I want to repopulate my KEF Reference 105 speakers: figuring that the cones and crossovers are all operating off spec and so not delivering the quality of sound I'm after. I drive them with a Mastersound Compact 845: so a bit more sensitivity won't hurt either (I'm no moneybags: the secondhand Mastersound cost less than any DIY 845 option or indeed any half decent Chinese 845 amp: and is obviously way better than either: plus I get gravel!).
The KEFs are interesting, 12" woofer in 71 litre closed box with nicely sloping baffle.. 5.25" midrange again in its own dedicated enclosure 3 litres or so.. and the tweeter sitting at the top. Sloping front lines the magnets up nicely and each driver has its own baffle and none of the enclosures are simple square cut boxes. Crossovers at 400 and 2500 Hz. They were top of the range in 1977 and were used in many a high end recording studio at that time.
Plan is sell of these valuable vintage drivers: and buy??? any suggestions? the magpie in me is already drawn towards:
 Fountek NeoCD1.0 Ribbon Tweeter (90db)
http://www.parts-express.com/pedocs/specs/296-701-fountek-neocd10-specifications-8786.PDF
Arum Cantus AC-130F1 (89db)
http://www.parts-express.com/pedocs/specs/296-400-aurum-cantus-ac-130f1-specifications-45624.pdf
The bass driver I'm not sure, this is where I need the most help? .. I like the higher spec that comes with PA drivers (although i want the best possible woofer I can find for less than $120/£80 each):
SoundLab L042G 30cm 12" PA - Bass speakers Aluminium Subwoofer Subwoofer | eBay
SoundLab 12" Black High Quality 350W Bass Speaker (8 Ohm) L041C | eBay
2 x 30cm 12" PA Bass speaker 300mm woofer SoundLab L042P PAIR | eBay
All crossed over at around 380Hz and 3800Hz
I'm open to suggestions really... I was hoping that you experienced guys would have built speakers using 12"/5.25"/ribbon tweeters and can say you found the right combination of great sounding drivers and the perfect crossover arrangement and have got a spare turkey in the freezer I can have, and maybe lend me your girlfriend for the weekend.
The KEFs are interesting, 12" woofer in 71 litre closed box with nicely sloping baffle.. 5.25" midrange again in its own dedicated enclosure 3 litres or so.. and the tweeter sitting at the top. Sloping front lines the magnets up nicely and each driver has its own baffle and none of the enclosures are simple square cut boxes. Crossovers at 400 and 2500 Hz. They were top of the range in 1977 and were used in many a high end recording studio at that time.
Plan is sell of these valuable vintage drivers: and buy??? any suggestions? the magpie in me is already drawn towards:
 Fountek NeoCD1.0 Ribbon Tweeter (90db)
http://www.parts-express.com/pedocs/specs/296-701-fountek-neocd10-specifications-8786.PDF
Arum Cantus AC-130F1 (89db)
http://www.parts-express.com/pedocs/specs/296-400-aurum-cantus-ac-130f1-specifications-45624.pdf
The bass driver I'm not sure, this is where I need the most help? .. I like the higher spec that comes with PA drivers (although i want the best possible woofer I can find for less than $120/£80 each):
SoundLab L042G 30cm 12" PA - Bass speakers Aluminium Subwoofer Subwoofer | eBay
SoundLab 12" Black High Quality 350W Bass Speaker (8 Ohm) L041C | eBay
2 x 30cm 12" PA Bass speaker 300mm woofer SoundLab L042P PAIR | eBay
All crossed over at around 380Hz and 3800Hz
I'm open to suggestions really... I was hoping that you experienced guys would have built speakers using 12"/5.25"/ribbon tweeters and can say you found the right combination of great sounding drivers and the perfect crossover arrangement and have got a spare turkey in the freezer I can have, and maybe lend me your girlfriend for the weekend.
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I sold these when they were new… i'm sure you can make them better or use the box as a starting point on something else.
i'd start out by tweaking them 1st… althou the vintage drivers will command some cash for people looking for spares.
A number of 3 or 4" full-range would fit the mid-pod. Who needs a tweeter?
(Alpair 7.3 would be my 1st suggestion)
Getting the XO right is the hardest part of getting things right (3-way typically harder than 2-way). Consider going active.
But, as Chris says, sometimes just easier to start from scratch.
dave
i'd start out by tweaking them 1st… althou the vintage drivers will command some cash for people looking for spares.
A number of 3 or 4" full-range would fit the mid-pod. Who needs a tweeter?
(Alpair 7.3 would be my 1st suggestion)
Getting the XO right is the hardest part of getting things right (3-way typically harder than 2-way). Consider going active.
But, as Chris says, sometimes just easier to start from scratch.
dave
I am considering fullrange, but if I did that I'd go all the way and build a box and have just one driver (MarkAudio Alpair 12P 8"? the graph looks good, but no off axis traces) ... I'm drawn in this direction as I'm running a 845SET amp.. and considering transformers for my DAC output... less is more: I like that.
But I'm still going to explore max-ing out these Kef boxes, which I think are fairly optimal for a three way design, and done right would have far better off-axis performance???
So I'm looking for the best 12" driver .... that's going to be crossed at no more than 500Hz... although I'm a Buddhist so am quite happy to be wrong!
But I'm still going to explore max-ing out these Kef boxes, which I think are fairly optimal for a three way design, and done right would have far better off-axis performance???
So I'm looking for the best 12" driver .... that's going to be crossed at no more than 500Hz... although I'm a Buddhist so am quite happy to be wrong!
My friend, I don't think you are going down the right road with 12" PA woofers here, for one thing...Very loud, you know. Hard to match to other stuff and a huge crossover redesign.
If the 12" polycone basses are shot, this might be a replacement:
WA - 308 Bass Diameter 308mm
The B110 mid can be replaced with:
Monacor SPH-135 AD Size 134x134mm
I don't know what the tweeter is, but the more you change it, the harder the crossover adjustments will be. A metal SEAS tweeter might be reasonable. 104mm? You might need to add a couple of attenuator resistors to get level right.
Also, recapping the tired old crossover 50V capacitor NP electrolytics with similar new ones can be worthwhile. Check the wiring and soldering is all in good shape too.
I'd certainly check the heavy basses for sagging voice-coil rubbing after all these years. Look, I'm telling you what is possible. You must assess what needs doing to restore these things.
If the 12" polycone basses are shot, this might be a replacement:
WA - 308 Bass Diameter 308mm
The B110 mid can be replaced with:
Monacor SPH-135 AD Size 134x134mm
I don't know what the tweeter is, but the more you change it, the harder the crossover adjustments will be. A metal SEAS tweeter might be reasonable. 104mm? You might need to add a couple of attenuator resistors to get level right.
Also, recapping the tired old crossover 50V capacitor NP electrolytics with similar new ones can be worthwhile. Check the wiring and soldering is all in good shape too.
I'd certainly check the heavy basses for sagging voice-coil rubbing after all these years. Look, I'm telling you what is possible. You must assess what needs doing to restore these things.
thanks system7,
indeed the monacorADs are on the shortlist for sure... all the drivers are in good shape, I turned the woofers yesterday- no sign of sagging at all, they had never been turned before, I had to lengthen the wires! They had been kept in an unheated room since new (no central heating in the house) and had seen little use as it was one of three music rooms (Lowthers and ESLs in the other two).
The tweeters are non original and the Xovers are shot, although they have been rebuilt before by Wilmslow Audio (caps)...
I'm weighing up my options... light restoration, new tweeters... rebuilt Xovers.. option1.........verses a more drastic reboot.. the enclosers are really promising..
I'm going to experiment with the various sections' damping/sound deadening materials- they are all overdamped/misdamped at present (much easier to voice as they are all separate): BBC regulation bitumen sheet in the mid box.. and a little foam; this will liberate more airvolume in the box, I'm trying to get to a BBC regulation 2 litres. The bass box again loses loads of volume to thick foam, which is going... I'll start by installing damping in line with an article at 6moons (for a bass bin) and tinker from there ... I can always just return them to standard.. but I want to liberate some crispness and dynamics in the bass, and calm down the mids (another reason for more modern mid range drivers).
then
option one: new tweeters and Xover recap
option two: vifa/seas tweeter, monacor sph-135AD, PEERLESS SLS-315 12 INCH or WA - 308 Bass cone...
option three: is go wild.. or really wild!! (option four).. these boxes could really sing and knock "off the shelf speakers" for six... and its suggestions on how to do that I'm looking for... Volt 12 woofers? .. soft dome midrange ... foster super tweeters/or ribbons??? are all possible... my favourite speakers are my trusty PMC TB1 s which I original bought for £120 with a broken tweeter... they just need a little more base extension, I know these 105 enclosures can provide that monitor sound.....
indeed the monacorADs are on the shortlist for sure... all the drivers are in good shape, I turned the woofers yesterday- no sign of sagging at all, they had never been turned before, I had to lengthen the wires! They had been kept in an unheated room since new (no central heating in the house) and had seen little use as it was one of three music rooms (Lowthers and ESLs in the other two).
The tweeters are non original and the Xovers are shot, although they have been rebuilt before by Wilmslow Audio (caps)...
I'm weighing up my options... light restoration, new tweeters... rebuilt Xovers.. option1.........verses a more drastic reboot.. the enclosers are really promising..
I'm going to experiment with the various sections' damping/sound deadening materials- they are all overdamped/misdamped at present (much easier to voice as they are all separate): BBC regulation bitumen sheet in the mid box.. and a little foam; this will liberate more airvolume in the box, I'm trying to get to a BBC regulation 2 litres. The bass box again loses loads of volume to thick foam, which is going... I'll start by installing damping in line with an article at 6moons (for a bass bin) and tinker from there ... I can always just return them to standard.. but I want to liberate some crispness and dynamics in the bass, and calm down the mids (another reason for more modern mid range drivers).
then
option one: new tweeters and Xover recap
option two: vifa/seas tweeter, monacor sph-135AD, PEERLESS SLS-315 12 INCH or WA - 308 Bass cone...
option three: is go wild.. or really wild!! (option four).. these boxes could really sing and knock "off the shelf speakers" for six... and its suggestions on how to do that I'm looking for... Volt 12 woofers? .. soft dome midrange ... foster super tweeters/or ribbons??? are all possible... my favourite speakers are my trusty PMC TB1 s which I original bought for £120 with a broken tweeter... they just need a little more base extension, I know these 105 enclosures can provide that monitor sound.....
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I used to have some 12" bextrene coned 3 ways, the Chartwell PM400 monitor.
My flatmate had the paper Wharfedale E70 speakers.
They were SO different! My BBC Chartwell's were smooth and a bit dull, the Wharfedale's were incredibly lively and dynamic.
It's hard to weigh up the complexities of reflex drivers and closed box drivers if reusing a cabinet. I don't quite know what the KEF 12" is TBH.
But the thing I always notice most on a speaker is a good top end. You know, the thing that makes snare drums sound good. I always admire the Vifa XT25 tweeter, which must be way better than anything made 30 years back. Why not start at the top and work down?
My flatmate had the paper Wharfedale E70 speakers.
They were SO different! My BBC Chartwell's were smooth and a bit dull, the Wharfedale's were incredibly lively and dynamic.
It's hard to weigh up the complexities of reflex drivers and closed box drivers if reusing a cabinet. I don't quite know what the KEF 12" is TBH.
But the thing I always notice most on a speaker is a good top end. You know, the thing that makes snare drums sound good. I always admire the Vifa XT25 tweeter, which must be way better than anything made 30 years back. Why not start at the top and work down?
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Hi,
Its a complete waste of time replacing working drivers with
other types and keeping the same crossover, it will be worse.
The foam in the bass box increases effective volume, it does not reduce it.
Stuffing / foam can increase effective volume by up to 20%. Overstuffing
can reduce it but KEF are not stupid. Foam on the walls and polyfill fill will
maximise effective volume.
Look up the original tweeter and try to match it well. May need an L-pad.
rgds, sreten.
Its a complete waste of time replacing working drivers with
other types and keeping the same crossover, it will be worse.
The foam in the bass box increases effective volume, it does not reduce it.
Stuffing / foam can increase effective volume by up to 20%. Overstuffing
can reduce it but KEF are not stupid. Foam on the walls and polyfill fill will
maximise effective volume.
Look up the original tweeter and try to match it well. May need an L-pad.
rgds, sreten.
Not worth even thinking about unless the XO is redone…
I'd call this a +1 on the "easier to start from scratch"
dave
I'm glad to see we all agree on that.
still looking for advice on a good combination of 12", 5.25",tweeter ...to repopulated these cabinets if I decide to go that route.
What's hard about THIS?
For the DIYaudio forum that claims to be the brightest on this planet, frankly I am disappointed.
But I'd concede that filter is very driver specific.
Say, with a new tweeter, you could simplify it a great deal into a regular third order tweeter filter. KEF got a bit over-elaborate at times back in the early days of computer modelling.
For the DIYaudio forum that claims to be the brightest on this planet, frankly I am disappointed.
But I'd concede that filter is very driver specific.
Say, with a new tweeter, you could simplify it a great deal into a regular third order tweeter filter. KEF got a bit over-elaborate at times back in the early days of computer modelling.
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thanks mr. hillage,
so here are my choices for replacing all three drivers (option2):
Product information:M12 Bass-Midrange
http://www.parts-express.com/pedocs/specs/296-400-aurum-cantus-ac-130f1-specifications-45624.pdf
http://www.parts-express.com/pedocs/specs/296-701-fountek-neocd10-specifications-8786.PDF
I reckon Xovers at 380Hz and 3800Hz...
so here are my choices for replacing all three drivers (option2):
Product information:M12 Bass-Midrange
http://www.parts-express.com/pedocs/specs/296-400-aurum-cantus-ac-130f1-specifications-45624.pdf
http://www.parts-express.com/pedocs/specs/296-701-fountek-neocd10-specifications-8786.PDF
I reckon Xovers at 380Hz and 3800Hz...
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you're up late dave... can I ask a couple of question... firstly if my cabinets are against the wall how much is the baffle step reduced?
my chosen 12" bass driver is only 3db more sensitive than the mid driver ...
sensitivity 1watt at 1m.... ? 2.85volts at 1m...?
whats the difference ... some spec sheet quote one or other and some quote both... sometimes the specs that quote both show the figure to be about the same, and others show a difference of 3 or 4db...? whats going on there?.. or are the specs sheets as fanciful as some of the graphs manufactures publish?
another aside... monacor.. sph135tc has twin coil... can this be wired to be a 4ohm, 8ohm or 16ohm load?
and finally.. if your coco isn't cold.... since my chosen drivers for my reboot kef 105s is 4ohm and the tweeter 5ohm, it makes sense for me to use a 4ohm mid.. making an easier Xover circuit? and to show my amp a 4ohm load ? (I just have to switch it inside from 8 to 4... This result in higher current from the amp? and extra watts? as I understand it.. Is that good? or is an 8ohm load more stable/better for the amp?
my chosen 12" bass driver is only 3db more sensitive than the mid driver ...
sensitivity 1watt at 1m.... ? 2.85volts at 1m...?
whats the difference ... some spec sheet quote one or other and some quote both... sometimes the specs that quote both show the figure to be about the same, and others show a difference of 3 or 4db...? whats going on there?.. or are the specs sheets as fanciful as some of the graphs manufactures publish?
another aside... monacor.. sph135tc has twin coil... can this be wired to be a 4ohm, 8ohm or 16ohm load?
and finally.. if your coco isn't cold.... since my chosen drivers for my reboot kef 105s is 4ohm and the tweeter 5ohm, it makes sense for me to use a 4ohm mid.. making an easier Xover circuit? and to show my amp a 4ohm load ? (I just have to switch it inside from 8 to 4... This result in higher current from the amp? and extra watts? as I understand it.. Is that good? or is an 8ohm load more stable/better for the amp?
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