Onken Alpair 10Bass

[_henry_]

After seeing HH article for the Alpair10 + 5, im searching for best application for them
I always like onken, and i found this onken calculator from mh-audio.nl - Downloads

I calculated based on publish parameters on markaudio.com, and i come up with this result

i need 97L box volume!!!

i wonder if this calculator is right

 

[_henry_]

if i calculated the box internal dimension would be 250mm x 400mm x 970mm.

Which still ok for floorstanding but with 8 ports, let say 4 each side, with height of 30mm and width of 18mm (3/4" materials).

cheers
henry

 

[_henry_]

I tried to do simple drawing

 

[GM]

One or more of the specs you used is wrong based on the average measured specs posted awhile back. It's Vas is way too low for Onken loading, only for the Onken 'look' as a ~aperiodically loaded alignment, i.e. DD's Fonken concept. A 6 ohm series resistance is going to dramatically increase the cab's net Vb/lower Fb over one designed for a SS or similar vanishingly low output impedance source though.

GM

 

[GM]

OK, looking at the published specs, you inputted the wrong Re and Sd plus markaudio's Sd spec is wrong unless it's some arcane metric unit not normally used as it should be an area unit of measure such as cm^2, etc..

Regardless, input Re = 5.4 and assuming the published Sd should be 89.9 cm^2, then input Sd = 8.99e-03 for a bit more realistic design, yet not so much considering its TL length vents.

GM

 

[planet10]

Henry,

Here is the planet10-hifi primeSize milliOnken (looks like an Onken but has nothing to do with Onken calculators),

http://p10hifi.net/tlinespeakers/FAL/downloads/MarKen10-1v0-map-181209.pdf

dave

 

[GM]

Dave,

For your drawing note 1: 14 L = ~854.33"^3 = ~0.4944 ft^3.

Got a measured response or at least a sim? The reason I ask is that the Onken calculator might make an excellent Fonken calculator to find cab net Vb, Fb, vent areas. For instance, ignoring any series resistance, this driver calculates a n = 6.34 ~12.86 L/44.6Hz Fb, so curious if the minor reduction audibly affects it.

Or, if it does and the calculator is off by roughly the same percentage on other Fonken designs, then we can change the 'n' factor as required to average them out enough to make a dedicated DIY designer same as the BIB.

GM

 

[planet10]

Interesting idea. When i do these i look for a specific curve shape and then estimate response by interpolating with the sealed response at the same volume.

Going back to the drawing, actual volume is 826 in^3 less whatever the driver takes up. 14 litre is the gross volume before braces & drivers, target was 13 litre net (just under 800 in^3)

Sim is 13 litre 50 hz tuning.

dave

 

[GM]

Thanks!

YGM,

GM

 

[_henry_]

Hi GM, thanks for correcting me.

Dave, thanks for sharing the plan, will it work for alpair10 bass? which have slightly different Q and mms.

cheers
henry

 

[planet10]

Maybe. I don't know.

If you want Alpair10 bass get them while you can, not a lot were made, and Mark has learned so much in the interim, he won't be able to resist improving on them with a new bass only driver.

dave

 

[_henry_]

i actually have 1 pair waiting.

i'll be looking forward for bigger bass driver like the 12.

i might as well try it.

thanks dave

henry

 

[vinylkid58]

Or, if it does and the calculator is off by roughly the same percentage on other Fonken designs, then we can change the 'n' factor as required to average them out enough to make a dedicated DIY designer same as the BIB.

Hi GM,

FWIW, I tried to duplicate Dave's Fonken in the XLS calculator ages ago when I built my boxes. I got an n = 5.3, but that was with Rg=0.6 ohms and the factory TS numbers. Vb Total was approx. 13.6 litres.

Jeff

 

[GM]

Hi GM, thanks for correcting me.

You're welcome!

Not an Onken (you can always either paint the vents on and/or route some fake slots as some have done to get the 'look'), but a MLTL floor-stander looks doable and with a 6 ohm output resistance it will have a vintage type of 'warm' bass response, so for a very low impedance some BSC may be required if not near/at a room boundary:

L = 54.187"
zdriver = 17.93" puts the driver at a typical ear height
zport = at bottom
SO, SL = 48.13"^2 (recommend 8.75" x 5.5")
dport = 3" or a slot of = area (7.07"^2)
Lport = 3"

All dims i.d. (inside) and approximate. Stuff with polyfil as required up to 0.5 lb/ft^3 to get the desired smoothness/roll off response including in the vent if there's still some 'one note' resonance. Such a high aspect ratio cab needs little bracing if built of void free plywood, so a vertical front-to-back motor brace is all it needs and of course a suitable base to keep it from easily tipping over, especially if kids and/or pets are around.

GM

 

[GM]

I got an n = 5.3.........

Greets!

The MLTL I just posted has a n = 6.34 calculated volume to keep the footprint as small as practical, but is too big IMO to meet either the Fonken's or my own ~aperiodic design criteria, yet too small to meet my MLTL design criteria based on its published specs + series R, so using an n factor based designer probably isn't going to work well enough.

GM