And Now For Something REALLY BIG

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#283
Well, You and I share a thread......
My beta build of P10 Emken, which is a 'sorta onken' has adjustable venting right?
Now, given that I'm 'one of those sorta people', how about you can kinda decide how WIDE to build the Onken vent.......then add a bit extra!
Then, one can predict how LONG the vent needs to be........build it slightly short.
THEN, one can either add extensions to the length and shim the width down.
I realised this after 20 secs of looking at my EmKen plans.
Send letter of thanks written on £20 / $10 x 3, marked 'Help Darrell finance First Watt F5T 4 pair'.
 
#286
tinitus said:
if I remember correctly, woofers with big Vas and lowish Qts

wasnt the original Onken a huge 500liter thing
Click to expand...

I tried online Onken calculators for my 12" Tannoys (huge Vas, lowish Qts, ideal port rather large and shorter than my cab walls are thick) once and only ever got the result that this driver is not suitable for Onkens. On the other hand Tannoys best cab for my driver, the Edinburgh, looks rather like an Onken although Tannoy call it 'distributed port'.
I gave up eventually.
 
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#287
Brett said:
That should be 12 and 24dB/oct respectively.
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It is not uncommon for custom DIY speaker designs to measure/simulate the room gain effects, and design a bass cabinet that complements this gain. The lower 1-2 bass octaves can be designed to have modest 6db/octave slopes, typical standard Qtc slopes, steep slopes, or bass shelf shapes to complement the room gain, placement near walls, room pressuriazation gain, and ground bounce effects.

I have done this for an Altec 604 MLTL. The speaker had to be put against the rear wall and the woofer height above the floor was carefully engineered to take baffle step and ground bounce into account on a carpeted floor.

Old-school solutions for simple gain stages without electronic equalization.

jbagby

"The Diffraction and Boundary Simulator" 1.20 spreadsheet and it's VBA modules by Jeff Bagby
Passive Crossover Designer - Design passive crossovers and equalization networks


KEF provides a Speaker Placement Tool application to help assist users in ...
laaudiofile.com
Custom Installed Speakers - Ci Series - Ci Software Download - KEF United States
 

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#289
Hi Line. I've read what you wrote and have read it elsewhere, but I still don't understand it.

I have JBL Barzilay cabs that I braced up really well. They ended up with an internal volume of 4.556 ft3. I just got my Lambda TD15X drivers yesterday. When I plug in everything into WinISD it shows an F3 at 40hz. That is with 2 4" ports each 9.5" long.

SO, What could I or should I be doing to make sure they work best in my room?
 
#290
djn said:
Hi Line. I've read what you wrote and have read it elsewhere, but I still don't understand it.

I have JBL Barzilay cabs that I braced up really well. They ended up with an internal volume of 4.556 ft3. I just got my Lambda TD15X drivers yesterday. When I plug in everything into WinISD it shows an F3 at 40hz. That is with 2 4" ports each 9.5" long.

SO, What could I or should I be doing to make sure they work best in my room?
Click to expand...

Your WinISD simulation of the TD15X looks correct with my data. Since your cabinet size is already fixed, your main option is to change the box tuning by changing the port dimensions after lowering the tuning frequency on the WinISD BOX window, and changing the speaker position in your room so the combination of room+speaker generates the best response.

Have you downloaded and entered your room/speaker setup into:
jbagby

"The Diffraction and Boundary Simulator" 1.20 spreadsheet and it's VBA modules by Jeff Bagby
Passive Crossover Designer - Design passive crossovers and equalization networks

This will give a rough estimate of rear wall, floor, corner, woofer height, open walls, etc.. effects.

Measurements are the next step for tuning the Xover.
 
#291
Thanks Line. Not only is my box size fixed, the placement in the room is faily locked in as well. So that leave an adjustable port tube to vary the turning frequency.

I'll download the D & B simulator and play with that this weekend.
 
#294
d to the g said:
I'm not sure why you'd be searching for an appropriate driver for the onken, when you can regularly get a pair of Altec 414 for $300 + shipping. That leaves quite a bit left in your budget.
Click to expand...

Pano said:
Finding a pair of 414 in the UK or Europe might be best for the budget. With those can can build the "Petit Onken"
Click to expand...

At around 22lb a pop its way too expensive to ship them over and tbh I'd want any 'vintage' drivers I get re-coned anyway. That puts the purchase + shipping + shipping to be re-coned + re coning + shipping back to me price way up there again

I wonder if my friends from Arizona are going to visit any time soon :idea:

I love the fact the petite onken is still a huffing great cavern of a box!!! I didn't realise it was soo BIG
 
#295
Ship them where? If you find them on that side of the pond, it should not be too bad. I'm sure you can get recones done in the UK. Westrex made a whole line of Altec drivers there in UK. They are often a bit better built than the USA versions.
 
#298
You never know what you'll get, unless you can measure them first. Even recones don't always go as planned.

As much as I love them, buying used Altec drivers is always a gamble. Lady Luck may smile on you, or she may not. For this project, new European drivers is probably the way to go. We've looked at a few good candidates.
 
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