[Rich Teer]

On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

What TT are you planning to use, and what's your budget? (What cartridge
too?)

--
Rich Teer, Publisher
Vinylphile Magazine

www.vinylphilemag.com

[Audio Empire]

On Sun, 25 Sep 2011 13:46:02 -0700, Rich Teer wrote
(in article ):

On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

What TT are you planning to use, and what's your budget? (What cartridge
too?)



The shape is not important, PER SE. What is important is the position of the
stylus on the record with relation to the arm pivot point. Curved arms allow
for a more ideal tracking angle with a shorter distance from stylus tip to
pivot point, I.E., a physically shorter arm tube.

[isw]

In article ,
Audio Empire wrote:

On Sun, 25 Sep 2011 13:46:02 -0700, Rich Teer wrote
(in article ):

On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

What TT are you planning to use, and what's your budget? (What cartridge
too?)



The shape is not important, PER SE. What is important is the position of the
stylus on the record with relation to the arm pivot point. Curved arms allow
for a more ideal tracking angle with a shorter distance from stylus tip to
pivot point, I.E., a physically shorter arm tube.

Whether the arm is straight or curved won't affect the tracking angle,
provided you're willing to set the cartridge at an angle to the
(straight) arm. Another thing that is important is the mass of the arm
(including the pickup, of course) -- it should be as low as possible for
best tracking, especially of warped or eccentric records (of which there
are more than you think). In this, a straight arm with an offset
cartridge will win.

Isaac

[Audio Empire]

On Mon, 26 Sep 2011 07:04:52 -0700, isw wrote
(in article ):

In article ,
Audio Empire wrote:

On Sun, 25 Sep 2011 13:46:02 -0700, Rich Teer wrote
(in article ):

On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

What TT are you planning to use, and what's your budget? (What cartridge
too?)



The shape is not important, PER SE. What is important is the position of
the
stylus on the record with relation to the arm pivot point. Curved arms
allow
for a more ideal tracking angle with a shorter distance from stylus tip to
pivot point, I.E., a physically shorter arm tube.

Whether the arm is straight or curved won't affect the tracking angle,
provided you're willing to set the cartridge at an angle to the
(straight) arm. Another thing that is important is the mass of the arm
(including the pickup, of course) -- it should be as low as possible for
best tracking, especially of warped or eccentric records (of which there
are more than you think). In this, a straight arm with an offset
cartridge will win.

Isaac


"(The mass of the arm) should be as low as possible for
best tracking"

Depends on the cartridge. Ideally, the total mass of the arm/cartridge,
combined with the stylus compliance should allow for a system resonance of
between 8-12 Hz. That would be a frequency lower than the lowest note on the
record (about 20 Hz for pedal notes) but above the frequency where foot-falls
and warped records would excite the system (around 6 Hz). Some cartridges
need low-mass arms to attain this ideal resonant frequency, and some need a
low-mass arm.

Generally speaking, Arms with high effective mass, when used in combination
with high-compliance cartridges will yield a resonant frequency which falls
below the ideal range making it susceptible to being being dislodged from the
groove by heavy footfalls and making the system overly sensitive to warp-wow.
On the other hand cartridges with low-compliance, used in conjunction with a
low-mass arm will move the system resonance up into the audible range,
resulting in overblown and muddy bass. Obviously both extremes should be
avoided for bast results.

While this is obviously simple physics, it is also one of the least
understood and one of the most ignored phases of most people's record playing
setups. People buy an arm (or a turntable/arm combo) and then pick a
cartridge based on reviews or upon having heard a certain model at a
friend's house or a hi-fi show, and pair the two without even a thought as to
compatibility. The industry hasn't helped much either. There are rarely any
guidelines given for pairing either arm or cartridge, and when there are,
they are vague and don't make a lot of sense to the average audiophile. What
the industry should have done, years ago, is to come up with some simple
number matching system for both arms and cartridges. Ideally, thei system
could have worked like this:

Cartridges could be classed using the numbering system 1 through 10 with 1
being an extremely high compliance cartridge and 10 being an extremely low
compliance cartridge. Then arms would be rated using the same scale 1 through
10, only with 1 being a low-mass arm and 10 being a high-mass arm. To gauge
compatibility all the buyer need do is match numbers. A cartridge with a
rating of 3 would match with an arm rated at three (with more or less
acceptable performance being obtained by using an arm rated from 2 to 4).
Some system like this would be very helpful, but nobody has ever done it.

I usually recommend that people buy complete turntable packages - preferably
those put together by the manufacturer, such as the Clearaudio Performance SE
Package (which comes equipped with suitable Benz MC cartridges) or the
various Rega or Music Hall turntable/cartridge combos. Generally speaking,
you'll get better performance with an inexpensive combo package where the arm
and cartridge are a well thought-out, synergistic system, than you will with
a more expensive setup where the arm/cartridge interface is left to chance.

[Dick Pierce[_2_]]

Audio Empire wrote:
On Sun, 25 Sep 2011 13:46:02 -0700, Rich Teer wrote
(in article ):


On Sun, 25 Sep 2011, Edward wrote:


i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

What TT are you planning to use, and what's your budget? (What cartridge
too?)

The shape is not important, PER SE. What is important is the position of the
stylus on the record with relation to the arm pivot point. Curved arms allow
for a more ideal tracking angle with a shorter distance from stylus tip to
pivot point, I.E., a physically shorter arm tube.

This is a common myth, but a myth, nonetheless.

Consider the following gedanken: Take ANY curved arm
shape you can imagine providing a "more ideal tracking
angle." Now, without changing the orientation of the
cartridge/stylus at all, draw a straight line between
the mounting point of the cartridge and the main
pivot of the tone arm, and replace the curved tone
arm with a straight tube follwiong that line. You
now have two different toen arms: one curved,
one straight, and BOTH provide the IDENTICAL "ideal
tracking angle."

Basically, what this tells us is tracking geometry
is not intrinsically linked to the shape of the tone
arm.

Beyond that, shape IS important for a number of
reasons.

All other things being equal, a straight tone arm
will have lower mass and higher mechanical stability
than a curved tone arm, and lower mass can be argued
as being a good thing. Even for those that might claim
that for a given cartridge, a higher moving mass is
required, that is trivially achieved by adding mass to
the mounting of the cartridge. It's MUCH more difficult
(read: it's pretty much impossible) to remove mass from
an arm whose mass is too high for a given cartridge.

One of the legitimate reasons for a curved arm is to
facilitate the design and implementation of a removable
headshell, along the lines of the original SME arm.
Here, a small machining facility (Small Model Engineering,
to be precise), had limited resources available. It used
a an existing 4-pin connector designed for another purpose
and used it to come up with a workable removable headshell.
Because the connector had to be straight-on, that dictated
the requirement of a curved tone arm in order to achieve the
offset angle required for proper tracking. Then, the use
of the size, material and wall thickness for the tone
arm tube put severe constraints on the amount and radius of
the bend in the tube before the tube ran the risk of collapse.
Finally, the the connector's mechanical requirements dictated
where thebend could occur.

The net result was that the shape of the old SME 3009 arm
tube was a compromise forced on the designers by the available
matericals and techniques on hand at the time (1950's).
It did, howver, establish a significant precedent for further
high-end arm design, a precedent whose origins were largely
lost in the usual high-end mythology and hype.

Subsequent justifications for curved tone arms, principally
by a number of Japanese manufactures in the 1970's, was that
a curved arm of the right profile could be statically
balanced by distributing the mass equally on either side
of the "imaginary" straight line connecting the pivot to
the stylus. But that same balance can be achieved, if it
is important, but simply using a straight tube along that
same imaginary straight line.

And, it's also interesting to note that for those arms where
this rtype of balance is crucial, i.e., unipivot arms, two
of the more pupoular unipivot arms, the A&D/Monks and the
Decca, BOTH used straight arm tubes with offset angles
implemented right at the headshell/mounting. The A&D "solved"
the quick interchangeability issue by allowing, through
its unique use of mercury-bath contacts, completely removable
arms, while the Decca solved it by simply not having quick
interchangeability.

Bottom line:

* Correct tracking angle idoes NOT require curved tone
arms.

* Any profile other than a straight line MUST have more
moving mass, all other things being equal.

Tone arm shape IS important, but the reasons often given
are irreleventa or just plain wrong.

Which is better: depends upon your requirements. Do
you need a commonly-available removable headshell
scheme (i.e. SME-type)? If yes, you're almost certainly
stuck with a curved tone arm? Do you require the absolute
minimum moving mass for your high-compliance cartridge?
Of yes, seek out straight tone arms with non-removable
headshells? Is achieving the correct tracking angle
important? If yes, arm shape is irrelevant. If no,
arm shape is still irrelevant.

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Audio Empire]

On Mon, 26 Sep 2011 07:06:39 -0700, Dick Pierce wrote
(in article ):

Audio Empire wrote:
On Sun, 25 Sep 2011 13:46:02 -0700, Rich Teer wrote
(in article ):


On Sun, 25 Sep 2011, Edward wrote:


i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

What TT are you planning to use, and what's your budget? (What cartridge
too?)

The shape is not important, PER SE. What is important is the position of
the
stylus on the record with relation to the arm pivot point. Curved arms
allow
for a more ideal tracking angle with a shorter distance from stylus tip to
pivot point, I.E., a physically shorter arm tube.

This is a common myth, but a myth, nonetheless.

Consider the following gedanken: Take ANY curved arm
shape you can imagine providing a "more ideal tracking
angle." Now, without changing the orientation of the
cartridge/stylus at all, draw a straight line between
the mounting point of the cartridge and the main
pivot of the tone arm, and replace the curved tone
arm with a straight tube follwiong that line. You
now have two different toen arms: one curved,
one straight, and BOTH provide the IDENTICAL "ideal
tracking angle."

Basically, what this tells us is tracking geometry
is not intrinsically linked to the shape of the tone
arm.

Which is what I said.

Beyond that, shape IS important for a number of
reasons.

All other things being equal, a straight tone arm
will have lower mass and higher mechanical stability
than a curved tone arm, and lower mass can be argued
as being a good thing.

Except when low-mass arms are combined with low compliance cartridges, and
make no mistake, there are plenty of high-end cartridges which are low
compliance.

Even for those that might claim
that for a given cartridge, a higher moving mass is
required, that is trivially achieved by adding mass to
the mounting of the cartridge. It's MUCH more difficult
(read: it's pretty much impossible) to remove mass from
an arm whose mass is too high for a given cartridge.

That's why matching arm to cartridge is so important. The best way I know to
render a large portion of a real-world record collection unplayable is to
afix a fairly low mass arm with a really high-compliance cartridge. The best
way I know to make one's records sound bass-heavy and muddy is to couple a
low mass tone arm with low compliance cartridge. And the result is FAR from
trivial in either case.

One of the legitimate reasons for a curved arm is to
facilitate the design and implementation of a removable
headshell, along the lines of the original SME arm.
Here, a small machining facility (Small Model Engineering,
to be precise), had limited resources available. It used
a an existing 4-pin connector designed for another purpose
and used it to come up with a workable removable headshell.
Because the connector had to be straight-on, that dictated
the requirement of a curved tone arm in order to achieve the
offset angle required for proper tracking. Then, the use
of the size, material and wall thickness for the tone
arm tube put severe constraints on the amount and radius of
the bend in the tube before the tube ran the risk of collapse.
Finally, the the connector's mechanical requirements dictated
where thebend could occur.

True enough.

The net result was that the shape of the old SME 3009 arm
tube was a compromise forced on the designers by the available
matericals and techniques on hand at the time (1950's).
It did, howver, establish a significant precedent for further
high-end arm design, a precedent whose origins were largely
lost in the usual high-end mythology and hype.

Subsequent justifications for curved tone arms, principally
by a number of Japanese manufactures in the 1970's, was that
a curved arm of the right profile could be statically
balanced by distributing the mass equally on either side
of the "imaginary" straight line connecting the pivot to
the stylus. But that same balance can be achieved, if it
is important, but simply using a straight tube along that
same imaginary straight line.

Yep.

And, it's also interesting to note that for those arms where
this rtype of balance is crucial, i.e., unipivot arms, two
of the more pupoular unipivot arms, the A&D/Monks and the
Decca, BOTH used straight arm tubes with offset angles
implemented right at the headshell/mounting. The A&D "solved"
the quick interchangeability issue by allowing, through
its unique use of mercury-bath contacts, completely removable
arms, while the Decca solved it by simply not having quick
interchangeability.

Bottom line:

* Correct tracking angle idoes NOT require curved tone
arms.

That's correct.

* Any profile other than a straight line MUST have more
moving mass, all other things being equal.

Also correct. But to say that low-mass in a tone arm is always desireable is
overly simplistic and not correct. The arm and cartridge must work together
as a synergistic system. Record players are mechanical systems and mechanical
systems have a number of criteria to meet before they can be considered a
successful solution.

Tone arm shape IS important, but the reasons often given
are irreleventa or just plain wrong.

Mostly they're irrelevant as there are, in engineering, usually more than one
path to a satisfactory solution.

Which is better: depends upon your requirements. Do
you need a commonly-available removable headshell
scheme (i.e. SME-type)? If yes, you're almost certainly
stuck with a curved tone arm? Do you require the absolute
minimum moving mass for your high-compliance cartridge?
Of yes, seek out straight tone arms with non-removable
headshells? Is achieving the correct tracking angle
important? If yes, arm shape is irrelevant. If no,
arm shape is still irrelevant.

Can't argue with your last statement.

[Dick Pierce[_2_]]

Audio Empire wrote:
On Mon, 26 Sep 2011 07:06:39 -0700, Dick Pierce wrote
All other things being equal, a straight tone arm
will have lower mass and higher mechanical stability
than a curved tone arm, and lower mass can be argued
as being a good thing.

Except when low-mass arms are combined with low compliance cartridges, and
make no mistake, there are plenty of high-end cartridges which are low
compliance.

Except that it's a trivial excercise to increase the mass of
a low-mass arm to something suitable.

Even for those that might claim
that for a given cartridge, a higher moving mass is
required, that is trivially achieved by adding mass to
the mounting of the cartridge. It's MUCH more difficult
(read: it's pretty much impossible) to remove mass from
an arm whose mass is too high for a given cartridge.

That's why matching arm to cartridge is so important. The best way I know to
render a large portion of a real-world record collection unplayable is to
afix a fairly low mass arm with a really high-compliance cartridge. The best
way I know to make one's records sound bass-heavy and muddy is to couple a
low mass tone arm with low compliance cartridge. And the result is FAR from
trivial in either case.

I did not say it's a trivial case. I said that if a higher
mass is required, which is the same as saying if the
effective arm mass is too low, the proper mass trivially
achieved by adding mass.

The same is NOT the case for an arm whose mass is already
too high: there is no real-world solution for reducing the
effective mass of an arm.

* Any profile other than a straight line MUST have more
moving mass, all other things being equal.

Also correct. But to say that low-mass in a tone arm is always desireable is
overly simplistic and not correct. The arm and cartridge must work together
as a synergistic system. Record players are mechanical systems and mechanical
systems have a number of criteria to meet before they can be considered a
successful solution.

Are we not getting it? If the mass of an arm is too low,
then ADD MASS TO IT. Why does this seem such a difficult
concept? A low-mass arm uis a far more suitable solution
for a much wider range of cartridge compliances than a high
mass arm. A low mass arm can work very well as-is for high-
compliance cartridges, can work very well for moderate-
compliance cartidges with the addition of a little extra mass,
and can work very well for low-compliance cartridges with
the addition of suitably greater amount of mass.

Thus it CAN be argued that a low-mass arm is suitable for
a wider range of cartridges than a high-mass arm simply
through the expedient of adjusting the mass accordingly.

The same is absolutely NOT true of high-mass arms.

Do you not agree, and if not, why not?

Tone arm shape IS important, but the reasons often given
are irreleventa or just plain wrong.

Mostly they're irrelevant as there are, in engineering,
usually more than one path to a satisfactory solution.

And as is often the case in high-end audio, for ever
path to a satisfactory solution, there are many more
paths to unsatisfactory solutions that are highly
revered.


--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Sigullyneinly]

3fc1f2e1ae1334d2

[Arny Krueger[_4_]]

"Rich Teer" wrote in message
...
On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

Correct. The shortest distance between the pivot and the stylus is always a
straight line. Therefore the straight tube with the cartridge mounted at an
appropriate offset angle and overhang distance is the most likely to have
minimal mass, all other things being equal.

[Audio Empire]

On Mon, 26 Sep 2011 07:06:44 -0700, Arny Krueger wrote
(in article ):

"Rich Teer" wrote in message
...
On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

Correct. The shortest distance between the pivot and the stylus is always a
straight line. Therefore the straight tube with the cartridge mounted at an
appropriate offset angle and overhang distance is the most likely to have
minimal mass, all other things being equal.



Again with the mythology that low-mass in a tone arm is always desirable. It
is NOT. Low mass and low compliance does not work just as high-mass and high
compliance don't work. Mass in an arm is, in no way, and indicator of an
arm's quality just as compliance in a cartridge is no measure of a
cartridge's quality. To say that these are indicators of quality or
performance (in and of themselves) is akin to asserting that a
high-efficiency speaker performs better than a low efficiency speaker and for
pretty much similar reasons.

[Dick Pierce[_2_]]

Audio Empire wrote:
On Mon, 26 Sep 2011 07:06:44 -0700, Arny Krueger wrote
(in article ):
Correct. The shortest distance between the pivot and the stylus is always a
straight line. Therefore the straight tube with the cartridge mounted at an
appropriate offset angle and overhang distance is the most likely to have
minimal mass, all other things being equal.

Again with the mythology that low-mass in a tone arm is always desirable. It
is NOT. Low mass and low compliance does not work just as high-mass and high
compliance don't work.

Fine, add mass to a low mass tone arm.

What's the problem?

Mass in an arm is, in no way, and indicator of an
arm's quality just as compliance in a cartridge is no measure of a
cartridge's quality. To say that these are indicators of quality or
performance (in and of themselves) is akin to asserting that a
high-efficiency speaker performs better than a low efficiency speaker and for
pretty much similar reasons.

No, mass IS an indicator of the RANGE of suitable compliances.

A low mass arm can be auitably and satsifactorily adapted
to a much wider range of cartridge compliances than a high-
mass arm.

With a high-mass arm, you are stuck with using low compliance
cartridges. You can't use high-compliance cartridges to
achieve reasonable performance.

With a low mass arm, you can use cartridges ranging from
low compliance to high compliance simply through the use
of appropriate additional mass.

What's the problem?

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Arny Krueger[_4_]]

"Audio Empire" wrote in message
...
On Mon, 26 Sep 2011 07:06:44 -0700, Arny Krueger wrote
(in article ):

"Rich Teer" wrote in message
...
On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

Correct. The shortest distance between the pivot and the stylus is always
a
straight line. Therefore the straight tube with the cartridge mounted at
an
appropriate offset angle and overhang distance is the most likely to have
minimal mass, all other things being equal.

Again with the mythology that low-mass in a tone arm is always desirable.
It is NOT. Low mass and low compliance does not work just as high-mass and
high
compliance don't work. Mass in an arm is, in no way, and indicator of an
arm's quality just as compliance in a cartridge is no measure of a
cartridge's quality. To say that these are indicators of quality or
performance (in and of themselves) is akin to asserting that a
high-efficiency speaker performs better than a low efficiency speaker and
for
pretty much similar reasons.

I agree. The mass and the compliance of the cartridge need to be matched so
that as you say, the tone arm resonance is in the 8 to 12 Hz region.
Ideally, the counterweight is also suspended in such a way that it becomes a
vibration absorber tuned to the resonance frequency of the arm.

I also agree with what Scott points out, which is that so called linear
tracking is preferable to a laterally pivoted tracking arm, all other things
being equal. In fact mostlinear tracking arms have a lateral pivot, but the
pivot is on a sled or trolly that moves across the record to minimize the
lateral deflection of the pivot. One big advantage of linear tracking is
reduction of low frequency FM distortion due to warping, eccentricity and
low frequency program material.

Mass is is pretty easy to add, but hard to subtract when excess mass is
inherent in a design. Therefore starting out with a design with the lowest
possible mass is often a good idea. The curved arms look sexy, and often
cause no harm.

[Audio Empire]

On Tue, 27 Sep 2011 06:35:42 -0700, Arny Krueger wrote
(in article ):

"Audio Empire" wrote in message
...
On Mon, 26 Sep 2011 07:06:44 -0700, Arny Krueger wrote
(in article ):

"Rich Teer" wrote in message
...
On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.

I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

Correct. The shortest distance between the pivot and the stylus is always
a
straight line. Therefore the straight tube with the cartridge mounted at
an
appropriate offset angle and overhang distance is the most likely to have
minimal mass, all other things being equal.

Again with the mythology that low-mass in a tone arm is always desirable.
It is NOT. Low mass and low compliance does not work just as high-mass and
high
compliance don't work. Mass in an arm is, in no way, and indicator of an
arm's quality just as compliance in a cartridge is no measure of a
cartridge's quality. To say that these are indicators of quality or
performance (in and of themselves) is akin to asserting that a
high-efficiency speaker performs better than a low efficiency speaker and
for
pretty much similar reasons.

I agree. The mass and the compliance of the cartridge need to be matched so
that as you say, the tone arm resonance is in the 8 to 12 Hz region.
Ideally, the counterweight is also suspended in such a way that it becomes a
vibration absorber tuned to the resonance frequency of the arm.

I also agree with what Scott points out, which is that so called linear
tracking is preferable to a laterally pivoted tracking arm, all other things
being equal. In fact mostlinear tracking arms have a lateral pivot, but the
pivot is on a sled or trolly that moves across the record to minimize the
lateral deflection of the pivot. One big advantage of linear tracking is
reduction of low frequency FM distortion due to warping, eccentricity and
low frequency program material.

Mass is is pretty easy to add, but hard to subtract when excess mass is
inherent in a design. Therefore starting out with a design with the lowest
possible mass is often a good idea. The curved arms look sexy, and often
cause no harm.



The problem with adding mass is knowing how much mass to add to obtain the
desired result and almost as importantly, where to add it. The math is pretty
obscure for making those determinations, and often the required parameters
are not forthcoming from the manufacturer. For instance, while some
cartridges' enclosed data sheets include the cartridge's mass and compliance,
not all do. Also, you need to know lots of things about the arm that aren't
generally known by the buyer.

Of course, most people just use trial and error - and it's mostly error. Like
I said in an earlier post the industry would benefit form some kind of
standard compatibility rating system. A simple match-the-numbers scheme would
be ideal. But it has never been done and I don't even know if anyone has ever
even proposed such a standard. The closest to it (AFAIK) was the "P-mount"
scheme of the late 70's where all P-mount arms were the same mass and
effective length and all P-mount cartridges were the same weight, same
compliance, same tracking force, and same stylus tip to pivot distance, same
VTA, etc. That didn't go over very well for any but the most inexpensive of
mass market players. I think the original Blue-Point high-output MC cartridge
was the "highest-end" P-mount cartridge ever offered.

[Dick Pierce[_2_]]

Audio Empire wrote:
The problem with adding mass is knowing how much
mass to add to obtain the desired result

Yhe problem with buying a high-mass tone arm is
knowing how much mass to buy to obtain the
desired result.

How, then, is the problem of adding mass to
an existing tone arm ANY different than selecting
the right arm mass (and, thus the "right" arm)
to begin with?

Both require EXACTLY the same starting information:
what mass is needed, and what is the mass of the arm.
Then the issue of adding mass is pretty damned simple:
subtract the existing mass from the required mass.
If the result is a positive number, add that mass,
if the result is a negative number, your arm mass
is too high for the cartridge chosen.

and almost as importantly, where to add it.

You're kidding, right? If 5 grams of additional
mass are needed, add 5 grams at the catridge.

The math is pretty obscure for making those determinations,

Really? If the recommended total moving mass is,
oh, 15 grams, the arm contributes 7 of those and
the cartridge adds 5, why is:

15g - 7g - 5g = 3g

obscure?

and often the required parameters are not forthcoming from
the manufacturer.

Like? Not an example, how about a comprehensive list as
an aid for those actually interested in the substance
of the discussion?

For instance, while some
cartridges' enclosed data sheets include the cartridge's mass and compliance,
not all do.

Why is this not a problem for choosing a high-mass vs low
mass arm, but IS a problem for adding mass to a low mass arm?

Also, you need to know lots of things about the arm that aren't
generally known by the buyer.

What "lot of things about the arm that aren't generally
known" aren't a problem for selecting a high-mass vs low-
mass arm but are a problem for adding mass to a low-mass arm?

Of course, most people just use trial and error - and it's mostly error. Like
I said in an earlier post the industry would benefit form some kind of
standard compatibility rating system. A simple match-the-numbers scheme would
be ideal. But it has never been done

Yes, it hasL: I did it 40 years ago. Many other people did.
The fact that the bulk of the high-end audio realm is
terrified of early high-school math is no excuse.

and I don't even know if anyone has ever
even proposed such a standard.

DIN, for one.

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Dick Pierce[_2_]]

In rereading, I find the following claim to be,
well, extraordinary:
Audio Empire wrote:
A simple match-the-numbers scheme would be ideal.
But it has never been done and I don't even know
if anyone has ever even proposed such a standard.

A simple google search suggests, somewhat overwhelmingly
if I may, the opposite. I had the idea of revising the
table I generated some 4 decades ago and, to populate
it, went searching for "phono cartridge compliance" and
got thousands of hits, including some in the top 10
which included precisely such a scheme. There's even
one site that has available a spreadsheet which has
a database of arm and cartridge specs that allows one
to easily calculate the resulting catridge/arm resonance.

Empire, in talking about "pretty obscure math", "the
required parameters are not forthcoming from the manufacturer,"
"lots of things about the arm that aren't generally known,"
and such might lead one to believe it's a mysterious, poorly
studied and largely unsolved problem. Indeed, it may be
to some, but the information and techniques have been well
understood by many for a long time.

The information is out there for anyone who wants to take the
minimal trouble to find it.


--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Arny Krueger[_4_]]

"Audio Empire" wrote in message
...

Mass is is pretty easy to add, but hard to subtract when excess mass is
inherent in a design. Therefore starting out with a design with the
lowest
possible mass is often a good idea. The curved arms look sexy, and often
cause no harm.

The problem with adding mass is knowing how much mass to add to obtain
the
desired result and almost as importantly, where to add it.

First off, since we have a system that rotates about pivots, it is not mass
that we want to add, it is intertia.

Inertia is maximized when the mass is added as far from the pivot as
possible.

The math is pretty
obscure for making those determinations, and often the required parameters
are not forthcoming from the manufacturer.

I wouldn't even go there. Experimentation is the way to do.

For instance, while some
cartridges' enclosed data sheets include the cartridge's mass and
compliance,
not all do. Also, you need to know lots of things about the arm that
aren't
generally known by the buyer.

Also, the resonance of the arm depends on the compliance of the stylus which
my not be specified or may be specified as a marketing number.

Of course, most people just use trial and error - and it's mostly error.

Until you add measurements.

The interesting thing about tone arm resonance is that you don't even need a
test record to measure it - the arm usually resonates strongly enough due to
warp and the like that it shows up big and strong, right there on the FFT.
Of course only about one vinylphile in a thousand or less actually measures
such things, even though the incremental cost is nearly zero.

[Dick Pierce[_2_]]

Arny Krueger wrote:
Ideally, the counterweight is also suspended in such
a way that it becomes a vibration absorber tuned to
the resonance frequency of the arm.

Sorry, doesn't work. What such a sceme ends up
doing is turning a second order resonant system
into a 4th order resonant system, and unless you
get ALL of the parameters right: cantilever
compliance, arm mass, counterweight suspension
compliance, counterweight mass, canitlever and
pivot losses, counterweight suspension losses,
it's more likely you'll end up with a WORSE
performance than a better one. It's a problem
that, physically, is completely analogous to
a vented box speaker system, and your suggestion
is reminicent of people taking a sealed box speaker,
punching a hole and sticking a port in and assuming
the result can only be better. It can only be better
if you START with a proper system design to begin
with: this fact is as true for your tone arm scheme
as it is for a loudspeaker system.


--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Audio Empire]

On Wed, 28 Sep 2011 10:17:58 -0700, Dick Pierce wrote
(in article ):

Arny Krueger wrote:
Ideally, the counterweight is also suspended in such
a way that it becomes a vibration absorber tuned to
the resonance frequency of the arm.

Sorry, doesn't work. What such a sceme ends up
doing is turning a second order resonant system
into a 4th order resonant system, and unless you
get ALL of the parameters right: cantilever
compliance, arm mass, counterweight suspension
compliance, counterweight mass, canitlever and
pivot losses, counterweight suspension losses,
it's more likely you'll end up with a WORSE
performance than a better one. It's a problem
that, physically, is completely analogous to
a vented box speaker system, and your suggestion
is reminicent of people taking a sealed box speaker,
punching a hole and sticking a port in and assuming
the result can only be better. It can only be better
if you START with a proper system design to begin
with: this fact is as true for your tone arm scheme
as it is for a loudspeaker system.




And that's true of any system designed to work as a synergistic whole. For
instance, with sealed box speakers, it's often true that the driver(s) rely
on the air sealed inside the box to be a part of the cone's suspension. Punch
a hole in the box, and even if the port is designed and executed correctly,
it still won't work because the cone, no longer pushing against trapped air,
will sag.

[Arny Krueger[_4_]]

"Dick Pierce" wrote in message
...
Arny Krueger wrote:

Ideally, the counterweight is also suspended in such
a way that it becomes a vibration absorber tuned to
the resonance frequency of the arm.

Sorry, doesn't work. What such a sceme ends up
doing is turning a second order resonant system
into a 4th order resonant system, and unless you
get ALL of the parameters right: cantilever
compliance, arm mass, counterweight suspension
compliance, counterweight mass, canitlever and
pivot losses, counterweight suspension losses,
it's more likely you'll end up with a WORSE
performance than a better one.

The above conclusion seems excessively negative. Most technical advances I
know of make things worse unless you get your parameters right, so why say
flatly that every tone arm vibration absorber "...doesn't work".?

They work if you do your homework.

There's no reason why a manufactorer couldn't make this technology work well
if they can control or guide the relevant parameters. For example, making a
vibration absorber work in a standardized tone arm based on P-mount
cartridges should be simple enough. I suspect this may be done quite often -
I just haven't kept up with practical implementations well enough to know.

It's a problem
that, physically, is completely analogous to
a vented box speaker system, and your suggestion
is reminicent of people taking a sealed box speaker,
punching a hole and sticking a port in and assuming
the result can only be better.

This paragaph seems equally and unecessarily negative. Vented box speakers
have become widely accepted by the audio industry for both home and
professional use. The turning point was the classic Thiel-Small paper
relating speaker parameters to box design. I watched the evolution of vented
box designs from the mid-1950s and it was known all along that random
combinations of boxes, drivers and vents didn't work. As far as it goes, the
same is true to a great extent in unvented box speaker systems. Grotesque
sound quality is likely with a random design whether or not the box was
vented.

It can only be better
if you START with a proper system design to begin
with: this fact is as true for your tone arm scheme
as it is for a loudspeaker system.

I totally agree.

[Peter Wieck]

On Sep 26, 10:06=A0am, "Arny Krueger" wrote:
"Rich Teer" wrote in message

...

On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "at
home" stereo set up. serious in the sense of quality and that i would
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.
I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. =A0That said, all the better arms
I can think of off the top of my head are straight, so I guess there's
your answer!

Correct. The shortest distance between the pivot and the stylus is always=
a
straight line. =A0Therefore the straight tube with the cartridge mounted =
at an
appropriate offset angle and overhang distance is the most likely to have
minimal mass, all other things being equal.

How come nobody to-date has mentioned a linear-tracking arm? I have
two in-service, a Rabco and a Revox. After the initial set-up and
tweaking, they both have performed flawlessly for many years - likely
with no more maintenance than with any given pivot-arm system - but
then I would not know that.

Sure, legacy equipment may be a bit tougher to find in excellent
condition - but not all that tough.

Peter Wieck
Melrose Park, PA

Pays you money, takes you chances.

[Arny Krueger[_4_]]

"Peter Wieck" wrote in message
...
On Sep 26, 10:06 am, "Arny Krueger" wrote:


How come nobody to-date has mentioned a linear-tracking arm? I

Look again. There was discussion of this issue by myself and others on 9/27,
etc.

have
two in-service, a Rabco and a Revox. After the initial set-up and
tweaking, they both have performed flawlessly for many years - likely
with no more maintenance than with any given pivot-arm system - but
then I would not know that.


Sounds like fun.

[Scott[_6_]]

On Oct 6, 11:20=A0am, Peter Wieck wrote:
On Sep 26, 10:06=A0am, "Arny Krueger" wrote:





"Rich Teer" wrote in message

...

On Sun, 25 Sep 2011, Edward wrote:

i'm looking at seriously upgrading the turntable situation for my "a=
t
home" stereo set up. serious in the sense of quality and that i woul=
d
like this to be the last turntable i buy. maybe...
so my question is this: do i go with a curved or straight tonearm??
remember, this is for my home set up and not for taking out of the
house and DJ'ing with.
I don't think the shape of the arm is important per se, provided the
offset angle ends up being correct. =A0That said, all the better arms
I can think of off the top of my head are straight, so I guess there'=
s
your answer!

Correct. The shortest distance between the pivot and the stylus is alwa=
ys a
straight line. =A0Therefore the straight tube with the cartridge mounte=
d at an
appropriate offset angle and overhang distance is the most likely to ha=
ve
minimal mass, all other things being equal.

How come nobody to-date has mentioned a linear-tracking arm? I have
two in-service, a Rabco and a Revox. After the initial set-up and
tweaking, they both have performed flawlessly for many years - likely
with no more maintenance than with any given pivot-arm system - but
then I would not know that.

Sure, legacy equipment may be a bit tougher to find in excellent
condition - but not all that tough.


No!!!! Not possible!!!! And you have to deal with two resonant
frequencies not just one!!!
I also have a linear tracking arm. Mine may be one of, if not the most
difficult arm to set up. Such is life when you have a surgeon
designing things. Luckily I have a job that is all about manual
dextarity so I could do the job of installing my cartridge myself. I
wouldn't wish that task upon anyone but the most cool, steady handed
and patient of people. But then race cars are not designed for ease of
use either.

[Dick Pierce[_2_]]

Scott wrote:
On Oct 6, 11:20 am, Peter Wieck wrote:
How come nobody to-date has mentioned a linear-tracking arm? I have
two in-service, a Rabco and a Revox. After the initial set-up and
tweaking, they both have performed flawlessly for many years - likely
with no more maintenance than with any given pivot-arm system - but
then I would not know that.

Sure, legacy equipment may be a bit tougher to find in excellent
condition - but not all that tough.

No!!!! Not possible!!!! And you have to deal with two resonant
frequencies not just one!!!

WHy, because it SEEMS like such arms must have
more mass in the horizontal plane than in the vertical.

With arms like the Rabco variants and the revox, those
that used a servo feedback system: guess what" they are
as much a pivoted arm in the horizontal as much as they
veryical plane, and, in fact, their measured horizontal
mass is pretty much the same as their vertical mass, and
analysis, confirmed by measurement, shows that the
resonant frequency is relatively independent of direction,
just like in a "normal" pivited arm (they ARE "normal"
pivoted arms: it's just that the pivot is moved by the
servo system, in effect).

If on the other hand, you're talking about what I refer
to as patholigical designs like the old Dennisen air-
bearing linear "tracker", well, they are just plain old
bad designs, and their operation defies any conventional
analysis. You can't simply state that they have one
resonant frequency in the horizontal plane and another
in the vertical: the behavior is much more complex than
that. It's not so much like the simple two-pendulum model
where both pendulums are coupled to the same non-rigid
pivot point, it's more like where one pendulum is hanging
off the mass of the other: the result, rather than being
a simple double-resonant system, actually acts more
chaotically. SInce it is very rarely the case that the
stimulus is strictly in one plane or another, the resonant
energy is chaotically exchanged between the two planes
in a very complex fashion. It's NOT a pretty sight, and
leads to a VERY interesting output of teh system, an output
that often has little to do with what's actually in the
groove.

Whatever inspired some of these "designers" of these air-
bearing linear arms, I really hope they got it out of
their system.

I also have a linear tracking arm. Mine may be one of, if not the most
difficult arm to set up.

WHat kind? There's a BIG difference between them. Like I said
above, the air-bearing non-servos linear trackers are nightmare
designs to begin with.

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Scott[_6_]]

On Oct 6, 5:48=A0pm, Dick Pierce wrote:
Scott wrote:

If on the other hand, you're talking about what I refer
to as patholigical designs like the old Dennisen air-
bearing linear "tracker", well, they are just plain old
bad designs, and their operation defies any conventional
analysis. You can't simply state that they have one
resonant frequency in the horizontal plane and another
in the vertical: the behavior is much more complex than
that. It's not so much like the simple two-pendulum model
where both pendulums are coupled to the same non-rigid
pivot point, it's more like where one pendulum is hanging
off the mass of the other: the result, rather than being
a simple double-resonant system, actually acts more
chaotically. SInce it is very rarely the case that the
stimulus is strictly in one plane or another, the resonant
energy is chaotically exchanged between the two planes
in a very complex fashion. It's NOT a pretty sight, and
leads to a VERY interesting output of teh system, an output
that often has little to do with what's actually in the
groove.


I don't know about the Dennisen but I can state it with my Forsell. It
clearly got excited on the test record at two distinctly different
frequencies that corolated with what one would expect from having two
distinct resonances in the lateral and vertical difections due to the
differences in effective mass. And I certainly have not had any
problems with the arm's performance.


Whatever inspired some of these "designers" of these air-
bearing linear arms, I really hope they got it out of
their system.

I also have a linear tracking arm. Mine may be one of, if not the most
difficult arm to set up.

WHat kind? There's a BIG difference between them. Like I said
above, the air-bearing non-servos linear trackers are nightmare
designs to begin with.


Forsell