2014 - Big Move toward custom drivers? Are They Better? Will others be weeded out?

[FrantzM]

Adam,

Just to put it more clearly the B139 in the Extrema's has a voice coil and a magnet - it is a full drive, not the BD139 ABR unit used for example in the KEF 104 kit. The voice coil is not connected to power but just to a variable damping resistor.

And, I hope that I am not spoiling any one business, but the myth of the market unavailability of the B139 is exaggerated - this driver was manufactured in very large quantities in the UK, and it shows regularly there in the used market at nice prices. There is currently an excellent pair being sold at eBay UK at a buy-it-now price of GBP 150, although sometimes you can get DIY speakers using them at less than this value, and even boxed units. http://www.ebay.co.uk/itm/KEF-B139-B139B-BASS-SPEAKERS-WOOFERS-SP1044-/161176622399?pt=UK_Sound_Vision_Speaker_Parts&hash=item2586e0153f
And sometimes even cheaper http://www.ebay.co.uk/itm/Vintage-KEF-B139-SP1044-Base-drive-units-Woofers-Pair-/171198868540?pt=UK_AudioVideoElectronics_HomeAudioHiFi_HiFiSpeakers&hash=item27dc3f6c3c&clk_rvr_id=567920136130

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Your deep knowledge of things related to High-End Audio will never cease to amaze me.

Happy New Year to you and all my fellow WBFers!!

 

[Elberoth]

Adam,
Just to put it more clearly the B139 in the Extrema's has a voice coil and a magnet - it is a full drive, not the BD139 ABR unit used for example in the KEF 104 kit. The voice coil is not connected to power but just to a variable damping resistor.

Yes, you are correct ! But still - the drive unit is not connected to the amp, so you cannot damage that driver due to voice coil overheating etc.

BTW - I said that getting the new B139 driver is almost impossible, not impossible at all. IMO it is difficoult to expect the speaker manufacturer to track ebay and buy used drive units.

 

[microstrip]

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Your deep knowledge of things related to High-End Audio will never cease to amaze me.

Happy New Year to you and all my fellow WBFers!!

Frantz,

Well, thanks, but having lived with Extrema's and having built many KEF kits when I was still a student to finance holiday trips in the UK helps!

Thanks and Happy New Year to you and all WBF members and readers.

 

[JonFo]

Just for fun, though I'd mention the ultimate example of custom drivers, ESL speakers.

MartinLogan, SoundLab, Sanders, etc, all make multiple versions of their electrostatic speakers. And I believe those three have lifetime support. So even 20 year old speakers can be repaired/updated using original (or slightly better than original) spec panels.

Interestingly enough, hybrid ESL (those with cone wooers) generally used fairly stock cone drivers from mainstream speaker houses like Eminence. Most of the Gen1 MartinLogans were bone-stock or slight variations on existing Eminence drivers. As most of the Gen1's are requiring updates/repairs these days, there are quite a few off-the-shelf options that one can use to repair a busted unit.

Like most other 'high-end' vendors, the part numbers for the OEM drivers are not the same as those for off-the-shelf, but once one checks the T/S parameters, it's easy to find the correct substitute.

 

[caesar]

Just for fun, though I'd mention the ultimate example of custom drivers, ESL speakers.

MartinLogan, SoundLab, Sanders, etc, all make multiple versions of their electrostatic speakers. And I believe those three have lifetime support. So even 20 year old speakers can be repaired/updated using original (or slightly better than original) spec panels.

Interestingly enough, hybrid ESL (those with cone wooers) generally used fairly stock cone drivers from mainstream speaker houses like Eminence. Most of the Gen1 MartinLogans were bone-stock or slight variations on existing Eminence drivers. As most of the Gen1's are requiring updates/repairs these days, there are quite a few off-the-shelf options that one can use to repair a busted unit.

Like most other 'high-end' vendors, the part numbers for the OEM drivers are not the same as those for off-the-shelf, but once one checks the T/S parameters, it's easy to find the correct substitute.

Good points. And we also don't see the electrostat manufacturers making their own mylar...

A discussion of the economic concepts is here:
http://www.whatsbestforum.com/showt...s-it-a-rip-off&p=240052&viewfull=1#post240052

 

[microstrip]

Good points. And we also don't see the electrostat manufacturers making their own mylar...

A discussion of the economic concepts is here:
http://www.whatsbestforum.com/showt...s-it-a-rip-off&p=240052&viewfull=1#post240052

No, but they choose from different brands, types and thickness. And they coat or have it coated using different techniques with different surface resistivity. The mechanical and electrical characteristics of 30 years old or current SoundLab mylar are very different.

Curiously, the recipe of manufacturing old ESL57 mylar panels is now known and we can have exact replacement of the old panels.

 

[JackD201]

Curiously, the recipe of manufacturing old ESL57 mylar panels is now known and we can have exact replacement of the old panels.

Really? I thought the secret recipe was lost forever. Was it found or did somebody reverse engineer it?