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  #11  
Old 2nd October 2011, 11:33 AM
saschagabor saschagabor is offline
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Default Re: WD25x with Exotic T35

I had a short chat with Greg about his post, and he pointed out that my intentions regarding building two cabinet pairs was unclear. I thought I'd straighten out any misunderstandings for others also.

My intention is to build two pairs of speakers, and I have acquired drivers for both sets. I'm not building two sets and intend to let one of them sit unused. We do have lots of trees in Norway, but I'm not about to start wasting them unnecessarily.

I do however feel that this is a design I'd want to prioritize, thus spending a little extra on one of the sets. This in turn gives me a great chance to test īstandardī and īpremiumī up against each other.

I've also recently acquired a pair of Scan-Dyna A25 (same as Dynaco A25, but for the Scandinavian marked and 4 Ohm) in great condition and with alnico drivers.
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  #12  
Old 4th July 2012, 01:24 PM
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petercom petercom is offline
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Default Re: WD25x with Exotic T35

I've only just discovered this thread but, even so, it is worthy of a response, even though I'm late to the equation.

It is true that a 35mm treble unit would be a better match to the 10 inch bass unit in WD25 if it could use a lower crossover frequency. Probably the ideal crossover for this bass unit is around 1kHz as the power response is falling in this region due to its diameter. Crossing over lower than the earlier designs would give a better off-axis response and help maintain the power response, in room, throughout the crossover region.

That said the Exotic T35 is not ideally aligned for a lower crossover frequency in WD25. Its fundamental resonance is at 600Hz, which is a promising start, but it uses no ferrofluid damping so not only is the power handling compromised but this resonance will be highly audible unless the crossover avoids it.

On paper the T35 therefore looks worse than Millenium, which has an F0 of 500Hz with the advantage of ferrofluid damping. In addition, as might be expected of a larger dome, the off-axis output starts falling at 3kHz which is a little low (because of the ear's high sensitivity at 4kHz it is sensitive to changes in the power response up to this frequency).

However I've always agreed with Gilbert Briggs that graphs and specifications tell little of the story of how a loudspeakers sounds. What T35 has going for it is an Alnico magnet, which should offer a sweet sound character with outstanding midrange detailing, and the lack of ferrofluid may enhance micro-dynamics. So it would always be worth a listen and, if I was still designing WD25, it would be one I would try.

One could, I suppose, use a steeper crossover slope than the 3rd order acoustic that I prefer in order to achieve a lower crossover frequency and avoid the resonance but, in my experience, its not easy to do that with a passive crossover and get good subjective results. Perhaps an active design would do better?

Alas I can no longer offer design advice on WD25 as I don't have the time to pursue it; looking after 5 brands of loudspeakers at IAG is a full time job! So for any crossover work the DIY constructor would be on his own. The constructor could get plenty of clues from the WD25 design write ups in Hi-Fi World (still available from the DIYArchive) and the use of tools like LspCAD to aid the listening evaluation is, in my mind, a necessary part of achieving a satisfactory design.

Best of luck!
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  #13  
Old 13th October 2012, 10:08 PM
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Cobblers Cobblers is offline
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Default Re: WD25x with Exotic T35

I have not visited for a very long time now but I thought I would see if the website is still going to let WD25 fans know that Seas are making a T35 version!
http://www.facebook.com/photo.php?fb...count=1&ref=nf

http://www.seas.no/

News at Rocky Mountain Audio Fest:
"The second big news for the show is a new loudspeaker kit, which you can say is a resurrection of the old mega success Dynaco A25,
and we have named it SEAS A26:
We have designed a new Excel T35 dome midrange/tweeter, and combined it with the A26RE4 undercoated paper cone woofer. Our conclusion after several hours of listening:
The SEAS A26 is a refined, yet simple and fun loudspeaker, meant for enjoying music to its fullest!

Welcome to Denver - to The Rocky Mountain Audio Fest - to the Madisound room - and take a closer look.
We are sure you will be amazed."


Petercom's active concept suggested here could transform the speaker.
4th order L/R. could be good with a little addition low end equalization.

Last edited by Cobblers; 13th October 2012 at 10:25 PM.
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  #14  
Old 13th October 2012, 10:47 PM
saschagabor saschagabor is offline
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Default Re: WD25x with Exotic T35

This is fantastic news!

Also, a big thanks to Mr. Comeau for his reply in this post, it's much appreciated.

Last edited by saschagabor; 13th October 2012 at 11:22 PM.
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  #15  
Old 13th October 2012, 11:19 PM
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Cobblers Cobblers is offline
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Default Re: WD25x with Exotic T35

On further examination it seems to be not using the existing "Exotic" version of that tweeter.
There is a brand new version of the driver using a neodymium ring magnet:

http://www.madisoundspeakerstore.com...m-mid-tweeter/

Last edited by Cobblers; 13th October 2012 at 11:33 PM.
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  #16  
Old 14th October 2012, 09:41 AM
saschagabor saschagabor is offline
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Default Re: WD25x with Exotic T35

While I would have preferred that they used the AlNiCo version in this construction, I see a couple of pros with it being a new design. (Albeit in the works for some time, as a 35 mm Excel tweeter was shown at RMAF already in 2010). Most importantly for WD25a/t-owners: The mounting plate is the same size as the tweeters used in both the XL and EX versions. This makes testing very convenient.

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  #17  
Old 15th October 2012, 11:35 AM
saschagabor saschagabor is offline
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Default Re: WD25x with Exotic T35

I can now confirm that the SEAS A26 uses only two components in the crossover; 3,3 uF and 10 Ohm in series with the tweeter.
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