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Multi-Way Conventional loudspeakers with crossovers

Seas Idunn revisited-project
Seas Idunn revisited-project
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Old 23rd December 2012, 12:36 PM   #21
Dissi is offline Dissi  Switzerland
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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.
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Old 23rd December 2012, 01:22 PM   #22
Juhazi is offline Juhazi  Finland
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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
AINOgradient speaker project
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Old 24th December 2012, 05:37 PM   #23
faija is offline faija  Finland
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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,

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Old 27th December 2012, 11:20 AM   #24
Bromle is offline Bromle  Norway
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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?
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Old 27th December 2012, 03:06 PM   #25
faija is offline faija  Finland
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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.
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Old 11th March 2013, 01:03 AM   #26
sreten is offline sreten  United Kingdom
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Location: Brighton UK

There is no point testing inverted tweeter polarity with
any good speaker design, it simply won't well at all.

I don't know what nonsense suggested that.

rgds, sreten.
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Old 8th July 2014, 02:20 PM   #27
AttokkarAcoustics is offline AttokkarAcoustics  United States
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Default Idunn project - Suggestions Invited

I have been working for months on a seas Idunn project and have built four speakers. They sound great and look great. I am posting pictures and frequency response graphs here. Would love suggestions and questions.


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Old 8th July 2014, 02:49 PM   #28
AttokkarAcoustics is offline AttokkarAcoustics  United States
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Click the image to open in full size.
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