SP1054
Hi everybody!
My name is Michele and I come form nord Italy.
This is my first post in this forum (i think) but i want to say that this forum is great! I've been signed since some years ago and in this place I've always found lots of intersting topics.
I need your help.
I own a pair of KEF SP1054. What do you think about its sound? And there is the crossover network of KEF Calinda speakers which mounted SP1054: Crossover for Calinda. What is this configuration? Why the 5uF cap doens't stay after the 3.29mH coil, in parallel with the woofer to make a 2nd order low pass filter?
Thankyouuuuu!
Miki
Hi everybody!
My name is Michele and I come form nord Italy.
This is my first post in this forum (i think) but i want to say that this forum is great! I've been signed since some years ago and in this place I've always found lots of intersting topics.
I need your help.
I own a pair of KEF SP1054. What do you think about its sound? And there is the crossover network of KEF Calinda speakers which mounted SP1054: Crossover for Calinda. What is this configuration? Why the 5uF cap doens't stay after the 3.29mH coil, in parallel with the woofer to make a 2nd order low pass filter?
Thankyouuuuu!
Miki
Ok, that's great! Thankyou! Simulated with MultiSim and I've found a very low crossover frequency (I don't remember, maybe about 250Hz). Any other info about those speakers?
My Sp1054 are mounted in a 18l bass reflex box tuned at 45Hz. I found them good except for the weak bass, but I'm not an expert...
My Sp1054 are mounted in a 18l bass reflex box tuned at 45Hz. I found them good except for the weak bass, but I'm not an expert...
The original KEF Calinda was a reflex (Well, ABR) design in a 45L box.
Here are the main T-S parameters for a KEF B200 SP1054 (large magnet, low Q) 8" bextrene bass/mid:
Vas 130L
Qm 3.27
Qe 0.25
Qts 0.23
Le 0.45mH
Re 7.0R
Fs 25Hz
TL Links
Back of a beermat, I got 18L as a good size for a closed box with F3 at 75Hz. KEF recommend 20-25L. Reflex, well, this is not so good for you at 18L. You need a bigger box for any real bass. 40-50L.
The shunt first bass crossover is unusual these days, especially since series first needs a smaller inductor. The tweeter is on a standard third order butterworth by the look of it. Probably around 2.5 to 3KHz depending on the impedance of the (7 ohm?) tweeter. The LCR trap on the bass is to tame cone breakup on the B200 around 2KHz. The smaller tweaks on the tweeter probably just equalise it a bit.
Here are the main T-S parameters for a KEF B200 SP1054 (large magnet, low Q) 8" bextrene bass/mid:
Vas 130L
Qm 3.27
Qe 0.25
Qts 0.23
Le 0.45mH
Re 7.0R
Fs 25Hz
TL Links
Back of a beermat, I got 18L as a good size for a closed box with F3 at 75Hz. KEF recommend 20-25L. Reflex, well, this is not so good for you at 18L. You need a bigger box for any real bass. 40-50L.
The shunt first bass crossover is unusual these days, especially since series first needs a smaller inductor. The tweeter is on a standard third order butterworth by the look of it. Probably around 2.5 to 3KHz depending on the impedance of the (7 ohm?) tweeter. The LCR trap on the bass is to tame cone breakup on the B200 around 2KHz. The smaller tweaks on the tweeter probably just equalise it a bit.
Quite right. KEF speakers with all their equalisation for smoothness also often had strangely huge peaks in impedance. I think the Calinda peaked at 60 ohms around 1-2 KHz. Michelino, your modded 18L unit probably has huge cone movement at low frequencies, which is not ideal.
A review I read had a huge dip in frequency response at 3Khz too. You'd think the tweeter was better wired the other way for phase alignment, but since the woofer and tweeter centres are nearly a wavelength apart at this frequency, effects would be unpredictable.
My own experience of bextrene bass/mid units is when they got hot at parties, they turned to jelly. Dull sounding too.
8" bass and 1" tweeter is just about as bad as it gets to have good midrange phase alignment and dispersion, but of course, easy to implement. Cries out for a midrange unit really!
Thankyou everybody
So... I've just re-simulated the calinda xover but I've found 250Hz @ -3db ... What's wrong? See the picture http://s17.postimage.org/xyvdf8qr3/sim_calinda.jpg .
About my speakers:
The sp1054 are in an 18 liters vented box tuned @45Hz in serie with a 0.5mH coil (cutoff should be at 2.3kHz) and a Zobel network (C=6.7uF, R=15Ohm, not really optimal value).
The tweeter is a Ciare ct 200 with a 2nd order high pass at 1.8kHz ....
Ok, there is something wrong with the frenquency of low pass filter, I actually don't have a bigger inductance
My amp is a modded NAD 304 ( swapped a lot of capacitor, even signal capacitor with polypropylene caps) and at high volume I found no big excursion but it puts out "only" 35+35w.
I've got a panasonic wm-61a mic and an Emu 0204 usb soundcard. Is there any free sotfware for some spectrum measurement?
So... I've just re-simulated the calinda xover but I've found 250Hz @ -3db ... What's wrong? See the picture http://s17.postimage.org/xyvdf8qr3/sim_calinda.jpg .
About my speakers:
The sp1054 are in an 18 liters vented box tuned @45Hz in serie with a 0.5mH coil (cutoff should be at 2.3kHz) and a Zobel network (C=6.7uF, R=15Ohm, not really optimal value).
The tweeter is a Ciare ct 200 with a 2nd order high pass at 1.8kHz ....
Ok, there is something wrong with the frenquency of low pass filter, I actually don't have a bigger inductance
My amp is a modded NAD 304 ( swapped a lot of capacitor, even signal capacitor with polypropylene caps) and at high volume I found no big excursion but it puts out "only" 35+35w.
I've got a panasonic wm-61a mic and an Emu 0204 usb soundcard. Is there any free sotfware for some spectrum measurement?
High qts. drivers have their limitations compared to low qts. drivers. Search this forum for transmission lines and much insight can be found. IPL Acoustics has used drivers with qts. of higher then generally accepted. I have also tried higher qts. drivers. Drivers meant for base reflex have a higher F ratio [fs/Qts.] compared to closed box drivers.
SEAS DRIVE UNITS
IPL ACOUSTICS TRANSMISSION LINE KITS
SEAS DRIVE UNITS
IPL ACOUSTICS TRANSMISSION LINE KITS
My own experience of bextrene bass/mid units is when they got hot at parties, they turned to jelly. Dull sounding too.
And by then, the T27's are just a distant memory.
jeff
Planet10 I found specs for the Kef B200G SP 1075 used in the CS3 and CS5 it is the 3 holed triangular version not the driver specs you requested but all I could find in my archives. Mmd 24.3 Grams Fs 27hz, .Vas 121 liters , Re 4.7ohms , Z min 5.3 ohms at 160 hz, Bl 6.82, Qms3.03 , Qes..42, Qts. .37, xmas 6mm peak to peak, voice coil diameter 32.6mm. 18 oz. ceramic magnet, Efficency 90db 1watt 1 mete,r Frequency response 25-3500hz. It also has box alignmensts In old Madisound catalog.
Couldn't quite follow all that, bjorno, but 3.29 mH makes no sense where it is in michelino's schematic, eh? I wasn't completely guessing in suggesting 0.6mH.
Dug up a couple of crossovers from the KEF 104 and KEF 104ab (later acoustic butterworth) speakers which had that ABR thingie. Here with the B200 SP 1039 which is 0.25mH Le and a bit higher Qts @ 0.4 or so. The tapped inductor is an acoustic contour switch with three positions. Gives +/_ 2dB @ 1.5 kHz.
KEF seemed to do some quite odd things with those B200 units. I expect the rising impedance makes the lowpass crossover point quite vague. The T27 seems to get a more exact treatment. The Calinda seems to exactly inherit the KEF 104ab highpass which is very near 3.5 kHz on 8 ohms when I checked it.
Dug up a couple of crossovers from the KEF 104 and KEF 104ab (later acoustic butterworth) speakers which had that ABR thingie. Here with the B200 SP 1039 which is 0.25mH Le and a bit higher Qts @ 0.4 or so. The tapped inductor is an acoustic contour switch with three positions. Gives +/_ 2dB @ 1.5 kHz.
KEF seemed to do some quite odd things with those B200 units. I expect the rising impedance makes the lowpass crossover point quite vague. The T27 seems to get a more exact treatment. The Calinda seems to exactly inherit the KEF 104ab highpass which is very near 3.5 kHz on 8 ohms when I checked it.
Attachments
Oh, just so you can more easily follow what we are scratching our heads over, it is this strange schematic for the KEF CALINDA and KEF B200 SP1054, which makes no sense at low frequencies.
An externally hosted image should be here but it was not working when we last tested it.
The lower half of the Xover for the T27. A 18 db/octave highpass filer and then some EQ filter on top seem pretty standard KEF style.
The LCR filter for the B200 might be OK my problem is that 5MicroFarad cap in front of the inducer? The large coil is not impossible the Calinda had a narrow baffle and to correct the 6 dB baffle step it is quite common to have about twise as large coil as classical calculations would predict. As there is not RC link across the B200 terminal the effect of the coil will be affected by the rising impedance of the B 200. But what the heck is the cap doing in front of the coil??
The LCR filter for the B200 might be OK my problem is that 5MicroFarad cap in front of the inducer? The large coil is not impossible the Calinda had a narrow baffle and to correct the 6 dB baffle step it is quite common to have about twise as large coil as classical calculations would predict. As there is not RC link across the B200 terminal the effect of the coil will be affected by the rising impedance of the B 200. But what the heck is the cap doing in front of the coil??
Yes, DrBoar, it may just be in the wrong place. I saw a photo of the Calinda crossover, and there WAS a large ferrite-core inductor there.
I was looking at the little KEF R101, which had the B110 unit in a BBC LS3/5A monitor type arrangement.
LO, the inductor is in front of the capacitor with a similar LCR trap! Don't have modelling software to look at that though...FWIW, KEF were kinda rough and ready with bass rolloff on the B200. Often nearer 2.5 kHz on the component values into 8 ohm.
I was looking at the little KEF R101, which had the B110 unit in a BBC LS3/5A monitor type arrangement.
LO, the inductor is in front of the capacitor with a similar LCR trap! Don't have modelling software to look at that though...FWIW, KEF were kinda rough and ready with bass rolloff on the B200. Often nearer 2.5 kHz on the component values into 8 ohm.
Attachments
Ok, thanks another time .... the strange Calinda XO is not a problem to me: maybe a 2nd order at 2-2.5-3kHz could be enough in my design...
Now, the big question is: how much should i spend to buy a mid-woofer that sounds better than SP1054? I have no experience, I'm only 21 and I can't afford expensive toys ... I only know that Sp1054 requires big enclosures (I have max 30-35liters...) and was mounted in Kef Calinda... 1970's speakers
.... the strange Calinda XO is not a problem to me: maybe a 2nd order at 2-2.5-3kHz could be enough in my design... Now, the big question is: how much should i spend to buy a mid-woofer that sounds better than SP1054? I have no experience, I'm only 21 and I can't afford expensive toys
... I only know that Sp1054 requires big enclosures (I have max 30-35liters...) and was mounted in Kef Calinda... 1970's speakers
I'd incline to stick with that B200 for now. 18L is alright if you stuff a sock in the reflex. I was really trying to figure out a crossover for you. I'd think you won't have much difficulty matching it to a 89dB or better tweeter with a third order crossover, like a Seas Prestige 27TFFC or Morel Classic CAT298. But you could even just buy a cheapie dome and run it off a single 2.2uF.
As it goes, I reckon 1.5-3mH and 5uF 2nd. order, with or without the trap, can't be very far wrong for that B200. I do think the coils go before the capacitor in the crossover, and looking at it confirms it. Red is woofer hot. Blue is tweeter hot and white is hot of input. Black is earth. The capacitor top right is the 5uF.
Enjoy the pictures of your B200 in it's youth!
As it goes, I reckon 1.5-3mH and 5uF 2nd. order, with or without the trap, can't be very far wrong for that B200. I do think the coils go before the capacitor in the crossover, and looking at it confirms it. Red is woofer hot. Blue is tweeter hot and white is hot of input. Black is earth. The capacitor top right is the 5uF.
Enjoy the pictures of your B200 in it's youth!
Attachments
Many years ago I aquired A B200 from a friend, who used it as the bass unit in a three way TL. I decided to try it in one of the 2 way designs common then using the above (largely Kef type), but using an Audax tweeter, I could not stand the T27. Anyway, the results were pretty poor, undynamic, flat, coloured. I could not understand why it was held in high regard.
A few days latter I deceided to try it out with a simpler Crossover, namily a single inductor, I think it was 1mH, and second order tweeter section. The differance was amazing. It showed me that the B200 was a much better driver than I thought. I have heard similar improvements from those who did similar things with the B110. The old Kef crossovers just sapped the life out of those drivers, all with aim to get the flatest response.
A few days latter I deceided to try it out with a simpler Crossover, namily a single inductor, I think it was 1mH, and second order tweeter section. The differance was amazing. It showed me that the B200 was a much better driver than I thought. I have heard similar improvements from those who did similar things with the B110. The old Kef crossovers just sapped the life out of those drivers, all with aim to get the flatest response.
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