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Old 28th April 2007, 06:27 PM   #571
ScottG is offline ScottG  United States
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Quote:
Originally posted by Variac


Makes it hard to believe that the Tone Tubby is very flat at the high end also. Which makes one wonder how it can work for hifi without serious eq. Maybe there's things more important than flat response? MAybe the TT actually is flatter?


Virtually all of the guitar drivers are based on the original Jensen stuff. Here is a fairly faithful reproduction from the "new" Jensen:

http://www.jensenvintage.com/p12n.htm

Some might say though that the Celestion versions actually bettered the design - for the guitar.

Now Tone Tubby IS different, and Lynn did the measuring here:

http://www.nutshellhifi.com/MLS/MLS6.html

Also carefully read his comments, particularly the fact that the measurement isn't averaged (i.e. is "unsmoothed").
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Old 28th April 2007, 06:58 PM   #572
ScottG is offline ScottG  United States
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Default Re: ALNICO and others

Quote:
Originally posted by mige0
Hi,

some interresting facts and opinions about different magnet materials under:

http://www.diyaudio.com/forums/showt...033#post605033
"http://www.diyaudio.com/forums/showthread.php?postid=605033#post605033"

greetings
Michael

What they didn't mention is that overtime as you increase the magnetization of the magnet, that Alinco is the worst for loosing field strength with most "blends". Neo is the best. For instance a Lowther with an Alinco magnet may well have gauss reduced by up to 20% after about 5 years - far worse still IF you have another similar magnet near them. The same is not true if the Lowther uses one of the newer neo based motors.

They also didn't discuss field precision/uniformity beyond extreme temperatures and counter current flux modulation.

Consider that Alinco is HIGHLY processed and the crystal structure of the magnet is both small and uniform. Neo is somewhat similar. Your average ceramic magnet is FAR worse.

IMO, if you combine counter current flux modulation resistance along with a highly uniform crystalline magnet structure and very high guass - you *can* get really good sound (..particularly clear and natural sounding provided other factors are "worked out").

Counter current flux modulation (and the resulting heat build up) is perhaps best reduced with the method that 18 Sound uses for their "Active Impedance Series".

Alternatively there are electromagnets, which *can* have greater field uniformity at least at lower input levels. A particular problem here is heat though, but it is less about heat as it alters the magnet and more about heat as it alters the VC.
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Old 28th April 2007, 07:16 PM   #573
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I had the mentioned disadvantage of demagnetization of alnico in mind (other than the high price) when I asked Lynn if he misses the immediacy he finds with alnico with neo magnets. Most pro audio manufacturers sell their neo drivers for about the price of the ceramic magnet versions, while hi-fi manufacturers (fostex for example) have exorbitant price tags on their alnico models.

As i seriously question that measured parameters can tell everything about a driver, better asking someone with good ears and with lots of experience hearing many systems. For example, I don`t think even spectral decay plots can point a warm "woody" cone like the hemp cones are said to be.
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Old 28th April 2007, 07:16 PM   #574
Variac is offline Variac  United States
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I stand corrected on the tone Tubbies- amazing!

The "Holy Grail" Celestion Blue's are flatter and go out quite high, alnico, handle 15 watts, 100db efficient

http://professional.celestion.com/gu...ion%20Blue.pdf

The Gold model is supposed to just handle more power, 50 watts, without blowing up, probably a good idea in that the blue is maxed out at 15 watts and distorting a lot. From reading the reviews, the gold doesn't break up as soon, so would be a lot cleaner, but is a somewhat different curve:

http://professional.celestion.com/gu...tail.asp?ID=32
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Old 28th April 2007, 07:40 PM   #575
Pano is offline Pano  United States
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Quote:
Originally posted by Variac
The "Holy Grail" Celestion Blue's are flatter and go out quite high, alnico, handle 15 watts, 100db efficient
Interesting driver. Not cheap. Would love to hear it.
Blue vs, Red? A Celestion - Tone Tubby shoot out?

I'll bet that 15 watt rating is plenty. Guitar speakers aren't rated the same way as Hi-Fi models. And at 100dB/w, just how much power will you be throwing at it?
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Old 28th April 2007, 07:49 PM   #576
Zen Mod is offline Zen Mod  Serbia
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15W is hell of power if it's AlNiCo..........

especially if bass helper is presumed ;

besides that.....I really didn't yet found ruined gutar cab nested AlNiCo ,except if abused with SS 200W bass amp.
AlNiCo deterioration is out of question ,if used in sane home ambient
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Old 28th April 2007, 08:39 PM   #577
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Quote:
Originally posted by Variac

I stand corrected on the tone Tubbies- amazing!

The "Holy Grail" Celestion Blue's are flatter and go out quite high, alnico, handle 15 watts, 100db efficient

http://professional.celestion.com/gu...ion%20Blue.pdf

The Gold model is supposed to just handle more power, 50 watts, without blowing up, probably a good idea in that the blue is maxed out at 15 watts and distorting a lot. From reading the reviews, the gold doesn't break up as soon, so would be a lot cleaner, but is a somewhat different curve:

http://professional.celestion.com/gu...tail.asp?ID=32
The resemblance of the Celestion Blue to the 12" Alnico Tone Tubby is startling! You don't get that sort of near-identical response, especially from something as ragged as a guitar speaker, by accident. The people who designed the TT are obviously no fools.

As for the Gold, eh, not so pretty. They discarded the paper voice-coil former and went for something else (Nomex? Kapton? Aluminum?) and it shows in the FR curve as added roughness in the critical midrange region. The choice of material of the VC former, and the method of attaching it to the base of the cone, are extremely critical to the overall sound of the speaker, since this is the area where the impulse from the magnetic system is mechanically transferred to the cone. When the material of the former has a substantially different speed-of-sound from the cone, that creates a reflection at the are of the join. Reflections in the VC area are probably the most important of any part of the speaker.

That, by the way, is the source of much of the coloration in the 2 ~ 10 kHz region, and the reason "wonder cones" don't always match their voice-coils - the materials are too dissimilar, which creates reflections. A soft rubber or felt dust-cap that is precisely joined to the VC former can help things by absorbing some of the reflection, but the best approach is to select VC formers that are acoustically compatible with the cone.

Oddly enough, very few VC formers are chosen for this reason - the main thing for most speaker manufacturers is resistance to destruction, not subtle sonic details in the midrange. And as mentioned earlier, dustcaps are mostly for looks and a place to put a big silk-screened logo.
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Old 28th April 2007, 09:12 PM   #578
ScottG is offline ScottG  United States
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Quote:
Originally posted by Lynn Olson


As for the Gold, eh, not so pretty. They discarded the paper voice-coil former and went for something else (Nomex? Kapton? Aluminum?) and it shows in the FR curve as added roughness in the critical midrange region. The choice of material of the VC former, and the method of attaching it to the base of the cone, are extremely critical to the overall sound of the speaker, since this is the area where the impulse from the magnetic system is mechanically transferred to the cone. When the material of the former has a substantially different speed-of-sound from the cone, that creates a reflection at the are of the join. Reflections in the VC area are probably the most important of any part of the speaker.

That, by the way, is the source of much of the coloration in the 2 ~ 10 kHz region, and the reason "wonder cones" don't always match their voice-coils - the materials are too dissimilar, which creates reflections. A soft rubber or felt dust-cap that is precisely joined to the VC former can help things by absorbing some of the reflection, but the best approach is to select VC formers that are acoustically compatible with the cone.

Oddly enough, very few VC formers are chosen for this reason - the main thing for most speaker manufacturers is resistance to destruction, not subtle sonic details in the midrange. And as mentioned earlier, dustcaps are mostly for looks and a place to put a big silk-screened logo.
..this mirrors the Mother of Tone site on their speaker page..

Funny, but that site takes a lot of flack, much of it undeserved by people who think they know better. (..i.e. your typical I "live and die by my commonly available measurements".) Considering how incredibly mechanically flawed a moving coil loudspeaker is - you would THINK they would know better.
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Old 28th April 2007, 10:07 PM   #579
mige0 is offline mige0  Austria
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Hi

Quote:
What they didn't mention is that overtime as you increase the magnetization of the magnet, that Alinco is the worst for loosing field strength with most "blends". Neo is the best. For instance a Lowther with an Alinco magnet may well have gauss reduced by up to 20% after about 5 years - far worse still IF you have another similar magnet near them. The same is not true if the Lowther uses one of the newer neo based motors.

They also didn't discuss field precision/uniformity beyond extreme temperatures and counter current flux modulation.

Consider that Alinco is HIGHLY processed and the crystal structure of the magnet is both small and uniform. Neo is somewhat similar. Your average ceramic magnet is FAR worse.

IMO, if you combine counter current flux modulation resistance along with a highly uniform crystalline magnet structure and very high guass - you *can* get really good sound (..particularly clear and natural sounding provided other factors are "worked out").

Counter current flux modulation (and the resulting heat build up) is perhaps best reduced with the method that 18 Sound uses for their "Active Impedance Series".

Alternatively there are electromagnets, which *can* have greater field uniformity at least at lower input levels. A particular problem here is heat though, but it is less about heat as it alters the magnet and more about heat as it alters the VC.
Puuhh, just finished reading the whole thread - it's all there - outlined in detail.

Bottom line: use the ALNICOs if you like its specific sound originating from its magnetic behaviour - otherwise stay away, there are severe disadvantages.

Greetings
Michael
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Old 28th April 2007, 10:23 PM   #580
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Quote:
Originally posted by ScottG


..this mirrors the Mother of Tone site on their speaker page..

Funny, but that site takes a lot of flack, much of it undeserved by people who think they know better. (..i.e. your typical I "live and die by my commonly available measurements".) Considering how incredibly mechanically flawed a moving coil loudspeaker is - you would THINK they would know better.
It's hard to put this in a "nice" way, but I think the desire to create speakers and amps that are "perfect" reflects a certain lack of maturity. You do this gig long enough, you realize there's always going to some form of coloration that's left over, no matter what you do, how good you think you are, or how much money you throw at it.

In a way, it's funny to read the propaganda from big companies like JBL, B&W, Revel, Wilson, etc. etc. With MLSSA and its successors, it's been a level playing field for some 15 years now. They measure the same things we do, and make dumb, obvious mistakes. The terrible measurements we see in $tereophile are testament to that.

Of course, it doesn't help that $tereophile measures the wrong distance (50 inches) when the industry standard has been 2 meters (80 inches) for many decades. Even for minimonitors, the wavefront doesn't "gel" until you get a minimum of 1.5 meters away - and the distance is correspondingly larger for large speakers.

Loudspeakers are grossly imperfect devices, and optimizing one parameters steals from others. There's just no way around that, no matter how much money and time are thrown at the problem.

Linear-phase speakers with 1st-order crossovers pay a terrible price in tweeter IM distortion and complex lobing in the vertical plane. No way around it, unless you multi-amp and use digital correction, a whole can of worms by itself. Speakers that are the last word in flatness tend to be overdamped, inefficient, and not very good at rendering vivid tone colors. Speakers that are optimized for ultralow IM distortion and sky-high efficiency contend with PA-type colorations. The MBL, remarkable as it is, suffers from astoundingly low efficiency and the assorted colorations of diaphragm materials forced to operate in "bending mode".

The Mother of Tone website has the great merit of reminding people why we build hifi systems in the first place - these are machines for creating musical illusions, nothing more, nothing less. And it turns out that is very hard to do, since hearing and musical enjoyment are extraordinarily complex phenomena, by no means fully understood by the research community.

Some of the questions about perception and emotional responses to music are as infinitely deep as "what is consciousness?" - something philosophers, religions, and mystics have been wrestling for millennia.
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