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Multi-Way Conventional loudspeakers with crossovers

What is the draw of older alnico drivers?
What is the draw of older alnico drivers?
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Old 7th December 2008, 09:27 PM   #1
S.Spielbergo is offline S.Spielbergo  United States
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Default What is the draw of older alnico drivers?

There seems to be a fairly devout following for these older drivers, such as the Saba's, Telefunken's, Philips, Siemens ect. I am wondering what it is about these speakers that makes them so desirable? As far as I can tell they all use thin paper cones, accordian surrounds (often paper) have high sensativity and use alnico motors. Aside from the alnico motors the rest of these qualities can be found in many modern pro-sound drivers like some of the B&C or Eminence drivers without the handicap of being over half a century old (in some cases). Are there other qualities I am missing aside from the coolness factor?
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Old 7th December 2008, 09:45 PM   #2
ttan98 is offline ttan98  Australia
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I bought a pair of old alnico 10" driver of Ebay in Australia, it does not have a brand name stamp on it, but made in Japan. Looks like an OEM model. It is at least 10 years old but still works very well. I paid US$8 each.

I use a number of modern day drivers like Usher and GR. I have to admit I like these alnico drivers, they will not give you the best distortion figures or waterfall compared to modern day drivers but the sonic quality is very good indeed. I use them as my main drivers. It has about 90-92dB Spl.

I am very happy with them. If they are reasonbly priced of Ebay do try them, they sound different from modern day drivers.
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Old 7th December 2008, 10:06 PM   #3
cowanrg is offline cowanrg  United States
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i've heard them a million times at many shows. and yeah, they can have good qualities to them (smooth, warm, musical, etc), they will never be even in the same ballpark as a modern driver.

its the same old story of a person buying a honda civic, putting on an exhaust and saying its just as good as a porsche. if he won the lottery, he would buy the porsche and the civic would be on the curb for the trash pickup...

sure, they WERE amazing and they can sound good, but there is much better.
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Old 7th December 2008, 10:18 PM   #4
gainphile is offline gainphile  Australia
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High Qms?

I noticed the more expensive ScanSpeak have high Qms and not too-flat response.


- Many "old" paper woofers still sound astonishingly good compared to modern drivers?

- Oh, yes. We have not always went to the better. What many driver manufacturers have done the last years, is to increase the damping to make the frequency response more flat. But some old drivers, like the famous 6,5" paper woofer that Jan Paus at Seas made several years ago, (The Seas CA 17 RCY, ed. note) was optimized for low loss. So they made a compromise between frequency response and sensitivity. This driver was very good, and was used by Wilson Audio for many years. Later, in the 80's, manufacturers started to add more mass, they added more damping, and they made surrounds with high loss. That gave an extremely flat frequency response, but also a lot of energy storage. This compared, the old drivers were much quicker. They had some resonances, but you could get rid of that in the crossover. It was this run for flat response that gave a lot of modern drivers this dull, uninteresting sound. And you can also measure higher second and third harmonic distortion in some of them. If you compare the on-axis response between an old and new driver; you will see that the energy in the treble is far higher than in the new drivers. These so-called "modern" drivers often has a Qms of maybe 0.8 or 0.6. The old drivers had Qms values of maybe 5 to 7! We found that drivers with a very high mechanical Q sound more open, more clean and dynamic. And when you look at it, you find it is very simple, because they have less loss. The surround is easier to move, the spider is better constructed, they have better air flow, higher sensitivity. So a high mechanical Q is a very good indicator of energy storage behavior. This is one of our secrets. One of the many!
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Old 7th December 2008, 10:50 PM   #5
S.Spielbergo is offline S.Spielbergo  United States
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Iwould love to audition a pair of Sabas but they tend to be quite expensive when all is said and done on ebay. I may try to grab some reasonably priced Magnavox or Zenith drivers but they are a crap shoot. I have been getting away from the more modern, super damped drivers and trying out more pro-drivers, the efficiency, dynamics and details have rekindled my interest in speaker building.
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Old 7th December 2008, 11:04 PM   #6
LineSource is offline LineSource  United States
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1) Alnico has a high Curie Temp(excellent), high remenance(very good), but modest inductive coercivity(poor).

2) When a current travels throgh the voice coil it generates a reverse magnetic field which can gradually demagnetize the fixed field in the permanent magnet if the inductive coercivity is low, as in Alnico.

3) Speaker motor designs which do not significantlh affect the permanent magnet inductive coercivity are good candidates for Alnico. e.g. High efficiency speakers, underhung motors, etc... Old School Altecs

I favor using NdFeB for high-end home audio speakers with underhung motors. It is technically the best material, and it's high Maximum Energy Product (BH)max allows both high gap flux and small motors which minimize the rear cone wave reflections off the motor assembly.

Since iron saturates at ~ 1.5T, the highest BH can be wasted in a poor motor design. An underhung motor creates a very linear flux over a long gap, allowing light weight short coils to produce high BL force.


Anisotropic Magnet: A magnet having a preferred direction of magnetic orientation, so that the magnetic characteristics are optimum in that direction.

Coercive force, Hc: The demagnetizing force, measured in Oersted, necessary to reduce observed induction, B to zero after the magnet has previously been brought to saturation.

Curie temperature: The temperature at which the parallel alignment of elementary magnetic moments completely disappears, and the materials is no longer able to hold magnetization.

Flux: The condition existing in a medium subjected to a magnetizing force. This quantity is characterized by the fact that an electromotive force is induced in a conductor surrounding the flux at any time the flux changes in magnitude. The unit of flux in the GCS system is Maxwell. One Maxwell equals one volt x seconds.

Gauss, Gs: A unit of magnetic flux density in the GCS system; the lines of magnetic flux per square inch. 1 Gauss equals 0.0001 Tesla in the SI system.

Hysteresis Loop: A closed curve obtained for a material by plotting corresponding values off magnetic induction, B (on the abscissa), against magnetizing force, H (on the ordinate).

Induction, B: The magnetic flux per unit area of a section normal to the direction of flux. The unit of induction is Gauss in the GCS system

Intrinsic Coercive Force, Hci: An intrinsic ability of a material to resist demagnetization. Its value is measured in Oersted and corresponds to zero intrinsic induction in the material after saturation. Permanent magnets with high intrinsic coercive force are referred as "Hard" permanent magnets, which usually associated with high temperature stability.

Irreversible Loss: Defined as the partial demagnetization of a magnet caused by external fields or other factors. These losses are only recoverable by remagnetization. Magnets can be stabilized to prevent the variation of performance caused by irreversible losses.

Isotropic Magnets: A magnet material whose magnetic properties are the same in any direction, and which can therefore be magnetized in any direction without loss of magnetic characteristics.

Magnetic Flex: The total magnetic induction over a given area.

Magnetizing Force: the magnetomotive force per unit length at any point in a magnetic circuit. The unit of the magnetizing force is Oersted in the GCS system

Maximum Energy Product, (BH)max.: There is a point at the Hysteresis Loop at which the product of magnetizing force H and induction B reaches a maximum. The maximum value is called the Maximum Energy Product. At this point, the volume of magnet material required to project a given energy into its surrounding is a minimum. This parameter is generally used to describe how "strong" this permanent magnet material is. Its unit is Gauss Oersted. One MGOe means 1,000,000 Gauss Oersted.

Oersted, Oe: A unit of magnetizing force in GCS system. 1 Oersted equals 79.58 A/m in SI system.

Permeability, Recoil: The Average slope of the minor hysteresis loop.

Polymer-Bonding: Magnet powders are mixed with a polymer carrier matrix, such as epoxy. The magnets are formed in a certain shape, when the carrier is solidified.

Rare Earths: A family of elements with an atomic number from 57 to 71 plus 21 and 39. They are lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

Remenance, Bd: The magnetic induction which remains in a magnetic circuit after the removal of an applied magnetizing force. If there is an air gap in the circuit, the remenance will be less than the residual induction, Br.

Reversible Temperature Coefficient: A measure of the reversible changes in flux caused by temperature variations.

Residual Induction, Br: A value of induction at the point at Hysteresis Loop, at which Hysteresis loop crosses the B axis at zero magnetizing force. The Br represents the maximum magnetic flux density output of this material without an external magnetic field.

Saturation: A condition under which induction of a ferromagnetic material has reach its maximum value with the increase of applied magnetizing force. All elementary magnetic moments have become oriented in one direction at the saturation status.

Sintering: The bonding of powder compacts by the application of heat to enable one or more of several mechanisms of atom movement into the particle contact interfaces to occur; the mechanisms are: viscous flow, liquid phase solution-precipitation, surface diffusion, bulk diffusion, and evaporation-condensation. Densification is a usual result of sintering.
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Old 7th December 2008, 11:31 PM   #7
wakibaki is offline wakibaki  United Kingdom
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Celestion and Jensen alnico guitar speakers still find a market because of their response to a distorted signal, particularly in overdriven tube amps. An alnico speaker costs 2-5 times as much as an equivalent ceramic.

They've largely fallen out of use otherwise. While there may be exceptions, I guess they're pretty much like germanium transistors and, looking further back, tubes.

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Old 8th December 2008, 10:51 AM   #8
S.Spielbergo is offline S.Spielbergo  United States
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I just noticed Supravox, Jensen, SEAS, PHY-HP and a few others are still using or reviving the use of alnico in there motors. Holy mother of god those french drivers are expensive though!! I noticed that PHY-HP's 8" driver has a moving mass of only 9.4 grams!! http://www.madisound.com/catalog/pro...oducts_id=1472
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Old 8th December 2008, 11:01 AM   #9
Scottmoose is offline Scottmoose  United Kingdom
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Welcome to the world of wide-band drivers, designed & built using trad. techniques a la Altec etc.

No, they're not cheap. But then, compare them against how much their equivalents of 40 years ago cost, relative to contemporary earnings, and you'll see they actually come out quite similar.
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Old 8th December 2008, 05:45 PM   #10
Pano is offline Pano  United States
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What is the draw of older alnico drivers?
Originally posted by S.Spielbergo
I may try to grab some reasonably priced Magnavox or Zenith drivers but they are a crap shoot.
Yes indeed. Many of them sound just like the stuff you'd be shooting. =)

Not all the old console drivers were good. Thus the high prices for those that are thought to be...
Take the Speaker Voltage Test!
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