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PeterDupont 6th April 2011 05:16 PM

Iwata for TAD 4003
1 Attachment(s)
Hi everybody,

Me and a friend are to build the Iwata's, but for the TAD 4003 driver, which is quite different to the 4001 in throat-size.

I downloaded the old drawings from this site and -angle and was worried about, if TAD had gone different ways in terms of the angle. I used Illustrator to make the following drawing (4003 overlaid by 4001) to show, that it should be in terms of the laws to make a adapter.

The "start" of the Iwata-horn lies perfect in the middle of the diapraghm.

Later this evening I will post the drawings of the vertical and horisontal curves in pdf.-format 1:1 that only needs printing for cutting out forms.
I will get back with the link if anyone are interested.

Regards and thanks for a brilliant forum.


PeterDupont 6th April 2011 06:09 PM

pdf-files for printing 100% (they are measurably perfect) can be found here:



PeterDupont 6th April 2011 07:27 PM

Sorry - the last link -

New to this forum, I am not certain if this is the relevant place for this thread - otherwise I indulge moderators to move it!

PeterDupont 6th April 2011 08:11 PM

As to the drawing: They are both equal in size and I have aligned the diapraghms. Look carefully at the phase-plugs! On the 4003 they are prolonged at the tip and the cavity in front are very different to the more round ditto on the 4001. Presumedly for better HF.
The angle are steeper than the 4001, but due to the shorter hornlengt in the 4004 it should not a probem to make a near-perfect adapter.
If anyone has inputs, please.


thorstenlarsen 6th April 2011 11:11 PM

Hej Peter !
It should be :
God arbejdslyst ;)
Thorsten Larsen

PeterDupont 7th April 2011 06:28 AM

Thx. Thorsten!


tatosdk 26th May 2011 07:55 AM

Opening angle of TAD TD-4003
Hi Peter.

I cheked my 4003 and indeed the opening angle is a couple of degrees less than the JBL standard 1.5-2.0 inch adapter that I use. But the difference is so small that I wont worry about that.
Why have you chosen the IWATA profile?
Why not make a horn that has been optimised to the 4003?
Like this one:

I want to make it in wood, something like this one:

If you are interested, lets join forces, I stay in Lyngby.


PeterDupont 26th May 2011 01:24 PM

Hi Erik, allready heard from Søren/Robert that you would maybe participate - great!
We go for the old, original Iwata and the 950 we allready got from Radian. I know about the Polish Iwata, but don't want to go the "plastic-way". I still think that wood has a certain role in dampening and strength. And the design has proven it's worth, so why tinker with a gem. The process of turning the horns is a tremendous job itself. A follow up will maybe be the Brush Wellman's. I have had several conversations with Mr. Yamamoto that concludes that fin's like found in the venerable TAD-horn is good for spreading but bad for the sonic's
And, great hearing from you again.


Pano 26th May 2011 02:33 PM

:cop: Peter. Please read this thread about images.
I have reduced the file size of your image and attached it.

Best of luck on the project, the Iwata horn is a great one. :checked:

PeterDupont 26th May 2011 03:55 PM

Thx. Pano! Fumble-fingers just need some pro adjustments..

And yes, wee'l see what the efford makes out sound-wise.


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