Thanks for the really helpful replies and time spent all.
I'm looking forward to digging into great new reading material and sources.
On Sun, Dec 18, 2011 at 1:10 PM, Eric Jacobs <[log in to unmask]>wrote:
> Confusion over linear-tracking and pivoted arms aside, I wanted to add
> to the pivoted straight-arm versus pivoted curved-arm discussion.
> From a tracking distortion point of view (Baerwald & Loefgren distortion
> curves and nulls, etc.), the pivoted straight- and curved-arms are
> identical. If the connection between the pivot point and the cartridge
> is rigid, its shape (straight or curved) has no bearing on the tracking
> distortion. It's all simply a matter of geometry, and specifically
> the position and orientation of the cartridge relative to the pivot
> point. The shape of the rigid arm between the cartridge and the pivot
> point really doesn't matter when it comes to tracking distortion.
> However, from a structural dynamics point of view, the pivoted straight-
> and curved-arms are different. Structural dynamics is the study of
> structural stresses, strains and modes of displacement (aka resonances).
> See http://en.wikipedia.org/wiki/Structural_dynamics and skip down to
> "Modal Analysis" to learn more about structural dynamics.
> A pivoted straight-arm has very simple modes (aka resonances), with a
> single fundamental mode, weak even harmonics, and yet weaker odd harmonics.
> A pivoted curved-arm has far more complex modes because of its shape,
> with multiple modes and a wider range of even and odd harmonics when
> compared to a pivoted straight-arm.
> Many would argue - including myself - that a pivoted straight-arm sounds
> better than a pivoted curved-arm (all else being equal, such as the pivot
> type and bearings, mass, etc.) because of the more complex modes and
> harmonics associated with its shape. Of course, things can be done to
> minimize these resonances by adding resonance damping material to any
> Aside from aesthetics, in particular the iconic look from the 1970s
> when the LP dominated and "S-shaped" or curved arms were popular,
> there are no sonic benefits to the pivoted curved-arm design over
> the pivoted straight-arm design (all else being equal, of course).
> There may be ergonomic benefits for some applications, although I
> haven't found that to be the case personally. I don't believe there
> are any pivoted curved-arm designs in present-day high-end audio.
> Eric Jacobs
> The Audio Archive, Inc.
> tel: 408.221.2128
> fax: 408.549.9867
> mailto:[log in to unmask]
> Disc and Tape Audio Transfer Services and Preservation Consulting
> On 12/17/11 1:18 PM, "Graeme Jaye" <[log in to unmask]> wrote:
> >On 17/12/2011 Andrew Hamilton wrote;
> >AH> I think Mr. Jaye meant to say "tangential tracking arms." However,
> >AH> tangential trackers do move along the radius of the disc. (: Better
> >AH> maybe to call the straight and S-shaped arms, pivoting.
> >Sorry to have confused anyone.
> >In my original post, I actually referred to "a radial tracking system"
> >- which means, of course, a linear tone arm (and tracks along the
> >radius of the disc, as you rightly say) - not a radial tone arm.
> >The main thrust of my comment was that Goran Finnberg had actually
> >confused the original question (which concerned the differences
> >between straight and curved radial tracking arms) with linear trackers
> >and went to great lengths to prove that he was right (which he was)
> >although not understanding the question.
> >Graeme Jaye
> >[log in to unmask]
> >Audio Restoration and Location Sound Recording