex box.
With a unique dual slot ports.
Keeping in mind if you want a 12" coaxial speaker that has a woofer that can crossover high enough to work
its usually gonna be a pro sound type driver. And most but not all live sound coaxial drivers are designed for stage monitors.
Which are typically small boxes.
And works in a vented box.
Its basically a reflex box.
With a unique dual slot ports.
Keeping in mind if you want a 12" coaxial speaker that has a woofer that can crossover high enough to work
its usually gonna be a pro sound type driver. And most but not all live sound coaxial drivers are designed for stage monitors.
Which are typically small boxes.
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Greets!
N = 5.7 performance wise is near enough identical to this T/S max flat design routine:
Vb = 20*Vas*Qts'^3.3
Fb = 0.42*Fs*Qts'^-0.96
N = 6.34 is more like an EBS, i.e. bigger cab with a higher F3 'shelf' for apps with high[er] room/boundary gain.
In short, a large Vas or high Qts' or a balance between the two is required for a typical LF driver's Fs.
[Qts']: [Qts] + any added series resistance [Rs]: Calculate new Qts with Series Resistor
Indeed! FWIW though, here's a 5.7n Celestion FTX1225 that with 1.5 ohms [Rs/Rg], 8" dia. vent = [8] 3.75 x 10 cm slots x 34.55 cm [corrected] that looks good in a sim for HIFI apps.
I misread Scottmoose's post, I missed the 'for a given tuning' bit. A highish Qts > 0.4 results in a large vented enclosure (therefore short ports), but also results in a low tuning frequency, for a given fs. A low tuning frequency increases port length again.
A highish Qts driver (> 0.4) in a vented enclosure, needs a highish fs to keep the tuning frequency moderate in the absolute sense.
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Thank you all!
And thank you for the equations.
More research…
Was looking at something like this,
h30coaxial
or the Great Plains Audio
http://greatplainsaudio.com/wp-content/uploads/2016/06/604_8H_III.pdf
Obviously not for experimentation, but more like a fantasy end game
And thank you for the equations.
More research…
Was looking at something like this,
h30coaxial
or the Great Plains Audio
http://greatplainsaudio.com/wp-content/uploads/2016/06/604_8H_III.pdf
Obviously not for experimentation, but more like a fantasy end game
I'd look at the 604-8H-III, the H30 has a piezo tweeter which I think is a concern.
If you are considering the 604 I would have a look at Jeff Markwarts crossover design pages for these 604 here:
Altec-Lansing 604-8H Crossover Revelations - Great Plains Audio
If you are considering the 604 I would have a look at Jeff Markwarts crossover design pages for these 604 here:
Altec-Lansing 604-8H Crossover Revelations - Great Plains Audio
Hi
I also want to build (mini) Onkens. I have two Wharfedale super 12 drivers, the t/s parameters differ unfortunately:
Driver 1 Driver 2
R(e) 11.28 12.39
F(s) 34.99 29.61
Q(ts) 0.3863 0.2816
Q(es) 0.4415 0.326
Q(ms) 3.095 2.07
L(e) mH(10k) 0.4835 0.5162
M(ms) 34 34
V(as) 336 liters 240 liters
Any idea whether these would work in Onkens?
I also want to build (mini) Onkens. I have two Wharfedale super 12 drivers, the t/s parameters differ unfortunately:
Driver 1 Driver 2
R(e) 11.28 12.39
F(s) 34.99 29.61
Q(ts) 0.3863 0.2816
Q(es) 0.4415 0.326
Q(ms) 3.095 2.07
L(e) mH(10k) 0.4835 0.5162
M(ms) 34 34
V(as) 336 liters 240 liters
Any idea whether these would work in Onkens?
I have your email. Now that we have data i will have a look to se eif they will work.
I have 2 Super 8s in my give away pile. Not really a pair by the T?S but someone who has one or more might find them useful
dave