KEF made lots of versions of that basic bextrene driver with different Q and inductance. These units are characterised by a smooth overdamped frequency response. Bit of cone-breakup and peakiness around 2kHz though. You can notch filter that.
Monacor and a few others make modern versions. Like the SPH-210.
Monacor SPH-210
Qts of 0.24. Fs of 28Hz. Pretty high Le there at 1mH so you'd want a Zobel and a low order crossover, but suitable for closed box (almost acoustic suspension) 15L, and reflex 27L.
Monacor and a few others make modern versions. Like the SPH-210.
Monacor SPH-210
Qts of 0.24. Fs of 28Hz. Pretty high Le there at 1mH so you'd want a Zobel and a low order crossover, but suitable for closed box (almost acoustic suspension) 15L, and reflex 27L.
Still off-topic, Sreten. When are you going to GET IT?
Hi,
Yeah and when are you going to get some manners ....
Its a minor aside i didn't start, like the last major one that
I plainly stated was seriously off topic. I get it. You don't.
Don't insultingly pontificate.
rgds, sreten.
Simulation
Ok, I've been playing around with LSPCad and I've obtained this:http://s14.postimage.org/87bc17jwx/SIMULAZIONE_CASSE.jpg .
The b200 unit is simulated by T&S parameters and VIFA XT19 TD simulated with .frd and .zma files found there: Driver FRD & ZMA files .
Offset between tw and wf is 20mm (obtained with a thicker baffle) and vertical offset between them is of about 18cm (from center to center of the voice coils).
All the inductances are simulated with the correct serie resistors.
I don't know why there is a -4db hole at 1.3-1.5kHz ...
If someone wants to help me with lspcad, there is the project Download Casse4.lsp for free on uploading.com
The values 20uF and 40uF are chosen beause I've a stock of 20uF ICEL 250V polypropylene caps
Thankyou everybody!!
Ok, I've been playing around with LSPCad and I've obtained this:http://s14.postimage.org/87bc17jwx/SIMULAZIONE_CASSE.jpg .
The b200 unit is simulated by T&S parameters and VIFA XT19 TD simulated with .frd and .zma files found there: Driver FRD & ZMA files .
Offset between tw and wf is 20mm (obtained with a thicker baffle) and vertical offset between them is of about 18cm (from center to center of the voice coils).
All the inductances are simulated with the correct serie resistors.
I don't know why there is a -4db hole at 1.3-1.5kHz
... If someone wants to help me with lspcad, there is the project Download Casse4.lsp for free on uploading.com
The values 20uF and 40uF are chosen beause I've a stock of 20uF ICEL 250V polypropylene caps
Thankyou everybody!!
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I think you're making it more difficult than it is!
Plenty of standard 3rd order butterworth designs for the similar Vifa XT19 and XT25 around. Troels Gravesen gives you enough! The tweeter is not the tricky bit.
DIY Loudspeaker Projects Troels Gravesen
The issue for you is getting the B200 well behaved. You want to roll it off quite sharply before it goes bextrene crazy around 3.5kHz IMO, and look out for that quacky 2kHz resonance. 0.45mH as opposed to 0.30mH on the KEF104ab unit needs a slight adjustment from any 104ab crossover. You really need about 0.47mH coil after the bafflestep, and then play with the 20uF capacitor a bit. I'm kinda hoping that filter will notch in the right place anyway.
You can try Zobel equalising the B200 SP1054 too. Ought to be (guesses...) about 9 ohms plus 7uF. Plenty to work with there. Should be fun.
Plenty of standard 3rd order butterworth designs for the similar Vifa XT19 and XT25 around. Troels Gravesen gives you enough! The tweeter is not the tricky bit.
DIY Loudspeaker Projects Troels Gravesen
The issue for you is getting the B200 well behaved. You want to roll it off quite sharply before it goes bextrene crazy around 3.5kHz IMO, and look out for that quacky 2kHz resonance. 0.45mH as opposed to 0.30mH on the KEF104ab unit needs a slight adjustment from any 104ab crossover. You really need about 0.47mH coil after the bafflestep, and then play with the 20uF capacitor a bit. I'm kinda hoping that filter will notch in the right place anyway.
You can try Zobel equalising the B200 SP1054 too. Ought to be (guesses...) about 9 ohms plus 7uF. Plenty to work with there. Should be fun.
The SPH 210 is nearly identical with those driver from the Linn model "NEXUS" and "HELIX" and thus a good replacement (do you know the actually manufacturer of this driver ??)
But by comparing while a listening test the differences are very large, even after create a crossover network with very flat frequency response (mainly through various speed of sound inside of the diaphragm so as different parameter for Qms).
Attachments
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I expect Sreten will say I am pontificating here, but I still like my original values with 6dB of bafflestep bass boost, especially since 40uF on the tweeter will cost you a bomb!
Offsetting the drivers is actually quite vintage Bowers and Wilkins, as in this KEF bextrene/celestion tweeter based DM2A. A very fine loudspeaker which I liked a lot. The inverted tweeters are designed to work nicely in phase.
Admit it, Sreten, I post some good stuff. You love it!
Offsetting the drivers is actually quite vintage Bowers and Wilkins, as in this KEF bextrene/celestion tweeter based DM2A. A very fine loudspeaker which I liked a lot. The inverted tweeters are designed to work nicely in phase.
An externally hosted image should be here but it was not working when we last tested it.
Admit it, Sreten, I post some good stuff. You love it!
Offsetting exactly like the B&W design does, FWIW, that's the RHS loudspeaker:
This is a well-known BBC technique to avoid some bafflestep problems:
http://www.diyaudio.com/forums/diyaudio-com-articles/158899-arpeggio-loudspeaker.html
Flipping masterclass, that Morgan Jones article. BTW, the inverted tweeter thing is optional, but I think it has a lot going for it since it is more phase linear, since the centres are equidistant from the listener.
When you add a 6 ohm resistor to the tweeter filter input, it changes the capacitor values to symettrical. I always like symettrical. Such elegance:
LC Filter Design
This is what you do at radio frequencies to match source and load.
An externally hosted image should be here but it was not working when we last tested it.
This is a well-known BBC technique to avoid some bafflestep problems:
http://www.diyaudio.com/forums/diyaudio-com-articles/158899-arpeggio-loudspeaker.html
Flipping masterclass, that Morgan Jones article. BTW, the inverted tweeter thing is optional, but I think it has a lot going for it since it is more phase linear, since the centres are equidistant from the listener.
When you add a 6 ohm resistor to the tweeter filter input, it changes the capacitor values to symettrical. I always like symettrical. Such elegance:
LC Filter Design
This is what you do at radio frequencies to match source and load.
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You are doubtless right, but I really don't care from a system's engineering point of view. All Bextrene in the end, whatever that is made from. Let's stay on-topic.
Michelino, it's quite OK to use two 20uf capacitors in a balanced configuration if you have loads lying about. Put 20uf on live, and 20uF on the earth rail in a second order configuration. Amounts to 10uF overall in the end. Some people think that balanced is better. I can see valid reasons for that reasoning.
Good morning Steve!
After some simulations, it seems that 20 uf + 20 uf for the 3rd order isn't the best configuration. But it's only a simulation! So i ordered 10uf caps and then I'll try with mic and ears ... Even for the b200 crossover, I've ordered bigger inductor since they cost quite the same...
After some simulations, it seems that 20 uf + 20 uf for the 3rd order isn't the best configuration. But it's only a simulation! So i ordered 10uf caps and then I'll try with mic and ears
... Even for the b200 crossover, I've ordered bigger inductor since they cost quite the same... TOY KEF CARA Speakers with sp 1193 drivers
Hi Sure I came across this sp 1193 drivers. I have KEF CARA 1985 2-way speaker which I would like to MODIFY to better sounding speakers wit the tweeter and Mid/Bass drivers preserved. I want to buy technically suitable Bass Drivers to go with original KEF drivers as they lack bass. Mid and High frequencies to me are GREAT but the problem with bass or correct musical performance to drums.
Here is the link to my opened speakers
https://plus.google.com/photos/103965235820975061444/albums/5710462045529170897
This using Mud/Bass drivers kef type sp 1193 I like it.
I 'm looking to buy paper cones specifically for handling bass.
I will need to modify Crossover from original 2-ways to high quality custom made 3-way crossover. I came across of a few people I found on the internet and eBay who sell different crossovers to help me with modification. The only challenge I think is to find KEF drivers Technical Specifications in order to prepare individual crossovers properly.
So far I have this details:
Specification: Cara
System Type: Two-way, stand-mount/floor standing
Enclosure type: Passive radiator
Size: 600 x 247 x 230mm (23.6 x 9.7 x 9.1 inches)
Weight: 7.9kg (17.3 lb)
Nominal Impedance: 8 ohms
Rated maximum power: 100 programme
Frequency response: 70Hz to 20kHz +/-3.0dB at 2m on design axis (-6dB at 55Hz)
Sensitivity: 90dB for a pink noise input of 2.83V (anechoic conditions)
Maximum output: 110dB on programme peaks under typical listening conditions
System: SP3076
Drive units: B200 bass unit (SP1193), BD200 passive radiator (SP1185), T33 tweeter (SP1192)
Crossover: SP2085
This is all I have so far. Is anyone know where to get the technical specifications? Is anyone doing or planning to do DIY on KEF speakers?
I truly want to get the best with this wonderful KEF paper drivers, sound very natural For the bass driver I found this model
AUDAX AM210G0
http://www.audax-speaker.de/index.php?module=shop_articles&index[shop_articles][action]=details&index[shop_articles][data][shop_articles_id]=16
and I think Most PREFERABLE
AUDAX HM210G6
audax speaker units from cadaudio.dk
If anyone has any ideas please join in.
Hi Sure I came across this sp 1193 drivers. I have KEF CARA 1985 2-way speaker which I would like to MODIFY to better sounding speakers wit the tweeter and Mid/Bass drivers preserved. I want to buy technically suitable Bass Drivers to go with original KEF drivers as they lack bass. Mid and High frequencies to me are GREAT but the problem with bass or correct musical performance to drums.
Here is the link to my opened speakers
https://plus.google.com/photos/103965235820975061444/albums/5710462045529170897
This using Mud/Bass drivers kef type sp 1193 I like it.
I 'm looking to buy paper cones specifically for handling bass.
I will need to modify Crossover from original 2-ways to high quality custom made 3-way crossover. I came across of a few people I found on the internet and eBay who sell different crossovers to help me with modification. The only challenge I think is to find KEF drivers Technical Specifications in order to prepare individual crossovers properly.
So far I have this details:
Specification: Cara
System Type: Two-way, stand-mount/floor standing
Enclosure type: Passive radiator
Size: 600 x 247 x 230mm (23.6 x 9.7 x 9.1 inches)
Weight: 7.9kg (17.3 lb)
Nominal Impedance: 8 ohms
Rated maximum power: 100 programme
Frequency response: 70Hz to 20kHz +/-3.0dB at 2m on design axis (-6dB at 55Hz)
Sensitivity: 90dB for a pink noise input of 2.83V (anechoic conditions)
Maximum output: 110dB on programme peaks under typical listening conditions
System: SP3076
Drive units: B200 bass unit (SP1193), BD200 passive radiator (SP1185), T33 tweeter (SP1192)
Crossover: SP2085
This is all I have so far. Is anyone know where to get the technical specifications? Is anyone doing or planning to do DIY on KEF speakers?
I truly want to get the best with this wonderful KEF paper drivers, sound very natural
For the bass driver I found this model AUDAX AM210G0
http://www.audax-speaker.de/index.php?module=shop_articles&index[shop_articles][action]=details&index[shop_articles][data][shop_articles_id]=16
and I think Most PREFERABLE
AUDAX HM210G6
audax speaker units from cadaudio.dk
If anyone has any ideas please join in.
OMG, MykhailoM, that is SO interesting! I didn't know KEF made a B200 SP1193 with a cardboard cone...
Reckon I've got one!
http://www.diyaudio.com/forums/multi-way/203461-restoring-monitor-audio-r300-bookshelf-speakers.html
You won't get more bass by adding another woofer. The 23L cabinet of the KEF Cara will be the limit. In fact the ABR passive thingie is probably as good as it will get. That unit was made by KEF for the Laskys Hifi chain. Crossovers really aren't hard though. Looks like you have a third order tweeter and second order bass XO there.
Reckon I've got one!
An externally hosted image should be here but it was not working when we last tested it.
http://www.diyaudio.com/forums/multi-way/203461-restoring-monitor-audio-r300-bookshelf-speakers.html
You won't get more bass by adding another woofer. The 23L cabinet of the KEF Cara will be the limit. In fact the ABR passive thingie is probably as good as it will get. That unit was made by KEF for the Laskys Hifi chain. Crossovers really aren't hard though. Looks like you have a third order tweeter and second order bass XO there.
Attachments
Hi Steve, I'm planning to make a new cabinets to accommodate the Bass (third driver) unit. I will be checking what is the minimum liters required and I think will either make them taller or dipper. Internal rewiring will need to be also changed to silver plated pure OFC copper between crossover and Mid/Bass drivers. I just thought in order for someone to make a custom crossovers they may need drivers specifications which I don't have and that is what bothers me.
If I were you, I'd try something much more straightforward. 6dB Bafflestep correction:
Loudspeaker Diffraction Loss and Baffle Step Compensation Circuits
It's effectively bass boost. The other crossover values are impacted. You attenuate the tweeter with a 6-7 ohm resistor on the input of the filter too.
That bass unit is unbalanced without some bafflestep. The T33 tweeter ferrofluid is probably drying out by now too. You need to write down the current crossover component values to go further. Caps are readable, coils, well you need a good multimeter with an inductance scale. It's usually measured at 1kHz.
Edit: FWIW, the bass unit is Re=6 ohms on mine. You'd need to look up or measure the tweeter resistance and usefully, its inductance Le. Can't be far off 6 ohms too.
Loudspeaker Diffraction Loss and Baffle Step Compensation Circuits
It's effectively bass boost. The other crossover values are impacted. You attenuate the tweeter with a 6-7 ohm resistor on the input of the filter too.
That bass unit is unbalanced without some bafflestep. The T33 tweeter ferrofluid is probably drying out by now too. You need to write down the current crossover component values to go further. Caps are readable, coils, well you need a good multimeter with an inductance scale. It's usually measured at 1kHz.
Edit: FWIW, the bass unit is Re=6 ohms on mine. You'd need to look up or measure the tweeter resistance and usefully, its inductance Le. Can't be far off 6 ohms too.
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In the early days of B&W they used some of the Audax line. There is a website by some of the former employees that tested the drivers.
Contrary to popular opinion there were several other reasons Bextrene was phased out.
Bextrene cones could not be used in auto sound.
They would melt in the heat.
Polypropylene could with stand auto sound environments.
Ferrofluid should last 30 years.
There were some high sensitivity bextrene cones made for oem uses. They used thinner cones longer pole pieces and oversized magnets approaching the double stacked magnet approach in todays designs.
Contrary to popular opinion there were several other reasons Bextrene was phased out.
Bextrene cones could not be used in auto sound.
They would melt in the heat.
Polypropylene could with stand auto sound environments.
Ferrofluid should last 30 years.
There were some high sensitivity bextrene cones made for oem uses. They used thinner cones longer pole pieces and oversized magnets approaching the double stacked magnet approach in todays designs.
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