the b200 has its merits as it omits the problems with a whizzer cone.
And it really is highly efficient
Some LTS50 or Modgepodge or alu tweak and EQ would make it sound less "papery".
Diffusing elements are not necessary could be integrated into a loudspeaker grill.
Some side tweeters would add high frequency dispersion easily without touching the driver
And it really is highly efficient
Some LTS50 or Modgepodge or alu tweak and EQ would make it sound less "papery".
Diffusing elements are not necessary could be integrated into a loudspeaker grill.
Some side tweeters would add high frequency dispersion easily without touching the driver
I would tweak the B200 - if I would be too lazy to put foil on it - like this
2 thin coats LTS 50 front side
1 thin coat LTS50 back side
If some dampening liquid available (I don't know what and where!) then a similar coating of the outer parts like with the Sica 12d.
Should be quite audible as effect (stabilizing, damping)
2 thin coats LTS 50 front side
1 thin coat LTS50 back side
If some dampening liquid available (I don't know what and where!) then a similar coating of the outer parts like with the Sica 12d.
Should be quite audible as effect (stabilizing, damping)
I found an old foto of my two modified fullrangers: Visaton B200 and Fostex Fe206e
At Visaton, I applied a thin coat of varnish damar and made sort of a phase plug. That improved the sound quite a bit.
With Fostex 206, I had made a mistake of inserting a wrench socket as a phase plug and could never pull it out...
At Visaton, I applied a thin coat of varnish damar and made sort of a phase plug. That improved the sound quite a bit.
With Fostex 206, I had made a mistake of inserting a wrench socket as a phase plug and could never pull it out...
Attachments
The B200 has always been an interesting driver, although a fairly narrowly focused unit.
With the old technical hat on for a moment, it's a high Q unit with relatively little mechanical, and only moderate electrical damping, and with a rated free air / infinite baffle Qts of 0.75[5] it is slightly underdamped even under those conditions without external compensation, and will always have some degree of peaking at resonance, with the possible exception of an optimally sized / designed baffle. You can use it in other ways, but the caveat above applies. It's also [a point Dave has made in the past] nothing like as efficient as claimed. Visaton state a mean SPL of 96dB 1m/2.83v which is a fairly clever piece of linguistic sleight of hand since that's actually a mean of the overall SPL, not the EM conversion efficiency normally used. Reference efficiency η0 from the published LF data is 0.8% [nearly] with a 1m/w efficiency rating of 91.03dB and a 1m/2.83v sensitivity of 93.07dB. As you can see from the published polar / directivity pattern, it's beaming like a good 'un from about 2KHz, although it's far from alone in this & better than some -a well-dimensioned pole-piece extension / 'phase plug' can help with this as Dave says.
Current source amplifiers are interesting, but (also as Dave says) you have to keep context in mind. The type dates from an era when hi-fi either didn't exist or was much more of a hands on hobby than it became, and assumed a system-design context, i.e. you were matching the speaker system to the amplifier -that's also why variable output impedance amplifiers were common, since it helped you to dial in the response. As you remove electrical damping, so you have two basic effects -at resonance, you in effect artificially raise the driver Q with all that entails in a speaker system / enclosure / baffle design sense, and higher up, the FR will as noted also start to follow the impedance curve. That's why Nelson, when he first produced the F1 etc., also added suggested Zobel values for different drive units to linearise the impedance & thereby the FR. Most valve amplifiers [especially SET types] lean this way, which is one of the main reasons they sound 'different' with most multiways if they haven't got any input Zobels as discussed above. The main value of current source amplifiers, as Nelson implies & referencing back to history, is with the highly damped [i.e. typically low Q], highly efficient drivers: back in the day, Watts cost money, and lots of it, so system efficiencies needed to be high relative to now, when clean power costs peanuts. Leaving other aspects aside, that meant current sources or variable output impedances were ideal, since you could tune / compensate for what would be [on a pure voltage source] an inherently overdamped drive unit to provide a desired / usable alignment. It wasn't quite as pat as that; more of a dog-bites-tail scenario since it was also easier for contemporary amplifiers to be designed like that, so many drivers were developed with high-power motors & significant damping for that reason as well -chicken / egg, & around we go. It's nice to have them back: they're a niche sort of item but used in the context they're meant / best for, they're as valid now as they always were.
With the old technical hat on for a moment, it's a high Q unit with relatively little mechanical, and only moderate electrical damping, and with a rated free air / infinite baffle Qts of 0.75[5] it is slightly underdamped even under those conditions without external compensation, and will always have some degree of peaking at resonance, with the possible exception of an optimally sized / designed baffle. You can use it in other ways, but the caveat above applies. It's also [a point Dave has made in the past] nothing like as efficient as claimed. Visaton state a mean SPL of 96dB 1m/2.83v which is a fairly clever piece of linguistic sleight of hand since that's actually a mean of the overall SPL, not the EM conversion efficiency normally used. Reference efficiency η0 from the published LF data is 0.8% [nearly] with a 1m/w efficiency rating of 91.03dB and a 1m/2.83v sensitivity of 93.07dB. As you can see from the published polar / directivity pattern, it's beaming like a good 'un from about 2KHz, although it's far from alone in this & better than some -a well-dimensioned pole-piece extension / 'phase plug' can help with this as Dave says.
Current source amplifiers are interesting, but (also as Dave says) you have to keep context in mind. The type dates from an era when hi-fi either didn't exist or was much more of a hands on hobby than it became, and assumed a system-design context, i.e. you were matching the speaker system to the amplifier -that's also why variable output impedance amplifiers were common, since it helped you to dial in the response. As you remove electrical damping, so you have two basic effects -at resonance, you in effect artificially raise the driver Q with all that entails in a speaker system / enclosure / baffle design sense, and higher up, the FR will as noted also start to follow the impedance curve. That's why Nelson, when he first produced the F1 etc., also added suggested Zobel values for different drive units to linearise the impedance & thereby the FR. Most valve amplifiers [especially SET types] lean this way, which is one of the main reasons they sound 'different' with most multiways if they haven't got any input Zobels as discussed above. The main value of current source amplifiers, as Nelson implies & referencing back to history, is with the highly damped [i.e. typically low Q], highly efficient drivers: back in the day, Watts cost money, and lots of it, so system efficiencies needed to be high relative to now, when clean power costs peanuts. Leaving other aspects aside, that meant current sources or variable output impedances were ideal, since you could tune / compensate for what would be [on a pure voltage source] an inherently overdamped drive unit to provide a desired / usable alignment. It wasn't quite as pat as that; more of a dog-bites-tail scenario since it was also easier for contemporary amplifiers to be designed like that, so many drivers were developed with high-power motors & significant damping for that reason as well -chicken / egg, & around we go. It's nice to have them back: they're a niche sort of item but used in the context they're meant / best for, they're as valid now as they always were.
I can only make some general comments. I have not heard all the drivers, and the kit can make a big difference. Taste & room as well.
Most of the Markaudio are at least good, the best are outstanding.
The really cheap, CHN-50/110 are better than good, cheap as they use an dirt-cheap off-the-rack basket (i haven’t heard the CHP-50). What they lack compaired to the Alpairs (and some of their decendents, ie P7HD, CHR/P-90).
The first 2 are quite smooth (trade off for DDR), the higher end metal drivers can have HF control issues. You see many people deciding they like to use band-stop notch filters to help ameriolate them. I prefer to tackle those issues at theproblem by modifying the drivers. Most of the MA i have listened to have been EnABLed. My favourite was/is Alpair 7.3eN. Almost as good as the MAOP 7. A7.3 is a bit better midTop than A10.3. I assume the same with the MAOPs, althou given the A10.3 brought the A10s closer to the A7 vrs A10.2 (i cannot recommend A10.1) so the M10.2 may …
The monoSuspension in the A5/7ms/11ms drivers have the potential for more DDR without a 2nd suspension with different resonance characteristics fighting the other. But it becomes hjarder to control the top. In find A11ms has some annoying stuff up top which i find is largely controlled by an simple coating of Acrylic Gloss. https://www.diyaudio.com/community/...-tweak-and-other-metal-cone-markaudio.409632/
I’d really like to hear some MAOP 5s.
The paper cone drivers (with some exclusions) are voiced differently with much greater control up top, a smooth “vintage” top end. The A10p was a favourite of the SE tube crowd, The A6p one of my favourites (i have kept 3 pair of A6PeN to build a triple A6 Mar-Ken, better midTop then A10PeN, triple the cone area down low as a single. I preferred a set og mMar-Ken with A6PeN to a set of Rogers LS3/5A i retored for a buddy.
I would avoid any of the first gen drivers, CHN-70/P7PHD are voiced for the Japanese market and are not to most western tastes. A7p takes a very long breakin and some treatment to minimize some HF ringing (uncharacteristic) from the less controlled cone.
dave
If you aren’t using it on an OB, or as a midTweeter figuring a box is a real conundrum. BIG aperiodic or a Boffle likely best.
dave
+1. Sealed if you don't mind a higher Q is an option, or even a very large depressured horn, but otherwise it does need some correction & at these frequencies that gets big -in components & cost [short of active, & that's assuming it's an available option, which it isn't for everybody].
That's why I used them on the Open Baffle, modified (dammar, phase plug) and driven by a Pass F2 amp, plus the correction network (resistor + zobel). Only then they could really shine 🙂
You can. Just crossovers a little different. If you leave crossovers the same use EQ
because they are less universal. The board you can buy from me 😁