Dave, If I put a 2nd order PLLXO HP @ 150 instead of the 1st, how would that effect my phase with the ribbon..I guess I could just try it & see,, it would take a 10k resistor & another cap, I think, worth playing with for fun..couple minutes to make. I would like to say that I am a huge fan of running fullrange with no filters of any kind & do so in other systems. I love them..Coherency is just so good....I could live easily without top end help on any of my systems..I am 40 this year so I don't have teenage hearing anymore..MY main system is a hobby in itself & if I just want to relax & just enjoy music & not the gear it is in other more simple systems I have..all tube of course, but simple..
PitGood idea Dave, I will try that with a SE NFB amp I have, I don't use it for anything under 150hz anyway..will be a cool experiement, didn't even think of that.....good one. let us know the results of the 108 experiment you talk of..I wish the Coral 103A had more effiecency, it has my dream tone on amplified guitars...No other driver I have can do it or what it does with guitars....amplified guitars believe it or not is the hardest for me to get correct for me..very hard. the 103A does is perfect..I am very curiouse how the OB Bass /108/FT17 experiment goes..
Quoting me:
"I will put the thinking cap on. It's all well and good to be able to replace the ribbons, but I for one could get very cranky if one popped at 10 in the evening!
The ribbons will sound even better with less LF energy any how."
Whoops, if it aint broke, don't fix it! I just went over the entire thread. He's got it licked, anyhow. JandG also indicates he may try a rear firing ribbon on a third amp. If there is a need to attenuate LF, that's the place to do it.
Geoff
"I will put the thinking cap on. It's all well and good to be able to replace the ribbons, but I for one could get very cranky if one popped at 10 in the evening!
The ribbons will sound even better with less LF energy any how."
Whoops, if it aint broke, don't fix it! I just went over the entire thread. He's got it licked, anyhow. JandG also indicates he may try a rear firing ribbon on a third amp. If there is a need to attenuate LF, that's the place to do it.
Geoff
I had a chance to listen to the B200 OBs with the horizontally mounted Fountek. The Fountek had a 1.5 uF cap and the Visaton BG40 an 8.5 mH choke.
The tweeter integration -- well lets say it sucked. Disconecting the tweeter transformed the speaker from unlistenable to quite good, but i know it could be better yet -- the woofer at the bottom really needs bi-amping and the B200 some roll-off to clean up the mids & tops. With the phase plugs in (the B200 also had a couple light coats of C37) i found the top end just fine.
dave
The tweeter integration -- well lets say it sucked. Disconecting the tweeter transformed the speaker from unlistenable to quite good, but i know it could be better yet -- the woofer at the bottom really needs bi-amping and the B200 some roll-off to clean up the mids & tops. With the phase plugs in (the B200 also had a couple light coats of C37) i found the top end just fine.
dave
Geoff H said:
I haven't measured them yet. Phase plugs spread the rising on-axis HF, giving a much larger sweet spot and flattening on axis reponse. When we 1st heard the B200 we were all thinking, these are good, but i wonder what a ribbon would add... after the phase plug "no need for a tweeter".
dave
Hi Dave ~
Let me see if I understood your post correctly... you are suggesting that after
inserting your phase plugs into the B200's, the upper frequency resolution
improved enough so that you no longer felt the need for the tweeter...
which I assume you were considering before the phase plugs were used(?)
Did that include the application of a resin coating to the cone of the B200
or are you speaking of just the effect of the phase plugs alone
regarding the upper frequency resolution?
Incidentally... I heard a speaker over the weekend that shed some light on
the use of ribbon tweeters with 8 inch paper cone drivers... not in OB...
but in a cabinet... the crossover was @ @2500Hz... and the designer shaped
the thick wood front panel so that it formed a kind of horn configuration to
both drivers... the designer thought the crossover point of his woofer/mid driver
and the Fountek 3.0 tweeter was seamless... it was not... to my ears I could
easily discern the different "temperatures" of both drivers... the Fountex seemed
hot to me and loaded the sound in a way that seemed entirely unnatural... the
upper frequency information said 'ribbon tweeter' and not the instruments that
were playing. And there were issues of beaming. The ribbon, instead of making
the sound transparent, actually contributed to a thickening effect.
I Agree with you, Dave... treated properly... and everyone thinks your phase
plugs and a few coats of varnish is the way to go... the B200 are marvelously
resolving of upper frequency musical material.
What is the varnish you recommend, Dave?
Warm Regards ~ Richard
Let me see if I understood your post correctly... you are suggesting that after
inserting your phase plugs into the B200's, the upper frequency resolution
improved enough so that you no longer felt the need for the tweeter...
which I assume you were considering before the phase plugs were used(?)
Did that include the application of a resin coating to the cone of the B200
or are you speaking of just the effect of the phase plugs alone
regarding the upper frequency resolution?
Incidentally... I heard a speaker over the weekend that shed some light on
the use of ribbon tweeters with 8 inch paper cone drivers... not in OB...
but in a cabinet... the crossover was @ @2500Hz... and the designer shaped
the thick wood front panel so that it formed a kind of horn configuration to
both drivers... the designer thought the crossover point of his woofer/mid driver
and the Fountek 3.0 tweeter was seamless... it was not... to my ears I could
easily discern the different "temperatures" of both drivers... the Fountex seemed
hot to me and loaded the sound in a way that seemed entirely unnatural... the
upper frequency information said 'ribbon tweeter' and not the instruments that
were playing. And there were issues of beaming. The ribbon, instead of making
the sound transparent, actually contributed to a thickening effect.
I Agree with you, Dave... treated properly... and everyone thinks your phase
plugs and a few coats of varnish is the way to go... the B200 are marvelously
resolving of upper frequency musical material.
What is the varnish you recommend, Dave?
Warm Regards ~ Richard
- RichardW - said:
I don't know if resolution is the right word. The phase plugs dramatically improve HF dispersion. With stock B200s if you get the speakers just right and lock your head into a vise at just the right point, there is top end -- the Germans listening with their measuring mics, record a rising top end (and dutifully add a filter to flatten it). But you move your head and all the top goes away and you start thinking tweeter.
The visual analogy is that the energy gets more and more laser-like as you go up in frequency, the HF energy is there but highly concentrated. The phase plugs take that energy and spread it out over a wider area, so that the sweet spot expands and the energy is spread over a larger area (volume).
The phase plugs also cure a tiny bit of chestiness in vocals (the dreaded voice coil oil can resonance) -- this last is just a tiny improvement, you don't notice it on stock ones until it is gone.
As to cone treatment, the jury is still out. This client just asked for C37 on the cones and i happen to have some as part of an on-going experiment. I haven't yet had an opportunity for a like-vrs-like comparison. What i can say is that the C37 dramtically reduced the noise floor on CSS FR125s (which have cones of similar material) resulting in what seemed like a whole 'nuther speaker. On the FE127s it illicited improvement but not nearly as much as the dammar pattern/puzzlecoat treatment in our regular modified FE127s. More trials are planned, since the pattern multiplies the possibilities,
With 4 B200s costing as much as 20 FE127s experimenting on them will be stretched out quite a bit more. To add to that the B200s now available are different from earlier ones. How much i haven't figured out yet.
I will note that over the last 30 years i haven't met a paper cone driver that didn't benefit somewhat from a judicial coat of puzzle coat.
dave
Hi Dave ~
A very concise and clear overview of your experiences with the B200 and
other drivers that have benefited from your phase plugs and applications of
what you call puzzle coat.
It would be helpful if you could go into what the puzzle coat is actually doing
for the sound that brings it to another level(?)
Is it that the puzzle coat stiffens the cone somewhat making it less resistant
to distortion as it moves through its excursion? In other words does puzzle coat
help the B200 driver (for example) reproduce music more accurately and therefore
exhibit more detail, separation of instruments, and so on?
Also, Dave... does the phase plugs create more refinement in the top end... or
as you indicated help radiate/disperse the top end extension over a wider area...
in other words does the phase plugs change the character of the musical material
at all?
Thanks so kindly for your help in explaining these details which I am very very
interested in.
Warm Regards ~ Richard
A very concise and clear overview of your experiences with the B200 and
other drivers that have benefited from your phase plugs and applications of
what you call puzzle coat.
It would be helpful if you could go into what the puzzle coat is actually doing
for the sound that brings it to another level(?)
Is it that the puzzle coat stiffens the cone somewhat making it less resistant
to distortion as it moves through its excursion? In other words does puzzle coat
help the B200 driver (for example) reproduce music more accurately and therefore
exhibit more detail, separation of instruments, and so on?
Also, Dave... does the phase plugs create more refinement in the top end... or
as you indicated help radiate/disperse the top end extension over a wider area...
in other words does the phase plugs change the character of the musical material
at all?
Thanks so kindly for your help in explaining these details which I am very very
interested in.
Warm Regards ~ Richard
At several places I read that people have used 1 mH +10 Ohm filter in series with B200 and they prefer the sound this way, because it sounds better (smoother?). I wonder if ayone has tried to compare the sound between a phase plug and no filter, versus filter-no phase plug.
Dave, you didn't use any filter on B200?
Regards,
Vix
Dave, you didn't use any filter on B200?
Regards,
Vix
Vix said:
I always try to fix the problem at the source instead of adding a band-aid. I wouldn't use B200s without phase plugs, just as i couldn't live with an unmodified FE126/127 (or CSS FR125 now). Once you have heard the improvement you can't go back, (of course i have a vested interest to say that -- but i learned long ago, that being as honest as i can (ie culturing what i call long term greed) is way better over time than trying to quickly pocket some cash by stretching reality)
dave
- RichardW - said:
http://www.t-linespeakers.org/design/tweeks.html
Note: i've not put puzzle coat on a B200 yet. I'd need to be able to afford 6 drivers (and potentially loose 4 of them -- althou experience says that is unlikely) to be able to properly assess puzzle-coat vrs C37 vrs stock.
Looking at it from a materials level, paper is a whole bunch of fibres (wood, banana, hemp, etc) that are loosely bonded together. get the paper moving and the fibres start moving relative to each other and make noise. By coating the yop layer of the paper (or in some cases soaking right thru) we bond the fibres together so they can't rub reducing a source of noise & coloration. The most dramatic example of this was when i recently put 2 vanishingly thin coats of C37 on a pair of FR125s. The onal balance of the speaker remained unchanged, but the noise floor plummeted revealing all sorts of information that had been biried in the noise. All that information added greatly to the music. In one sense the speaker sounded the same, but in totality it was transformed. Something like that will not show up on a FR plot.
One has to be exceedingly careful with stiffening the cone. To achieve its frequency range the driver needs to be able to flex and become effectively smaller as the frequency increases. The dramtic curvelinear profile is one of the design options used in the B200 to achieve this. Too much goop and the HF goes away (i have a 15" pro coax where i proved this to myself in dramatic fasin... i now need to make it a 3-way). Puzzlecoat is a particular formulation of PVA that tends to remain quite flexible. On the FE126/127 i use as little as i can (and quite watered down) to achiev the goal of bonding the fibers. Note that the approach whe sed on a woofer can be quite different.
I don't think they create more refinefinement -- it is probably more a case of spreading things out so you can hear the refinement of the top end... another way to look at it is that at the HF the beaming is so intense that it isn't wide enuff to ompinge on both the ears at the same time... without the interaural differences you mind does not have enuff information to construct the subtlies of the sound field. Spread out a bit both ears can participate and the brain can process what is there and create a better illusion. On that sense you would be allowing for more resolution to be assimilated (now that last bit just came out of my head, is speculation on my part, and might be a crock -- bt at 2:30 in the morning, it seems like it might be a workable hypothesis)
dave
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