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-   -   mini onken english translation (http://www.diyaudio.com/forums/multi-way/198292-mini-onken-english-translation.html)

vega65 11th October 2011 09:04 AM

mini onken english translation
 
Hello
I would like to read an english version of this article


La Mini-Onken

I am considering to make a mini onken with supravox 215 GMF
or if there is a better choice for driver .on top iwata 300 with a decent cd


Best regards Vegard

NEO Dan 11th October 2011 09:10 AM

You need OCR software and then Google translate

planet10 11th October 2011 10:13 AM

Deja Vu

dave

vega65 18th October 2011 05:49 AM

1 Attachment(s)
Thanks for the OCR tip..The outcome of my first attempt was not excellent :D
Need to spend some time with the text to obtain a descent result.
anyway attached is a pdf showing supravox 215gmf in the calculator.Comments on results/values

jamikl 18th October 2011 06:31 AM

That looks OK to me Vega65 if you do't mind the larger box. The one reservation I might have is the as[pect ratio of
the slots. I have read somewhere that they should have a lower aspect ration that 8:1. This may not be a problem
though as kit was only an opinion I read.
jamikl

Pano 18th October 2011 01:52 PM

The mini-onken was used with a fullrange driver on top. I heard the pair that were built in that article and they used a Lowther on top. A 300Hz Iwata horn seems a bit overkill. Better suited to the petit onken or the bigger one.

If I get the time, I'll translate the article. It has some rather good info on the Onken tuning.

A section of the article asks: "Is the Onken a classic, well tuned bass-reflex box?"
After doing the math the answer was: "In conclusion we can confirm that the Onken box (derived from the Jensen baffle) is a perfectly tuned bass reflex that rigorously follows a 4th order law."

There you have it. The hard part is figuring out the tuning of the slot ports.

vega65 18th October 2011 02:02 PM

Thanks
as you can see the proposed volume for 215 gmf is almost twice the cabinets for focal 10c01.I stumbled across the supravox driver as one of few ? suited for a smaller onken cab.Any proposals for another driver resulting in a smaller cabinet ?
Links to information on the ports dimensions and how to settle them ?

best regards Vegard

Pano 18th October 2011 02:09 PM

IIRC, the Onken box likes a driver with high Vas and low Qt. Many modern drivers are not like that.

Basically you're building a bass reflex box with a port area about 75% of the cone surface area. There are many ways to do that, of course, but with the Onken you'll have slot ports along the sides. Figuring out the port correction for those slots is not something I've been able to do, but the spreadsheet helps. You may also notice that the 3 boxes designed in Paris have a port length right at the long edge of "acceptable."

kevinkr 18th October 2011 02:25 PM

Quote:

Originally Posted by Pano (Post 2750037)
IIRC, the Onken box likes a driver with high Vas and low Qt. Many modern drivers are not like that.

Basically you're building a bass reflex box with a port area about 75% of the cone surface area. There are many ways to do that, of course, but with the Onken you'll have slot ports along the sides. Figuring out the port correction for those slots is not something I've been able to do, but the spreadsheet helps. You may also notice that the 3 boxes designed in Paris have a port length right at the long edge of "acceptable."

I can definitely confirm the first and last sentences, (and >80% of sd on port area IIRC) the ports on my Onkens are just a small number of cm shorter than the maximum allowed. I'm still as thrilled with them as the day I built them.. (About 5yrs ago now!) Pano incidentally provided a lot of encouragement. :D

GM 18th October 2011 06:00 PM

Quote:

Originally Posted by vega65 (Post 2749662)
anyway attached is a pdf showing supravox 215gmf in the calculator.

Hmm, if I did the math right, a mini-Onken would be ~ 57.69 L net, so tuned to Fs, its vents would be quite long, though tuned up around its ~60 Hz 4th order roll-off, they should just barely meet the max recommend length for minimum vent area.

GM


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