On 15/12/2011 14:10, Goran Finnberg wrote:
> Mike Biel:
>
>> Unless you back-cue, you are better off with the
>> S-shaped arm.
>
> The straight arm gives less wow and flutter.
>
> Also it gives less distortion as the S-shaped arm cannot be adjusted to have
> more than two points of distortion minima and all other places are the
> tracking distortion much higher.
>
> Furthermore a bent arm creates the need for anti skate adjustment. Without
> it the right channel will distort much earlier than the left channel.
>
> Also the cartridge stereo channel separation will become nonsymmetrical
> without anti-skate adjustment.
>
> So on...so on.
>
> Straight line is always better in all respects as it mimics the way the disk
> was cut.
>
>
I'm sorry, but what rubbish!

Wow and flutter is a function of the turntable. Warp wow depends on the 
height of the horizontal pivot, not the arm shape. The requirement for 
bias correction arises from the necessary offset of the pickup to 
minimise tracking error. Whether this takes place in the arm or the 
headshell is immaterial.

A straight arm on a pivot does not mimic the way a record is cut. All 
modern lathes move the cutter along a radius of the disc. A straight arm 
without offset traces a deep arc which bears little relation to the 
cutter's path, hence the need for offset.