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Posted

I have a pair of old Scan Speak 200 kit speakers that I am thinking of refurbing for use in a second system.  I already have some solid 50mm thick jarrah blocks that were leftovers from a housing project cut to size for me to act as new tops and bottoms.  The design is circa ~1986 and is a two way bass reflex using 18W 8452 bass/midrange drivers and D2905 tweeters I think.  At a bare minimum I may just replace the speaker cloth but if somewhere has any details of the cross over I may look at refurbishing that too.  Or maybe this is just a waste of effort given their age?  AFAIK the drivers are still in good condition.  I know the foam surround degrades with time on the 18W 8452 bass/midrange drivers but I did replace them as recently as five years ago I think.

 

I do also have a bit of a sentimental attachment to them as they were a big $ purchase for me at the time (from Penny Lane Audio if anyone remembers that store?)/

  

 

 

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  • 4 months later...
Posted

Ok I refurbed them.  New grill cloth and solid jarrah tops and bottoms.  Pretty happy with the end result.  They go very low and live in corners so perfect for TV room and doubt I need a sub now.  Drivers have been replaced about 10 years ago and are in good condition.  Crossovers are screwed to the bottom of the cabinet (probably before initial assembly) and difficult to remove.  All in all very happy with the result.   :thumb:

 

 

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  • 1 month later...
Posted (edited)

I  designed these speakers in 1985, nice to know there are still a few pairs out there. I'd love to hear them again just for old times sake. The scariest day of my life was the day I first played them for Neville Theile at Penny Lane.

Edited by Number 9
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Posted (edited)

Thats awesome!  Do you have any details about the x-over in the archive number 9?  I remember they got a really good review in Australian Hifi at the time?  I remember I used to drive them with a NAD 3155 which was an amazingly good combo for the time!

Edited by WINEDS
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Posted (edited)

Thats awesome!  Do you have any details about the x-over in the archive number 9?  I remember they got a really good review in Australian Hifi at the time?  I remember I used to drive them with a NAD 3155 which was an amazingly good combo for the time!

Hi Wineds,

I can't tell you how much joy it gives me to hear from some-one who is still getting enjoyment from my work almost thirty years later.

 

The X-over was a 2nd order series setup @ 2K5hZ. Bog standard Bessel stuff. But it was, I believe the first commercial X=over to use all Metalised Polypropylene caps. I used 250 - 415VAC Rifa Motor start caps which are pretty much indestructable and inductors by Frank at Dyne Industries which were many gauges heavier than the norm at the time.

 

But the overall performance of the system had almost nothing to do with the crossover apart from it's inherently low TIM characteristics.

 

Most of the the performance of the 200 is down to a very freakish behavior at a very particular tuning and a chance encounter with some ancient wisdom. Somebody, I can't remember who, lent me a book published in 1934 called Seashores Anatomy of Music.In this book was a chart showing the energy distribution of the various harmonics of an open E string on a violin. Rather than what you'd expect, less 0.1% of the total energy of the note was at the center frequency at E. 93% of the spectral energy was evenly distributed between the 2nd and 3rd harmonic. The only possible conclusion, at least where string instruments were concerned was that what we had conventionally regarded as the fundemental note was in fact the difference frequency product of the 2nd and 3rd harmonic  So I experimented with a tuning that produced the lowest possible Intermodulation Distortion at the 2nd and 3rd harmonic of the lowest frequency of interest, that would produce a highly acurate difference tone a full octave lower. It Worked.

 

The second trick was the Dihedral Baffle time alignment system. This was a unique solution to the edge diffraction problems of earlier stepped baffle designs, JBL bought out a range of speakers the following year incorporating this technique, with permission, but Wilson have been using it for years in the Pups without permission, and to this day, Dave and Cheryl-Lee wonder why people don't have much time for Mormons.

 

 

Steve

Edited by Number 9
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Posted

Hi Wineds,

Most of the the performance of the 200 is down to a very freakish behavior at a very particular tuning and a chance encounter with some ancient wisdom. Somebody, I can't remember who, lent me a book published in 1934 called Seashores Anatomy of Music.In this book was a chart showing the energy distribution of the various harmonics of an open E string on a violin. Rather than what you'd expect, less 0.1% of the total energy of the note was at the center frequency at E. 93% of the spectral energy was evenly distributed between the 2nd and 3rd harmonic. The only possible conclusion, at least where string instruments were concerned was that what we had conventionally regarded as the fundemental note was in fact the difference frequency product of the 2nd and 3rd harmonic  So I experimented with a tuning that produced the lowest possible Intermodulation Distortion at the 2nd and 3rd harmonic of the lowest frequency of interest, that would produce a highly acurate difference tone a full octave lower. It Worked.

 

Steve

 

Very interesting stuff, Steve. :)

 

I'm about to change the 3-way active XOs on my Maggies and I'd like to understand more about what you said about using a tuning that produced the lowest possible IMD at the 2nd / 3rd harmonic of the lowest frequency of interest.  I guess (with 2nd / 3rd harmonics) we're talking of 1 - 3KHz?

 

Perhaps we can talk about this next time we have coffee?

 

 

Regards,

 

Andy

Posted

Very interesting stuff, Steve. :)

 

I'm about to change the 3-way active XOs on my Maggies and I'd like to understand more about what you said about using a tuning that produced the lowest possible IMD at the 2nd / 3rd harmonic of the lowest frequency of interest.  I guess (with 2nd / 3rd harmonics) we're talking of 1 - 3KHz?

 

Perhaps we can talk about this next time we have coffee?

 

 

Regards,

 

Andy

Hi Andy,

Happy to discuss this process with you over coffee, I believe it's your shout this time.

Posted

Hi Andy,

Happy to discuss this process with you over coffee, I believe it's your shout this time.

 

Haha - yes it is, Steve.

 

In a weekend or 2.

 

 

Regards,

 

Andy

Posted

In a weekend or 2.

 

I'll have my people contact your people and set up the timing.

 

Warmest Marginal Regards,

 

Steve.

Posted (edited)

Steve,

                     Happy to arrange is listening for you.  But at the moment they are being driven by an old Denon 3805 so its hardly Hifi.  In a few months hopefully I will have a FC-100 amp hooked up to them.  That might be a better time for a listen!  I am guessing the D2008 tweeters are the weak link?  I have had to replace them a few times over the years what with people getting carried away at parties and smoking them...

 

 

Edit also just found this!   http://www.speakerbits.com/index.php?page=shop.product_details&flypage=child_special.tpl&product_id=5206&category_id=1202&option=com_virtuemart

Edited by WINEDS

Posted (edited)

Steve,

                     Happy to arrange is listening for you.  But at the moment they are being driven by an old Denon 3805 so its hardly Hifi.  In a few months hopefully I will have a FC-100 amp hooked up to them.  That might be a better time for a listen!  I am guessing the D2008 tweeters are the weak link?  I have had to replace them a few times over the years what with people getting carried away at parties and smoking them...

 

 

Edit also just found this!   http://www.speakerbits.com/index.php?page=shop.product_details&flypage=child_special.tpl&product_id=5206&category_id=1202&option=com_virtuemart

Hi Wineds,

The 200 was never designed as a "top end" system. My reference amps at the time were a NAD 3020B & a Hafler DH-500, both of which I still own. Happy to bring the 3020 with me. Any problems with the tweeter are down to total Dickheads too pissed to realise the system was clipping its head off. I have been to a lot of partiies and to date I have never seen any-one ever try to smoke a Scan 200, despite my invention of the 16 paper Spliff in 1978 ( a record that I believe still stands).

 

As to the D2008 question , sure, this was even at the time a very old design from the days when Eyvind Skanning (later of Dynaudio) was running Scanspeak  prior to the dark days of "Dave Does Denmark" , when Devid Hafler bought Ortofon., which owned Scanspeak and a bunch of other companies at the time and  put the lot into bankruptcy as a tax writeoff against his massive profits from Dynaco and while I came to regard Dave and Getrude as freinds in later years, It's not a name to casually drop at a dinner party in Scandinavia. The mere mention of David Haflers name provokes a serious reaction from audio people to this day.

 

It took years for Scanspeak to recover and in the early days they were forced to continue using Eyvinds tweeter design. the only flaw in the D-2008  design is the card back which allowed some vibration from the woofer to come thru,  this was corected in the D-2010 which had a mounted plastic back. All their design notes on tweeter development   were kept in one folder which was stolen by an employee who went to work for Proac.

 

Most the new tweeters were designed by Vifa people and a couple of guys they pinched from Dynaudio after Magnus Nesdam took over Scan, arguably Scan are making better tweeters today, but so are a lot of people.

 

Thanks for the Speakbits link. It's nice to know that Tom finally has a well designed speaker on his floor.

 

The numbers are interesting though, in 1985 we sold the speaker at $698 a pair, now he's offering  them at 425, 61%  of their original full whack retail value 30 yeatrs ago, a drop of only 2% per year, at which point one has to ask, which would have been the better long term investment at the time, 10 pairs of  Scan 200's or $7000 worth of Telstra shares?

 

 

Steve

Edited by Number 9
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