I have coming a pair of Kef B200, and a pair of Vifa D19TD which was suggested as a T27 substitute on this forum. I like it and it's used in my Mission 761 speakers. Similar 19mm poly dome.
What would you suggest as a crossover for a 2-way in a sealed cabinet? Typical X-over frequency is 3.5K
B200 SP1014 + T27 were used in Cantor(1971), Chorale(1970), KEFKIT1(1974), Monitor Audio MA4, Linn Index Mk1, Tangent TM1, 2, 3
Chorale crossover was SP1015 or SP1016
SP1014 – constructors, small magnet, Chorale
SP1022 – Qts .41, large magnet
SP1039 – med. Q, large magnet 104, 104aB, Monitor Audio MA4, 103 Ref. Best
SP1054 – Qts .23
SP1063 – med. Q, small magnet
SP1047 (1974) Used in: KEFKIT 1(1974)
SP1054 1976 Used in: Calinda(1976)
SP1063 1976 Used in: Caprice(1977), Corelli(1976), C40(1979), C65(1979)
Attached Monitor Audio MA5, Tangent TM1 and TM2
What would you suggest as a crossover for a 2-way in a sealed cabinet? Typical X-over frequency is 3.5K
B200 SP1014 + T27 were used in Cantor(1971), Chorale(1970), KEFKIT1(1974), Monitor Audio MA4, Linn Index Mk1, Tangent TM1, 2, 3
Chorale crossover was SP1015 or SP1016
SP1014 – constructors, small magnet, Chorale
SP1022 – Qts .41, large magnet
SP1039 – med. Q, large magnet 104, 104aB, Monitor Audio MA4, 103 Ref. Best
SP1054 – Qts .23
SP1063 – med. Q, small magnet
SP1047 (1974) Used in: KEFKIT 1(1974)
SP1054 1976 Used in: Calinda(1976)
SP1063 1976 Used in: Caprice(1977), Corelli(1976), C40(1979), C65(1979)
Attached Monitor Audio MA5, Tangent TM1 and TM2
Attachments
Hard to see the B200 reaching up to the D19.
The biggest failing of the Tangents (the best of the B200/T27 i ever heard) was in the upper range of the B200.
i would not `XO it higher than something like 2.5kHz.
And i do have issues with the data KEF provides to model a proper box. By that the box wants to be considerably larger than any that came to market (i have 16 x B200 SP1014, cost almost nothing).
dave
The biggest failing of the Tangents (the best of the B200/T27 i ever heard) was in the upper range of the B200.
i would not `XO it higher than something like 2.5kHz.
And i do have issues with the data KEF provides to model a proper box. By that the box wants to be considerably larger than any that came to market (i have 16 x B200 SP1014, cost almost nothing).
dave
Hello Dave. Indeed, the crossover frequency needs some thought. Here's the D19 data and T27 data
https://cdn.shopify.com/s/files/1/0809/2387/files/D19TD05-08.pdf?1883630718988819778
http://nedlab.com/wp/wp-content/uploads/2014/06/KEF-T27-SP1032.pdf
Fs of T27 is lower at 900Hz than D19 at 1.7K. The D19 was crossed over around 3.1K in the Mission 700LE but 4.2K in the later 761 model.
https://cdn.shopify.com/s/files/1/0809/2387/files/D19TD05-08.pdf?1883630718988819778
http://nedlab.com/wp/wp-content/uploads/2014/06/KEF-T27-SP1032.pdf
Fs of T27 is lower at 900Hz than D19 at 1.7K. The D19 was crossed over around 3.1K in the Mission 700LE but 4.2K in the later 761 model.
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Not sure i understand the question Greg.
Probably a reason for that, i typically see the D19 XOed above 5kHz. 700 vbrs 1.7 kJz is over an ocatve diufference in potential extension.
dave
Probably a reason for that, i typically see the D19 XOed above 5kHz. 700 vbrs 1.7 kJz is over an ocatve diufference in potential extension.
dave
Have you heard them?
KEF used there midbasses much higher than they were really capable of. Except the B110.
dave
KEF used there midbasses much higher than they were really capable of. Except the B110.
dave
I think it should work in a reasonable fashion, but I am not 100% convinced it would give you a T27 and DN 12 crossover response of the kef original design.
It might be sensible to stick 1 ohm at the input and try 3.3uF as the first capacitor instead of the 5.6uF shown in post 6. If not quite correct then try without the 1ohm and if that still leaves a perceived gap increase to 4.7uf or 5.6uf as per the diagram.
As you know and understand measurement would make it somewhat easier to get right.
It might be sensible to stick 1 ohm at the input and try 3.3uF as the first capacitor instead of the 5.6uF shown in post 6. If not quite correct then try without the 1ohm and if that still leaves a perceived gap increase to 4.7uf or 5.6uf as per the diagram.
As you know and understand measurement would make it somewhat easier to get right.
Pretty confident I haven't unless I happened to audition them and not know it in any of the long gone Atlanta DIY Meet's listening room.
I think you are asking too much of the D19 Vifa. It is not happy playing that low at any volume level. The D20 would be a little better but still not ideal. KEF was very optimistic pushing the T27 that low as well. It has very low excursion and often died by breaking the tinsel leads going to the voice coil.the other advantage of a Vifa D20 is they are rebuildable. D19 are not.
I stumbled on this thread which may, or may not be of some interest to you. https://www.diyaudio.com/community/threads/goodmans-minister.205387/
jeff
Contrary to my experience. They are rebuilabke, but the butterflies i got were from other D19 (different bezels). There ar ea whole lot of these used in commercial loudspeakers.
Note: i don’t plan on usin gmy B200 over 400 Hz.
dave
Lateral thinking - if you wanted to cross the B200 over lower, what tweeter would you use and what crossover?
Kef did use different tweeters in their B200 models, and there would be modern equivalents.
Kef did use different tweeters in their B200 models, and there would be modern equivalents.
I’d use Alpair 5.2/3 (CHN-50 if keeing the budget theme, the 16 B200s cost me $200 CAD) or The Fostex FF85wk (with at least a few easy tweaks).
XO somewhere between 350-450 Hz, enuff overlap to use a first order XO, lots of amps in the “closet", so a PLLXO. Given the clash in box sizes, maybe a sealed isobarik with an after the fact Linkwitz transform to roll off the box appropriately since first pass will be a number pulled from the air for box size.
dave
XO somewhere between 350-450 Hz, enuff overlap to use a first order XO, lots of amps in the “closet", so a PLLXO. Given the clash in box sizes, maybe a sealed isobarik with an after the fact Linkwitz transform to roll off the box appropriately since first pass will be a number pulled from the air for box size.
dave
Hi Dave - I've just moved on from my Alpairs, so looking for a standard tweeter here, and standard size would also be useful for experiments. I guess crossover around 2.5K - 2.8K or so. Nothing fancy. I'm not throwing money at this. Simple 2-way.
That XO should work.
I’m not up on tweeters Shipped some decent modified SEAS off to Scott. @Scottmoose
He is much more up on the subject of tweeters currently available.
dave
I’m not up on tweeters Shipped some decent modified SEAS off to Scott. @Scottmoose
He is much more up on the subject of tweeters currently available.
dave
A further comment on the top of the B200. Its lacks in the range just below where KEF crossed them (2.5-3.5k+) was the stark difference in the Tangent TM3 and the RS4 which was essentially the same box with an Audax HD200 swapped in. Same T27. RS4 was one of my favorite speakers of the time. Others were Dayton-Wright XG8, IMF TLS50 (with KEF B200 SP1014), and the Spendor BC-1.
Moving the XO down should move the B200s deficincies out of band.
dave
Moving the XO down should move the B200s deficincies out of band.
dave