If we were not to be concerned with tracking warped or off-centre
records, would a heavy tonearm produce a better image?

I ask because it would be logical that the heavier the arm, the less
resonances in the audio band (real world) and more punch, due to the
increased inertia of the arm.

lighter arms tend to vibrate more, and dissipate energy.

has anybody done side-by side comparisons?


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alfred wrote:
If we were not to be concerned with tracking warped or off-centre
records, would a heavy tonearm produce a better image?

I don't think so, as imaging is a function of the cartridge's separation
and channel balance. As far as I know, arm mass isn't relevant.

I ask because it would be logical that the heavier the arm, the less
resonances in the audio band (real world) and more punch, due to the
increased inertia of the arm.

I don't understand the expression "punch" in this context.

lighter arms tend to vibrate more, and dissipate energy.

The resonance of an arm is dependant on arm mass and its stiffness. The
weight of the cartridge hanging on the end of the arm will add to the
arm mass and affect the resonance frequency. Cartridge compliance will
affect how much energy is fed into the arm, which is one reason why low
compliance cartridges should be used with stiff arms. The low compliance
also requires a massive arm if the arm/cartridge resonance is to be
positioned above warp frequencies and below rumble and music
frequencies. However, a very heavy cartridge may be heavy enough by
itself that a high arm mass will push the resonance too low, so you can
end up with the counter-intuitive situation of a heavy cartridge in a
light arm.

The exact question you asked has a very easy answer, no, but what I
suspect is behind your question has a very complex series of answers in
which arm mass, stiffness and cartridge compliance are all interconnected.

S.


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Serge Auckland wrote:
alfred wrote:
If we were not to be concerned with tracking warped or off-centre
records, would a heavy tonearm produce a better image?

I don't think so, as imaging is a function of the cartridge's separation
and channel balance. As far as I know, arm mass isn't relevant.

Unless the effective total mass and stylus compliance are
SO mismatched that it results in substiantial problems that
actually modify the audible portion of the signal.

In other words, the problem could be severe enough that it
deteriorates the audio.

I ask because it would be logical that the heavier the arm, the less
resonances in the audio band (real world) and more punch, due to the
increased inertia of the arm.

I don't understand the expression "punch" in this context.

lighter arms tend to vibrate more, and dissipate energy.

False, absolutely false for any number of reasons.

First, the amount of energy stored is proportional to the mass.
The higher the mass, the more energy is stored for a given
velocity.

Second, the lower the mass, the higher in frequency the
arm/cartridge resonance occurs and, all other things being
equal, the lower the Q at resonance, i.e., the better damped
that resonance is.

Third, mass does NOT "dissipate energy." Energy is stored
in masses as kinetic energy of motion.

The resonance of an arm is dependant on arm mass and
its stiffness.

No, the fundamental resonant frequency is dependet upon
the stiffness of the cartidges suspension, NOT on the stiffness
of the arm.

The weight of the cartridge hanging on the end of the arm
will add to the arm mass and affect the resonance frequency.

Cartridge compliance will affect how much energy is fed into
the arm,

Wrong. Cartidge compliance, in league with the total effective
mass of the arm/cartrdige, determines the resonant frequency
of the tone arm.

which is one reason why low compliance cartridges should
be used with stiff arms.

The mechanical "stiffness" of the tone arm is SO much higher
than even the lowest compliance carttrdige that it simply is never
a factor. Many orders of magnitude stiffer, in fact (like hundreds
of thousands or millions of times stiffer). Thus, the notion that
there has to be some "match" between cartidge compliance
and arm stiffness is simply ludicrous.

The low compliance also requires a massive arm if the
arm/cartridge resonance is to be positioned above warp
frequencies and below rumble and music frequencies.

Correct. the ideal region for the arm/cartidge resonance is
in the realm of about 8-15 Hz.

However, a very heavy cartridge may be heavy enough by
itself that a high arm mass will push the resonance too low,
so you can end up with the counter-intuitive situation of a
heavy cartridge in a light arm.

Well, if it's "counterintuitive," then it's yet another example of
how audio "intuition" is just plain wrong.

The exact question you asked has a very easy answer, no,
but what I suspect is behind your question has a very
complex series of answers in which arm mass, stiffness
and cartridge compliance are all interconnected.

Once again, the arm "stiffness" is simply irrelevant in all
but the most outlandish pathological cases, like wet pasta.
Even in some of the more esoteric DIY arms that used thin
strips balsa wood it's irrelevant, primarily because in such
cases the largest contributor to the toal moving mass is the
cartidge itself,, which is one the front side of the compiance
of the arm itself..

If the stiffness of the arm IS relevant, it's a sign of a VERY badly
designed tone arm.

Check out http://www.cartchunk.org/audiotopics...mMechanics.pdf


--

wrote:
Serge Auckland wrote:
alfred wrote:
If we were not to be concerned with tracking warped or off-centre
records, would a heavy tonearm produce a better image?
I don't think so, as imaging is a function of the cartridge's separation
and channel balance. As far as I know, arm mass isn't relevant.

Unless the effective total mass and stylus compliance are
SO mismatched that it results in substiantial problems that
actually modify the audible portion of the signal.

In other words, the problem could be severe enough that it
deteriorates the audio.

Agreed. I wasn't thinking of such gross mismatches

I ask because it would be logical that the heavier the arm, the less
resonances in the audio band (real world) and more punch, due to the
increased inertia of the arm.
I don't understand the expression "punch" in this context.
lighter arms tend to vibrate more, and dissipate energy.

False, absolutely false for any number of reasons.

First, the amount of energy stored is proportional to the mass.
The higher the mass, the more energy is stored for a given
velocity.

Second, the lower the mass, the higher in frequency the
arm/cartridge resonance occurs and, all other things being
equal, the lower the Q at resonance, i.e., the better damped
that resonance is.

Third, mass does NOT "dissipate energy." Energy is stored
in masses as kinetic energy of motion.

The resonance of an arm is dependant on arm mass and
its stiffness.

No, the fundamental resonant frequency is dependet upon
the stiffness of the cartidges suspension, NOT on the stiffness
of the arm.

I think you misunderstood my point. I was referring to the beam
resonance of the arm itself, which IS dependant on the total mass of arm
and cartridge and the stiffness of the arm itself. The arm will have a
resonance frequency regardless of whether it is tracking a record or
not. You are correct that the arm/cartridge main resonance is dependant
on cantilever compliance resonating with the arm/cartridge mass but
that's not what I was talking about.

The weight of the cartridge hanging on the end of the arm
will add to the arm mass and affect the resonance frequency.

Cartridge compliance will affect how much energy is fed into
the arm,

Wrong. Cartidge compliance, in league with the total effective
mass of the arm/cartrdige, determines the resonant frequency
of the tone arm.

Wrong. Cartridge compliance, in league with the total effective mass of
the arm/cartridge determines the resonant frequency of the ARM/CARTRIDGE
combination. The arm's own resonance is a different thing as you point
out below.

which is one reason why low compliance cartridges should
be used with stiff arms.

The mechanical "stiffness" of the tone arm is SO much higher
than even the lowest compliance carttrdige that it simply is never
a factor. Many orders of magnitude stiffer, in fact (like hundreds
of thousands or millions of times stiffer). Thus, the notion that
there has to be some "match" between cartidge compliance
and arm stiffness is simply ludicrous.

Yes, if the arm is well designed, but not all a Please see below.


The low compliance also requires a massive arm if the
arm/cartridge resonance is to be positioned above warp
frequencies and below rumble and music frequencies.

Correct. the ideal region for the arm/cartidge resonance is
in the realm of about 8-15 Hz.

However, a very heavy cartridge may be heavy enough by
itself that a high arm mass will push the resonance too low,
so you can end up with the counter-intuitive situation of a
heavy cartridge in a light arm.

Well, if it's "counterintuitive," then it's yet another example of
how audio "intuition" is just plain wrong.

I couldn't agree with you more :-)


The exact question you asked has a very easy answer, no,
but what I suspect is behind your question has a very
complex series of answers in which arm mass, stiffness
and cartridge compliance are all interconnected.

Once again, the arm "stiffness" is simply irrelevant in all
but the most outlandish pathological cases, like wet pasta.
Even in some of the more esoteric DIY arms that used thin
strips balsa wood it's irrelevant, primarily because in such
cases the largest contributor to the toal moving mass is the
cartidge itself,, which is one the front side of the compiance
of the arm itself..

If the stiffness of the arm IS relevant, it's a sign of a VERY badly
designed tone arm.

Check out http://www.cartchunk.org/audiotopics...mMechanics.pdf


You may well be right about badly designed tone arms but I think you
will find that these were more common than perhaps you may think. I am
thinking particularly of the Transcriptors fluid arm, a unipivot device
which had such a thin arm tube that it would "ping" if flicked, like a
ruler on the edge of a table!

By the way, please give my regards to Geoff Steadman if you're in
contact with him.

S.



--------------020500030809000405070409--



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wrote:


Once again, the arm "stiffness" is simply irrelevant in all
but the most outlandish pathological cases, like wet pasta.
Even in some of the more esoteric DIY arms that used thin
strips balsa wood it's irrelevant, primarily because in such
cases the largest contributor to the toal moving mass is the
cartidge itself,, which is one the front side of the compiance
of the arm itself..

If the stiffness of the arm IS relevant, it's a sign of a VERY badly
designed tone arm.

Check out http://www.cartchunk.org/audiotopics...mMechanics.pdf


Funny, the designers and manufacturers of highend tonearms say
otherwise. I suppose it is possible they are wrong and you are right.
But I'd have to with the people with a track record on the subject.
(pun intended)


Scott


--

wrote:
wrote:


Once again, the arm "stiffness" is simply irrelevant in all
but the most outlandish pathological cases, like wet pasta.
Even in some of the more esoteric DIY arms that used thin
strips balsa wood it's irrelevant, primarily because in such
cases the largest contributor to the toal moving mass is the
cartidge itself,, which is one the front side of the compiance
of the arm itself..

If the stiffness of the arm IS relevant, it's a sign of a VERY badly
designed tone arm.

Check out http://www.cartchunk.org/audiotopics...mMechanics.pdf


Funny, the designers and manufacturers of highend tonearms say
otherwise. I suppose it is possible they are wrong and you are right.
But I'd have to with the people with a track record on the subject.
(pun intended)


Yet even the SME V isn't stiff enough to move arm resonance out of
the audible band.
One must realize that the amount of energy transmitted into the arm by
the cart is a function of the cart compliance and mass as well.

In the review on their website, reviewers couldn't detect energy into
the arm from a cart so they went to actually striking the arm to
calculate impulse response. Neat way to test the arm but does it
really have any correlation to the real world?

Transmissibility of a simple spring isolator (which I suppose
reasonably models a cart)
is usually = 1/[(Fd/Fn)^2 -1 ]. You can see that energy from the
cart into the arm is going to diminish rapidly as a function of freq.
Say Fn (natural or res freq) fo 10 Hz.. then energy into the arm will
down to 1% of input to the cart at 100 hz.

How much can be gained by moving arm resonance from 500 Hz to 2 kHz?
I think going to a system that offers a shorter arm (linear tracker) is
more effective than exotic stiffening aproaches and has other benefits.

ScottW


--

ScottW wrote:

How much can be gained by moving arm resonance from 500 Hz to 2 kHz?
I think going to a system that offers a shorter arm (linear tracker) is
more effective than exotic stiffening aproaches and has other benefits.

I think it would be interesting to see the top designers of pivoting
arms debate the subject with the top designers of linear tracking arms.
Personally the best i have heard has come from linear tracking arms.


Scott


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