curved or straight tonearm?
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.
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