Bob, is this Doppler distortion listening experience with or without high pass filter?
It's kind of hard to answer this without sounding condescending, but....
Doppler distortion is a fact of life with a wide-range driver. When you ask a driver to produce 40Hz up, you are going to get Doppler distortion. The amount of distortion depends on how hard you run the driver. A driver with a 3mm Xmax will produce three times as much distortion as a driver with a 1mm Xmax. Of course, you can avoid audible Doppler distortion by high passing the driver at 200Hz or better, but then why use an 8" driver?
Bob
One of the reasons why some people prefer bigger drivers from 200hz up is to get more "body". Very light cones tend to sound thin.
I'd like to know your opinion about that, because my Saba Greencone's are famous of this lightness and I want to find sound that is just a litle bit heavier. I'm using DEQ and a know that it is not just a matter of EQing. Saba's cones are about 8 grams and qts is about 1.6. Why oh why Visaton B200 (with BSC) sounds crisper in direct comparison ?
I wonder if I should buy B200 or look for smaller driver for 200hz up.
I have seen variations that large across multiple (much less expensive) Fostex units, Larger units were measured on different days (different weather) so the data does not have the same confidence levels.
Can you post the T/S calculations?
Looks like your random selection of drivers probably represent the ends of the bell curve. Given the expense of these units, i;d be talking to PE about getting a better matched pair.
dave
Yet another example of the fact that there are no industry-wide accepted QC tolerances, nor do most manufacturers state what they work to. 
The average for the speaker industry seems to be anything within ~ +/- 10%, although you sometimes see units which clearly employ +/- 20% or even wider (and sadly, that last does not necessarily just apply to the kind of thing you'd pick up for tuppence).
Given that 'crisper' could mean almost anything, pick a reason at random from the air. Possibly the Visaton better matches your amplifiers. Perhaps it's simply down to it being better damped (although with a Qt around 0.755 IIRC, it's not exactly the most heavily damped driver itself). Perhaps it has lower linear or non-linear distortion, wider BW providing superior transient response, or a greater nominal acceleration factor.
The average for the speaker industry seems to be anything within ~ +/- 10%, although you sometimes see units which clearly employ +/- 20% or even wider (and sadly, that last does not necessarily just apply to the kind of thing you'd pick up for tuppence). Given that 'crisper' could mean almost anything, pick a reason at random from the air. Possibly the Visaton better matches your amplifiers. Perhaps it's simply down to it being better damped (although with a Qt around 0.755 IIRC, it's not exactly the most heavily damped driver itself). Perhaps it has lower linear or non-linear distortion, wider BW providing superior transient response, or a greater nominal acceleration factor.
any new news ?
Here is a design from Tom Evans (saw it mentioned in stereophile in front under shows).
He uses a Jordan 4" in a sealed box then rolls in a woofer with a single inductor.
Tom Evans Model One For Sale | AudiogoN
serial number 1 and 2 are for sale on audiogon right now for just over $9,000 us
Tom Evans Audio Design | SORAsound
"SORAsound is proud to have a pair of Tom Evans speakers (6,000 GBP) on demo in our showrooms. All of the speaker electronics were designed using a Jordan Jx92s run full range without a crossover. In this new design the Jordan driver is limited to 120 Hz only by the volume of air behind it (lowering distortion with the reduced excursion without any crossover parts). The bass system is deep tight and very fast. It works from 120Hz down. This driver is (like most mid bass units ) is a little peaky at 2Khz and because it starts to roll off at 120Hz the peaky rubbish is greater than 24db down (inaudible). Because it has a narrow bandwidth, it does not excite the cabinet (no box honk). Tom Evans is on a mission to reproduce the recorded arts accurately."
Here is a design from Tom Evans (saw it mentioned in stereophile in front under shows).
He uses a Jordan 4" in a sealed box then rolls in a woofer with a single inductor.
An externally hosted image should be here but it was not working when we last tested it.
Tom Evans Model One For Sale | AudiogoN
serial number 1 and 2 are for sale on audiogon right now for just over $9,000 us
Tom Evans Audio Design | SORAsound
"SORAsound is proud to have a pair of Tom Evans speakers (6,000 GBP) on demo in our showrooms. All of the speaker electronics were designed using a Jordan Jx92s run full range without a crossover. In this new design the Jordan driver is limited to 120 Hz only by the volume of air behind it (lowering distortion with the reduced excursion without any crossover parts). The bass system is deep tight and very fast. It works from 120Hz down. This driver is (like most mid bass units ) is a little peaky at 2Khz and because it starts to roll off at 120Hz the peaky rubbish is greater than 24db down (inaudible). Because it has a narrow bandwidth, it does not excite the cabinet (no box honk). Tom Evans is on a mission to reproduce the recorded arts accurately."
I heard field coil Lowthers for the first time at the Dallas show.
I'm assuming they were well set up? Got favorarable remarks
from those who like that style of driver. I'm not one of them.
No wonder the TB didn't impress me, its got the same sound...
I'm worried now, cause I got BetsyK's coming... What have I
gotten myself into? I'm not against whizzer cones or anything.
I've always liked the Beta12LTA...
I'm assuming they were well set up? Got favorarable remarks
from those who like that style of driver. I'm not one of them.
No wonder the TB didn't impress me, its got the same sound...
I'm worried now, cause I got BetsyK's coming... What have I
gotten myself into? I'm not against whizzer cones or anything.
I've always liked the Beta12LTA...
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They sounded okay to me, though the bass horn was a bit too big / mismatched to the them and the room.
Better start working on heaping wax in them ears then
Well, as you know, I have a pair of Beta 12 LTA amongst my horde of drivers.
1772's an ok driver to me - somewhat shy of spl I like for bass drum (BM12CXA does 118dB @1M alright in K12 in-room - would do more if I had like 60W amp) Zobsky - your K12 might like 12LTA - put a tweeter on top, or on a bracket or 1" ID K-tube on top. GB thought 12LT was soft/mushy in K12 but I'm not sure - worth a try
LTA with <=8K top end, and constant directivity dispersion from the KSlot.
Constant directivity will probably roll that 8K down somewhat... But still,
I think it could cross well above vocal range into something like an ST324
slot tweeter... Few drivers have that sort of bandwidth without sounding
all Lowthery.
Whizzers smaller than 1.5 inch, and larger than 3inch don't bug me. Its
them ones in the 2 - 2.5 range that sound just gawdawfull. Maybe two
whizzers might do the job less obnoxious than one? How did Diffusicone
whizzer work?
Constant directivity will probably roll that 8K down somewhat... But still,
I think it could cross well above vocal range into something like an ST324
slot tweeter... Few drivers have that sort of bandwidth without sounding
all Lowthery.
Whizzers smaller than 1.5 inch, and larger than 3inch don't bug me. Its
them ones in the 2 - 2.5 range that sound just gawdawfull. Maybe two
whizzers might do the job less obnoxious than one? How did Diffusicone
whizzer work?
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(I've used ST324 for years = great bargain) - not heard that many fullrange drivers yet - - this little test coupler is being built for FE206EN front mount, and 1772 in from rear - to be JEK "approved" it has Fig6 reflector and lots of reflective surface including plexi on the inside of the wings. I'm convinced Karlson are a good alternative to blh - this cab is little so will have less "bass" than 8" drivers in K12/Karlsonette - hopefully it'll get some impression of good tone on the drums - I'm not sure what 1772 could do on bass drum in Karlsonette but I saw 108dB peak on ratshack meter at 1M within its xmax - that's about 10dB low compared to getting an in-room presentation of a drum - my BM12CXA on a different cd/ensemble track did 118dB peak and didn't reach its xmax so K12 with 12" should be capable of 120dB peak - of course there's no low bass ..but it will sound better with certain things than speakers which make small-signal bass graphs but possess no dynamic capability.. we should start a K-thread soon.
http://img194.imageshack.us/img194/4066/superk8v2cn.png`
http://img194.imageshack.us/img194/4066/superk8v2cn.png`
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