Does headshell offset actually matter?

[Ammonite Audio]

There is a fascinating piece by Roy Gregory on the Audio Beat about a new tonearm design that deliberately flies in the face of accepted wisdom regarding the need for headshells to be offset, to minimise tracing errors. See http://www.theaudiobeat.com/blog/viv_labs.htm

Maybe the designers of this particular product are right in thinking that the balance of benefits does, in fact, tilt towards nil offset and therefore no need for bias compensation?

What do the panel think?

[YNWaN]

I've looked at offset angle and have concluded it is necessary.

[struth]

I was with you all the way to headshell:lol:

[YNWaN]

There was a very similar (perhaps a bit more in depth) report on this arm in Stereophile some months back.

[Reffc]

I've looked at offset angle and have concluded it is necessary.

+1

It's simple geometry, so it would appear to fly in the face of geometric realities to suggest that it doesn't matter.

[awkwardbydesign]

I thought the point was that the other compromises needed to make it work were more important than the offset. No idea if it's true, though.

[hifi_dave]

There's nothing new.

Back in the 80's, my old pal Be Yamamura, made a short arm using graphite. It sounded excellent and his explanation was that making it stiff and non resonant was the most important part of the design. Far more important than reducing the tracing distortion.

[RobbieGong]

+1

It's simple geometry, so it would appear to fly in the face of geometric realities to suggest that it doesn't matter.

+2 Offset defo matters in my experience, obviously where you can see it needs to be done.

[Ammonite Audio]

+2 Offset defo matters in my experience, obviously where you can see it needs to be done.

Where you can 'see' it needs to be done, or 'hear' that it needs to be done?

I'm genuinely interested in this question - nobody doubts that offsetting the cartridge brings benefits in terms of reduced tracing errors; also it means being able to place the tonearm pivot closer to the spindle than would otherwise be necessary. But, when you consider the forces acting on the cartridge's cantilever when bias compensation is applied, is the bias cure worse than the increased tracing distortion that no offset necessarily brings?

Roy Gregory talks about hearing the benefits of accurately aligning a cartridge, using a Feickert protractor and I am with him there, even though I use a (possibly inferior) Clearaudio alignment jig. Accurate (optimal) alignment is actually a different matter to the offset question raised in the article. A cartridge mounted in a tonearm with nil offset will still be optimally aligned at certain points across its arc, in the same way as with a 'normal' tonearm. It's just that the errors in-between those points will be greater, but does that matter, bearing in mind the barrel-load of compromises that encompass vinyl reproduction as a whole?

[NRG]

Its an interesting idea, however, is BIAS compensation really that bad?

Messing about with the spreadsheet on Enjoythemusic the 14" arm makes more sense to me than a 7" one would. You can NULL both at around 66mm but distortion is approx. 3% and 6% respectively at 145mm outer groove. Overhang would be -6 and -12mm…or thereabouts.

[awkwardbydesign]

I've had a drink (or two), but isn't there only one null point with a straight arm?

[NRG]

Yes, possible to arrange it to null on the inner tracks but the outer null will be way beyond the LP outer track...

[Barry]

I've had a drink (or two), but isn't there only one nil point with a straight arm?

Correct - a straight arm does not have an offset, so one is left with only a single degree of freedom: that of an adjustable overhang. There will only thus be one null-point. The radius of the single null-point will depend on the chosen overhang.

[YNWaN]

Looking at the length and geometry of this arm I suspect that there isn't even one null point.

[NRG]

Yes there is, -6mm or thereabouts to null around 66mm

[YNWaN]

I'll have a closer look (than I have done previously) at the geometry. Ultimately, I don't feel very convinced by this design; it's not so much saying 'here's a better solution' as much as saying 'this design has a different collection of fatal flaws than the standard method', sort of 'our faults are less bad than your faults'.

[awkwardbydesign]

I'll have a closer look (than I have done previously) at the geometry. Ultimately, I don't feel very convinced by this design; it's not so much saying 'here's a better solution' as much as saying 'this design has a different collection of fatal flaws than the standard method', sort of 'our faults are less bad than your faults'.

Isn't that exactly what the designers are saying?
As someone who posts here said (about cables), they all do bad things, it's just that the best ones do less bad things. And as I have changed valves, opamps, resistors, capacitors, pulse and step-up transformers, inductors, cables, etc, etc, and heard how they all can change the sound, this idea interests me.

[YNWaN]

Yes... It's a summary.

[Barry]

Yes there is, -6mm or thereabouts to null around 66mm

Correct, a straight arm without any angular headshell offset, requires an underhang (i.e. negative overhang) to minimise the tracking error (and not tracing error, as refered to in the article, the latter is due to the profile of the stylus used for playback being dissimilar to that of the cutter stylus).

If one is sufficiently interested one can read Baerwald's analysis of tone arm geometry to understand this: H. G. Baerwald, ‘Analytic treatment of tracking effort and notes on optimal pick-up design’. Journal of the Society of Motion Picture Engineers. pp. 591 – 622, 1941.