Seas Idunn revisited-project

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The acoustic response of the tweeter in the Seas Idunn is close to a 4th order Linkwitz-Riley high-pass filter (green curve):

Seas Idunn Tweeter.jpg

The acoustic response of the tweeter in Mark's ER18DXT is close to a 2nd order Linkwitz-Riley high-pass filter (green curve):

ER18DXT Tweeter.jpg

Sorry Steve, that's not "almost identical". A Boxsim simulation using the TW70 tweeter and crossovers completely different from Idunn/ER18DXT to prove your theory is pure fiction.
 
Steve, I'm sorry to say that you loose 6-1 to MarkK

You can show us only an on-axis simulation.

MarkK has shown us his measurements of a real speaker


This happens too often. Someone puts out arguments that are just of marginal relevance. I'm not competent enough to go to details. I close the case.

rgds, Juha
 
Thank you Steven and streten for an informative argumentation. And special thanks to Juha who has willingly taken a role as my tutor. The level of the discussion often moves beyond my knowledge ans understanding and I do accept the fact that I have still a long way to go in my learning process.

My cabinets are a tower design and the tweeter center is 78cm high. The cabinet designers have not mentioned/observed the impact of the inversely placed elements. I am getting closer to understansing what Steven means and I will test the change of tweeter polarity. It has confused me that Seas uses the the change to demonstrate that the elements are in phase at the x/o frequency.

A peaceful X-mas to you all,

Jouko
 
Hi all!

This thread is very interesting for me, since having built the original Idunn design. But I'm not satisfied, feeling the speaker being voiced to brigth. Male voices like Leonard Cohen doesen't sound convincing, the reproduction lacks authority...

Troels Gravensen recent Curv design use the U16 midwoofer, and Troels experimented with what he describes as a "typical" second order filter for the woofer with a 1.8 mH inductor in series and 10 uF cap in parallell, with a crossover freq of 2.2 kHz - very similar to the Idunn woofer XO (2.2 mH and 10 uF, 2.2 kHz).

However, Troels rejected this approach and instead he reduced the inductor to 1.2 mH, increased the capacitor to 22 uF (with 2.2 ohm resistor). Then he introduces a LCR circut to smoothen out the response.

I would like to adapt this design approach to the Idunn as well, keeping the DXT tweeter and filter as is (maybe?) but unfortunately my skills are not up to the task. What do you think, could this be a good idea? Should the filter be redesigned from scratch?
 
Hei Bromle,
you are most welcome to join cooking our soup.
I must be at least as uncabable of answering you question as you but I am trying to make progress through sharing. It is most difficult to put myself into your listening position because of room acoustics, speaker placement and even hardware. You gave me an excellent benchmark, however , because I've been listening Cohen a lot for 10+ yrs with my old speakers. Leonards voice is rather like a violoncello and even a contrabass lately. I've been using the sub successfully, give it a try.
Let's listen for the wiser guys for the x/o changes.
MVH,
Jouko
 
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