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  »  New  Romy's Horns..  RE: Still Romy's horns...  Horn-Loaded Speakers Forum     3  45676  04-14-2005
  »  New  Vitavox S2 with Electromagnets..  Cutter Head/Servo...  Horn-Loaded Speakers Forum     91  780329  01-12-2006
  »  New  S2 Hissing Sound..  Cleaning Time Revisited......  Horn-Loaded Speakers Forum     12  77153  07-18-2006
  »  New  Big mama 1.5" horns......  Crossover point...  Horn-Loaded Speakers Forum     27  157514  09-08-2006
  »  New  Satisfying result: the RMAF Show + Cogent..  A Subject for your post!...  Horn-Loaded Speakers Forum     22  200970  10-25-2006
  »  New  Vitavox S2 driver made in china..  What does it do right?...  Horn-Loaded Speakers Forum     36  184945  12-20-2006
  »  New  Make Your Own Horns..  Texture and Consistency...  Horn-Loaded Speakers Forum     2  21816  01-26-2007
  »  New  Musique Concrete horns..  Electricity and different compression drivers’ diaphrag...  Horn-Loaded Speakers Forum     5  74418  06-12-2007
  »  New  Compression drivers and the “clean signal”...  The NEW “Compression drivers and the clean signal”....  Horn-Loaded Speakers Forum     14  110537  07-12-2007
  »  New  Entry level DSET Melq?..  Look outside the Lundhal if you need more current to dr...  Melquiades Amplifier  Forum     10  75147  01-25-2008
  »  New  Vitavox S2 coupling..  Adaptor thickness etc....  Horn-Loaded Speakers Forum     18  56252  12-20-2008
  »  New  The ferrofluiding of compression drivers?..  The ferrofluiding of compression drivers?...  Horn-Loaded Speakers Forum     0  11024  02-20-2009
  »  New  Phoenix..  Mute vitavox...  Horn-Loaded Speakers Forum     2  16221  03-20-2009
  »  New  Fake Vitavox S2 diaphragms on ebay..  The vintage brain virus....  Horn-Loaded Speakers Forum     6  39201  06-11-2009
  »  New  Living Voice Loudspeaker..  A Polish Infomercial from Kevin Scott....  Horn-Loaded Speakers Forum     80  438860  08-09-2009
  »  New  French Horns/drivers shootout (oops! S2 came last)..  My bad...  Horn-Loaded Speakers Forum     7  46400  12-07-2010
  »  New  "O Vitavox, Vitavox! Wherefore art thou Vitavox?&q..  Niche...  Horn-Loaded Speakers Forum     22  141723  06-27-2011
  »  New  For one day only..  Yes , but…....  Horn-Loaded Speakers Forum     12  54454  03-07-2013
04-13-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,544
Joined on 05-28-2004

Post #: 21
Post ID: 882
Reply to: 96
Life sucks with Vitavox S2!

I recently made some highly attractive changes with the way in which I use S2. Now, since the S2’ top got cleaned up the universal misery of universe bothers me tremendously. :-)

Really, the S2 runs in my 400Hz horn up to 12.5kHz and the S2’s 12.5kHz sound more effective then TAD 4001’s or JBL 007’s 20kHz. I was trying to compliment the S2 with tweeter but it really unnecessary. Most of people out there use the S2 in thier default 330Hz 26” horns that put the driver deeper into the horn where it cuts-off ~2kHz. With the shorter horn the last 2khz jumps out and the S2 do not really need any tweeter. Well, it would be nice to have one (do not ask me why – probably juts in order to please my spectral-analyses) but I do not think there is any tweeter out there the would be able to handle what S2 dose at 12Khz.

Now, how should I use the bottom end of the S2? This is real dilemma! From one perspective I might drop the crossover point and drive it at 500Hz into 250Hz horn. But then I will loose 2kHz at the top. I’m clossing now the upperbass at 70Hz where the S2 kicks in… So, I was wondering.... How about to palace the S2 into an ultra-small ~5kHz horn and then to compliment it from bottom with another S2 in 250Hz horn at 500Hz. In the 5kHz horn the S2 will push probably 16hz and it will be HF that would be untouchable. Ay the bottom this HF channel will face the identical driver in a larger horn. The lower knee of the HF channel would decay acoustically with the horn rate and the low pass on the MF would be a first order. Considering that the are identical drivers it would not be problem to have a tail of any length in there…

Hm, this sounds quite interesting. At the bottom S2 channel I would use probably a plastic diaphragm as they can dissipate more power and less prone to that cracking… This sound quite attractive… Did anyone went to those extremes of Votavoxisisation?

From a different viewpoint now I have the S2 running in it’s optimum configuration for 4-way installation: S2 has a spare octave at the bottom allowing a nice midbass channel entry and it sits in a shorter and wider horn allowing to use it’s maximum HF. What the hell I want from it? I want somebody else to try and tell me how it was… Then I would object it... :-)

:-)
The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-14-2005 Post does not mapped to Knowledge Tree
cv
Derby, United Kingdom
Posts 173
Joined on 09-15-2004

Post #: 22
Post ID: 884
Reply to: 882
Twin S2s per channel...
Do you even need a horn to run it at 5kHz? The acoustic transformation's probably done by the time the wave reaches the throat. Or is this more just to shape the rolloff below 5kHz? I once tried a hornless S2 as a tweeter; it was quite lovely but didn't quite go high enough for me.

I'm currently running *one* S2 barbarically, while tweaking a few things. It's x/o'd 1st order before the amp at 500Hz on a 340Hz JMLC horn. Btw, the JM flare has a "T factor" parameter that can be used to control how open the flare is - larger T, shorter horn - you may be able to produce a horn that loads the S2 correctly down to 500Hz without sacrificing top.

Anyway, I need to setup my measurement rig to see exactly what my drivers do because crude measurements indicate that they are all over the shop, sensitivity and response wise. Then I can match a pair up and see how they really perform.

Not that any of this will help you, my reference points are crude, my source neanderthal and the amplfication chain fit only for troglodytes... but I'm working on it...

What you really need Romy is to find someone who will build 2 scale models of the S2; one twice the size for midbass and one half the size with electropolished phasing slits for tweeter duty, stick the standard S2 in the middle and you're done...

cheers
04-14-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,544
Joined on 05-28-2004

Post #: 23
Post ID: 885
Reply to: 884
Authorized hallucination…

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 cv wrote:
  The acoustic transformation's probably done by the time the wave reaches the throat.

Yes, it is. If we loom how the S2 internal channel done then it would clearly indicate the it should not be a great tweeter but what whatever reasons it is. Go figure…

 cv wrote:
I'm currently running *one* S2 barbarically, while tweaking a few things. It's x/o'd 1st order before the amp at 500Hz on a 340Hz JMLC horn. Btw, the JM flare has a "T factor" parameter that can be used to control how open the flare is - larger T, shorter horn - you may be able to produce a horn that loads the S2 correctly down to 500Hz without sacrificing top.

Are you saying that the JMLC curve could be shorter then tractrix to the same flare rate?

 cv wrote:
What you really need Romy is to find someone who will build 2 scale models of the S2; one twice the size for midbass and one half the size with electropolished phasing slits for tweeter duty, stick the standard S2 in the middle and you're done...

Here we go! Not we are taking!!! I would not need the S2 tweeter and what it dose now in 400Hz horn is perfectly enough. I would go only for the midbass S2.  Something with 6” cellulose diaphragm, low to medium compression, 3-4” throat, >2T in the gap and with Fs around 80-90hz. Something similar to the Community M4 compression driver only that would sound good

Ok, now I am officially hallucinating..
The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-14-2005 Post does not mapped to Knowledge Tree
guy sergeant
United Kingdom
Posts 258
Joined on 08-03-2004

Post #: 24
Post ID: 886
Reply to: 885
Re: adventures where bats communicate...

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Romy,

If you use the plastic surround S2's from 500-5KHz won't you still have the bulge that concerned you at around 1.2K? I thought you suggested that the metal suspension units didn't have this bulge.
Otherwise it seems a nice idea, albeit a bit expensive for many of us to try. We don't all have cupboards of unused S2's lying around!

I still think that the Alnico JBL2405 has enough of what the S2 does to be a worthwhile tweeter working above it S2. I remember you describing it as 'punchy' I don't find that at all. It does seem to be fussy about what type of coupling cap feeds it but I suppose thats to be expected with any half decent tweeter.


Chris,

Where did you get the JM Le Cleach horns made? Was it someone in France or did you calculate what you needed and get someone in the UK to make them. As a fellow barbarian, I always strive to become more civilised and I can see that these may be one way of achieving it. I don't fancy giving up the raping, pillaging and raw meat though.
04-14-2005 Post does not mapped to Knowledge Tree
slowmotion


Oslo, Norway
Posts 60
Joined on 07-22-2004

Post #: 25
Post ID: 887
Reply to: 884
Re: 5K horn?

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Hi Chris, all Allthough most of the work is done by the compression driver at 5 K , I would still use a proper horn, a horn that loaded the driver down to 2500Hz would be minimum IMHO. You can still use a Le Cléac'h horn if you wish.
Wink cheers Wink
04-14-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,544
Joined on 05-28-2004

Post #: 26
Post ID: 888
Reply to: 886
S2 with plastic surround.

 guy sergeant wrote:
If you use the plastic surround S2's from 500-5KHz won't you still have the bulge that concerned you at around 1.2K? I thought you suggested that the metal suspension units didn't have this bulge.Otherwise it seems a nice idea, albeit a bit expensive for many of us to try.

S2_NoCrossover_300Hz_Horn.jpg

Well, look at the sweep of S2 with plastic surround. This is a sweep with no filter as all, a wide-open driver. If I pleace it into my 400Hz horn then it will gently roll-off 12dB++ at 800Hz. However this is a sweep in 300Hz horn. When I used the plastic surround then I presumed that 74dB (~108d with 1W) would me target output and I flatter the bubble with a first order at 3.5K (loosing 4dB sensitively). However, whan I begun to use the older cones then they are flat at 78-79dB at the presented sweep. So, it might be considered that the plastic surround cones juts have thier HF rolled-off at 3K,  could it be?If so, then it would be possible to have upper bass S2 driver that would cover from 500Hz to 3.5Hz and arrive at 4K-5K at –3dB, perhaps without using a low pass filter and let the plastic cone to kill the HF.

The caT




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-14-2005 Post does not mapped to Knowledge Tree
slowmotion


Oslo, Norway
Posts 60
Joined on 07-22-2004

Post #: 27
Post ID: 889
Reply to: 885
Re: Authorized hallucinations… ?
Hi Romy, all

Romy wrote:

" Are you saying that the JMLC curve could be shorter then tractrix to the same flare rate? "

JMLC made a spreadsheet based on his approach to designing horns,
with that spreadsheet you can design almost any kind of horn you wan't to.
We should maybe have Jean-Michel describe his theories himself,
but I don't think he is on this list?


The short, wide Le Cléac'h horns we are used to seing are just one of many
possible ways to design such a Le Cléac'h horn.

cheers
04-14-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,544
Joined on 05-28-2004

Post #: 28
Post ID: 890
Reply to: 889
JMLC curve.

 slowmotion wrote:
JMLC made a spreadsheet based on his approach to designing horns, with that spreadsheet you can design almost any kind of horn you wan't to.  We should maybe have Jean-Michel describe his theories himself, but I don't think he is on this list? 
I do not know a lot about the JMLC curve and I never used it. If you know his email then shot to him a pointer to this thead. Perhaps he would jump-in and would explain what he was perusing with his horn profile.

JMLC.jpg


Rgs,
Romy


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-14-2005 Post mapped to one branch of Knowledge Tree
slowmotion


Oslo, Norway
Posts 60
Joined on 07-22-2004

Post #: 29
Post ID: 891
Reply to: 890
Re: JMLC curve.
Hi

Some links:

http://site.voila.fr/musique_concrete

http://mailman.io.com/pipermail/sound/2004-May/006297.html

http://mailman.io.com/pipermail/sound/2004-May/006323.html

http://mailman.io.com/pipermail/sound/2004-February/005088.html

http://mailman.io.com/pipermail/sound/2004-February/005093.html

http://mailman.io.com/pipermail/sound/2004-February/005095.html

http://mailman.io.com/pipermail/sound/2004-February/005096.html

cheers Jan

04-14-2005 Post does not mapped to Knowledge Tree
cv
Derby, United Kingdom
Posts 173
Joined on 09-15-2004

Post #: 30
Post ID: 892
Reply to: 891
Re: JMLC curve, 340Hz horns etc etc

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Romy wrote: "Here we go! Not we are taking!!! I would not need the S2 tweeter and what it dose now in 400Hz horn is perfectly enough. I would go only for the midbass S2.  Something with 6” cellulose diaphragm, low to medium compression, 3-4” throat, >2T in the gap and with Fs around 80-90hz. Something similar to the Community M4 compression driver only that would sound good"

Well, the Cogent (Steve Schell and Rich Drysdale) boys are building just such a beast: field coil magnet, (possible) permendur polepieces for >2T, Fs 70Hz, throat - dunno, but at least 3" dia, reduced compression ratio relative to midrange units. They tried various diaphragms, phenolic originally but I believe have decided that carbon fibre is king [cv ducks for cover...?]. I've seen pictures of the internals of the drivers and they certainly *look* incredible. A very, very early prototype of the smaller midrange unit may be seen at: http://www.oswaldsmill.com/id29.html but you've probably seen that already.

As for JMLC, I don't have his email address, but you should be able to find his details on the web. That musique concrete site that Jan attached was very interesting - a French fella by the name of Marc Henri did some interesting research on the damping properties of different horn materials. He uses a similar flare horn as I have for the S2, but made of plaster of paris IIRC.

Guy:

My 340Hz/T=0.8 flare horns were made by expat Martin Seddon in Oz. They have a threaded moulding and screw right on to the S2... sort of. The moulding compound shrunk a bit which meant they didn't quite fit to start with, however, they went on to my RCA drivers a treat. A few removals/re-attachments and now they fit onto the S2s too :-) With this knowledge, I'm sure he could make you a pair that would fit straight off.

I'm commissioning Martin to build me some 160Hz horns with the same mounting... should be interesting with the RCAs, which can go down low allegedly (circa 5" phenolic dia with felt surround). May also be making some 5-600Hz JMLC flares for me - the idea being RCA 150-1k, S2 1k+, if the RCA works well down there.

What's your email address? I'll put you guys in touch.

Cheers
cv
04-14-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,544
Joined on 05-28-2004

Post #: 31
Post ID: 893
Reply to: 892
Concrete horns and the Cogent Boys

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 cv wrote:
Well, the Cogent (Steve Schell and Rich Drysdale) boys are building just such a beast: field coil magnet, (possible) permendur polepieces for >2T, Fs 70Hz, throat - dunno, but at least 3" dia, reduced compression ratio relative to midrange units. They tried various diaphragms, phenolic originally but I believe have decided that carbon fibre is king [cv ducks for cover...?]. I've seen pictures of the internals of the drivers and they certainly *look* incredible. A very, very early prototype of the smaller midrange unit may be seen at: http://www.oswaldsmill.com/id29.html but you've probably seen that already.

Yes, I have seen them; never head what those guys do though. I had some concerns about that project. I read somewhere that they were planning to put this drive all the way up to 10Khz, equipping it with some kind of phase plug and so on. I do not think that it would be good idea. The base theory of horn loudspeaker contradicts the wide frequency operation. I would personally love to have such an upperbass driver optimized from 70-80Hz to sub 1000Hz, which would perfectly fit into the 4-way installation.

Anyhow, no one never knows why those compression driver sound in the way how they sound. We get pretty much sound “as is” from those drivers and try to make out of it something. All drivers that I like of use do not do well on the specks. The very same S2 driver has very ordinary datasheet. Go figure how they all will sound!

Anyhow, I was argue (my normal state of mind) with someone of Cogent boys in past about a necessity to use a paper cone for mid bass driver (even compression). At that time they were big on the metal cones. So, you said that now they have decided that the “fibre is king”… Dose it mean that I won and now I can pat my ego :-), or perhaps to have the driver to try? Also, I hope that this drive will not come with a digital EQ… :-)

 cv wrote:
As for JMLC, I don't have his email address, but you should be able to find his details on the web. That musique concrete site that Jan attached was very interesting - a French fella by the name of Marc Henri did some interesting research on the damping properties of different horn materials. He uses a similar flare horn as I have for the S2, but made of plaster of paris IIRC.

I do not really think that different horn materials are so important. The horns obviously should not be made with the Coca-Cola cans (courtesy to Altec-BL-Klipsh-EV-Vitavox and many others). A proper horn should have above critical mass that should be projected to the lower cut off frequency (LF push to mass). If is it heavy enough then the material become irrelevant but if a horn is too light for the given lowest frequency then the material maters. I think in those concrete horns the material is very secondary (they have enough mass and it is all the they should have). The really interesting thing in those concrete horns is not the concrete itself but the finishing surface. I have paid attention that the more “hairy” and granular horn’s surface is that more “interesting” the horn sounds. With a glossy horn sound juts “slips” vs. the “hairy” horn sound “flows”. John Hasquin once taught me to pain horns with structured paint to make them not smooth but abrasive. All his horn made this way. I tried to do the “structured paint” on some of my prototype horns and get very good and very predicable result. I think that the beauty of those concrete horns is in thier structured, abrasive surface that Marc Henri mistakably recognized as the “contribution of material”

Rgs,
Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-14-2005 Post does not mapped to Knowledge Tree
cv
Derby, United Kingdom
Posts 173
Joined on 09-15-2004

Post #: 32
Post ID: 894
Reply to: 893
Re: Concrete horns and the Cogent Boys
Well, I have a theory that the rough surface may be helping to attenuate multiple back-forth axial reflections, but from what you say, it may be that it results in - what's the proper term? - irregular as opposed to laminar flow at the surface. Reynolds number in pipes, all that sort of stuff. Not sure how that would help sound, but again, I think it may help limit *radial* reflections. Which, incidentally, is one reason why all front loaded Lowthers I've heard have a "disconnected" treble to my ears - complete mismatch of whizzer (itself a yucky idea) to the horn throat.

Ah, *turbulent* flow, that's it. I can imagine the vortices at the horn surface attenuating reflections. But then it's entirely possible I'm talking out of my rear chamber.

As for Cogent, they were using DEQX, but I believe they are now considering going for a more purist approach. I think, as you imply, you're just going to have to try and listen to them, although on paper, they certainly have many fine ingredients.

Fun thread this btw.
cheers
04-14-2005 Post does not mapped to Knowledge Tree
slowmotion


Oslo, Norway
Posts 60
Joined on 07-22-2004

Post #: 33
Post ID: 895
Reply to: 892
Re: Fun thread.....and Cogent
Hi all

The first link, to the musique_concrete website was because there's
pictures of some horns made for the S2 .

I hope anyone interested in JMLC horns read the last four links,
where Jean-Michell writes about his reasoning for his horn profile.

I think the Cogent effort is very interesting, not many people
are into making field coil compression drivers these days.
I wish them the best of luck.
I don't know why they insist on using conical horns , though.
In my not so humble opinion conical horns suck. Big time.
Maybe they know something I don't. Wink

Regarding horn bandwith, this is of course a subject in where
everyone and his/her grandmother have their own opinion.
Personally I think 2,5 to 3 octaves should be reasonable.
But sometimes it isn't.
I have given up on 2-way systems, the compromises are just to great.
4-way systems seems like the most reasonable compromise,
at least to me, you may even have to go 5-way.
If you are very skilled or very lucky you just might make it with a 3-way. Wink

Just some personal observations based on years of hornbuilding,
I should probably mention that most of the horns I build end up in the trash
or in the fireplace. Wink

cheers ,
Jan
04-14-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,544
Joined on 05-28-2004

Post #: 34
Post ID: 896
Reply to: 895
Fun thread.....and fireplace

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 slowmotion wrote:
I hope anyone interested in JMLC horns read the last four links,  where Jean-Michell writes about his reasoning for his horn profile.

Yes, Jan, tanks it was interesting. Unfortunately the words means little in this and it is necessary to have both of them with the same drive in order to say anything. Also, only God know how each driver would react to different profile and not different curves would couple with the rooms. This is the biggest problem with horn – no one could say anything and very few people actually had a chance to go over different scenarios and to evaluate what works and what do not. With those horns there are so many variables that nothing is objectively predicable…

 slowmotion wrote:
I think the Cogent effort is very interesting, not many people are into making field coil compression drivers these days. I wish them the best of luck.

Probably because to make a permanent magnet of this size would be too expansive? BTW, My personal experience with field-coil was not so thrilling. The field-coil is very popular idea within EBay intelligence and among the drivers droolers but in my room none of them behave interesting (none of them were compression) for bass. At least for bass they all were too soft. I am not saying that the Cogent guys would end up with the same results as I did but I feel that for upperbass a driver should be dry and crispy instead of “soft” and “wet”. The field-coils that I used were too “wet” and were locking some testerone.

 slowmotion wrote:
I don't know why they insist on using conical horns , though. In my not so humble opinion conical horns suck. Big time. …

May I ask why? The only problem that I see is the size, that it king of their problem… Unless they would run 70Hz horn with a curve and then it all will go to a toilet.
 

 slowmotion wrote:
Regarding horn bandwith, this is of course a subject in where  everyone and his/her grandmother have their own opinion. Personally I think 2,5 to 3 octaves should be reasonable.  But sometimes it isn't.  I have given up on 2-way systems, the compromises are just to great. 4-way systems seems like the most reasonable compromise, at least to me, you may even have to go 5-way. If you are very skilled or very lucky you just might make it with a 3-way.

Exactly!!!

 slowmotion wrote:
Just some personal observations based on years of hornbuilding, I should probably mention that most of the horns I build end up in the trash or in the fireplace.

Oh, Jan, shut up! I’m trying to encourage people to "go horns" and even begun to brew a small community of my local Boston guys with horn installations among the local 300W SS idiocy. Then you, show up and discourage the people by disclosing to them the bitter Truth. :-)

The caT




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-14-2005 Post does not mapped to Knowledge Tree
cv
Derby, United Kingdom
Posts 173
Joined on 09-15-2004

Post #: 35
Post ID: 897
Reply to: 896
Fieldcoils was Re: Fun thread.....and fireplace

The point of the field coil is to saturate the piss out of the magnetic circuit so that the coil flux does not modulate the motor. Romy, I suspect that your experience of them may be based on an older drivers where saturation was not the name of the game; I would expect a proper saturated motor to lean more to the sonic characteristics you're after.

In theory, you could achieve much the same result with alnico (a la ALE, Lowther PM4) or neodymium but there may be something more to the field coil approach. The Cogent boys are convinced of the superiority of the FC approach; they are not about saving money, rather, creating the best driver they know how. Hence the proposed use of permendur polepieces.
 
It would probably be *much* cheaper to achieve a similar flux with Nd magnet but there is probably more to it than that. I know Guy has some experience of the AudioNote FC MC cartridge and will hopefully chime in here.

Cheers

04-14-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,544
Joined on 05-28-2004

Post #: 36
Post ID: 899
Reply to: 897
Horns, fireplace and Vaseline...

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 cv wrote:
The point of the field coil is to saturate the piss out of the magnetic circuit so that the coil flux does not modulate the motor. Romy, I suspect that your experience of them may be based on an older drivers where saturation was not the name of the game; I would expect a proper saturated motor to lean more to the sonic characteristics you're after.

Probably. I have experimented with vintage 8-14 inchers.  None of them were contemporary design.

 cv wrote:
It would probably be *much* cheaper to achieve a similar flux with Nd magnet but there is probably more to it than that. I know Guy has some experience of the AudioNote FC MC cartridge and will hopefully chime in here.

Yes, Peter told me about his new venture. It is still remains to be seen if it will be a FC MC cartridge or it will be a new Peter Qvortrup “nice on paper” marketing Vaseline wrapped around the story how he used the magnetic force of Erath to aroused the spirit of the Furtwangler’s recordings… :-)

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-15-2005 Post does not mapped to Knowledge Tree
guy sergeant
United Kingdom
Posts 258
Joined on 08-03-2004

Post #: 37
Post ID: 902
Reply to: 893
Re: It's not about field strength...
I don't know the full story of how loudspeakers went from field coils to permanent magnets. I believe that ultimately it was dictated by the price and availability of Alnico. Eventually Alnico became cheap enough to make similar or higher strength magnetic fields viable and the additional complications in implementing a field coil(DC Supplies, heat build up etc) made field coils unnattractive.

I think that something was lost when this technology was abandoned and I admire the Cogent people for their efforts in trying to resurrect the RCA driver. I've never heard one so I can't comment on whether it's a good design but I can imagine it could be. Having said that I've never heard a properly working WE555 or 594 either and given the problems of getting the S2 to work well I can't imagine there are many installations using those drivers with the right sort of horns to get a really good result anyway.

A friend, whose ears I trust, listened (I urged him to go there) to the Cogent System at the MAF last year and said it was poor which disappointed me. I'd have to say maybe their room acoustics were bad but he said they were reasonably happy with the result they were getting. Time will tell.

I did have alot of experience with the Japanese made Audio Note cartridges. (I know Romy isn't a fan) I even spent some time at their factory learning how to build them so I learnt something of why the designs ended up being how they are. What was interesting was that while the diamond, cantilever, coils, former, and body stayed the same between the Io and the Io Ltd the only thing that changed was the magnetic circuit. The Io used 2 alnico magnets and (as I recall Iron pole pieces) whereas the Io Ltd used a 2 piece horseshoe of Permendur, each piece wound with a coil that were joined in Series to form an electromagnet. 2 additional wires down the arm supplied 1.2v at half an amp to this.

What was interesting was the field strength (and output signal) from the electromagnetic cartridge were significantly lower than that from the permanent magnet design. However the performance of the two was incomparable. (bear in mind the body and all the moving parts were exactly the same on each model. The Io Ltd had it seemed a fraction of the distortion of the standard Io (and any other cartridge imho) but this was NOT because of the field strength, rather the linearity of the field and how it replenished itself when bent out of shape. It's rare to have the opportunity to do a truly like for like comparison between a field coil and a permanent magnet, I can't think of any pair of speaker drivers that would allow you to do it. But what could be heard was the potential improvements that could be made everywhere there is a permanent magnet in your system.

I'd love to have a pair of S2's spare that I could put field coils into. Having seen Mike Harvey's cut-away S2 I'm sure it could be done. I'd also like to change to Permendur pole pieces but that would be expensive. It's why the Ale drivers cost so much. I've got some redundant JBL2361's, maybe I should attack those!

Chris, Do you have & use some of the RCA drivers? I'd love to hear them. Where abouts are you?

enough for now,

Guy
04-15-2005 Post does not mapped to Knowledge Tree
cv
Derby, United Kingdom
Posts 173
Joined on 09-15-2004

Post #: 38
Post ID: 903
Reply to: 902
Re: It's not about field strength...

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Hello Guy,
Please excuse the rapid fire response, bit short of time today.

1)Your comments about the Io cart are most interesting; clearly it ain't about saturation. Here's another idea: if the domains in the magnetic material limit resolution (leading to quantisation at very low levels), maybe the field coil is most effective here, what with the tiny magnetic volume. Note also the correlation between MC stepup sonics and size - I gather the Expressive Tech units are on massive cores...

2) Cutaway S2? I'd love to see that - don't suppose any pics are available?

3) Re Cogent at RMAF: yep, reading between the lines of some reviews, I got that impression. I think they had teething troubles, eg probs with reflections from the back wall into the horns, also, I expect the rectangular section conicals weren't the best way to showcase the drivers. The stuff is apparently sounding much better now. Knowing what's involved, I can't see how the drivers would be to blame.

4) RCAs - yeah. Me in the capital. Alas, both units have voice coil rub; managed to sort out most of it on one, but I have a lot of maintenance to do. Might be tricky to get right with the paper formers; I hope to get a pair of the Cogent carbon fibre diaphragms were available. I asked the guys if they could do an 800 ohm voice coil... could then have a nice OTL SET to drive it with...
Unfair to reach any judgements just yet. Oh, you have to see the phasing plug casting on them RCAs - looks like it was done with an army of nanobots, incredible piece of engineering.
Anyway, if I eventually manage to sort them out, you'd be welcome to visit, so long as you didn't reveal how turd the rest of the system was...

5) I know a chap who has 555s and RCAs: his 555s are gathering dust.

Likewise, I've read a couple of comments where people have heard the S2 and 555 and preferred the Brit.
Not sure there's many of the field coil crowd who've heard what the S2 can do...

6) Complete aside: I'm about to start looking at low temp MHCD discharge - this is a way of generating large volume glow discharge (a la plasmatronics, not to be confused with the corona discharge of ionovac etc) in air without helium etc. Nice 9ft line source emitter with JMLC horn, direct drive with a 450TL or something, 150Hz+ say, with fast tanning and ozone room freshening functions to boot...... total pipedream, but can you imagine?...

Gotta dash
Best wishes,
cv
04-15-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,544
Joined on 05-28-2004

Post #: 39
Post ID: 904
Reply to: 902
About the Klangfilm and armadillos.

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 guy sergeant wrote:
Having said that I've never heard a properly working WE555 or 594 either and given the problems of getting the S2 to work well I can't imagine there are many installations using those drivers with the right sort of horns to get a really good result anyway.

Quite correct observation. There is a lot of myths about the uniqueness and beauty of some older drivers: WE, Vitavox, Telefunken, Klangfilm, Goodman’s and many-many others but the interesting fact the all those conversations about the “superior vintage technique” NEVER got transformed into the really interesting sound in listening room. In fact, all installations that I head that were excessively based on what the “vintage drivers did” sounded like crap. The better sound usually came from a selective using of some selected benefits of some vintage drivers and incorporating of those benefits into own sound reproducing objectives. In the end, a blind use of those Klangfilm and WE always end up with garbage result. An “interesting sound” comes only form a will of a system creator and from the intentions of the systems orchestrator. If person knows what she/he wants to build then some chosen opportunities that exist in some vintage drivers would be used as “tools” instead as the “crutches” or “excuses”

 guy sergeant wrote:
A friend, whose ears I trust, listened (I urged him to go there) to the Cogent System at the MAF last year and said it was poor which disappointed me. I'd have to say maybe their room acoustics were bad but he said they were reasonably happy with the result they were getting. Time will tell.

You see, Guy, there is another aspect of it. As soon you mention the MAF then you refer to the very specific (audio?) awareness.  Generally that crowd could be characterized as low-class hoodlums with taste of pterodactyl and reference points of “Texas armadillo hunters”. I personally never was at MAF but a friend of my (and his taste I trust) who is one of a leaders of their community told me the that the MAF population is conglomeration of Midwest white trashes who walk from room to room, belching louder then bass horn driven with 400 Krell amplifier and to anticipate form them any interesting views or accomplishments about sound is like an attempt to bult a high performance acoustic system based upon the Radio Shack ingredients. Interesting that he calls those MAF Morons as “bottomfeeders” (his word) that I find is very correct observation. Really, if you look in-depth at the personalities that “in sine” at the MAF then one would make very intriguing overviews … primary about the abortion clinics bombers, guys bashers, blacks-hater and other “low IQ Americans” … who are so deep in the tunnels of own asses that they need a big horn to be able to see the world. I know, that I sound not like an overly stressed “a liberal form Massachusetts” but I do know personally too well a number of MAF’s “spiritual leaders” and it is enough for me to express a strong negative attitude toward all that Midwest Audiofest. Certainly I would not associate the Cogent boys with my overview above (I do not know them personally) but the fact they so much spin around the MAF idiots made me wonder what the hell they do in there….

 guy sergeant wrote:
I'd love to have a pair of S2's spare that I could put field coils into. Having seen Mike Harvey's cut-away S2 I'm sure it could be done.

I had in past those thoughts, however I was not thinking about the field coils but rather to invert the driver and use the new larger tunnels enabling it to go down to 100Hz. I was thinking to talk to Mike and to order a pair of custom durable and heavier coils with thicker weir and a dropped resonance frequency. Then I realized that I would like to have a t least 5-6” diaphragm and there was some other S2 limitation that would make it not perfect for that project. Perhaps I should find another driver to torture. There are none that I know worth to excrement… The only driver that I was thinking to torture and to rebuild was Community M4 but I never when to it since I discovered the Studio 8M

The Cat




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-15-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,544
Joined on 05-28-2004

Post #: 40
Post ID: 905
Reply to: 903
Expressive 555?

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 cv wrote:
Note also the correlation between MC stepup sonics and size - I gather the Expressive Tech units are on massive cores...

Nope, they are not. The Expressive MC transformers  (the actulal transformers) are very small. I have seen the raw transformers from ET1 and ET2 and it was very “insulting” for the ego of those huge boxes. :-)

 cv wrote:
Likewise, I've read a couple of comments where people have heard the S2 and 555 and preferred the Brit. Not sure there's many of the field coil crowd who've heard what the S2 can do...

CV, make an experiment: find some WE droolers and interview them about music and the reasons why they selected his/her 555. I did it. If you do it you will have very interesting observations about thier eBay-inspired intelligence and about their crow-driven motivation. I personally do not find in 555 anything interesting at all but I love how the 555 users push out themselves the bogus reasons and motivation that encourage them to use this driver.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
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