Have you heard Kevin Carter's latest power amp? It's a variation on the theme. (He uses it to drive Ariels.)
I agree just about 100%. The market-dominant long-coil/short-gap (overhung) just sounds murky compared to the alternative. Most of us don't have the fabulous luxury of designing our own drivers from scratch, we have to pick and choose from the dreck that is available commercially. For better or worse, nearly all commercial bass and midbass drivers are overhung, most of all the high-power, long-excursion prosound products designed for theater and sound-reinforcement use.
Magnet selection, saturation of the gap, and field-line linearity are more subtle and seem to escape the notice of most audiophiles and magazine reviewers. All most folks care about is how loud the bass is from 30 to 50 Hz; a few engineering types will look at the THD vs frequency curves, but that doesn't reveal the details of magnetic design.
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No, I haven't. Kevin and I go way back; he was one of the first people in the world to build Ariels, and was also one of the first to build an Amity. To his credit, he's gone off in his own direction, which I think is great. I have a lot of respect for the work he's doing.
http://www.lamaisonduhautparleur.com/hp/PHL/Pdf/SP5010.pdf ? Easily sourcable in USA ? mms 90 g (with double side cone treatment...more détails in the bass-mids ? )
or stiffer cone (carbone fibers, less cone breakups?) with voice coil like a 416 : Davis Acoustics 40RCA15 (8?) but mms 5 mm only : too shy but two in an W Onken (expensive)
Audax PR380M2 : http://www.audax.com/archives/PR380M2 - Catalogue 1994.pdf : close from the 416 too ?
http://www.emspeaker.com/fiche_B15MKII.pdf : hugre breakups with mms of 57 g raw paper ???
links given more for the data lovers
Let stay with GPA as everybody know them better ! Possible cone treatment for a better damping for more détails in the higher range if XOed higher (around 700 hz) than raw paper ? Or just good stock as it is....
MAYBE Just a treatment from the center to the middle of the diameter of the cone for FR > 150 Hz (below our ears are less sensible ?! Fletcher Munson curve.)
Certainly tried by many, at least to protect the cone from sun and humidity for outside events...
or stiffer cone (carbone fibers, less cone breakups?) with voice coil like a 416 : Davis Acoustics 40RCA15 (8?) but mms 5 mm only : too shy but two in an W Onken (expensive)
Audax PR380M2 : http://www.audax.com/archives/PR380M2 - Catalogue 1994.pdf : close from the 416 too ?
http://www.emspeaker.com/fiche_B15MKII.pdf : hugre breakups with mms of 57 g raw paper ???
links given more for the data lovers
Let stay with GPA as everybody know them better ! Possible cone treatment for a better damping for more détails in the higher range if XOed higher (around 700 hz) than raw paper ? Or just good stock as it is....
MAYBE Just a treatment from the center to the middle of the diameter of the cone for FR > 150 Hz (below our ears are less sensible ?! Fletcher Munson curve.)
Certainly tried by many, at least to protect the cone from sun and humidity for outside events...
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I thought that I would throw in my typically counter view on woofers.
As I have stated many times, I believe that the drivers themselves are mostly a commodity - one can make a very good system out of almost any "good" brand of drivers. While it is true that "no loudspeaker is perfect" as they get closer and closer to perfect the differences must vanish (that's only logical.) Over the years drivers have gotten significantly better (at least objectively) and as such the differences are becoming vanishingly small, perhaps even negligible. In non-blind test, of course people will always hear differences, but these are not necessarily real.
In an important test for me many years ago, we had four speaker systems. Two were of identical design but with different drivers (each system optimized for its driver set.) In a blind subjective test of 20 people the systems with just different drivers were not statistically different from each other but were from the other designs. This told me a lot and is the basis for my belief that it is the design that matters and not the drivers.
As to magnets, I have a huge amount of experience here with software simulations of motor designs. Basically I can make any magnet type create an identical magnetic field at the voice coil. How can there be an audible difference here? Sure there are the eddies to be concerned with because all the magnets have different electrical conductivity and hence will have different internal eddies. The lower the conductivity the greater the eddy current (contrary to what has been stated here before.) But in any circuit with a flux modulation controlling ring, it's resistivity will be well below that of any magnet and as such it will stabilize the flux as well as negate any eddies in the magnet itself. Hence any motor structure with a flux modulation ring (the only kind that I would ever use) will have basically the same "sound" regardless of the magnet material.
There is however one aspect that I have not mentioned but I have had a lot of experience with. The magnet is cantilevered on the back of the frame and there will always be a resonance from this structure. The more mass of the magnet the lower and greater this resonance will be. Take for example a B&C 15TBX100 versus a 15NDX100. The ceramic version has a measurable resonance at about 600 Hz, while in the virtually identical neo design it is gone. This may be a marginally audible effect, but it is well down on the list of audible effects in a loudspeaker system. I have seen this resonance in virtually every woofer that I have ever measured - except the newer Neo ones.
As I have stated many times, I believe that the drivers themselves are mostly a commodity - one can make a very good system out of almost any "good" brand of drivers. While it is true that "no loudspeaker is perfect" as they get closer and closer to perfect the differences must vanish (that's only logical.) Over the years drivers have gotten significantly better (at least objectively) and as such the differences are becoming vanishingly small, perhaps even negligible. In non-blind test, of course people will always hear differences, but these are not necessarily real.
In an important test for me many years ago, we had four speaker systems. Two were of identical design but with different drivers (each system optimized for its driver set.) In a blind subjective test of 20 people the systems with just different drivers were not statistically different from each other but were from the other designs. This told me a lot and is the basis for my belief that it is the design that matters and not the drivers.
As to magnets, I have a huge amount of experience here with software simulations of motor designs. Basically I can make any magnet type create an identical magnetic field at the voice coil. How can there be an audible difference here? Sure there are the eddies to be concerned with because all the magnets have different electrical conductivity and hence will have different internal eddies. The lower the conductivity the greater the eddy current (contrary to what has been stated here before.) But in any circuit with a flux modulation controlling ring, it's resistivity will be well below that of any magnet and as such it will stabilize the flux as well as negate any eddies in the magnet itself. Hence any motor structure with a flux modulation ring (the only kind that I would ever use) will have basically the same "sound" regardless of the magnet material.
There is however one aspect that I have not mentioned but I have had a lot of experience with. The magnet is cantilevered on the back of the frame and there will always be a resonance from this structure. The more mass of the magnet the lower and greater this resonance will be. Take for example a B&C 15TBX100 versus a 15NDX100. The ceramic version has a measurable resonance at about 600 Hz, while in the virtually identical neo design it is gone. This may be a marginally audible effect, but it is well down on the list of audible effects in a loudspeaker system. I have seen this resonance in virtually every woofer that I have ever measured - except the newer Neo ones.
Seing your flag ship design you talk to 15" driver Xoed at around 700 hz. So even Harmonic distorsion R3, R5 will not contaminate the upper frequencies of the compression driver ? (big slope of the filter?)
So the question could be : is it possible to a standalone vented 15" driver enclosure to have pistonic in bass with greater cone movement without too much breakups if the highs if this same driver climbs to 700 hz as some Altec 416 do ?
I already know your are for many 10" bass sub in the room...below the 15" if needed.
Altec Vott 808 enclosure seems to make both (Pano input iirc) with vented Under 150 hz and front horn impedance air loading with upper Fhz, always with a 15" !
Sorry if I mistake in the concepts and theories... more to understand the trade offs of this thread.
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I reignited the magnet material issue a few pages back because the apparent Alnico superiority keeps telling us to spend an enormous amount of money on perhaps total Alnico drivers systems.
The heart of the issue is the physical properties and the huge variations of choice in each type of magnet material and very dependent whether fully saturated to peak BH or not. This is plus all the other usual parameters.
Also, using excellent and typical source material into the amplifier end unless you use a Karna or another SET or PP DHT or the best SS offering you will be hard pressed not to form a true character assessment of the basis magnet material, or true character for that matter of the cone or dome materials and construction and whatever forms the membrane for the driver and any suspension.
We may agree that Neodymium has displaced ceramics but ceramics being so cheap will hang on in there with faraday stuff whatever doing a pretty good job. But if Alnico has an unassailable place above Neodymium we would all like to know why.
It could save us a lot of money which can be better spent on better priced precision engineered drivers not using Alnico and not picking up Rolex diamond sentiment investment price tickets.
The investment prices can make the hobby unsustainable for many, and that would hurt DIY driver manufacturers. We do not want that. They a have suffered under the credit crunch and need to be able to make reasonable margins from higher volume sales.
Neodymium magnets are just now about cheap enough for the general DIYer and manufacturers to be used fully in any kind of speaker we could want to make or buy.
The heart of the issue is the physical properties and the huge variations of choice in each type of magnet material and very dependent whether fully saturated to peak BH or not. This is plus all the other usual parameters.
Also, using excellent and typical source material into the amplifier end unless you use a Karna or another SET or PP DHT or the best SS offering you will be hard pressed not to form a true character assessment of the basis magnet material, or true character for that matter of the cone or dome materials and construction and whatever forms the membrane for the driver and any suspension.
We may agree that Neodymium has displaced ceramics but ceramics being so cheap will hang on in there with faraday stuff whatever doing a pretty good job. But if Alnico has an unassailable place above Neodymium we would all like to know why.
It could save us a lot of money which can be better spent on better priced precision engineered drivers not using Alnico and not picking up Rolex diamond sentiment investment price tickets.
The investment prices can make the hobby unsustainable for many, and that would hurt DIY driver manufacturers. We do not want that. They a have suffered under the credit crunch and need to be able to make reasonable margins from higher volume sales.
Neodymium magnets are just now about cheap enough for the general DIYer and manufacturers to be used fully in any kind of speaker we could want to make or buy.
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What I find important in sound reproduction is the same to what you and Lynn describe (tone colour, enjoyment, getting the emotional feeling across).
But I am also sensitive to dynamic (micro and larger) differences between the different drivers in a multi-way system and I perceive that there is an advantage when these differences are small: a wider range of listening volumes and a wider range of music will sound right. My remark about the 418-8B was only related to the fact that whether this is the best driver will depend on the other drivers in your system.
The 1st time Jean Hiraga had an Onken system over in Paris, I was disappointed and thought 'is this really what he was raving about?'. Gerard Chretien (editor-in-chief of l'Audiophile magazine) wrote a similar opinion. The room was larger than a typical living room and the system had to put out a little more sound pressure, but it was clear that a single 416-8B was not a good match with the rest of the system. There was no problem with tone colour or freedom of resonances, but it was slightly left behind dynamically and sounded detached from the rest of the system in certain musical passages. A few years later a heard an Onken system with a double woofer (515-B I think) and that did not have this problem at all.
My example of a high-end PA driver (PD-122) was to illustrate that also the opposite can happen, that compression drivers can be the ones that will be left behind dynamically.
The crossover filter will have no effect on the distortion harmonics since they are generated after this filter. The HF response of the woofer will have an effect and one that dies above say 1 kHz would be best, but it is good to remember that THD is simply not very audible in a woofer (well a HP 15" one for sure) so this is all a moot point anyways.
Seing your flag ship design you talk to 15" driver Xoed at around 700 hz. So even Harmonic distorsion R3, R5 will not contaminate the upper frequencies of the compression driver ? (big slope of the filter?)
A good woofer does not have any breakup within its passband. The ones that I use don't - some might.
The PD122 is a ceramic magnet sub and just £145 from Thomann. and no customs charges in Europe. If quite reaonably the Jean Hiraga Onken was a disappointment, JMLC (RIP) had a similar system with Onken Tweeters Musique Concrete JMLC horns in a large room. Perhaps you have auditioned that system. I think there is more personal variation of perception than we all perhaps would like to admit. Not an unreasonable assumption. I prefer a lighter tight fast bass that is in good timing with the mid.
.. and if those other drivers were, hypothetically, Neo10, RAAL 70-20XR and 18" subs in a 4-way?
If find it hard to believe that a CD would ever be left behind dynamically compared to a 15" woofer of any type or make
. Funny you mentioned PD though because I've been looking at their new PD.155N01, which sims like this in 70 L @ Fb 40 Hz:
An externally hosted image should be here but it was not working when we last tested it.
.. but not so great in sealed, without EQ, so I'll pass...
Have you considered using auto/transformers for level matching CD to woofer? That's supposed to be Shindo design recipe for his speakers also reading John Hasquin old posts he always stated that resistors in the HF networks used with fast opening horns like tractrix and LeCleach kill the the sound making it soft and dull .
And maybe in addition to that there is a large variation with time - opinions change. And suppose that this variation were so great and unstable that personal biases entered the picture making the perceptions the slave of our inherent biases. Wouldn't then that make any of the claims made here that are based on these perceptions rather pointless?
What to do!???
Measurements perhaps?!! No those never agree with these perceptions (that are all over the map) so they can't be accepted.
Perhaps it is interesting to add to my last post that splitting the low-& midrange over 2 drivers and crossing the midrange driver over at 180Hz and <800 Hz reduces the audibility of a dynamic imbalance. So in Gary Dahl his setup changing from a 416-8B to the larger magnet size of the woofer section of a 604E or to a 515 B or E (and equalized: adapted box volume, changed filter components for same Q and flat frequency response) will most likely be irrelevant.
I can not comment on drivers I have not heard in a similar system. And there are many other aspects to consider in finding a good compromise. But the above x-over frequencies will be helpful.
Yes, it surprises most people when they hear it.
alnico
Only guitarist really know is sound
Alnico Magnet Strengths - MyLesPaul.com
Questions about Alnico ll and V magnets. - MyLesPaul.com
speakers too..
Only guitarist really know is sound
Alnico Magnet Strengths - MyLesPaul.com
Questions about Alnico ll and V magnets. - MyLesPaul.com
speakers too..