Anti-skate

This is getting pretty confused. Has anyone read any analysis, theoretical or actual measurement, that shows that skating force is higher when playing the inner groove? Distortion generally will be higher because the grooves make progressively sharper turns as the diameter of the record gets smaller, but, I don't see why skating force gets higher. The offset angle does not change, so the variable is friction between the stylus and the groove wall which is, as Stringreen noted, determined by stylus shape and the modulation of the groove which is something generally not dependent on the diameter of the record.

As for the force setting on tonearms, the units for antiskating force are arbitrary, often using numbers intended to correspond with tracking force utilized, but not measuring force by any standard units. You can choose to follow the manufacturer's recommendation or set it by ear.

I use a test record with musical signals that are at progressively higher modulation levels (Shure Obstacle Course Test record). At some point, the cartridge will start mistracking, more so in one channel than the other. I adjust antiskating to even out such distortion. I have found with my Vector arm and Lyra Titan cartridge, with my Graham 1.5t arm and various cartridges, with a friends Graham Phantom arm and Transfiguration Orpheus cartridge, and a friend's SME 309 and Transfiguration Orpheus cartridge, the optimum antiskating force is significantly LESS than the manufacturer's recommendation.

I can't say there is any universal finding here, but I am not surprised when others find that lower values of antiskating work well. I personally haven't tried no antiskating, but, I am not surprised that some owners and manufacturers actually prefer no antiskating.

Mmakshak,

The skating force has nothing to do with the diameter of the record. It has to do with the fact that the drag of the stylus in the groove is pulling backwards along a line tangent to the groove (along the same line as the cantilever), but that is not the same line as from the stylus to the pivot because of the offset angle of the cartridge. If you did a vector analysis, you would see that there is a vector component that is inward. If there is somehow greater drag toward the inner groove, then yes, there should also be a bigger vector component of antiskating. I just don't see a reason to expect appreciably greater drag at the inner grooves.

Greater distortion in the inner groove is most likely the product of the physical compression of the waveform, described by the groove, into a smaller space. This is why some early proposals for records had the stylus playing from the inside out. Because music typically has its peak volume (climax) at the end of the piece, it made sense to put those wide swinging grooves at the outside diameter where they would not be so compressed into a smaller space.

Audiofeil raised an interesting point about the effective velocity being reduced for the inner groove. When I said earlier that there was no obvious reason why skating force should be different for the inner groove, I did not consider the change in velocity. This is obviously a big difference between inner and outer grooves (funny how things are so obvious once someone else thinks it up).

But, I am less certain about whether the lower inner groove velocity would increase or decrease skating force.

From my own experience, whenever I found asymmetric distortion (one channel more than the other) when playing the inner groove, it has lead me to decrease antiskating. While this suggests that skating forces are lower for the inner groove, it could also be the case that my arm does not apply the same force at all positions and has simply increased antiskating too much for the inner groove position. Greater minds are needed here.

Hi Sirspeedy,

I am wondering if you will have the opportunity to compare the Kuzma linear tracking arm with their new pivoted arm. I've seen the linear arm demonstrated by Frank Kuzma at a show and was quite impressed by the build quality (I also personally like Mr. Kuzma).

I am also interested in comparisons of linear tracking with long arms that minimize tracking error. While the long arms don't completely eliminate geometric tracking error, and don't eliminate skating force, they have an advantage over very short linear tracking arms -- the VTA does not change appreciably with changes in thickness of records. I don't change VTA for different records, yet, when setting up my arm, I noticed significant changes in sound from quite small changes in VTA. To me, VTA is a bigger issue than exact antiskating (or no antiskating).

Thanks Sirspeedy for another great description of your listening experience. I've heard a few linear trackers myself, and long ago, I owned a Mapenoll linear tracker. That table/arm was an operational nightmare, but it did sound good the few moments that I got it to work.

Mmakshak, I think it would be a good idea, as you suggest, to optimize antiskating for the inner grooves where cartridges are particularly challenged when it comes to tracking the groove. I have done that myself by ear. My settings by ear have always been MUCH less antiskating than recommended by the manufacturer of the arm.