Onken bass box with 2 Eminence Deltalite ll 2510 10" bass drivers

[albertli]

Guys,

Lately I got 4 2510 10" and would love to make couple Onken bass box for my future project. My intention is to put 2 drivers in one box and aim at highest db as possible so to cope with my 2A3 and 300B amps. I really would love to match it with a mid horn and a tweeter. I've been searching all over the forum and seems not too many Onken box with 10" driver. I finally come with a calculation posted by GM and have the following result. I know the result doesn't look right and I have to admit that I'm not good on math.
Please take a look at the attachment and I'd appreciate any ideas provided.
BR

Albert

[albertli]

ONKEN CALCULATOR by Cyr-Marc Debien 2000 © cdebien@cmaisonneuve.qc.ca
After original research from M. Eijiro Koïzumi and Jacques Mahul and Jean Hiraga calculations.
Koïzumi factor K= 1.57 K= 83.210 Hz

You can modify the RED value. The Green Value are calculated by the software. In many case it's for validation.

TS parameters
Fs 53.000 Hz driver frequency resonnance
Re 5.060 ohms dc resistance of driver
Qms 5.760 mechanical Q of the driver
Qes 0.450 electrical Q of the driver
Qts 0.417 total Q of driver at Fs calculated by the software
Mms/d 31.000 gr total cone assembly mass
Sd 3.501E+00 m^2 effective radiation area of the driver cone
Rg 0.300 ohms total components resistance (xover coil, terminal, wire, amplifier, etc.)
Cms 2.91E-04 driver suspension compliance calculated by the software
Vas 499309.099 litres air volume driver compliance calculated by the software
Vas*Qts2 96774.541 calculated by the software
n = 6.340 (best 5.7) Onken alignment (best alignment = 5.7, Onken alignment = 6.34)
note : you can play with the n factor to maintain the L' vent under 30 cm
but try to don't used a excessive value because you don' t respect the Onken approach


Box and system response
F-3 47.812 Hz box cutoff frequency at -3dB
Fb 46.951 Hz box cutoff frequency
Cab 43825.042 acoustical box compliance 0.477
Map 0.003 acoustical mass box 0.440
S vent 304.000 cm^2 this value is calculated by the vent dimension section 0.000
nO 159.243 Vas*Qts2’ 96774.541
dB 1w/1m 133.520 dB total efficiency of the system including Rg


Vent lenght
L vent 0.006 cm effective lenght vent
L’ vent -9.732 cm corrected effective vent lenght (use this lenght in your vent calculation)
note : If the L' vent is over 35 cm, your driver is not suitable for the Onken speaker application


Vent dimension (habitually an Onken speaker have a S vent equal or -15 % smaller to the driver Sd)
Width 4.000 cm indicate the width of one vent
Height 9.500 cm indicate the height of one vent
Quantity 8.000 indicate the number of vent you can use (Onken speaker have 6 or 8 identical vent)
S vent 304.000 cm^2 total vent area (try to obtain a S vent equal or maximum 15% less to the Sd)
Vent volume -2.959 litres total volume occupied by all vent in the box


Total Box Volume
Vb 613550.590 litres total internal volume of the box
Vb Total 613547.631 litres total internal volume of the box plus the required volume for the vent


I filled in all numbers I know on the red box and come up with the above numbers.

[revintage]

According to my spreadsheet based on the "Petite Onken" article you get for two drivers in one box:

Vb=117dm3, F3=50,1Hz, Sev=700cm2/L=53cm.

Unfortunately this isn´t the optimal Onken, as F3 is to high and L is to long.

Using the pair in a 3m long, 35Hz basshorn and 1075dm3 volume sims very well though. Over 115dB sensitivity!

[albertli]

Lars,

Thanks for the input, but I don't know what is a basshorn look like. Can you send me a link I could take a look at ???

Albert

[ra7]

Don't worry about it albert. You seem to have done ur research. Go for the build, and let us know how it turns out.

[albertli]

Originally Posted by ra7

Don't worry about it albert. You seem to have done ur research. Go for the build, and let us know how it turns out.

I want to build, but the size of box volume doesn't look right to me.

[jamikl]

Using your data on the Onken spreadsheet and using the two speakers in parallel
I get the following, provided I have entered the data correctly:
jamikl

[albertli]

Originally Posted by jamikl

Using your data on the Onken spreadsheet and using the two speakers in parallel
I get the following, provided I have entered the data correctly:
jamikl

Jamikl,

Thanks for the help.
Now I got 2 box volume. Which one I should go for, the 149.337 litres/or 165.781 litres. Also I have 8 vent, 4.25 x 15 cm each. How deep ??
Albert

[albertli]

Let say 150 litres is the number. I come up with the following numbers upon 3/4" for vent dividers, 24.5" H 21" W 18" D and the vents volume also include into the size, or I have to exclude the vents from the box size

Albert

[albertli]

I draw the diagram as attached.